Clinical characteristics of patients with GFAP-IgG coexisting with AQP4-IgG or MOG-IgG

Qingchen Li^1*Xinyun Chen²

• ¹Department of Neurology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
• ²Department of Neurology, Third People’s Hospital of Zhengzhou, Shuncheng, Henan Province, China

BAbstractBackground: Glial fibrillary acidic protein-immunoglobulin G (GFAP-IgG) can coexist with aquaporin-4-IgG (AQP4-IgG) or myelin oligodendrocyte glycoprotein-IgG (MOG-IgG). We aimed to investigate the clinical characteristics of GFAP-IgG coexisting with AQP4-IgG or MOG-IgG. Methods: We retrospectively collected data from 81 GFAP-IgG positive patients. Described and compared the clinical characteristics of patients with GFAP-IgG coexisting with AQP4-IgG or MOG-IgG.Results: (1) Among the 81 GFAP-IgG positive patients, 9 (11.1%) were positive for AQP4-IgG and 7 (8.6%) were positive for MOG-IgG. The clinical manifestations of overlapping syndromes were diverse. They all met the clinical phenotype of autoimmune GFAP astrocytopathy (A-GFAP-A) and also fulfilled the diagnostic criteria for neuromyelitis optica spectrum disorders or MOG antibody-associated disorders. Compared with the GFAP-AQP4 overlapping syndrome, the GFAP-MOG overlapping syndrome had more seizures (57.1% vs. 0, P=0.019). (2) Compared with non-overlapping syndrome group, overlapping syndrome group had more females (68.6% vs. 32.3%, P=0.008), more optic neuritis (ON) (43.8% vs. 4.6%, P<0.001), a lower CSF white blood cell counts (median 30 vs. 94 cells/mm3, P=0.001) and protein (median 0.375 vs. 0.78 g/L, P<0.001), and a higher proportion of patients receiving long-term immunotherapy (68.8% vs.13.8%, P<0.001). Conclusions: Among patients with A-GFAP-A, 20% had concurrent AQP4-IgG or MOG-IgG and showed distinct clinical features, suggesting a different disease phenotype driven by overlapping autoimmune mechanisms.