[An immunopathological study during steroid-responsive and steroid-nonresponsive stages on a patient with neuro-Behçet's disease].

We followed up the clinical course and changes of brain magnetic resonance imaging (MRI) findings in a case of neuro-Behçet's disease, and performed serial immunological examinations of the cerebrospinal fluid (CSF). On the two episodes of acute exacerbation, gadolinium (Gd)-enhancement effects on brain MRIs were observed in the brain stem and the deep white matter of cerebral hemispheres. The CSF abnormality of this period was characterized by increases in proportions of polymorphonuclear leukocytes and intrathecal IgG synthesis in addition to the findings suggesting breakdown of the blood brain barrier (BBB). These findings disappeared in parallel with clinical improvement by corticosteroid therapy. In contrast, during a subsequent chronic progressive stage, steroid-resistant neuropsychiatric symptoms and an absence of Gd-enhancement effects on brain MRIs were observed despite progressive breakdown of BBB. These findings suggest that neuro-Behçet's disease should comprise two distinct immunopathogenetic stages, that is, a relatively early steroid-responsive stage with a relapsing-remitting clinical course and a late steroid-nonresponsive stage with a chronic progressive course.