Nature of cryoglobulinaemia.

Cryoimmunoglobulins seem to differ from non-cryoimmunoglobulins in not having carbohydrate groups, most probably sialic acid residues. It is proposed that cryoimmunoglobulinaemia is a physiological event and that desialylated immunoglobulins are a normal byproduct of the immune system. The rise in serum levels of cryoimmunoglobulins is either a pre-secretory event which follows enhanced stimulation of B lymphocytes or a post-secretory event secondary to the generation of serum neuraminidase-like activity by invading microorganisms or their products. It is also proposed that the liver is the main organ which removes cryoimmunoglobulins from the serum. The removal is mediated by specific hepatocellular receptors for desialylated glycoprotein. Clinical or subclinical liver diseases are therefore commonly associated with significantly increased levels of serum cryoglobulins.