[PD-1/PD-L1 expression and its implications in patients with chronic lymphocytic leukemia]

Objective: To observe the expression levels of PD-1/PD-L1 costimulatory molecules and explore the clinical significance in patients with chronic lymphocytic leukemia (CLL) . Methods: The expression of PD-1/PD-L1 in peripheral blood CD8(+) T cells, CD4(+)T cells, CD19(+)B, and dendrites cells (DC) was detected by flow cytometry in 57 CLL patients and 20 healthy controls. The correlations of PD-1/PD-L1 expression with disease stage, CD38 expression, ZAP-70 expression, chromosome karyotype abnormality and β(2)-MG expression were analyzed. Results: ①Compared with control, CLL patients, including 39 males and 18 females with the median age of (63.7±10.7) years, had no statistically significant difference in age and gender (P>0.05) . CLL patients had the higher PD-1/PD-L1 expression than healthy controls (P<0.05) . ②In Rai staging, the later the stage, the higher expression of PD-1/PD-L1 (P<0.05) . ③PD-1 expression in CD8(+)CD38(+) group (11 cases) was higher than that in CD8(+)CD38(-) group (46 cases) (P=0.004) , and CD8(+) poor prognosis chromosome group (14 cases) also had significant higher PD-1 expression than CD8(+)good prognosis chromosome group (28 cases) (P=0.004) . ④The expression of PD-L1 was higher in CD38(+)group, ZAP-70(+)group, and poor prognosis group, as compared to that in CD38(-)group (P=0.002) , in ZAP-70(-)group (P<0.001) , in good prognosis group (P=0.023) . There was no correlation between the expression of PD-1/PD-L1 and β(2)-MG (P>0.05) . Conclusion: This data reveals that PD-1/PD-L1 was highly expressed in CLL patients. Its expression levels were correlated with Rai stage, CD38, ZAP-70, chromosome karyotype, but not with β(2)-MG. PD-1/PD-L1 may be a prognostic factor in patients with CLL.