PD‐1 expression on the surface of peripheral blood CD4+ T cell and its association with the prognosis of patients with diffuse large B‐cell lymphoma

The aim of the study was to investigate the relationship between PD-1 expression on the surface of CD4+ T cells and prognosis of patients with diffuse large B-cell lymphoma (DLBCL). Sixty patients who were newly diagnosed with DLBCL and 39 healthy controls were enrolled. In CD4+ T cells of DLBCL patients, the median MFI of PD-1 were 541.5 (range: 348.25-758.75), significantly higher than 250 (range: 211-326) in healthy controls (P < 0.001). The ZAP70, PI3K, and NFAT mRNA expression levels of patients were 0.47, 0.47, and 0.62 times, respectively, of those of the healthy controls (P < 0.05). In patients with the percentage of PD-1 on CD4+ T cells ≥30.25%, their EFS and OS were significantly lower than patients with PD-1+ CD4+ T cells <30.25% (P < 0.05). The possible explanation is that high PD-1 expression on CD4+ cells of DLBCL patients may impair T-cell function and thus contribute to poor prognosis. There was no relationship between PD-1 surface expression on CD4+ T cells and PD-1 expression within the biopsy of tumor microenvironments from DLBCL patients.