The kinetics of immunoglobulin synthesis by pokeweed mitogen stimulated peripheral blood lymphocytes in multiple myeloma.

As a means of investigating the immunoglobulin (Ig) deficiency in multiple myeloma, the effects of pokeweed mitogen (PWM) on morphologic transformation and concomitant immunoglobulin synthesis and secretion kinetics were studied in peripheral blood lymphocytes (PBL) of normals and patients with myeloma. Lymphocyte Ig production kinetics, both in the unstimulated state and after five days of culture with PWM, were evaluated by 3H-leucine incorporation. B-lymphocytes were found to be decreased by EC3 rosetting in the myeloma patients studied. In addition their lymphocytes had a mean of 30% transformation compared to 53% for normals (P less than 0.005). After five days of mitogen stimulation in culture, myeloma PBL failed to show the rise in intracellular Ig production seen in normal PBL under similar conditions. Thus, myeloma patients were found to have decreased numbers of EC3 rosetting B-cells, decreased morphologic transformation rate in response to mitogenic stimulation, and failure to increase intracellular Ig after mitogenic stimulation. Possible etiologic mechanisms for the decreased Ig production are discussed.