OBJECTIVETo investigate the expression of apoptosis receptor FAS (CD95) and apoptosis related protein Bcl-2 and Bax in CD34 positive bone marrow cells of the patients with polycythemia vera (PV).

METHODSThe expressions of apoptosis receptor FAS (CD95) and apoptosis related protein Bcl-2 and Bax in bone marrow CD34(+) cells from 21 PV patients, 8 essential thrombocythemia (ET) and 11 normal persons were assessed by bicolor flow cytometry (FCM), and the expressions of Bcl-2 and Bax mRNA were assessed by RT-PCR, and their correlation was analysed.

RESULTSThere was no difference between the expressions of CD95 in CD34(+) bone marrow cells of PV patients (42.65 +/- 15.56)%, and that of ET patients (45.31 +/- 17.62)% and of normal person (37.55 +/- 15.19)% (P > 0.05). There was no difference between the expression of Bax in CD34(+) bone marrow cells of PV patients (35.83 +/- 9.33)% and of normal persons (41.65 +/- 9.04)% (P > 0.05). The expression of Bcl-2 in CD34(+) bone marrow cells of PV patients (79.35 +/- 14.43)% was significantly higher than that of normal controls (55.84 +/- 13.43)% (P < 0.01). The ratio of Bax/Bcl-2 of PV patients (0.47 +/- 0.14) was significantly lower than that in normal controls (0.76 +/- 0.24) (P < 0.01). The expression of Bcl-2 mRNA in PV patients' bone marrow hematopoietic cells was higher than that of normal controls (P < 0.01). There was no difference between the expression of Bax mRNA in bone marrow hematopoietic cells of PV patients and that of normal controls. Bcl-2 expression was negatively correlated with Annexin V expression in CD34(+) bone marrow cells of PV patients.

CONCLUSIONOver-expression of Bcl-2, one of anti-apoptosis genes, in CD34(+) bone marrow cells might be involved in the lower apoptosis of PV patients.