OBJECTIVETo observe the relationship between macrophage proliferation and cell apoptosis in patients with myelodysplastic syndromes (MDS).

METHODSA double labelling method of immunohistochemistry (alkaline phosphatase anti-alkaline phosphatase, APAAP) and ISEL (DNA in situ end labelling) was used to detect the positive CD68 expression (macrophages) and apoptosis on cold plastic embedded bone marrow biopsy sections in 30 MDS cases. 12 cases of iron deficient diseases (IDA) were used as the control.

RESULTS(1) The number of CD68 positive cells in MDS were higher than that in controls (29.2 +/- 33.0/mm(2) bone marrow tissue vs 21.2 +/- 16.7/mm(2)) (P > 0.05); (2) The number of apoptotic cells in MDS group was much higher than that in the controls (71.5 +/- 70.9/mm(2) vs 37.3 +/- 23.0/mm(2), P < 0.05); (3) The number of CD68 expression (35.5 +/- 37.0/mm(2)) and apoptosis (90.7 +/- 74.6/mm(2)) in less advanced MDS were much higher than that in advanced MDS group (14.6 +/- 11.7/mm(2) and 26.8 +/- 33.1/mm(2), P < 0.05 and < 0.01 respectively); (4) CD68 expression showed an obvious positive correlation to apoptosis in MDS cases (r = 0.83, P < 0.001); (5) CD68 positive cells did not show location correlation to apoptotic cells; (6) CD 68 positive cells in MDS showed simultaneous apoptosis.

CONCLUSIONSOver-apoptosis existed in MDS. Less advanced group has a higher ratio of apoptosis than in advanced group. The correlation between macrophages and apoptosis indicates the participation of TNFalpha in apoptosis-induction during MDS development.