OBJECTIVETo investigate the relationship of PD-L1 expression with the clinical features and prognosis of patients with primary acute leukemia.

METHODSSixty patients with primary acute leukemia(AL) from January 2013 to May 2015 in our hospital were selected as AL group, while 40 healthy persons were selected as control group. The flow cytometry was used to detect the PD-L1 expression in serum, the clinical data were collected and the treatment and lethality in AL patients were traced; the therapeutic efficacy in AL patients with different expression level of PD-L1 was compared.

RESULTSThe expression rate of PD-L1(+) in primary AL patients was significantly higher than that in controls(P<0.05). There was no significant difference in age, sex, WBC count, Plt count, Hb level and blast ratio in bone marrow between PD-L1(+) and PD-L1(-) patients(>0.05). The complete remission rate in PD-L1(+) patients was all lower than that of the negative patients after 1 and 2 course of treatment,the difference was statistically significant (P<0.05); the death rate of PD-L1(+) patients was higher than that of PD-L1(-) patients after treatment, while the survival rate of PD-L1(+) patients was lower than that of PD-L1(-) patients, the difference between 2 groups was statistically significant (P<0.05); the expression rate of PD-L1(+) in patients with ALL was not significantly different from that in AML (>0.05). The short-term remission rate and long-term survival rate of PD-L1(+) patients were significantly lower than those of PD-L1(-) patients, while the long-term mortality was statistically significant higher than that of PD-L1(-) patients in ALL and AML patients(P<0.05).

CONCLUSIONThe positive expression rate of PD-L1 in the patients with acute leukemia is higher, providing an indication for the evaluation of treatment efficacy and prognosis of patients.