Decreasing M Spike With Increasing Tumor Burden in Multiple Myeloma

To the Editor. —In a previous issue of theArchives(1981;141:1152-1153), Sahasrabudhe and Parker described three patients with multiple myeloma in whom M spikes decreased while the tumor burden was increasing. A similar occurrence was observed in a patient with double paraproteinemia who was not receiving treatment. Report of a Case. —A 79-year-old woman was hospitalized in October 1978 for cardiac arrhythmia. Electrophoretic analysis of serum samples, which was prescribed because of an increased ESR (50 mm/hr), disclosed two M spikes in the γ-globulin area (Fig 1, left). The two paraproteins were found to be IgG-κ, with H and L chains of homogenous molecular weights of 55,000 and 25,000 daltons, respectively, as disclosed by sodium dodecyl sulfate polyacrylamide gel electrophoresis on reduced purified paraprotein preparation (Fig 1, right). Levels of serum IgA and IgM were low (Fig 2), and no Bence Jones protein was found in serum or urine sam