[Expression of Fas, FasL and Bcl-2 and apoptosis of bone marrow CD34+ cells in patients with myelodysplastic syndrome].

In order to observe the expression of Fas, FasL and Bcl-2 and apoptosis of bone marrow CD34(+) cells in patients with myelodysplastic syndrome (MDS), and to explore the relation between the expression of these antigens and apoptosis, the expression of Fas, FasL and Bcl-2 and apoptosis of bone marrow CD34(+) cell were evaluated by flow cytometry in 26 patients with MDS including 9 cases of refactory anemia (RA), 1 case of RA with ringed sideroblasts (RAS), 9 cases of RA with excess blasts (RAEB) and 7 cases of RAEB in transformation (RAEB-t), 10 patients with acute myeloid leukemia (AML) and 6 control patients with normal bone marrow. The results showed that the expression of Fas and FasL of CD34(+) cells significantly increased in all types of MDS patients compared with control group (P < 0.01). The expression of Bcl-2 on CD34(+) cells in RAEB and RAEB-t patients was much higher as compared with that in control group (P < 0.01), but there was no significant difference between RA/RAS patients and control group (P > 0.05). The expression rates of Fas on CD34(+) cells were almost identical in all kinds of MDS, but there was significant difference on the expression of Bcl-2 (RA/RAS < RAEB < RAEB-t). Apoptosis of CD34(+) cells significantly increased in RA/RAS and RAEB patients compared with control group (P < 0.01), but there was no difference between RAEB-t and control group. Moreover, apoptosis of CD34(+) cells in control much higher than that in AML group (P < 0.01). There was no correlation between the expression of Fas or FasL and apoptosis on CD34(+) cell of MDS patients. Nevertheless, there was a negative correlation between the expression of Bcl-2 and apoptosis. It is concluded that apoptosis of CD34(+) cells was affected by a lot of factors in MDS, in which Bcl-2 is an important factor of depressing apoptosis. During the progress from MDS to AML, apoptosis changes from overgoing to deficiency in CD34(+) cell.