Immunoglobulins on the Surface of Neoplastic Lymphocytes

Abstract Peripheral lymphocytes from 25 patients with chronic lymphocytic leukemia (CLL) and three with chronic lymphosarcoma-cell leukemia, and lymph-node cells from three of four with lymphocytic lymphoma bore on their cell surface IgM, which was readily demonstrated with fluorescein-conjugated antiserums. The lymphosarcoma cell differed from the cell of CLL in possessing much more surface immunoglobulin. Light-chain analysis of the surface IgM showed that cells bore either kappa or lambda determinants, but not both, indicating the clonal nature of these neoplasms. The serum of four leukemic patients was also found to contain small amounts of IgM M-components. Since the B lymphocyte (bone-marrow-derived) of laboratory animals bears large amounts of surface immunoglobulin and the T lymphocyte (thymus processed) does not, the findings favor the B-cell origin of these leukemic cells. A less likely possibility is that the CLL lymphocyte is a derepressed T cell.