Therapy for hepatitis C virus-related cryoglobulinemic vasculitis.

Copyright © 2013 Massachusetts Medical Society. Cryoglobulins are immunoglobulins characterized by their insolubility at low temperatures and their dissolution after rewarming.1,2 On the basis of their immunochemical composition, cryoglobulins are classified as either single (type I), consisting of a monoclonal immunoglobulin, or mixed, comprising two or more immunoglobulin isotypes, with (type II) or without (type III) a monoclonal component.3 For many years, mixed cryoglobulinemia was referred to as “essential” because of its undefined cause. In the early 1990s, it became evident that more than 90% of patients with mixed cryoglobulinemia were infected with hepatitis C virus (HCV).4-7 The pathophysiology of mixed cryoglobulinemia, as it is currently understood, is depicted in Figure 1. Cryoglobulins can be detected in 25 to 30% of HCV-positive patients, but in asymptomatic cases, treatment is unnecessary. Cryoglobulin-related illness, known as cryoglobulinemic vasculitis, appears in a minority (10 to 15%) of patients and includes a spectrum of symptoms (Fig. 2), ranging in severity from mild (sporadic purpura) to life-threatening.1,2 Consequently, not all patients should be treated to the same extent.16 This review covers both established treatments for HCV-related cryoglobulinemic vasculitis and emerging therapeutic perspectives (Fig. 3).