Expression of programmed death 1 and programmed death-ligand 1 in T-lymphoblastic lymphoma/leukemia and their clinical significances / 白血病·淋巴瘤

ABSTRACT

Objective To study the expression of programmed death 1 (PD-1) and its ligand PD-L1 in T lymphoblastic lymphoma/leukemia (T-LBL/ALL), and to explore the relationship between their expression and clinical pathological factors and prognosis of the disease. Methods PD-L1 and PD-1 were detected in 56 patients with T-LBL/ALL by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR). Twenty patients with reactive hyperplasia were selected as the control group. Results Immunohistochemical results showed that PD-1 was not expressed in T-LBL/ALL tumor cells and 17.9 %(10/56) in tumor infiltrating immune cells,which was statistically significant compared with control group(18/20,90 %) (P= 0.000). The positive rates of PD-L1 protein were 37.5 % (21/56) and 10.0 % (2/20) in the experimental group and the control group, respectively and accordingly the difference between the two groups was statistically significant (P =0.044). Results of qRT-PCR showed that the relative expression levels of PD-L1 and PD-1 mRNA in 56 cases of T-LBL/ALL were significantly higher than those in control group (12.255 vs. 2.575, 37.990 vs. 3.615), and the differences were both statistically significant (both P < 0.05). Univariate analysis showed that age, PD-L1 protein and mRNA expression were closely correlated with prognosis(all P <0.05). Multivariate Cox regression analysis showed that overexpression of PD-L1 protein and age (≤25 years old)were independent prognostic risk factors(both P <0.05).Conclusion In T-LBL/ALL,PD-1/PD-L1 may be involved in the immune escape of the tumor,which is expected to be a new target for the treatment of diseases.