IgD myeloma. Report of a case with unusual clinical and immunologic features

A case of IgD myeloma in a 48-year-old Caucasian man is reported. The unusual features of this case included the absence of osteolytic lesions by x-ray, absence of anemia, absence of monoclonal spike on serum electrophoresis, association of kappa light chains, absence of Bence Jones proteinemia and Bence Jones proteinuria, and a remarkable, temporary clinical response to therapy. Immunoelectrophoresis of whole serum yielded a pattern consistent with IgD kappa monoclonal gammopathy. Immunoelectrophoresis of a pure serum IgD preparation, previously separated by gel chromatography (Sephadex G-200), revealed definitive information about an IgD kappa monoclonal gammopathy. Immunomicroscopic examination of bonemarrow smears showed the presence of delta and kappa chains only in the cytoplasm of plasma cells.