SCOT Hickman, MD, Assistant Professor in Medicine, Washington University School of Medicine, St Louis: A 73-year-old man was referred to the hematology clinic in January 1979 for evaluation of hyperglobulinemia detected at a routine visit to his private physician. The serum total protein level at that time was 9.1 g/dL with an albumin level of 4.4 g/dL. He denied bone pain, fevers, chills, bleeding episodes, and easy bruising. Findings from a physical examination were normal. Examination of the skin showed no petechiae or rashes. No bone pain could be elicited, and he had no notable adenopathy or organomegaly. Pertinent laboratory studies disclosed the following values: hemoglobin, 14.6 g/dL; hematocrit, 43%; platelets, 200,000/cu mm; and WBCs, 7,000/cu mm, with a normal differential cell count. A serum protein electrophoresis demonstrated an M spike of 3 g/dL, found by immunoelectrophoresis to be an IgG monoclonal immunoglobulin with k light chains. Levels of IgM