Efficacy and safety of rituximab in type II mixed cryoglobulinemia.

The best treatment of type II mixed cryoglobulinemia (MC) has still to be defined. Antiviral treatment for the frequent underlying infectious trigger hepatitis C virus (HCV) may be ineffective, contraindicated, or not tolerated in a fraction of cases, whereas current immunosuppressive treatments may lead to relevant complications. Selective B-cell blockade with rituximab was used in this study, based on favorable results in preliminary experience. Fifteen consecutive patients with type II MC (HCV-related in 12 of 15) were treated with rituximab, 375 mg/m(2) intravenously weekly for 4 weeks. Only medium- to low-dose steroids were allowed, if already administered at the time of recruitment. All patients had active disease, poorly controlled or difficult to manage with previous treatments, including corticosteroids in all. Efficacy and safety of rituximab therapy were evaluated in the following 6 months. The overall follow-up after rituximab treatment ranged from 9 to 31 months. Rituximab proved effective on skin vasculitis manifestations (ulcers, purpura, or urticaria), subjective symptoms of peripheral neuropathy, low-grade B-cell lymphoma, arthralgias, and fever. Nephritis of recent onset went into remission in one case. Laboratory features, that is, significantly decreased serum rheumatoid factor and cryoglobulins and increased C4, were consistent with the clinical efficacy. Treatment was well tolerated, with no infectious complications. Thrombosis of retinal artery or self-limiting panniculitis occurred in one patient each. Rituximab may represent a safe and effective alternative to standard immunosuppression in type II MC. Controlled studies are needed to better define drug indications and the cost-efficacy profile in the different systemic manifestations.