Cryoglobulinemia in a patient with Sjögren's syndrome, and factors of cryoprecipitation.

The IgGK cryoglobulin in a patient with Sjögren's syndrome showed deviations from normal IgG involvine its amino acid composition as well as its carbohydrate components. The heavy chains showed abnormal numbers of arginine, threonine, valine and isoleucine residues, and there was an impressive reduction of fucose and hexose components. The carbohydrate deficits appear to be the reason for the incomplete solubility of the isolated IgGK(Ru) at 37 degrees C. with completion at 52 degrees C.