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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.〔(【引用サイトリンク】title=Cryoglobulinemia )〕 ==Classification== Cryoglobulinemia is classically grouped into three types according to the Brouet classification. Type I is most commonly encountered in patients with a plasma cell dyscrasia such as multiple myeloma or Waldenström macroglobulinemia. Types II and III are strongly associated with infection by the hepatitis C virus.〔 Type III is strongly associated with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. There are three different types of cryoglobulins that have been observed to form in the blood. Types II and III have rheumatoid factor (RF) activity and bind to polyclonal immunoglobulins. These two types are referred to as mixed cryoglobulinemia (MC). When the temperature is raised, the precipitated cryoglobulins will dissolve back into the serum. In 2006 it was discovered that there are unusual cryoglobulins that show a microheterogeneous composition, with an immunochemical structure that cannot be fit into any of the classifications. A classification of a type II-III variant has been proposed because they are composed of oligoclonal IgMs with traces of polyclonal immunoglobulins 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cryoglobulinemia」の詳細全文を読む スポンサード リンク
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