Clinical manifestations of multiple myeloma: relation to class and type M component.

From analysis of serum samples and clinical data from 632 patients with multiple myeloma it was determined that IgG was the commonest class of myeloma and that this type seemed to be the most benign. IgD myeloma and lambda light-chain disease were the most aggressive types; patients with these types were usually younger at diagnosis and more commonly had azotemia, osteolytic lesions and Bence Jones proteinemia. The sexes were equally represented in all but IgD myeloma, in which males predominated. Prognosis was more favourable when the M component had kappa light chains.