Monoclonal proteins in chronic lymphocytic leukemia.

One hundred patients with chronic lymphocytic leukemia and a monoclonal protein in serum or urine were recognized during the period January 1971 to July 1984. IgG monoclonal proteins predominated, with the following distribution: IgG kappa 36% (0.36), IgG lambda 15% (0.15), IgM kappa 27% (0.27), IgM lambda 11% (0.11), IgA lambda 1% (0.01), and free monoclonal light chains in 10% (0.10) (kappa in 8% [0.08] and lambda in 2% [0.02]). The median concentration of M-protein was 1.0 g/dL (10 g/L) or less. The median survival (Kaplan-Meier) for the 100 patients after recognition of an M-protein was six years. The median survival was longer for patients with an IgG monoclonal protein (7.2 years) than for patients with an IgM monoclonal protein (5.2 years), although the difference was not significant. The authors found no important differences in patients with chronic lymphocytic leukemia, whether they had an IgG or an IgM monoclonal protein or a free monoclonal light chain.