Clinical Manifestation, Auxiliary Examination Features, and Prognosis of GFAP Autoimmunity: A Chinese Cohort Study

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

From June 2016 to December 2019, patients suspected to have neurological autoimmune disease after having their serum and cerebrospinal fluid (CSF) tested for conventional neural antibodies were scanned for additional autoantibodies by immunohistochemistry. Samples that showed a characteristic immunoreactive pattern reminiscent of the GFAP of astrocytes were selected and confirmed by cell-based assay using cells-expressing human GFAPα.

A total of 15 patients (eight male and seven female) with a median age at onset of 53 years (range 28-72) were identified as GFAP-IgG-positive. Fourteen cases had GFAP-IgG detected in the CSF, while serum GFAP-IgG was detected in 11 cases. Eleven of the fifteen patients (73.3%) presented with an acute monophasic course, of which 10 (90.9%) had antecedent flu-like symptoms. The predominant phenotype was meningoencephalitis (46.7%), followed by meningoencephalomyelitis in 40% of the cases. The most common clinical features included long tract signs, brainstem symptoms, tremors, headaches, and psychiatric symptoms. Magnetic resonance imaging (MRI) revealed the enhancement of the meninges, the surface of the brainstem, the cerebellum, and the spinal cord as predominant. Inflammatory CSF showed mild lymphocyte-predominant pleocytosis with a median of 51/μL and elevated protein with a median of 87.5 mg/dL. Five patients had coexisting antibodies, including NMDAR-IgG in three patients and Yo and MOG-IgG in one patient each. One patient underwent a stereotactic brain biopsy, and the neuropathology diagnosis was diffuse large B-cell lymphoma. One patient had ovarian teratoma. Eleven of the fifteen (73.3%) patients received both intravenous immunoglobulin and steroids. Among them, three patients also received immunosuppressive agents later. During a two-year follow-up, 9 of the 15 (60%) patients achieved complete clinical remission.

The clinical presentation of GFAP astrocytopathy is heterogeneous. It can be characterized by an acute monophasic course and a chronic relapsing course. Tremors are a prominent clinical manifestation in patients with an acute monophasic course with GFAP-IgG antibodies only. Most patients responded well to immunotherapy. In patients with GFAP autoimmunity, presenting with a chronic relapsing course, one should actively search for immunogenic factors and the culprit antibodies. In the case of primary central nervous system lymphoma, GFAP autoimmunity does not always equate to autoimmune GFAP astrocytopathy.