To report the clinical manifestation and auxiliary examination features of 15 Chinese patients with glial fibrillary acidic protein (GFAP) autoimmunity.

GFAP astrocytopathy is a corticosteroid responsive inflammatory central nervous system (CNS) disorder spectrum predominantly affecting meninges, brain, spinal cord, and optic nerve mimics infectious meningoencephalitis. IgG antibodies binding to GFAP are specific biomarkers with diagnostic significance.

From June 2016 to December 2019, patients with suspected neurological autoimmune disease were scanned for autoantibodies by immunohistochemistry. Samples showed a characteristic immunoreactive pattern reminiscent of GFAP of astrocytes were selected and confirmed by cell-based assay. 

Fifteen patients (8 male, 7 female) with a median age at onset of 53 years were identified as GFAP-IgG positive. Eleven of 15 patients presented with an acute monophasic course, of which 10 had antecedent flu-like symptoms. The predominant phenotype was meningoencephalitis (46.7%), followed by meningoencephalomyelitis in 40% of cases. Magnetic resonance imaging revealed enhancement in 10 of 13 patients. Inflammatory CSF showed mild lymphocyte-predominant pleocytosis with a median of 51/μl, elevated protein with a median of 87.5mg/dl. Five of six patients tested for CSF specific oligoclonal bands were positive. Five patients had coexisting antibodies, including NMDAR-IgG in 3 patients, Yo and MOG-IgG in one each patient. One patient underwent stereotactic brain biopsy and neuropathology diagnosis was diffuse large B-cell lymphoma with normal reactive fibrillary astrocytes. One patient had ovarian teratoma. Eleven of 15 patients received both intravenous immunoglobulin and steroids. Among them, 3 patients also received immunosuppressive agents later. During 2-year follow-up, nine of 15 patients achieved complete clinical remission. 

The clinical presentation of GFAP astrocytopathy is heterogeneous,including acute monophasic course or chronic relapsing courses. Patients with an acute monophasic course with antecedent infection symptoms responded well to immunotherapy. In case of primary central nervous system lymphoma, GFAP autoimmunity doesn’t equal to autoimmune GFAP astrocytopathy.