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The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial

The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial

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April 10, 2024 | by Khashayar Eshaghi, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

—-

Introduction

You may have heard of current clinical trials striving to uncover new treatments for autoimmune encephalitis (AE). An exciting trial to look out for is the ExTINGUISH Trial — a promising clinical study in this field.

The Extinguish trial is set to evaluate the use of a monoclonal antibody in the treatment of anti-NMDAR Encephalitis, which is a subtype of AE. Recent successes in employing monoclonal antibodies, notably in treating complex neurological conditions like Alzheimer’s disease1, emphasize the potential breakthrough that this trial could signify.

The main goal of the ExTINGUISH trial is to assess the effectiveness of a specific monoclonal antibody, known as inebilizumab, in treating anti-NMDAR encephalitis2. Monoclonal antibodies are routinely utilized in the treatment of AE. However, the goal of researchers is to continue to make this technology better and more effective for patients.

What is inebilizumab?

In patients with autoimmune encephalitis, the body’s immune system mistakenly attacks the brain, causing inflammation. Inflammation causes the immune system to produce a kind of protein called an antibody. Typically, these antibodies flag things like invading viruses or bacteria for the immune system to find and destroy. In AE, antibodies play a harmful role by mistakenly flagging brain cells. As the immune system attacks the brain, patients with AE develop a host of symptoms, like seizures, mood changes, altered mental status, and memory loss3.

In an attempt to alleviate the symptoms of AE, scientists have long been interested in designing a drug that would prevent the immune system from making harmful antibodies. Recent research suggests that the best approach might be to fight fire with fire: by engineering a monoclonal antibody that specifically targets the immune cells responsible for generating the harmful antibodies at the onset of AE4. A monoclonal antibody is a special kind of protein created in a lab that can target and attach to specific harmful substances or cells in the body, helping the immune system to identify and neutralize them (figure 1).

monoclonal antibodies - The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial

Figure 1. Monoclonal antibodies serve to assist the immune system in neutralizing cells responsible for producing detrimental antibodies in AE.

 

A new monoclonal antibody called inebilizumab has shown promise as a potential treatment for a subtype of AE, called anti-NMDAR encephalitis5.

Inebilizumab was recently approved for the treatment of neuromyelitis optica spectrum disorder (NMOSD), a rare autoimmune disorder affecting the central nervous system.

The fact that this monoclonal antibody is proving effective for patients with another autoimmune neurological disorder suggests it could work for AE as well6.

How is inebilizumab different from current monoclonal antibody treatments for anti-NMDAR Encephalitis ?

Another monoclonal antibody called rituximab is already a secondary treatment option for anti-NMDAR encephalitis that is used when first-line therapies fail or produce an adequate response7. Rituximab works by targeting one group of immune cells making the harmful antibodies in AE, called B cells. While rituximab can help manage anti-NMDAR encephalitis for some patients by getting rid of B cells, it does not work for everyone7. This could be because B cells live for a short time, but produce other longer-lived versions of themselves, called plasma cells and plasmablasts.

Moreover, monoclonal antibodies work by recognizing a specific marker on the cells that they aim to neutralize. For instance, rituximab targets all cells that express a specific marker called CD20 on their surface. While rituximab removes the B cells that express CD20, it leaves the plasma cells and plasmablasts in the body because they often lack the CD20 surface marker. Therefore, these long-lasting immune cells can continue to produce the problematic antibodies that lead to anti-NMDAR encephalitis8.

This is where inebilizumab comes into play. Inebilizumab targets a different surface marker called CD19. This marker is not only expressed by B cells, but it is also present on the surface of their longer-lasting progeny, the plasma cells and plasmablasts. Therefore, by targeting all cells that express CD19 inebilizumab is capable of neutralizing the original B cells as well as the longer-lasting plasma cells and plasmablasts (figure 2)8.

Screenshot 2024 04 09 at 8.52.58 AM - The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial

Figure 2. Inebilizumab inhibits the production of plasma cells and plasmablasts that produce harmful antibodies against the brain.

By getting rid of more of the immune cells producing harmful antibodies against the brain, inebilizumab may be an even more effective treatment for anti-NMDA encephalitis than rituximab8,9.

The ongoing clinical trial

Clinical trials are scientific tests for new medications or treatments to determine if promising new treatments are more effective than what is currently on the market. In what are called placebo-controlled clinical trials, some participants get the new treatment, while others get a placebo. A placebo is a version of the treatment without the active ingredient of the medicine in it. This helps researchers compare how well the real treatment works by checking if there is a noticeable difference between those who get the medicine and those who get the placebo. It is a way to make sure the treatment is genuinely effective. Following the trial’s conclusion, should the new treatment prove effective, members of the placebo group will likewise be granted access to it.

The clinical trial for inebilizumab is called the ExTINGUISH Trial. The ExTINGUISH Trial aims to assess the effectiveness of inebilizumab compared to a placebo in treating moderate-to-severe NMDAR encephalitis alongside standard therapies. This trial involves 120 participants with moderate to severe anti-NMDAR encephalitis and evaluates patient outcomes using various measures that assess their daily functioning, brain abilities, quality of life, and predict how they may progress over a 16-week period. The study also aims to find biological markers that can be used to predict how well the treatment will work in future patients. Doctors and researchers will monitor levels of the anti-NMDAR antibodies responsible for the symptoms of AE as well as a measure of activation of the B cells that produce these harmful antibodies2,10. This will allow doctors to determine whether patients with certain levels of these substances in their body respond better or worse than others.

Ultimately, this trial aims to find more effective treatments for anti-NMDAR encephalitis, paving the way for improved care for individuals facing this condition. Looking ahead, these advancements in clinical trials offer hope for developing better treatments and understanding AE, potentially leading to breakthroughs in managing and preventing the disease in the future.

Additionally, while the current trial focuses on anti-NMDAR encephalitis, the insights gained from understanding the mechanisms of action and treatment response could potentially apply to other types of AE as well. While the immediate beneficiaries of this trial are individuals with anti-NMDAR encephalitis, the broader implications may extend to those with different forms of AE in the future, offering hope for improved treatment options and outcomes across various autoimmune encephalitis conditions.

References

  1. van Dyck, C. H., Swanson, C. J., Aisen, P., Bateman, R. J., Chen, C., Gee, M., Kanekiyo, M., Li, D., Reyderman, L., Cohen, S., Froelich, L., Katayama, S., Sabbagh, M., Vellas, B., Watson, D., Dhadda, S., Irizarry, M., Kramer, L. D., & Iwatsubo, T. (2023). Lecanemab in Early Alzheimer’s Disease. The New England journal of medicine, 388(1), 9–21. https://doi.org/10.1056/NEJMoa2212948
  2. Day, G., Titulaer, M., Wong, K.-H., Torner, J., Cudkowicz, M., Coffey, C., Lungu, C., Klawiter, E., Singleton, J. R., Mitchell, D., Fedler, J., Ecklund, D., Klements, D., Costigan, M., & Clardy, S. (2022). The extinguish trial: A phase-2b randomized placebo-controlled trial of inebilizumab in Anti-NMDA receptor encephalitis (P5-1.004). Neurology, 98(18_supplement). https://doi.org/10.1212/wnl.98.18_supplement.1651
  3. Hébert, J., Muccilli, A., Wennberg, R. A., & Tang-Wai, D. F. (2022). Autoimmune Encephalitis and Autoantibodies: A Review of Clinical Implications. The journal of applied laboratory medicine, 7(1), 81–98. https://doi.org/10.1093/jalm/jfab102
  4. Frampton J. E. (2020). Inebilizumab: First Approval. Drugs, 80(12), 1259–1264. https://doi.org/10.1007/s40265-020-01370-4
  5. Samanta D, Lui F. Anti-NMDAR Encephalitis. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551672/
  6. Nie, T., & Blair, H. A. (2022). Inebilizumab: A Review in Neuromyelitis Optica Spectrum Disorder. CNS drugs, 36(10), 1133–1141. https://doi.org/10.1007/s40263-022-00949-7
  7. Smets, I., & Titulaer, M. J. (2022). Antibody Therapies in Autoimmune Encephalitis. Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 19(3), 823–831. https://doi.org/10.1007/s13311-021-01178-4
  8. Chen, D., Gallagher, S., Monson, N. L., Herbst, R., & Wang, Y. (2016). Inebilizumab, a B Cell-Depleting Anti-CD19 Antibody for the Treatment of Autoimmune Neurological Diseases: Insights from Preclinical Studies. Journal of clinical medicine, 5(12), 107. https://doi.org/10.3390/jcm5120107
  9. Day, G. (2023). State of care for autoimmune encephalitis and the extinguish trial of inebilizumab. Neurology live. https://www.neurologylive.com/view/state-care-autoimmune-encephalitis-extinguish-trial-inebilizumab
  10. The extinguish trial of inebilizumab in NMDAR encephalitis (extinguish). Yale Medicine. (2024). https://www.yalemedicine.org/clinical-trials/the-extinguish-trial-of-inebilizumab-in-nmdar-encephalitis-extinguish

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On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

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International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - The Future of Anti-NMDAR Encephalitis Treatment: Exploring the ExTINGUISH Clinical Trial

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Seven questions you can ask your doctor to help you navigate an autoimmune encephalitis diagnosis

Seven questions you can ask your doctor to help you navigate an autoimmune encephalitis diagnosis

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March 13, 2024 | by Kara McGaughey, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

—-

Receiving a diagnosis of any kind can be overwhelming. In cases like autoimmune encephalitis (AE) where the diagnostic process is often long and complicated, finally getting an answer can bring a sense of relief. At the same time, coming to terms with new information about your body and your health might be unsettling and full of uncertainty. What happens next? What should you know? How can you best advocate for yourself?

In this post, we will explore 7 questions you can ask while beginning the process of navigating an AE diagnosis. While this list is certainly not exhaustive (and not medical advice), we hope it can be a resource as you and your loved ones begin to make sense of the barrage of new information that comes with an AE diagnosis. These questions can be helpful discussion points so you can head into your next appointment with an AE specialist feeling confident and empowered.

1. Can you explain why we have landed on a diagnosis of autoimmune encephalitis?

When settling on a diagnosis, clinicians often make use of a checklist of expected symptoms and test results called the diagnostic criteria. Having your doctor explain the diagnostic criteria for AE (Figure 1) can help you understand how your symptoms and recent test results relate to the bigger picture. It is one of the easiest and most helpful ways to make sense of a new AE diagnosis.

IAES Fig1 500x358 - Seven questions you can ask your doctor to help you navigate an autoimmune encephalitis diagnosis

Figure 1. The requirements for an AE diagnosis are seen in bold above. Notably, there are subtypes of AE that are “seronegative,” meaning that patients will not have AE-associated autoantibodies. The asterisk next to this diagnostic criteria indicates that, because of this seronegativity, not all patients with AE will satisfy the requirement. It’s important to recognize that while these diagnostic criteria represent the current consensus, they may change as researchers and clinicians continue to learn more about AE.1-3

It’s important to keep in mind that there are many subtypes of AE, each with their own assortment of symptoms and caveats for diagnosis. In other words, some of the symptoms and test results listed as part of the AE diagnostic criteria are more likely to occur in some subtypes of AE than others. For instance, patients with some subtypes of AE (like anti-NMDAR, anti-GABAB, or anti-LGI1) experience frequent, severe seizures, while patients with other AE subtypes will have no seizure activity.4 As another example, while most AE subtypes are defined by the antibodies causing inflammation in the brain, there are some subtypes of AE, called antibody-negative AE or “seronegative” AE, where patients have no detectable autoantibodies in their blood or cerebrospinal fluid (CSF) samples.5 All this to say, don’t be alarmed if there are symptoms present on the diagnostic criteria list that you’ve never experienced. Because of AE’s diverse presentation, understanding exactly which AE subtype you have is crucial for beginning to interpret the ins and outs of your particular diagnosis. It can also be tremendously helpful for filtering information if you’re wanting to read more about AE or AE research online as sometimes literature only applies to particular kinds of AE. You should also keep in mind that even people with the same AE diagnosis might present with drastically different symptoms, receive different treatments, and recover on totally different timelines.

2. Given my diagnosis, what is the best treatment available?

In some sense, the best treatment for AE is one you can start quickly and keep up with consistently. Research shows that, given the rapid onset of AE, early treatment is key for getting the body’s inflammation under control and achieving a good outcome.6-7 Specifically, early access to therapeutics plays an important role in both promoting complete recovery and decreasing long-term complications.7-8 With this in mind, in some cases, a doctor might advise that you begin treatment for AE before all the test results come in and you’re officially diagnosed.

There are a variety of different treatment options that aim to reduce inflammation and provide relief from the symptoms of AE. Oftentimes, treatment begins with first-line therapies, like steroids, plasma exchange (PLEX), or intravenous immune globulin (IVIG).2,6 If there is no meaningful response after 2-4 weeks of therapy, physicians often move to second-line therapeutics, like Rituximab or Cyclophosphamide.6 When meeting with an AE specialist, it’s important to understand which treatment you’ll be trying first as well as what the range of future treatment options might look like in your case. Like with most conditions, the treatment plan may vary depending on your AE diagnosis as well as any other health conditions you may have. Patients with paraneoplastic AE (AE triggered by a tumor present somewhere in the body), for example, generally require the tumor to be removed to achieve remission.7 Regardless of treatment specifics, it can be reassuring to know that there is a Plan B in place if Plan A isn’t going perfectly.

Importantly, new treatments for autoimmune conditions like AE are a hot area of research. Immunotherapy drugs, for example, are increasingly emerging as “third-line” therapy for AE patients whose symptoms are not resolved by traditional treatment options.9 So, while AE symptoms can be stubborn and unrelenting for some patients, there is hope to be found in the fact that new options continue to move through the drug-development pipeline.

3. What treatment side effects should I be aware of?

When agreeing to a particular treatment plan, it’s important to not just ask about treatment options, but also their potential side effects. Exactly which side effects to look out for depends entirely on which treatment you’re taking. But, whatever they are, you’ll probably feel most confident starting a particular medication or therapy if you know both the beneficial changes to anticipate and the symptoms or signs that might tag along for the ride. Some side effects are little, short-term nuisances you can push through in order to recover long-term. Others might be much harder to tolerate or signs that you might need to return to the doctor’s office. Explicitly asking your physician which side effects fall into which of these categories can help put your mind at ease.

4. Are there AE signs or symptoms I should look out for that would warrant a call to my doctor?

In addition to keeping track of treatment side effects, it’s important to have a clear sense of AE symptoms to look out for that might indicate treatment isn’t working and the condition is progressing. Asking your doctor to list reasons for concern can help you be proactive in monitoring your AE symptoms as they ebb and flow over the course of the treatment process. Knowing what to look out for can also help you distinguish any treatment side effects from AE symptoms. It might also be worth asking your doctor to clarify when AE symptoms warrant a call to your doctor’s office or a visit to the emergency room. Having a sense of what merits a mental note vs. immediate action will not only make a tremendous difference in your care, but also help you feel more confident and secure in your AE management skills.

5. Are there any clinical trials I should consider participating in?

All drugs that are available, either at the hospital or from your local pharmacy, have been carefully tested through the clinical trial process. However, you might have the opportunity to try new medications by participating in a clinical trial yourself. People choose to participate in clinical trials for a number of reasons. For one, these trials are a way to access the newest treatments coupled with additional care from physicians on the clinical trial team. Participating in a clinical trial is also an opportunity to help accelerate scientific research and the development of safer, more effective treatment options for your condition. For rarer conditions, like AE, participating in clinical trials can have an even larger impact since it can be much more difficult to recruit enough participants to fill and complete a successful clinical trial.10

While it is understandably a big decision to participate in the testing process for a new drug, it’s important to remember that clinical trials are closely supervised and heavily regulated.11-12 Before deciding to participate, you’re provided an “informed consent document” describing the study’s purpose, duration, required procedures, risks, and potential benefits. The potential risks and benefits depend largely on the specifics of the clinical trial (i.e., the drug involved and what phase of the clinical trial process you’d be participating in). However, in most cases and phases, clinical trials are organized such that participants receive at least the same care they otherwise would at their doctor’s office.11,13 Importantly, consenting to participate in the trial is not a contract. You are free to change your mind and withdraw at any time or refuse particular treatments and tests.

If you’re interested in considering a clinical trial, it’s a good idea to discuss the details with your AE specialist. They should be able to explain the nuances, know whether or not you qualify for a particular trial, and offer their opinion on whether participating is in your best interest. Often, AE clinical trials will focus on a new drug for a particular AE subtype, meaning you’d need a specific AE diagnosis to participate. It is also worth knowing that not all clinical trials involve testing new drugs (so-called “interventional trials”). Many, especially in the world of AE, are observational trials that track patients and their responses to existing treatments over time. You can learn more about the clinical trial process using these detailed guidelines from The National Institutes of Health, and explore a list of AE clinical trials here.

6. How will my condition be monitored moving forward?

Whether or not you choose to participate in a clinical trial, your AE journey will likely still involve a lot of visits to the clinic. One of the trickiest parts about AE is the long-term outpatient management required due to residual symptoms that some patients experience following their initial episode.6,14  While there is variation depending on the subtype of AE, it has been estimated that 10-20% of patients experience an AE relapse.7 In order to help AE patients achieve the highest possible level of functionality and reach complete remission, “maintenance therapy” is usually considered.7

Because of the diversity of AE subtypes and symptoms, identifying a single clinician with appropriate expertise can be a major obstacle. As such, AE patients often accumulate a team of clinicians, each tasked with managing a part of their long-term care. You might, for example, have follow-up appointments with a psychiatrist for psychiatric symptoms; a neurologist for seizures, movement disorders, or dysautonomia; a speech therapist; an occupational therapist; and so on. The specialists you see might also change over time. This is because, while in some cases the AE symptoms a patient experiences with relapses are the same ones they experienced with the condition’s onset, in others, relapses can present differently than the initial wave.14-15

All these clinicians should have access to your medical records and charts so they can read each other’s notes, thoughts, and observations. However, it can’t hurt to relay the big picture at each appointment to make sure both you and the doctor are up to date. You can find helpful tips for how to compile and maintain a record of your personal health information here on the IAES website.

7. What resources exist for both patient and caregiver support?

While your clinicians can help manage your physical and mental symptoms, an AE diagnosis can also have tremendous emotional and social impacts. In addition to managing new medications and other therapies, many patients with AE must learn to manage their expectations of what day-to-day life will look like for a while. While it can be difficult, it’s important to remember that you do not need to navigate your AE diagnosis alone.

In addition to support from friends and family, it can be especially helpful to find and connect with other AE patients and caregivers. Organizations such as the International Autoimmune Encephalitis Society (IAES) have compiled a list of resources (including apps). Asking your doctor if they have additional recommendations — either online or in your area — can increase the chances that you’re able to find the support that’s right for you. It’s important to have lots of options as the type and level of support you need can change over the course of your AE journey.

References

  1. Graus, F., Titulaer, M. J., Balu, R., Benseler, S., Bien, C. G., Cellucci, T., Cortese, I., Dale, R. C., Gelfand, J. M., Geschwind, M., Glaser, C. A., Honnorat, J., Höftberger, R., Iizuka, T., Irani, S. R., Lancaster, E., Leypoldt, F., Prüss, H., Rae-Grant, A., … Dalmau, J. (2016). A clinical approach to diagnosis of autoimmune encephalitis. The Lancet Neurology, 15(4), 391–404.https://doi.org/10.1016/S1474-4422(15)00401-9
  2. Lancaster, E. (2016). The Diagnosis and Treatment of Autoimmune Encephalitis. Journal of Clinical Neurology (Seoul, Korea), 12(1), 1–13. https://doi.org/10.3988/jcn.2016.12.1.1
  3. Cellucci, T., Van Mater, H., Graus, F., Muscal, E., Gallentine, W., Klein-Gitelman, M. S., Benseler, S. M., Frankovich, J., Gorman, M. P., Van Haren, K., Dalmau, J., & Dale, R. C. (2020). Clinical approach to the diagnosis of autoimmune encephalitis in the pediatric patient. Neurology Neuroimmunology & Neuroinflammation, 7(2), e663.https://doi.org/10.1212/NXI.0000000000000663
  4. Davis, R. & Dalmau, J. (2013). Autoimmunity, Seizures, and Status Epilepticus. Epilepsia 54, 46–49.
  5. Lee, W.-J., Lee, H.-S., Kim, D.-Y., Lee, H.-S., Moon, J., Park, K.-I., Lee, S. K., Chu, K., & Lee, S.-T. (2022). Seronegative autoimmune encephalitis: Clinical characteristics and factors associated with outcomes. Brain, 145(10), 3509–3521.https://doi.org/10.1093/brain/awac166
  6. Abboud, H., Probasco, J. C., Irani, S., Ances, B., Benavides, D. R., Bradshaw, M., Christo, P. P., Dale, R. C., Fernandez-Fournier, M., Flanagan, E. P., Gadoth, A., George, P., Grebenciucova, E., Jammoul, A., Lee, S.-T., Li, Y., Matiello, M., Morse, A. M., Rae-Grant, A., … Titulaer, M. J. (2021). Autoimmune encephalitis: Proposed best practice recommendations for diagnosis and acute management. Journal of Neurology, Neurosurgery & Psychiatry, 92(7), 757–768.https://doi.org/10.1136/jnnp-2020-325300
  7. Shin, Y.-W., Lee, S.-T., Park, K.-I., Jung, K.-H., Jung, K.-Y., Lee, S. K., & Chu, K. (2017). Treatment strategies for autoimmune encephalitis. Therapeutic Advances in Neurological Disorders, 11, 1756285617722347.https://doi.org/10.1177/1756285617722347
  8. Titulaer, M. J., McCracken, L., Gabilondo, I., Armangué, T., Glaser, C., Iizuka, T., Honig, L. S., Benseler, S. M., Kawachi, I., Martinez-Hernandez, E., Aguilar, E., Gresa-Arribas, N., Ryan-Florance, N., Torrents, A., Saiz, A., Rosenfeld, M. R., Balice-Gordon, R., Graus, F., & Dalmau, J. (2013). Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: An observational cohort study. The Lancet Neurology, 12(2), 157–165. https://doi.org/10.1016/S1474-4422(12)70310-1
  9. Yang, J., & Liu, X. (2021). Immunotherapy for Refractory Autoimmune Encephalitis. Frontiers in Immunology, 12.https://www.frontiersin.org/articles/10.3389/fimmu.2021.790962
  10. Blackburn, K. M., Denney, D. A., Hopkins, S. C., & Vernino, S. A. (2022). Low Recruitment in a Double-Blind, Placebo-Controlled Trial of Ocrelizumab for Autoimmune Encephalitis: A Case Series and Review of Lessons Learned. Neurology and Therapy, 11(2), 893–903. https://doi.org/10.1007/s40120-022-00327-x
  11. U.S. Department of Health and Human Services. (2022). NIH Clinical Research Trials and You: The Basics. National Institutes of Health. https://www.nih.gov/health-information/nih-clinical-research-trials-you/basics
  12. Van Norman, G. A. (2016). Drugs, Devices, and the FDA: Part 1: An Overview of Approval Processes for Drugs. JACC. Basic to Translational Science, 1(3), 170–179. https://doi.org/10.1016/j.jacbts.2016.03.002
  13. American Cancer Society. (2020). Making Decisions and Managing Your Treatment: Types and Phases of Clinical Trials. https://www.cancer.org/content/dam/CRC/PDF/Public/6800.00.pdf
  14. Abboud, H., Briggs, F., Buerki, R., Elkasaby, M., BacaVaca, G. F., Fotedar, N., Geiger, C., Griggins, C., Lee, C., Lewis, A., Serra, A., Shrestha, R., Winegardner, J., & Shaikh, A. (2022). Residual symptoms and long-term outcomes after all-cause autoimmune encephalitis in adults. Journal of the Neurological Sciences, 434, 120124.https://doi.org/10.1016/j.jns.2021.120124
  15. Zeng, W., Cao, L., Zheng, J., & Yu, L. (2021). Clinical characteristics and long-term prognosis of relapsing anti-N-methyl-d-aspartate receptor encephalitis: A retrospective, multicenter, self-controlled study. Neurological Sciences, 42(1), 199–207.https://doi.org/10.1007/s10072-020-04482-7

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On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

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Become an Advocate by sharing your story. It may result in accurate diagnosis for someone suffering right now who is yet to be correctly identified. Submit your story with two photos to IAES@autoimmune-encephalitis.org  

 

 

International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - Seven questions you can ask your doctor to help you navigate an autoimmune encephalitis diagnosis For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - Seven questions you can ask your doctor to help you navigate an autoimmune encephalitis diagnosis

Be a part of the solution by supporting IAES with a donation today.

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Critical thinking: How networks in the brain may be optimally organized

Critical thinking: How networks in the brain may be optimally organized

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February 14, 2024 | by Joseph Stucynski, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

Joeseph Stucynski has graciously allowed us to republish an article he recently wrote for the weekly PNK series the students participate in aside from the articles they write for IAES.

Thank you UCB for sponsoring all 2024 AE Awareness Month blogs.

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—-

Introduction

Sleep is critical. Each one of us with AE has experienced fatigue at one time or another during our AE journeys. We, also, know how important it is to pay attention to the fatigue and do our best to get adequate rest for optimum recovery. Sleep is crucial for our brains. Joseph has explained another reason or in another way just how critical sleep is for us to be able to operate on a day-to-day basis to our best ability! We hope you enjoy this as much as we have.

If you’ve ever stared at falling sand in an hourglass, you might have noticed that when it accumulates on the pile below, every so often it will trigger an avalanche. Most of the time the avalanches are tiny and quick, just involving the top sand rolling lower, but sometimes the weight of the sand overcomes friction of the pile and a large chunk of sand fractures off and slides lower. It turns out that this seemingly simple sand pile is a mathematically interesting system that exhibits a trait called self-organizing criticality.1 The term ‘criticality’1,2 in this case refers to the fact the sand pile is constantly balancing at a critical transition point between stability (the sand pile building up), and chaos (sand avalanches triggering).  Notably, criticality doesn’t just apply to sand, it also may be an important part of how your brain works,2,3,4,5 and new research shows that sleep might be very important for maintaining this property!6

The edge of chaos

The idea that the brain, with its billions of neurons, operates at the edge of chaos might sound crazy at first, but it turns out that operating on this knife’s edge of criticality allows a system to process information at optimum efficiency.3,4,5,6 And since the brain needs to perform so many tasks, computations, and behaviors, it also needs to organize and activate its systems in an efficient manner.

Like avalanches on the sand pile, the firing of neurons throughout the brain seems to follow the mathematical criteria for criticality. That is, small numbers of neurons fire more frequently in mini avalanches of activity, but the larger the number of neurons that fire together, the more rare those neural avalanches are. For those interested, this is called a power law.3,4,5 In this way, the brain maintains balance between too few neurons firing, and too many at once, both of which may prevent the brain from functioning well.

In a related way, the brain must also maintain balance between order and chaos. If neurons fire too chaotically it results in a sub-critical state, and it is harder for the brain to process information, like when a person is under the influence of certain drugs or anesthetics.6 But if neurons fire in perfect order across the brain in a super-critical state, you can end up with an epileptic seizure.By operating in a critical state at the transition point between order and chaos, the brain processes information efficiently to deal with an ever-changing environment.

Admittedly, neuroscientists don’t all agree that the brain meets the definition for criticality, but the field is growing due to a steady trickle of evidence and a dedicated field of researchers. But still, what does all this mean for you? What does it mean for your brain to be at criticality, and could you even feel when it’s not? As it turns out, one of the reasons you need to sleep at night may be to maintain this criticality.

Sleep is critical

As you go about your day and the refreshing effects of a good night’s sleep wash away, you may feel like your brain is slipping further from an optimal state. In a recent paper, neuroscientists tested whether your brain moves increasingly farther away from criticality during the day, and if sleep can help restore this critical state for the next day.7

To do this, the neuroscientists recorded from many neurons in the brains of rats while they were awake and asleep. The team then measured mathematical aspects of criticality to compare the rats’ awake brains to their sleeping brains. They found that while their brains’ ‘closeness to criticality’ changed from moment to moment, in general their brains were farther from criticality the longer they were awake.7 Likewise, their brains were closer to criticality during sleep and closest just before they woke up after long durations of sleep. In other words, the longer the rats were awake, the further their brains were from criticality, while sleep reset their brains to a critical state.

While the authors of this study did not investigate exactly how sleeping moves the brain closer to a critical state, their findings present a provocative new view of the central function of sleep and why it is so important to maintaining brain health and function. Ultimately, this represents another piece of evidence suggesting that criticality is a core operating principle of how the brain works – just something to remember the next time you find yourself exhausted at the end of a workday feeling like you need to take a nap.

References

  1. Abelian sandpile model, Wikipedia.https://en.wikipedia.org/wiki/Abelian_sandpile_model
  2. Ouellette, J. Sand pile model of the mind grows in popularity. Scientific American, 2014.https://www.scientificamerican.com/article/sand-pile-model-of-the-mind-grows-in-popularity/
  3. O’Byrne, J., and Jerbi, K. How critical is brain criticality? Trends in Neurosciences, 2022.https://www.cell.com/trends/neurosciences/fulltext/S0166-2236(22)00164-3
  4. Beggs, J.M., Timme, N. Being critical of criticality in the brain. Frontiers in Psychology, 2012.https://www.frontiersin.org/articles/10.3389/fphys.2012.00163/full
  5. Cocchi, L., Gollo, L.L., Zalesky, A., Breakspear, M. Criticality in the brain: A synthesis of neurobiology, models and cognition. Progress in Neurobiology, 2017.https://www.sciencedirect.com/science/article/pii/S0301008216301630
  6. Maschke, C., O’Byrne, J., Colombo, M.A., Boly, M., Gosseries, O., Laureys, S., Rosanova, M., Jerbi, K., Blain-Moraes, S. Criticality of resting-state EEG predicts perturbational complexity and level of consciousness during anesthesia. BioRxiv, 2023. https://www.biorxiv.org/content/10.1101/2023.10.26.564247v1
  7. Xu, Y., Schneider, A., Wessel, R., Hengen, K.B. Sleep restores an optimal computational regime in cortical networks. Nature Neuroscience, 2024.https://www.nature.com/articles/s41593-023-01536-9

Cover photo by Nathan Dumlao on Unsplash

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On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

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Become an Advocate by sharing your story. It may result in accurate diagnosis for someone suffering right now who is yet to be correctly identified. Submit your story with two photos to IAES@autoimmune-encephalitis.org  

 

 

International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - Critical thinking: How networks in the brain may be optimally organized For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - Critical thinking: How networks in the brain may be optimally organized

Be a part of the solution by supporting IAES with a donation today.

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A Mother’s Heartbreak

A Mother’s Heartbreak

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January 31, 2024 | by Laura Zendejas

Introduction from the IAES Blog Team:

A diagnosis of Autoimmune Encephalitis can be devastating and overwhelming. It is difficult for patients, family members, caregivers, and medical teams. Watching a loved one suffer can be excrutiating. Being a parent of a suffering child is a level of mental pain that no one ever wishes to encounter. We share with you a beautiful poem written by Laura Zendejas that speaks to the heartbreak a loving Mother feels for her sick child.

—-

NMDAR encephalitis

You took away my child

You took away my peace

You took away my feelings of blessings and feeling pleased

I was happy before you came

I was worry free

I knew my child was safe and healthy

Then you came to be

You attacked her brain

You attacked me

You made me realize I had no control

That you were the all mighty

I begged

I cried

I asked why

Still I have no answers

Still I search today

Now that you have left my child

Why do I still feel this way?

Why do I still feel you near?

You attacked her brain and you set her free….

So why are you still attacking me?

~a poem from mom

IMG 9622 - A Mother's Heartbreak

 

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On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

guidestar platinum logo 300x300 1 e1605914935941 - A Mother's Heartbreak

 

Become an Advocate by sharing your story. It may result in accurate diagnosis for someone suffering right now who is yet to be correctly identified. Submit your story with two photos to IAES@autoimmune-encephalitis.org  

 

 

International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - A Mother's Heartbreak For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - A Mother's Heartbreak

Be a part of the solution by supporting IAES with a donation today.

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Memory and Autoimmune Encephalitis

Memory and Autoimmune Encephalitis

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January 24, 2024 | by Ryan Rahman, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

—-

Introduction

Our brains are what make us human – consciousness, emotion, and memory all come from a tapestry of over 100 trillion connections. When this intricate network is bombarded by misguided immune cells, as in the case of autoimmune encephalitis, the brain can no longer carry out some of its most important functions. One such function that is often prominently affected is memory.1,2 Memory is a central aspect of our daily lives, allowing us to recall cherished moments, learn from our experiences, and navigate the world. However, for individuals battling autoimmune encephalitis, memory can become a complex and challenging puzzle. In this blog post, we will describe the memory difficulties patients face when living with autoimmune encephalitis (AE).

What is memory?

Memory is a fundamental cognitive function that enables individuals to absorb, store, and recall information and experiences. It plays a crucial role in shaping our perception of the world and our ability to learn, make decisions, and navigate daily life. There are different types of memory that work together to enable us to learn, adapt, and navigate the complexities of life. Broadly, it can be helpful to think of grouping different types of memory by where they are in the brain because the brain organizes its functions into different locations. For example, the hippocampus is the main brain structure that helps record information and start the formation of memories.3 In addition, it is also important to consider the kind of information being stored and how long it is stored for (Figure 1). Here, we break down a few types of memory that are relevant to patients living with AE:

Sensory Memory: Sensory memory4 is responsible for briefly holding information from our sensory organs, such as vision and hearing. This short-lived memory lasts for a fraction of a second and is composed of all the information we get from our senses before our brain filters out the unimportant parts. It typically relies on parts of the brain that receive direct information from the sensory organs, such as the eyes and ears.

Short-Term Memory: Short-term memory4 is the next shortest type of memory, lasting for a few seconds to minutes. When you solve a quick math equation in your head or remember mid-conversation what someone just told you, you’re using your short-term memory.6 Short-term memory relies largely on communication between two parts of the brain called the prefrontal cortex and hippocampus.

Long-Term Memory (LTM): Long-term memory4 is exactly what it sounds like – the kind of memory that helps us remember things for long periods of time. It has an almost unlimited capacity and can last for a lifetime. Long-term memory includes our ability to remember personal experiences, facts, skills, and habits. Our ability to form these memories relies on the hippocampus and another part of the brain called the frontotemporal lobes, but where exactly long-term memory is stored is still unclear.

Procedural Memory: Procedural memory4 is a special type of long-term memory often mistakenly called “muscle memory” (because memory comes from the brain, of course!) that allows us to ride a bicycle, type on a keyboard, or tie our shoelaces with little conscious effort. Procedural memory does not depend on the hippocampus or prefrontal cortex. Instead, it tends to be formed and stored in the brain areas involved in planning motions, such as the cerebellum and the motor cortex.

Because different types of memory rely on different parts of the brain, sometimes patients with damage to only some parts of the brain can have deficits in only one type of memory, while the other types of memory are preserved.

Another concept that is central to most types of memory is the idea that brain cells, which are called neurons, can change the strength of their connections. Connections between neurons are called synapses, which are tiny gaps between the cells bridged by chemical and electrical signals.5 A bunch of neurons working together can mirror an electrical circuit, and the more synapses in a circuit are activated, the tighter and more numerous these connections become. This concept is known as synaptic plasticity, and the ability to retrieve memories may be dependent on how strong certain connections are.6

memory 1 - Memory and Autoimmune Encephalitis

Figure 1. Memories form in discrete steps over time and are associated with specific parts of the brain.

 

How does autoimmune encephalitis affect memory?

Over the course of many years and research studies, doctors and scientists have shown that AE causes changes in memory. Both short-term and long-term memory impairments can occur in patients with AE; however, procedural memory impairments do not usually occur in AE.1,7-9 For patients with AE, deficits in short term memory can take the form of confusion and attention challenges; whereas deficits in long term memory can take the form of difficulty remembering facts, struggles with planning/organizing, and loss of personal memories. Although many patients show significant improvement in their memory symptoms after treatment of AE, many patients can unfortunately continue to experience residual memory problems, even long after other symptoms of AE have gone away.10

As discussed in a prior IAES blog post, AE is divided into different types based on which brain protein is attacked by a patient’s immune system. People with some subtypes of AE are more likely to have certain memory challenges.11 For example, patients with LGI1 autoimmune encephalitis (patients who have antibodies against Leucine-rich Glioma Inactivated protein 1) tend to have the most severe memory deficits with a profound loss of memories about personal life events. In contrast, memory loss and confusion are less common in patients with GABAAR encephalitis (~27%) and GABABR encephalitis (~47%). The reason behind these differences may in part be due to the fact that some of these proteins are only present in specific parts of the brain, which, as we previously discussed, control specific types of memory. Additionally, these targeted proteins play different roles in the circuits of the brain and disruption of different parts may impair synaptic plasticity in various ways. Please see the table below for more details about the memory changes experienced in different types of AE.

antibodies - Memory and Autoimmune Encephalitis

Table 1. Different types of AE are associated with different memory challenges for patients. Adapted from Gibson et al. – Cognitive impact of neuronal antibodies: encephalitis and beyond (2020).

 

To understand more about how AE causes memory changes, scientists first worked with patients using magnetic resonance imaging (MRI) to look at changes in the physical structure of their brains.12 Even as early as 1968, scientists saw drastic changes in the temporal lobes of patients with AE, which is a large region of the brain that contains the hippocampus.13 Importantly, recent studies have directly demonstrated that most patients with autoimmune encephalitis have structural changes in the hippocampus, and those with more damage in the hippocampus have more severe challenges with memory.14  

In addition to large structural changes, the microscopic science behind how AE causes memory loss has been explored in animal studies, which are more manipulable models for scientists to determine how diseases work in an entire system.15,16 In one experiment, scientists injected mice with antibodies from human patients with AE. They then tested the mice for any memory changes. Mice that were given the AE-associated antibodies could not remember objects they had seen before and developed anxiety-like behaviors.15 Importantly, scientists also showed that antibodies targeting the Nmethyl-Daspartate (NMDA) glutamate receptor (as seen in patients with Anti-NMDAR encephalitis) reduced the number of these proteins at the connections between brain cells which in turn disrupted synaptic plasticity.16

As previously mentioned, synaptic plasticity refers to the dynamic strength of circuits in the brain which increases when more neurons are activated together. Since glutamate is the main activating signal of the brain, it may be that destruction of the glutamate signal in certain types of AE leads to impaired memory by changing the strength of connections in the brain.

Lastly, an exciting early development occurred when scientists discovered that injecting Ephrin-B2, a protein that helps in the development of connections in the brain, was able to prevent memory loss caused by anti-NMDA antibodies in mice.16,17 Based on these findings, Ephrin-B2 may one day become a potential treatment for memory loss in patients living with AE!

Conclusion

In conclusion, autoimmune encephalitis is a neurological disorder that can have a profound and lasting impact on memory. Memory deficits in autoimmune encephalitis are not only distressing for patients but can also pose challenges to their daily functioning and quality of life. A better understanding of the mechanisms underlying these memory impairments and the development of targeted treatments are crucial to improving outcomes for individuals affected by autoimmune encephalitis and their memory-related challenges.

 Research in this field is ongoing, and with continued advancements in science and treatment, we can piece back together the lives of those affected by autoimmune encephalitis, one memory at a time.

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References

1          Heine, J. et al. Long‐Term Cognitive Outcome in Anti–N‐Methyl‐D‐Aspartate Receptor Encephalitis. Annals of Neurology 90, 949-961 (2021). https://doi.org/10.1002/ana.26241

2          McKeon, G. L. et al. Cognitive outcomes following anti-N-methyl-D-aspartate receptor encephalitis: A systematic review. Journal of Clinical and Experimental Neuropsychology 40, 234-252 (2018). https://doi.org/10.1080/13803395.2017.1329408

3          Bird, C. M. & Burgess, N. The hippocampus and memory: insights from spatial processing. Nature Reviews Neuroscience 9, 182-194 (2008). https://doi.org/10.1038/nrn2335

4          Camina, E. & Güell, F. The Neuroanatomical, Neurophysiological and Psychological Basis of Memory: Current Models and Their Origins. Front Pharmacol 8, 438 (2017). https://doi.org/10.3389/fphar.2017.00438

5          Südhof, T. C. & Malenka, R. C. Understanding Synapses: Past, Present, and Future. Neuron 60, 469-476 (2008). https://doi.org/10.1016/j.neuron.2008.10.011

6          Citri, A. & Malenka, R. C. Synaptic Plasticity: Multiple Forms, Functions, and Mechanisms. Neuropsychopharmacology 33, 18-41 (2008). https://doi.org/10.1038/sj.npp.1301559

7          Dalmau, J. et al. Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies. Lancet Neurol 7, 1091-1098 (2008). https://doi.org/10.1016/s1474-4422(08)70224-2

8          Finke, C. et al. Cognitive deficits following anti-NMDA receptor encephalitis. Journal of Neurology, Neurosurgery & Psychiatry 83, 195-198 (2012). https://doi.org/10.1136/jnnp-2011-300411

9          Hansen, N. Long-Term Memory Dysfunction in Limbic Encephalitis. Frontiers in Neurology 10 (2019). https://doi.org/10.3389/fneur.2019.00330

10        Titulaer, M. J. et al. Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: an observational cohort study. Lancet Neurol 12, 157-165 (2013). https://doi.org/10.1016/s1474-4422(12)70310-1

11        Gibson, L. L., McKeever, A., Coutinho, E., Finke, C. & Pollak, T. A. Cognitive impact of neuronal antibodies: encephalitis and beyond. Translational Psychiatry 10 (2020). https://doi.org/10.1038/s41398-020-00989-x

12        Kelley, B. P. et al. Autoimmune Encephalitis: Pathophysiology and Imaging Review of an Overlooked Diagnosis. American Journal of Neuroradiology 38, 1070-1078 (2017). https://doi.org/10.3174/ajnr.a5086

13        CORSELLIS, J. A. N., GOLDBERG, G. J. & NORTON, A. R. “LIMBIC ENCEPHALITIS” AND ITS ASSOCIATION WITH CARCINOMA. Brain 91, 481-496 (1968). https://doi.org/10.1093/brain/91.3.481

14        Finke, C. et al. Structural Hippocampal Damage Following Anti-N-Methyl-D-Aspartate Receptor Encephalitis. Biological Psychiatry 79, 727-734 (2016). https://doi.org/10.1016/j.biopsych.2015.02.024

15        Haselmann, H. et al. Human Autoantibodies against the AMPA Receptor Subunit GluA2 Induce Receptor Reorganization and Memory Dysfunction. Neuron 100, 91-105.e109 (2018). https://doi.org/10.1016/j.neuron.2018.07.048

16        Planagumà, J. et al. Ephrin‐B2 prevents N‐methyl‐D‐aspartate receptor antibody effects on memory and neuroplasticity. Annals of Neurology 80, 388-400 (2016). https://doi.org/10.1002/ana.24721

17        Hruska, M. & Dalva, M. B. Ephrin regulation of synapse formation, function and plasticity. Molecular and Cellular Neuroscience 50, 35-44 (2012). https://doi.org/10.1016/j.mcn.2012.03.004

Figure 1 and Table 1 made by Ryan Rahman in BioRender.com.

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Tabitha Orth 300x218 - Memory and Autoimmune Encephalitis

 

 

On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

guidestar platinum logo 300x300 1 e1605914935941 - Memory and Autoimmune Encephalitis

 

Become an Advocate by sharing your story. It may result in accurate diagnosis for someone suffering right now who is yet to be correctly identified. Submit your story with two photos to IAES@autoimmune-encephalitis.org  

 

 

International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - Memory and Autoimmune Encephalitis For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - Memory and Autoimmune Encephalitis

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What is the connection between cancer and autoimmune encephalitis?

What is the connection between cancer and autoimmune encephalitis?

November 29, 2023 | by Sophie Liebergall and Ayan Mandal, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

—-

Introduction

When a patient is admitted to the hospital with symptoms that suggest a diagnosis of autoimmune encephalitis (AE), doctors start ordering a dizzying array of lab tests and scans. Although AE is a disease of the brain, many of these tests, such as CT scans of the chest or ultrasounds of the pelvis, don’t seem to have much to do with the brain at all. The purpose of these scans is to search for a tumor that lies somewhere in the body. The reason why doctors conduct this search for a tumor is because some AE patients have a subtype of the disease, called paraneoplastic encephalitis, in which their disease is actually caused by a tumor outside of the brain. In this post we will shed some light on paraneoplastic encephalitis, why it occurs, and how its treatment compares to other types of AE.

What is paraneoplastic encephalitis?

As we explained in a previous post, paraneoplastic encephalitis is a type of AE caused by a tumor somewhere outside of the brain. The symptoms of paraneoplastic encephalitis, which could include seizures, memory loss, confusion, and dizziness, are often the first signs of an underlying cancer.1 For this reason, a patient who is suspected to have autoimmune encephalitis will often undergo scans of each organ in their body (colloquially called a “pan-scan”) to search for a possible cancer that may be responsible for the patient’s symptoms.

Some malignancies that are especially likely to trigger paraneoplastic encephalitis include cancers of the breast, ovaries, and lungs.2 But why would a tumor in one of these organs outside the brain cause the immune system to attack the brain? To understand why, we need to learn a bit about how the immune system responds to cancer.

How does the immune system respond to cancer?

Though it may be an unsettling thought, abnormal cells with the potential to become cancer are born in the body all the time. We tend not to be aware of this because most of the time the immune system successfully squashes these abnormal cells before they become a full-blown cancer. Many scientific experiments have proven how effectively the immune system monitors the body for these cancer cells. For example, when mice are genetically engineered to lack key immune cells, they become much more susceptible to developing tumors – implying that the removed immune cells were necessary to prevent tumor development.3 Because the immune system plays a crucial role in protecting the body from cancer, many cutting edge cancer treatments work by empowering the patient’s own immune system to kill their cancer cells.

The immune system prevents the growth of tumors by reacting to abnormal proteins that are a sign of cancer. Tumors tend to produce mutated proteins that are not found in the healthy body. Once an immune cell sniffs out one of these proteins it hasn’t seen before, it eats the protein and starts sending out alarm bells to other immune cells. These alarm signals tell one set of immune cells, called B cells, to start making antibodies that bind to this suspicious protein. Antibodies function like little flags that mark the cell with the mutated protein for destruction. Specifically, in the case of paraneoplastic AE, the initial alarm bells also activate another set of immune cells called cytotoxic T cells.4,5 The role of cytotoxic T cells is to expertly survey for cells that have been marked as harmful as potentially cancerous. Then, once they find these potentially dangerous cells, they release toxins that kill the cells (Figure 1).

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Figure 1. How the immune system responds to cancer. 1. A “first-line” immune cell chews up breast tumor cells, which contain proteins not normally found in breast cells. These proteins are represented as crabs. 2. The “first-line” immune cell realizes that it has eaten a cancer cell and so it sends signals that activate B and cytotoxic T cells. 3. Activated B cells produce antibodies which bind to the crab proteins. At the same time, activated cytotoxic T cells start to look for the cells that are tagged by the antibodies. 4. Antibodies bind to the crab protein in the breast tumor cells. Once the cytotoxic T cells find these tagged cells, they release toxins to kill the breast tumor cells. This figure was created using Biorender.com.

 

Why do some people get paraneoplastic encephalitis?

Sometimes, tumors produce suspicious proteins that look very similar to proteins also found in the brain. For example, some breast cancers can produce a protein that looks very similar to a protein inside of specific neurons in the cerebellum (a part of the brain important for balance and coordination).6 In this way, as the immune system prepares for battle against the breast cancer, sometimes the brain with it’s cancer look-alike cells can get caught in the crossfire. When an immune cell detects the breast cancer cells, it will chew up the proteins in those breast cancer cells, including the ones that look like cerebellum proteins. Because these cerebellum proteins were found inside a breast cancer cell, the immune cell thinks that they are harmful. Therefore, the immune cell will tell B cells to make antibodies targeting the cerebellum protein. At the same it will also tell cytotoxic T cells to kill all cells with the cerebellum protein. When these cytotoxic T cells try to find and kill more tumor cells, they may also try to kill healthy cells in the cerebellum that  make the protein.7

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Figure 2. How the immune system responds to cancer causes paraneoplastic AE. 1. A “first-line” immune cell chews up breast tumor cells, which contain proteins not normally found in breast cells. These proteins are represented as crabs. 2. The “first-line” immune cell realizes that it has eaten a cancer cell and so it sends signals that activate B and cytotoxic T cells. 3. Activated B cells produce antibodies which bind to the crab proteins. At the same time, activated cytotoxic T cells start to look for the cells that are tagged by the antibodies. 4. Because the crab protein is normally found in healthy cerebellum cells, antibodies bind to the crab protein in the cerebellum. Once the cytotoxic T cells find tagged cerebellum cells, they release toxins to kill the cerebellum cells.

What is the difference between paraneoplastic and non-paraneoplastic AE?

In the case of paraneoplastic encephalitis, the immune system is trying to do its job correctly by killing tumor cells, and the harm that it does to healthy neurons is collateral damage.7 This is different than cases of non-paraneoplastic encephalitis, where the problem lies within the immune system itself. In non-paraneoplastic AE, the immune system mistakenly decides that proteins that are normally found on the outside of neurons are actually harmful.7 (See this previous IAES post for a more detailed explanation of antibodies against proteins on the inside vs. the outside of cells.) In both paraneoplastic and non-paraneoplastic autoimmune encephalitis, the patient’s immune system tells B cells to make antibodies that target a neuronal protein. These antibodies then bind to the target protein in neurons and cause the patient to experience symptoms. However, cases of paraneoplastic encephalitis tend to involve more permanent damage to the neurons and more severe and long-lasting symptoms than cases of non-paraneoplastic autoimmune encephalitis. This is because the tumor also activates cytotoxic T cells in addition to B cells. These cytotoxic T cells are responsible for the increased damage and more severe symptoms in paraneoplastic AE.9

 

Paraneoplastic Encephalitis

Non-paraneoplastic Autoimmune Encephalitis

Target Protein

Usually intracellular proteins (e.g. Hu, Ma1/2, Ri), sometimes cell surface proteins

Cell surface proteins (e.g. NMDA receptor, GABABreceptor, Caspr2)

Age

Mostly older people

All ages

Tumor present

Yes

No

Immune system involvement

Cytotoxic T cells + antibodies

Antibodies

Response to treatment

Treatment less effective

Generally good response to treatment

Adapted from Rosenfeld et al. Neurol Clin Pract. 20128

How is paraneoplastic autoimmune encephalitis treated?

When treating paraneoplastic AE, doctors often use the same therapies that are used for non-paraneoplastic AE.10The majority of these treatments, such as plasma exchange, IVIg, and rituximab, are aimed at eliminating the antibodies that target the neuronal protein.10-12 (You can learn more about antibody-targeting treatments in this post.) For patients with non-paraneoplastic AE, once the antibodies are no longer bound to the neuronal proteins their symptoms often go away. But, unfortunately, in the case of paraneoplastic encephalitis, both antibody-producing B cells and cytotoxic T cells are activated.9 The cytotoxic T cells can unfortunately do more permanent damage to their neurons than the antibodies alone. Because of this, patients with paraneoplastic encephalitis tend to have poorer responses to treatment when compared to patients with non-paraneoplastic autoimmune encephalitis.13

When treating paraneoplastic encephalitis, it is very important to treat the underlying cause of the encephalitis: the cancer.13-14 When patients receive treatment for their cancer, either in the form of surgery to remove the cancer or chemotherapy drugs to shrink the cancer, they can sometimes see some improvement in their paraneoplastic encephalitis symptoms.13 When treating patients with paraneoplastic AE, doctors are often faced with a particular challenge: the immune system serves as both friend and foe. On one hand, the immune system is what is causing the patient’s paraneoplastic AE symptoms. While on the other hand, as discussed above, a strong immune system is important for keeping cancer at bay. As such, doctors often must carefully consider whether they want to give patients drugs that suppress the immune system, especially if the patient is actively undergoing treatment for their cancer.9

There are already a number of new therapies on the horizon for paraneoplastic AE that will hopefully improve the symptoms and long-term outcomes of this disorder. For example, understanding the role of cytotoxic T cells in paraneoplastic AE has led scientists to start to test treatments that directly target cytotoxic T cells.15 Conducting clinical trials in a relatively rare disorder like paraneoplastic AE can be especially challenging. But a growing awareness among physicians about paraneoplastic AE has led to an increased number of patients receiving a proper diagnosis for their neurologic symptoms. Clinical trials that enroll larger numbers of patients with paraneoplastic AE will hopefully hasten the development of more effective treatments.

References:

  1. Overview of paraneoplastic syndromes of the nervous system – UpToDate. https://www.uptodate.com/contents/overview-of-paraneoplastic-syndromes-of-the-nervous-system.
  2. Dalmau, J. & Rosenfeld, M. R. Paraneoplastic syndromes of the CNS. Lancet Neurol 7, 327–340 (2008).
  3. Shankaran, V. et al. IFNgamma and lymphocytes prevent primary tumour development and shape tumour immunogenicity. Nature 410, 1107–1111 (2001).
  4. Raskov, H., Orhan, A., Christensen, J. P. & Gögenur, I. Cytotoxic CD8+ T cells in cancer and cancer immunotherapy. Br J Cancer 124, 359–367 (2021).
  5. Cano, R. L. E. & Lopera, H. D. E. Introduction to T and B lymphocytes. in Autoimmunity: From Bench to Bedside [Internet] (El Rosario University Press, 2013).
  6. Paraneoplastic cerebellar degeneration – UpToDate. https://www.uptodate.com/contents/paraneoplastic-cerebellar-degeneration.
  7. Melzer, N., Meuth, S. G. & Wiendl, H. Paraneoplastic and non-paraneoplastic autoimmunity to neurons in the central nervous system. J Neurol 260, 1215–1233 (2013).
  8. Neumann, Harald, Isabelle M. Medana, Jan Bauer, and Hans Lassmann. “Cytotoxic T Lymphocytes in Autoimmune and Degenerative CNS Diseases.” Trends in Neurosciences 25, no. 6 (June 1, 2002): 313–19.https://doi.org/10.1016/S0166-2236(02)02154-9.
  9. Chaigne, Benjamin, and Luc Mouthon. “Mechanisms of Action of Intravenous Immunoglobulin.” Transfusion and Apheresis Science 56, no. 1 (February 1, 2017): 45–49. https://doi.org/10.1016/j.transci.2016.12.017.
  10. Lehmann, Helmar C., Hans-Peter Hartung, Gerd R. Hetzel, Olaf Stüve, and Bernd C. Kieseier. “Plasma Exchange in Neuroimmunological Disorders: Part 1: Rationale and Treatment of Inflammatory Central Nervous System Disorders.” Archives of Neurology 63, no. 7 (July 1, 2006): 930–35.https://doi.org/10.1001/archneur.63.7.930.
  11. Taylor, Ronald P., and Margaret A. Lindorfer. “Drug Insight: The Mechanism of Action of Rituximab in Autoimmune Disease—the Immune Complex Decoy Hypothesis.” Nature Clinical Practice Rheumatology 3, no. 2 (February 2007): 86–95. https://doi.org/10.1038/ncprheum0424.
  12. Dalmau, Josep, and Myrna R. Rosenfeld. “Update on Paraneoplastic Neurologic Disorders.” Community Oncology 7, no. 5 (May 1, 2010): 219–24.
  13. Gultekin, S. H. et al. Paraneoplastic limbic encephalitis: neurological symptoms, immunological findings and tumour association in 50 patients. Brain 123 ( Pt 7), 1481–1494 (2000).
  14. Bastiaansen, Anna E M, Adriaan H C de Jongste, Marienke A A M de Bruijn, Yvette S Crijnen, Marco W J Schreurs, Marcel M Verbeek, Daphne W Dumoulin, Walter Taal, Maarten J Titulaer, and Peter A E Sillevis Smitt. “Phase II Trial of Natalizumab for the Treatment of Anti-Hu Associated Paraneoplastic Neurological Syndromes.” Neuro-Oncology Advances 3, no. 1 (January 1, 2021): vdab145.https://doi.org/10.1093/noajnl/vdab145.

Figures 1 and 2 were created using Biorender.com.

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