Light chain isotype associated suppression of surface immunoglobulin expression on peripheral blood lymphocytes in myeloma during plateau phase.

Light chain isotype suppression in multiple myeloma has been reported in the plasma cells of the lamina propria of the gut (Leonard et al, 1979). In this paper we present further evidence of systemic suppression of the light chain isotype of the paraprotein expressed on normal peripheral blood lymphocytes in myeloma. Twenty patients with myeloma in plateau phase were monitored over 6 months for the expression of either kappa or lambda light chains on the surface of peripheral blood lymphocytes using monoclonal antibodies. The surface markers were analysed on an Ortho Spectrum III flow cytometer. Results of these studies indicate a selective suppression of the cells expressing the light chain isotype of the paraprotein in stable myeloma. Thus, in kappa myeloma there is a low kappa/lambda ratio and in lambda myeloma there is a high kappa/lambda ratio, and this suppression is lost with progressive disease.