Cryoglobulinemia

Cryoglobulinemia or cryoglobulinaemia is a medical condition in which the blood contains large amounts of cryoglobulins – proteins (mostly immunoglobulins themselves) that become insoluble at reduced temperatures. This should be contrasted with cold agglutinins, which cause agglutination of red blood cells. Cryoglobulins typically precipitate at temperatures below normal body temperature (37 °C) and will dissolve again if the blood is heated. The precipitated clump can block blood vessels and cause toes and fingers to become gangrenous. Cryoglobulinemia can be associated with various diseases such as multiple myeloma and hepatitis C infection. Cryoglobulins usually consist of IgM directed against the Fc region of IgG.