The Distribution of Lymphocytes with T- and B-Cell Surface Markers in Human Bone Marrow

Abstract

Abstract This study demonstrates that lymphocyte subpopulations are distributed differently in peripheral blood and bone narrow. The proportion of T (thymus-dependent) and B (bone marrow-derived) lymphocytes was simultaneously assayed in the peripheral blood and bone marrow of children with acute lymphocytic leukemia (ALL) in continuous remission for 3 to 8 years who had received no therapy for 1 month to 5 years. T cells were identified by spontaneous rosette formation with sheep erythrocytes (RFL) and B cells by immunofluorescence of surface immunoglobulins. Most bone marrow lymphocytes carried neither B- nor T-cell surface markers. These markers were not detected in 78% of bone marrow lymphocytes and in 39% of peripheral blood lymphocytes. In a majority of these children the proportions of T and B lymphocytes were different in blood and bone marrow. Percentages of RFL and of lymphocytes bearing IgG were greater in blood than in bone marrow in 95% of the patients assayed. In contrast, the proportion of IgM-bearing lymphocytes in the bone marrow of 65% of the children was equal to or greater than in their peripheral blood. In the bone marrow the average ratio of lymphocytes bearing IgG to lymphocytes bearing IgM was 1:5 while it was 1:1 in the peripheral blood. Similar results were obtained when the proportion of T and B lymphocytes were analyzed in a group of nine children in remission who had received no therapy for more than 1 year and who were normal as assayed by several clinical, hematologic and immunologic criteria. Thus, we conclude that a low proportion of T cells and IgG-bearing lymphocytes and a predominance of B lymphocytes with IgM receptors represent the physiologic distribution of lymphocytes in human bone marrow.