[Expression and Significance of PD-1/PD-L1 in MDS Blast Cells, T Lymphocyte Cell Subsets and Treg Cells].

Objective: To investigate the expression and significance of PD-1/PD-L1 in MDS blast cells, T lymphocyte cell subsets and Treg cells.

Methods: Eighty-eight MDS patients and 19 AML patients were collectd as the study subjects, and Iron deficiency anemia and healthy bone marrow donors were used as control group. The expression of PD-1/PD-L1 in MDS/AML blast cells, T lymphocyte cell subsets and Treg cells was detected by flow cytometry, and the expression level of Th1/Th2/Th17-related cytokines in peripheral serum was detected.

Results: The expression of PD-1/PD-L1 in blast cells, T lymphocyte cell subsets and Treg cells in low risk MDS group were lower than that in control group, medium and high risk MDS group and AML group（all P < 0.01）, and Th1/Th17 type cytokines were dominant. The expression of PD-1/PD-L1 in blast cells, T lymphocyte cell subsets and Treg cells of intermediate and high risk MDS group and AML group were higher than that of control group and low risk MDS group (all P < 0.01), and Th2 type and Treg type (IL-10、TGF-β) cytokines were dominant. After treatment, the differences of PD-1/PD-L1 expression were not statisticatly significant in blast cells, T lymphocyte cell subsets and Treg cells between the MDS remission group and the control group (all P >0.05). The expression of PD-1/PD-L1 in blast cells, T lymphocyte cell subsets and Treg cells in MDS non-remission group were significantly higher than that in remission group and control group (all P < 0.01).

Conclusion: The high expression of PD-1/PD-L1, dominance of Treg (IL-10、TGF-β) and Th2-related cytokines and inhibition of effector T lymphocyte cells in patients with MDS is conducive to tumor cell proliferation and immune escape, which may promote the progression of MDS disease.