Objective  To investigate the expression of adenosine A2A receptor (A2aR) in tumor tissue and on the surface of CD8⁺T cells and its correlation with clinicopathologic characteristics and prognosis of patients with diffuse large B cell lymphoma (DLBCL).

  Methods  A retrospective analysis was performed on the clinicopathologic characteristics of 72 newly diagnosed patients at Tianjin Medical University Cancer Institute and Hospital from January 2010 to December 2015. The expression of A2aR and CD8 was evaluated by multiple immunohistochemical staining assays. The associations between the expression of A2aR in tumor tissue and on the surface of CD8⁺T cells and clinicopathologic characteristics were then assessed using the Chi-square test. The Kaplan-Meier method was used for the analysis of survival.

  Results  The positive rate of A2aR total expression in DLBCL was 41.7% (30/72), which was associated with several clinicopathologic characteristics including stage, International Prognostic Index (IPI) score, Ki-67 index score, β-2 microglobulin (MG), and B symptoms (P < 0.05). Survival analysis showed that patients with positive A2aR expression had poorer overall survival (OS) than those with negative A2aR expression (P < 0.05). The rate of positive A2aR expression on the surface of CD8⁺T cells was 22.2% (16/58). The expression of A2aR on the surface of CD8⁺T cells was correlated with several clinicopathologic characteristics including stage, IPI, Ki-67, β2-MG, lactate dehydrogenase levels (LDH), extranodal involvement, and B symptoms (P < 0.05). Survival analysis showed that patients with A2aR⁺CD8⁺ status had significantly poorer OS than those with A2aR^-CD8⁺ status (P < 0.001).

  Conclusions  Positive expression of A2aR in tumor tissue and on the surface of CD8⁺T cells is significantly correlated with clinicopathologic characteristics and prognosis of patients with DLBCL. The detection of A2aR on the surface of CD8⁺T cells is superior to evaluate the prognosis of patients with DLBCL.