Immunoglobulin D benign monoclonal gammopathy. A case report.

The authors report a case, perhaps the first, of immunoglobulin D (IgD) benign monoclonal gammopathy. The patient, a 48-year-old black woman, initially had a 500 mg/dl IgD-lambda M-spike, hypercalcemia, and anemia. There was no bone pain, lytic bone lesions, or evidence of renal failure. The bone marrow showed 2.8% plasma cells with a diffuse (not nodular) IgD plasmacytosis and strong lambda predominance. Only trace amounts of free lambda light chains could be demonstrated by immunoelectrophoresis in serum and concentrated urine. The anemia responded quickly to iron therapy. Chemotherapy was not initiated. Over the 6+ years of follow-up, the patient has had no progression of clinical disease attributable to her IgD monoclonal gammopathy. The IgD M-spike has steadily decreased.