The researcher, who revolutionized the specialty by describing new types of autoimmune encephalitis, investigates the aftermath that these processes leave in the body

At 24, Susannah Cahalan, a journalist for The New York Post, began to experience changes in her perception of the world, hallucinations, numbness, and erratic behaviour. After a series of misdiagnoses, she was eventually diagnosed with autoimmune encephalitis, a rare and terrifying disease where the immune system attacks the brain’s neurons. Her struggle is detailed in her book «Brain on Fire«, which was later adapted into a movie. Cahalan’s diagnosis in 2009 was made possible by Dr. Josep Dalmau, a neurologist who had discovered the mechanisms of a type of encephalitis caused by antibodies against the NMDA receptor. His discovery has had a global impact and has led to the identification of 12 out of 16 types of autoimmune encephalitis. Dalmau’s work has been recognized by the National Academy of Medicine in the United States, and he is one of only three researchers in Spain to have received this honor. Autoimmune encephalitis is a complex group of diseases that were not well understood 20 years ago. The immune system may attack the brain due to similar proteins found in tumors and the brain, prompting an immune response. The patient’s experience can vary widely, affecting any brain function and often requiring intensive care. Depending on the type, it can affect young women and children or individuals over 50. Dalmau’s discovery has significantly advanced knowledge about these diseases, revealing that they can affect much younger patients and are not always linked to cancer. The standard treatment is to remove the antibodies, using techniques like plasmapheresis or certain monoclonal antibody treatments. If the encephalitis is caused by a tumor, the tumor must be found and removed. Depending on the type of encephalitis and associated antibodies, the tumor can often be located in specific areas such as the abdomen, ovaries, or lungs. Since 2007, 16 types of antibody-mediated encephalitis have been defined, but there are still more to be described. Each year, around 50 patients present types of encephalitis potentially linked to an unidentified antibody. Current research is focused on understanding why recovery time varies among patients and why some alterations persist.