Immunoregulation and prognosis in myeloma.

In patients in the plateau phase of myeloma, expression of the light-chain isotype concordant with the malignant paraprotein on peripheral-blood lymphocytes is suppressed. This light-chain-isotype suppression (LCIS) is lost when the disease becomes progressive. LCIS is identified by quantifying kappa and lambda cells in peripheral blood in an indirect immunofluorescence assay. In 27 patients presenting with myeloma, the prognosis was significantly better for patients with LCIS at presentation than for those without. Bone-marrow mononuclear cells, studied in 7 patients with myeloma and LCIS in peripheral blood, did not show LCIS.