Cryoglobulin
- Cryoglobulins are antibodies that can be directed against other immunoglobulins, which form immune complexes that precipitate in the cold.
- They can lead to type III hypersensitivity reactions, with typical clinical manifestations including
- purpuric rash, often of the lower extremities,
- arthralgia and
- peripheral neuropathy.
- Cryoglobulins are classified into three types, depending on the properties of the immunoglobulin involved
- Testing for cryoglobulins requires the transport of a serum specimen to the laboratory at 37°C.
- Cryoglobulins should not be confused with cold agglutinins; cold agglutinins are autoantibodies directed against surface antigen of red cells, which can cause intravascular haemolysis in the cold.