[Upregulated PD-1 on CD8+T cells is positively correlated with activation of T cells during HIV-1 infection].

Objective To investigate the expressions of programmed death-1 (PD-1), CD38, human leukocyte antigen DR (HLA-DR) and anligen KI-67(ki67) on CD8+ T cells, and the correlation between PD-1/PD-L1 pathway and activation, immunodepletion during HIV-1 infection. Methods Peripheral blood mononuclear cells were isolated by density gradient centrifugation from 87 HIV-1 patients and 22 healthy controls. The expression levels of PD-1, CD38, HLA-DR and ki67 on CD8+T cells were detected by flow cytometry. Furthermore, we evaluated the production of interferon-γ (IFN-γ) and tumor necrosis factor α (TNF-α) in CD8+ T cells by blocking PD-1/PD-L1 pathway in the presence of PD-L1 mAb. Results Compared with healthy controls, HIV-1 infection resulted in a significant increase in PD-1 expression on CD8+T cells. Correlation analysis showed that PD-1 expression on CD8+T cell was positively associated with HIV-1 viral loading (VL) and negatively associated with the number of CD4+T cells. Furthermore, PD-1 expression was positively correlated with CD38 and HLA-DR expressions on CD8+T cells in HIV-1 infected patients. There was no association between PD-1 and ki67 expression on CD8+T cells in HIV-1 infected patients. Blockage of the PD-1/PD-L1 pathway increased TNF-α and IFN-γ production in CD8+T cells. Conclusion PD-1 expression on CD8+T cells is significantly upregulated during HIV-1 infection. PD-1 expression is correlated with CD8+T cell inhibition, immunodepletion and disease progression. Moreover, the blockage of PD-1/PD-L1 pathway can restore the function of CD8+T cells in HIV-1 patients.