GFAP and infection: Infection may be a common trigger of GFAP autoimmunity in humans, with 2 cases currently reported in China, with evidence of herpes simplex virus infection before onset.[3,5] Other components of the immune system (microglia, macrophages, cytokines, and chemokines) may also contribute to pathogenesis.[2] GFAP is an intracellular antigen, so it is difficult for antibodies to interact with it; therefore, it is generally considered nonpathogenic.