Interleukin-6 receptor(Tosoh Corp.)

Neuro-Behçet's disease (NBD) is a rare and potentially severe manifestation of Behçet's disease, frequently associated with poor neurological outcomes. Management relies on high-dose corticosteroids and immunosuppressive agents, yet a subset of patients develops rapidly progressive and treatment-refractory disease. We report the case of a 39-year-old man with Behçet's disease who presented with progressive neurological deterioration. Brain magnetic resonance imaging (MRI) revealed multiple inflammatory lesions involving the brainstem and cerebral hemispheres, with subsequent radiological progression despite intensive immunosuppressive therapy. Tocilizumab, an interleukin-6 receptor antagonist, was introduced as salvage treatment in the context of rapid disease worsening. Follow-up MRI demonstrated a striking regression of inflammatory lesions. However, this radiological improvement was not accompanied by clinical recovery, and the patient ultimately died due to severe systemic complications. This case illustrates a marked dissociation between radiological response and clinical outcome in severe, refractory neuro-Behçet's disease. While the imaging findings suggest a potential effect of IL-6 blockade on inflammatory brain lesions, they also underscore the limitations of radiological improvement as a surrogate marker of clinical benefit. This observation highlights the complexity of disease progression in NBD and the critical importance of early intervention and comprehensive systemic management.