FLOW CYTOMETRIC MEASUREMENT OF DNA S-PHASE IN HUMAN BONE-MARROW CELLS- CORRECTING FOR PERIPHERAL-BLOOD CONTAMINATION

The relationship between bone marrow (BM) cells with S-phase DNA conte nt and the amount of peripheral blood contamination estimated as perce ntage lymphocytes + monocytes (L + MO) present in BM samples has been investigated in a total of 136 BM aspirates and biopsy expellates from 35 hematologically healthy individuals. A significant negative correl ation was demonstrated between total, erythroid and myeloid BM cells i n S-phase and the percentage of Lf MO in the aspirates (r = 0.84, 0.57 and 0.49, respectively; p < 0.0001). Based on the equation of the slo pe of the regression line, a correction formula adjusting the measured value of BM cells in S-phase to varying amounts of L + MO percentage has been worked out for the total and erythroid BM cells. In contrast, highly proliferating myelomonocytic cells and CD34(+) cells did not s how any significant correlation between cells in S-phase and percentag e L + MO, indicating that peripheral blood contamination of BM aspirat es is not a problem regarding kinetic investigations of these cells. I n conclusion, the described flow cytometric method of analysing BM asp irates estimates the degree of peripheral blood contamination, as well as make possible a correct estimation of the DNA synthesis of several BM populations. The method is especially applicable when frequent BM sampling is required.