Autoantibodies in postinfectious acute cerebellar ataxia

The authors found serum immunoglobulin M (IgM) autoantibody in a patient with typical acute cerebellar ataxia (ACA) and identified the antigen molecule as triosephosphate isomerase (TPI). TPI antigenicity to the patient’s antibody was the highest in the cerebellar tissue. Eight of 23 patients with ACA had increased IgM anti-TPI antibody titers vs those of healthy controls. Preceding Epstein–Barr virus infection was confirmed serologically in all 8 patients. Anti-TPI antibody decreased with clinical improvement.