Cell-surface immunoglobulins in chronic lymphocytic leukemia and allied disorders

Abstract

Immunoglobulin on the surface of peripheral blood lymphocytes from 57 patients with chronic lymphocytic leukemia (CLL) and allied disorders was investigated by fluorescence microscopy and correlated with circulating immunoglobulin. In 38 of 48 patients with CLL, the predominant surface immunoglobulin identified on peripheral blood lymphocytes was M (IgM) of either kappa or lambda light chain type. In five patients, the predominant surface protein was immunoglobulin G (IgG) of either kappa or lambda type. In three others, the lymphocyte surface immunoglobulin could not be definitely identified and in two, no surface immunoglobulin was detected. Circulating immunoglobulin levels, particularly IgM, were depressed in the majority of patients with CLL. In three subjects with IgM-bearing lymphocytes, the serum contained a circulating IgM M component and three of the five subjects with IgG-bearing cells, had a circulating IgG M component. In three patients with CLL, immunoglobulin disappeared from the cell surface with progression of the disorder, although neoplastic cells remained in the circulation. The amount of immunoglobulin on the surface of cells from patients with chronic lymphosarcoma cell leukemia was much greater than that on cells from patients with CLL, and the surface immunoglobulin pattern in hairy cell leukemia also appeared distinctive. Study of immunoglobulin on the surface of lymphocytes has helped to define the cellular origin and monoclonal nature of CLL, the source of circulating M components in this disease, and the relationship of CLL to other lymphoproliferative disorders. Although technically demanding, the study of surface immunoglobulin should prove useful in clinical medicine.