Abnormal function of B lymphocytes from peripheral blood of multiple myeloma patients. Lack of correlation between the number of cells potentially able to secrete immunoglobulin M and serum immunoglobulin M levels.

Abstract

Multiple myeloma patients are deficient in normal polyclonal serum immunoglobulins. To determine the reasons for this decrease, we quantitated and compared the number of surface IgM+ B lymphocytes, and the number of B cells susceptible to transformation by Epstein-Barr virus (EBV) with the con- centration of IgM in serum. Serum IgM levels varied consid- erably in individual patients, temporally shifting from unde- tectable to normal amounts and then dropping again to unde- tectable levels. A transient rise to normal serum IgM concentrations was seen in 42% of patients assessed at two or more time points.