LAG3 and PD1 Regulate CD8+ T Cell in Diffuse Large B-cell Lymphoma Patients

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is a clinically and genetically heterogeneous lymphoid malignancy. The unsatisfactory outcome for refractory patients has prompted efforts to explore new therapeutic approaches for DLBCL. However, the mechanisms involved in treatment associated with immune checkpoints remain unclear. This study is aimed at investigating the potential roles of programmed cell death protein 1 (PD1) and lymphocyte activation gene 3 (LAG3) in CD8+ T cells for treatment in DLBCL. METHODS: Utilizing flow cytometry, we examined the content of T cells, the levels of cytokines, and the expression of PD1 and LAG3 in patients with DLBCL as well as in healthy controls. Levels of cytokines in CD8+ T cells from DLBCL patients before and after treatment were compared by blocking of PD1 and LAG3 in magnetic bead-sorted CD8+ T cells. RESULTS: We found that the proportion of CD4+ T cells and CD8+ T cells was increased in DLBCL patients after treatment. The levels of cytokines trended toward those of healthy controls in treatment. PD1 (+), LAG3 (+), or PD1 (+) LAG3 (+) were all expressed in lower amounts in CD4+ T cells and CD8+ T cells after treatment than in untreated DLBCL patients. In addition, blockade of PD1 and LAG3 in sorted CD8+ T cells markedly inhibited cytokine production in response to treatment. CONCLUSION: PD1 and LAG3 in CD8+ T cells may be important targets of therapy and play therapeutic role in patients with DLBCL.