Cryoglobulins (cold-precipitable proteins in serum) may be idiopathic, related to an underlying lymphoproliferative syndrome or plasma cell dyscrasia, or secondary to a disorder such as hepatitis C infection. Cryoglobulins may be IgG, IgM, or IgA. Mixed cryoglobulins are usually composed of IgM complexed with a monoclonal or polyclonal IgG. The immune complexes can interfere with normal platelet function and fibrin polymerization. Hyperviscosity and direct vascular trauma due to circulating cryoglobulins cause small-vessel hemorrhage. Cryoglobulinemia can manifest with acral hemorrhagic necrosis, palpable purpura, livedo reticularis, and leg ulcers.
By permission of the publisher. From Deitcher S. In Atlas of Clinical Hematology . Edited by JO Armitage. Philadelphia, Current Medicine, 2004.