Combined studies of complement receptor and surface immunoglobulin-bearing cells and sheep erythrocyte rosette-forming cells in normal and leukemic human lymphocytes.

Human lymphocytes from normal peripheral blood, thymus, spleen, thoracic duct, and peripheral lymphocytes from patients with chronic lymphatic leukemia were studied for complement receptor sites (CRL), surface immunoglobulin (SIg), and for the ability to form rosettes with sheep erythrocytes (TRFC). The two B cell markers (CRL and SIg) were found to be in overlapping, but not totally identical populations, whereas cells that were able to form rosettes were found in a totally unrelated population of lymphocytes; TRFC is therefore probably a reliable marker for T cells. In peripheral blood 24% of lymphocytes had SIg, but only half of these were also CRL. Almost all of the non-SIg peripheral blood lymphocytes were TRFC. In the spleen and thoracic duct only a few lymphocytes were observed that had SIg and were not CRL. On the other hand, in two of three spleens studied 10-20% of cells were CRL that did not have SIg. In the thoracic duct all non-CRL that did not have SIg. In the thoracic duct all non-CRL, non-SIg cells were TRFC. In chronic lymphatic leukemia three findings were made: (a) The presence or absence of CRL was independent of the presence or absence of SIg so that in individuals whose cells were non-SIg. CRL were usually plentiful. (b) Leukemic cells were essentially negative for TRFC. (c) Leukemic cells reacted poorly with human C3 compared to mouse C3, EACmo detecting up to 20-fold more CRL than EAChu. This latter finding was in sharp contrast to normal CRL that reacted somewhat preferentially with EAChu. These data suggest that altered surface Ig receptors and complement receptors are present in chronic lymphatic leukemic cells. Since the cells obtained from all leukemic patients tested in this study had either the complement receptor or surface immunoglobulin in a high percentage of their cells and were essentially negative for TRFC, it is strongly suggested that leukemic lymphocytes are of B cell origin. The finding of lymphocytes with only one of the two B cell markers suggests that these markers are not uniformly present on all B cells and that depending on the source, one or the other may be deficient.