Lymphocyte subsets in normal human bone marrow harvested for routine clinical transplantation

Bone marrow and peripheral blood of 25 healthy bone marrow donors from our allogeneic bone marrow transplantation program were assessed for cell subsets bearing T11(CD2), T4(CD4), T8(CD8), B1(CD20) J5(CALLA, CD10), Mo1(CD11b), MY7(CD13). Mo2(CD14), MY9(CD33) and NKH-1 antigens. Bone marrow cell samples were taken for analysis at the start or at the end of the harvesting procedure of aspiration from the iliac crest. All samples were analysed on a flow cytometer at the lymphocyte window as obtained on the two-parameter (L90oLSxFALS) scatter diagram. There were no differences in the lymphocyte subset composition of bone marrow samples taken at the start or at the end of the harvesting procedure. In contrast to the majority of literature data, a high CD4/CD8 ratio was detected in bone marrow samples: it did not differ from that in the peripheral blood. The proportions of CD2 and CD4 T cell markers in the bone marrow correlated with those in the peripheral blood, thus further documenting a substantial bone marrow contamination with peripheral blood cells. A relatively large aspirate volume (4-5 ml) obtained from individual aspiration sites was identified as the only factor possibly accounting for the high-level contamination of bone marrow samples with peripheral blood. This conclusion was corroborated by low T cell proportions and low CD4/CD8 ratios found in the bone marrow washed from bone fragments and in bone marrow samples aspirated at first bone puncture in a volume of 1.0 ml. Taken together, these findings imply that less vigorous suction may decrease the number of T lymphocytes in bone marrow harvested for transplantation purposes.