HCV-associated Cryoglobulinemia

Cryoglobulins are immunoglobulins that precipitate in cold and dissolve with warming.

HCV infections is associated with Type II or essential mixed cryoglobulinemia (polyclonal IgG and a monoclonal IgM rheumatoid factor directed against the IgG) and Type III or mixed cryoglobulin (polyclonal IgG and rheumatoid factor IgM).

Deposition of antigen-antibody complexes in small and medium-sized arteries leads to the clinical findings of cyroglobulinemia. It is unclear, however, why cryoglobulins are produced and which antigen triggers this process. HCV RNA itself may serve as the inciting agent.

Clinical features include palpable purpura, nonspecific systemic symptoms, arthralgias, lymphadenopathy, hepatosplenomegaly, peripheral neuropathy, and hypocomplementemia (low C4).

Here is a review on the topic.

*image is papable purpura (non-blanching erythematosus papules) found in a patient with chronic HCV infection with mixed cryoglobulinemia.