Rituximab in the treatment of refractory dermatomyositis.

Dermatomyositis is an inflammatory myopathy characterized by muscle weakness and inflammation. In contrast to polymyositis and inclusion body myositis, humoral immune mechanisms appear to contribute to the pathogenesis of dermatomyositis. A 56-year-old man with dermatomyositis resistant to conventional therapies was treated with 6 weekly infusions of the anti-CD-20 monoclonal antibody, rituximab, at a dosage of 100 mg/m in addition to other agents. The patient demonstrated a remarkable clinical response as indicated by an increase in muscle strength and a decline in creatine kinase enzymes. B-cell depletion therapy with rituximab used alone or in combination with other immunosuppressive therapies may be a viable option in patients with dermatomyositis as well as other autoimmune diseases refractory to current therapies.