Cryoglobulins are immunoglobulins that precipitate at temperatures below 37 c and redissolve above 37 c. They are identified in the laboratory by storing clotted blood at 4 c for 7 days and looking for a precipitate.
There are 3 types of cryoglobulinaemia:
- Type 1 cryoglobulinaemia
- Monoclonal, usually IgM
- Accounts for 10-15% of cases of cryoglobulinaemia
- Associated with
- Multiple myeloma
- Waldenstroms macroglobulinaemia
- CLL
- Features of type 1 cryoglobulinaemia include
- Raynaud’s
- Acrocyanosis
- Gangrene
- Type 2 and Type 3 cryoglobulinaemia = mixed cryoglobulinaemias
- Type 2 is mono and poly clonal while type 3 is polyclonal only
- Type 2 is the commonest, accounting for 50-60% of all cases of cryoglobulinaemia
- The IgM of mixed cryoglobulinaemia typically has rheumatoid factor activity
- Features include
- ‘Classic triad’
- Purpura
- Arthralgia
- Weakness
- Widespread vasculitis
- Ulcers
- Peripheral neuropathy
- Membranoproliferative glomerulonephritis
- Associated with
- Hepatitis C (most common association)
- HIV
- Sjogren’s syndrome
- Mixed cryoglobulinaemia may be complicated by
- B cell lymphoma
- Hepatocellular carcinoma
- Thyroid cancer
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