[A case of chronic progressive neuro-Behçet disease with extensive cerebral atrophy and elevated CSF IL-6 activity treated with infliximab].

A 43-year-old man without a previous episode of uveitis presented with slowly progressive neurological symptoms that appeared within the past year such as dysarthria, ataxic gait, and behavioral changes. Brain MRI findings showed atrophic lesions in the brainstem and cerebellum. Because these clinical symptoms and abnormal MRI findings indicated spinocerebellar degeneration as the initial diagnosis, he was admitted to our hospital. On admission, we noticed that he had non-neurological manifestations of Behçet disease, such as stomatitis, genital ulcers, and folliculitis. HLA-B51 was positive. He also showed pleocytosis (29 cells/mm3, predominantly mononuclear cells) and elevated cerebrospinal fluid (CSF) IL-6 levels (213 pg/ml), hence he was diagnosed with chronic progressive neuro-Behçet disease (CPNBD). The therapeutic effect of a high-dose intravenous methylprednisolone pulse (1,000 mg/day for 3 days) and methotrexate (maximum dosage, 16 mg/week) was poor against both neurological symptoms and CSF findings. Intravenous infliximab therapy (5 mg/kg, 2 weeks) dramatically decreased CSF IL-6 levels (13 pg/ml) but clinical symptoms remained unchanged. MRI findings of extensive cerebral atrophy and increased CSF IL-6 levels at the pretreatment time point reflected irreversible neurological involvement in CPNBD. For cases with progressive psychiatric symptoms and cerebellar ataxia in the early stage of the disease, skin manifestations should be examined immediately, CSF IL-6 levels measured, and immunosuppressive therapy initiated before CPNBD progresses to brainstem atrophy.