Biclonal immunoglobulin M dysglobulinaemia: evolving aspects in a case of primary Sjögren's syndrome.

The observation of suggestive clinical symptoms in a patient suffering from a Gougerot-Sjögren syndrome led to a search for a cryoglobulin. Unusual physico-chemical features of this cryoglobulin were discovered, using standard electrophoresis, immunoelectrophoresis, immunofixation and electroimmunotransfer. The main unusual finding was that the cryoprecipitate was made up of a biclonal IgM kappa associated to polyclonal IgG. Therefore, we suggest that this new form of cryoglobulin be classified as a subtype IIb, thus distinguishing two subtypes in the usual classification.