IgD Multiple Myeloma: A Report of Five Cases

Immunochemical analysis of sera from 180 patients with multiple myeloma disclosed five cases of IgD myeloma—an incidence of 2.8%. The IgD paraprotein concentrations in the sera were relatively low in three cases, and in two cases were 1,010 and 1,400 mg. per 100 ml., respectively. Starch-gel electrophoresis demonstrated the monoclonal protein band in the serum with the lowest concentration and exposed the other monoclonal protein bands when they had been obscured by merging with Bence Jones protein and/or normal ᵝ mobility proteins. Bence Jones proteinuria was present in all five patients, and extraosseous tumors causing cord compression were present in three. The light-chain type of the IgD paraproteins and corresponding Bence Jones proteins was A. in each of four patients and k in one. All patients were men. Their ages ranged from 41 to 84 years, with an average of 54 years, although three were under 50 and their ages averaged 44 years. Cyclophosphamide therapy rapidly reduced the high IgD serum concentrations of two patients to appreciably lower values, which have remained low—for three years in one patient. The availability of anti-IgD antiserum and an awareness of the anomalous serumprotein characteristics, the urine feature, and the often-aggressive clinical behavior should aid materially in the detection of additional cases of IgD multiple myeloma