Benefit and a possible risk of tocilizumab therapy for adult-onset Still's disease accompanied by macrophage-activation syndrome.

We report a 57-year-old female case of intractable adult-onset Still's disease (AOSD). Initial high-dose prednisolone therapy was ineffective, and macrophage-activation syndrome (MAS) manifested after one session of additional tocilizumab therapy. After successful treatment for MAS with lipo-dexamethasone and cyclosporin, tocilizumab therapy aided in the rapid reduction of the therapeutic steroid dose. Tocilizumab may be useful for maintenance therapy for AOSD, although its efficacy is unclear for the highly active phase of the disease.