Serum glial fibrillary acidic protein (GFAP)-antibody in idiopathic intracranial hypertension.

AIM: Idiopathic intracranial hypertension (IIH), a disease of obscure origin, is characterized by headache and visual disturbances due to increased intracranial pressure. Recent line of evidence has suggested involvement of inflammation in IIH pathogenesis thus bringing forward anti-glial autoimmunity as a potential contributor of IIH. Glial fibrillary acidic protein (GFAP) is a major astrocytic autoantigen associated with a specific form of meningoencephalitis. MATERIALS AND METHODS: In this study, we investigated the presence of GFAP-antibody in 65 sera (49 obtained during active disease and 16 during remission) and in 15 cerebrospinal fluid (CSF) samples of 58 consecutively recruited IIH patients using cell based assay and indirect immunohistochemistry. RESULTS: GFAP-antibody was found in active period sera of 2 IIH patients with classical symptoms and good treatment response. Two remission period sera obtained at different time points from one of these cases showed lower titers of GFAP-antibody positivity. IgG from positive samples yielded an astrocytic immunoreactivity pattern. None of the CSF samples showed GFAP-antibodies. CONCLUSIONS: These results suggest that anti-astrocyte autoimmunity might be present in a fraction of IIH patients. Exact pathogenic significance of this association needs to be further studied.

Glial fibrillary acidic protein (GFAP)-antibody in children with focal seizures of undetermined cause.

Anti-neuronal antibodies that are related with autoimmune encephalitis syndromes may also be found in children with new onset seizures or chronic epilepsy. To unravel the significance of autoimmune astrocytopathy in epilepsy, we investigated serum antibody to glial fibrillary acidic protein (GFAP), another autoantigen described in autoimmune encephalitis with seizures, in 38 children with focal seizures of undetermined cause. GFAP antibody was screened with cell based assay and indirect immunohistochemistry and was found in two boys with normal brain MRI and unrevealing medical history prior to seizures. The 2-year-old boy had chronic treatment-resistant frontal lobe epilepsy. The 2.5-year-old boy had a single episode of focal seizures and remained seizure free thereafter in a follow-up period of 4 years. Nevertheless, he showed severe cognitive and language impairment. These results suggest that autoimmune astrocytopathy may be present in some epilepsy patients. Whether this immune response is a bystander effect generated by seizure-induced astrocytosis or directly involved in epileptogenesis needs to be further studied.