Cryoglobulins

Immunoglobulins that are precipitated by cold temperatures (4ºC) and dissolved by warm temperatures (37ºC)

Cryoglobulinemia

Brouet classification

Three types

• type I (25%):
  • monoclonal - IgG or IgM
  • associations: multiple myeloma, Waldenstrom macroglobulinaemia
• type II (25%)
  • mixed monoclonal and polyclonal: usually with rheumatoid factor
  • associations: hepatitis C, rheumatoid arthritis, Sjogren's, lymphoma
• type III (50%)
  • polyclonal: usually with rheumatoid factor
  • associations: rheumatoid arthritis, Sjogren's

Possible features

• Raynaud's only seen in type I
• cutaneous
  • vascular purpura
  • distal ulceration
  • ulceration
• arthralgia
• renal involvement
  • diffuse glomerulonephritis

Investigations

• low complement (esp. C4)
• high ESR

Management

• treatment of underlying condition e.g. hepatitis C
• immunosuppression
• plasmapheresis