Successful treatment with rituximab for type III cryoglobulinemia

Abstract A 71-year-old man with rheumatoid arthritis was referred to our hospital with complaints of face and leg edema and was admitted for management of acute renal failure. Type III cryoglobulinemia was diagnosed based on histopathological findings of a kidney biopsy which revealed cryoglobulinemic nephropathy. Immunofixation showed no serum M-proteins. Steroid pulse and apheresis were initiated but the proteinuria did not improve. Rituximab was administered four times weekly as a second-line treatment, eliminating the proteinuria, after which the steroid dose was gradually tapered until discontinuation. No recurrence of proteinuria was observed more than 1 year after termination of rituximab therapy. This suggests that rituximab exerts a long-term effect. Although this patient developed candidiasis during rituximab therapy, the therapy could be continued as the antifungal agents prevented exacerbation of the infection. Rituximab can be used for the treatment of steroid-refractory cryoglobulinemia. However, clinicians should remain aware of possible infections associated with immunosuppression.