Immunoadsorption Therapy in Managing NMDAR Antibodies Encephalitis

This study is testing a treatment called immunoadsorption therapy — a process that filters harmful antibodies out of the blood — in children with a severe brain inflammation called anti-NMDAR encephalitis, where the body's immune system mistakenly attacks the brain. **You may be eligible if...** - You are between 0 and 18 years old - You have been diagnosed with definite anti-NMDAR encephalitis (confirmed by a specific antibody in the spinal fluid) - Your condition is still severe (scores of 4 or above on standard disability scales) even after receiving standard first-line treatments (steroids and/or intravenous immunoglobulin) **You may NOT be eligible if...** - You have brain inflammation caused by something other than NMDAR antibodies - Your condition has improved enough with first-line treatment - You cannot have a central line (IV catheter) placed safely - You are pregnant, breastfeeding, or a teenager without effective contraception - You have certain blood clotting problems, active serious infection, severe immune deficiency (such as AIDS), or an allergy to components used in the filtering process Talk to your doctor to see if this trial is right for you.