ASSESSMENT OF PROGNOSTIC-SIGNIFICANCE OF CD95(FAS APO-1) ANTIGEN EXPRESSION ON THE CELLS OF PATIENTS WITH MYELODYSPLASTIC SYNDROME (MDS), ACUTE MYELOGENOUS LEUKEMIA (AML) AND CHRONIC MYELOGENOUS LEUKEMIA (CML)/

Aim. The expression of CD95(Fas/APO-1) antigen was studied on bone mar row cells of 19 MDS patients, peripheral blood blast cells of 15 acute myeloid leukemia (AML) patients, blast cells and granulocytes of 68 p atients with chronic myeloid leukemia (CML) - 24 in chronic, 9 in acce lerated phase and 35 in blastic crisis (BC) - by indirect surface immu nofluorescence assay using flow cytometry (FACScan, Becton Dickinson, USA). Results. CD95(Fas/APO-1) antigen was revealed on bone marrow cel ls of 8 out of 19 (36.8%) MDS patients; the percentage of antigen-posi tive cells was 38.1 +/- 19.2%; on 45.5 +/- 22.8% of cells in 6(45%) of 15 AML patients. Fas/APO-1 antigen was totally absent in CML chronic stage; its expression was found in 34%; (12 of 35) of out patients wit h CML BC on peripheral blood blasts and in 56% (5 of 9) on peripheral blast cells of CML patients in acceleration phase. Conclusion. The dat a on overall survival of CD95-positive MDS patients suggest that the p resence of Fas antigen is a favorable prognostic sign for patients wit h MDS. The patients from CD95-negative group represent a risk group bo th for survival and AML transformation. In CML BC group the survival d oes not depend upon Fas-antigen expression.