In Stiff Person Syndrome, which is a rare autoimmune disease in the central nervous system with autoantibodies targeting glutamic acid decarboxylase (GAD65), the humoral autoimmune response was shown to consist of a Rituximab-sensitive part rapidly cleared after treatment, and a Rituximab-resistant part from long-lived and persistent plasma cells acting as a reservoir for secretion of autoantibodies. This evidence concerns the gene GAD2 and autoimmune disease.