Cryoglobulinaemia

Key points

• Immunoglobulins which undergo reversible precipitation at 4 deg C, dissolve when warmed to 37 deg C. One-third of cases are idiopathic Three types
• type I (25%): monoclonal
• type II (25%): mixed monoclonal and polyclonal: usually with rheumatoid factor (RF)
• type III (50%): polyclonal: usually with RF Type I
• monoclonal - IgG or IgM