By Amanda Backner, Neurology Product Director

February 20, 2020 Better Health

World Encephalitis Day is February 22, and it can’t come too soon. Most of the general US population—78%—is unaware of encephalitis, including common symptoms, diagnostic protocols, and treatment options for this devastating disease.1,2

Encephalitis is an inflammation of the brain. The patient presentation may include flu-like illness or headache, drowsiness, uncharacteristic behavior, inability to speak or control movements, and seizures.2 These symptoms usually come on quickly and severely. Encephalitis is commonly caused by viruses. A lesser-known fact is that many types of encephalitis are caused by an autoimmune disorder or in response to an underlying tumor. Ninety-thousand people worldwide develop autoimmune encephalitis (AE) each year.2 Some of the most common antibodies involved in AE are Hu (ANNA1), Ma2, GAD, NMDAr, AMAPAr, GABAr, LGI1, CASPR, AQP4, and DPPX.3 Additionally, there have been over 22 antibodies discovered since 2017. Treatment outcome is generally favorable and treatment options could include any of the following: tumor removal, treatment with steroids, intravenous immunoglobin, immunosuppressant, or plasma exchange.2

At Quest Diagnostics, we offer a range of testing, including our Encephalitis Antibody Evaluation with Reflex to Titer and Line Blot. This test can be performed on both on serum and cerebrospinal fluid. This panel includes the antibodies listed above as part of the initial evaluation and has an expedited turnaround time for quicker results for critically ill patients.

As Dr. Stanley Naides points out in his paper, The Role of the Laboratory in the Expanding Field of Neuroimmunology: Autoantibodies to Neural Targets,4 Darnell and Posner proposed use of multiple methods,

“Ideally,…immunostaining should be done against several CNS tissues….In addition, western blots or ELISA should be performed using both against cloned fusion proteins…as well as extracts of neurons…” (Darnell and Posner, 2011). A study of anti-neural IgG autoantibodies in 16,741 samples tested at Euroimmun Clinical Immunological Laboratory (Luebeck) is informative. One positive antibody was found in 13.6% of samples submitted. Two or more positive antibodies were found in only 0.5% of specimens. For those samples positive, the sample was positive for the requested analyte 53.4% of the time. Of interest, the positive samples were positive for an analyte that was not requested 46.6% of the time (Stoecker, 2015). This finding along with numerous case reports and series suggests that a given antibody may present with varying clinical presentations, a given presentation may be caused by several autoantibodies, and that a specific tumor, when a PNS is present, may be associated with different autoantibodies (Darnell and Posner, 2011).”

This means that if single antibody tests are ordered, a potentially positive antibody could be missed by not performing a comprehensive test.

To help raise awareness of this devasting, yet treatable, disease, Quest Diagnostics is sponsoring the World Encephalitis Day 2020 Conference. You can learn more about this event by visiting https://www.encephalitis.info/Event/wed-conference-2020.

Please also help raise awareness by wearing the color red in celebration of World Encephalitis Day on February 22.

References

  1. Encephalitis facts and figures. Encephalitis Society website. Accessed February 17, 2020. https://www.encephalitis.info/facts
  2. AE FAQs. Autoimmune Encephalitis Alliance website. Accessed February 17, 2020.
    https://aealliance.org/faq/#a-new-disease
  3. Encephalitis facts and figures. Encephalitis Society website. Accessed February 17, 2020. https://www.encephalitis.info/what-is-encephalitis
  4. Naides SJ. The role of the laboratory in the expanding field of neuroimmunology. Journal of Immunological Methods. 2018;463:1-20. doi: 10.1016/j.jim.2018.04.003