Myeloma and other paraproteinemias.

The paraproteinemias, a large heterogeneous group of diseases, are best characterized by the type of immunoglobulin moiety (paraprotein) produced. For the most common disorder, myeloma, response to treatment with alkylating agents has been objectively shown. Waldenström's macroglobulinemia and heavy-chain disease are more closely related to lymphoma than to myeloma. Some patients with paraproteinemia have a benign course with a constant, abnormal, immunoglobulin level.