Mixed cryoglobulinemia in hepatitis C patients. GERMIVIC

Cryoglobulins are immunoglobulins that persist in the serum, precipitate with cold temperature and resolubilize when rewarmed. Types II and III are mixed cryoglobulins (MC), composed of different immunoglobulins, with a monoclonal component in type II and only polyclonal immunoglobulins in type III. Mixed cryoglobulins are associated with connective-tissue disease, malignant hematological disorder (type B lymphoproliferation) or obvious infectious process. Mixed cryoglobulinemia syndrome is characterized by the clinical triad of purpura, arthralgia and asthenia associated with type II or type III MC. The disorder is the consequence of an immune-complex-type vasculitis as supported by clinical features, analysis of the cryoglobulins, the usually depressed level of complement during the active phase of the disease, and the deposition of immunoglobulins and complement in the lesions. Such cryoglobulinemia vasculitis may involve numerous organs, particularly the peripheral nervous system and the kidneys. MC is frequently associated with clinical and biological evidence of liver disease. There has been some controversy about which comes first, MC or chronic liver disease, but it seems fairly clear that MC is often a manifestation of underlying chronic active or persistent hepatitis. In MC patients, the hepatotropic antigen(s) capable of triggering production of antibodies which can later form immune complexes has been sought for many years. In the last ten years, numerous studies have demonstrated that infection with hepatitis C virus is involved in the pathogenesis of most mixed cryoglobulinemia. This review analyzes the main published data on hepatitis C virus-mixed cryoglobulinemia, the role of liver alterations, the predictive factors associated with MC production in HCV patients and its symptomatic nature or not, and the different types of vasculitis associated with HCV chronic infection.