Clinical features of a recently identified disease: GFAP autoimmunity

Glial fibrillar acidic protein (GFAP) autoimmunity is a recently identified disease at the interface between autoimmune encephalitis and gliopathies. Results of a French cohort study showed that GFAP autoimmunity was generally associated with a favourable outcome, and monophasic course with low risk of relapse [1].

GFAP autoimmunity (autoimmune GFAP astrocytopathy) was first described in 2016 by researchers of the Mayo Clinic (USA) [2]. GFAP is a type III intermediate filament protein with several isoforms and is expressed by astrocytes and ependymocytes in the central nervous system. Auto-antibodies against GFAPα are a biomarker of autoimmune GFAP astrocytopathy.

In a French cohort study, all patients from 2 referral centres who tested positive for GFAP antibodies were included (n=46). Clinical, biological, and imaging features were reported, as well as clinical course and outcomes. Median age at onset was 43 years; 65% were male.

Other autoimmune diseases were found in 22%, coexisting neural autoantibodies in 11% (including MOG-IgG and AQP4-IgG). Infectious prodromal symptoms were reported in 82%. The most frequent presentation was meningoencephalitis (61%) and meningoencephalomyelitis (24%). Other/associated clinical presentation included: myelitis (30%), visual tract involvement (35%), and peripheral nervous system involvement (28%).

Cerebrospinal fluid showed pleocytosis (98%), oligoclonal bands (77%), and low glucose level (15%). MRI findings were heterogeneous: radial enhancement was found in 26%, periventricular diffuse T2 hyperintensity in 39%, brainstem involvement in 33%, leptomeningeal enhancement in 23%.

There is no standard treatment regimen for GFAP autoimmunity, which is one of the unmet needs. Immunotherapy was given to 17 patients. Though high severity at presentation was common, 39/46 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89% at 15.5 months).

1. Gravier Dumonceau A, et al. GFAP auto-immunity: a French cohort study. MSVirtual 2020, Abstract FC01.05.
2. Fang B, et al. JAMA Neurol. 2016 Nov 1;73(11):1297-1307.