Molecular typing of cryoglobulins by mass spectrometry

A cause of potentially devastating pathologies, cryoglobulins are immunoglobulin complexes that precipitate out of serum at temperatures lower than 37°C. They often arise secondary to underlying conditions, such as hepatitis infections, although may be idiopathic. Brouet et al 1 classified cryoglobulins according to their immunoglobulin composition: type I (monoclonal), type II (mixed with monoclonal rheumatoid factor (RF)) and type III (mixed with polyclonal RF).