IS APOPTOSIS A MASSIVE PROCESS IN MYELODYSPLASTIC SYNDROMES

We looked for increased apoptosis in fresh bone marrow aspirates in 40 cases of myelodysplastic syndrome (MDS), by detection of DNA fragment ation using TdT incorporation of nucleotides on 3' ends of DNA (TUNEL technique). No DNA laddering was seen. In six cases (15%) the TUNEL te chnique showed a moderate increase in the percentage of apoptotic cell s (2 . 5-5% in comparison with <2% in controls). In seven of the 34 pa tients with normal findings by TUNEL analysis, apoptosis was reanalyse d after short-term (18 h) bone marrow culture without inducers of apop tosis. Increased apoptosis was shown in four of the seven cases by mor phological analysis and/or the TUNEL technique. Increased apoptosis pr edominated on erythroblasts in three of them. The percentage of apopto tic cells, however, was <40% in all samples. Our findings suggest that increased apoptosis can be detected in one half of MDS cases after ce ll culture. Furthermore, the precise relationship between increased ap optosis of myeloid precursors and cytopenias will have to be more prec isely explored in MDS.