Preliminary exploration of the association of CXCR6⁺T lymphocytes in T2D

Type 2 diabetes (T2D) is a metabolic disease, in which inflammation is a key factor. It has been well established that T cells play important role in antigen-driven immune disorders or immune defense, but were less discussed in inflammatory metabolic diseases. However, accumulating evidences suggest that CD186 (also known as CXCR6)-positive tissue infiltrating T cells might play a key role in inflammatory metabolic diseases. Here, as a preliminary and exploratory study, we detected the expression levels of CXCR6 on peripheral blood T-lymphocytes of human subjects of T2D. Additionally, the expression levels of CXCR6 in BSK-db/db mice, a murine T2D model, were also detected. Results showed that, compared with the healthy control group, T2D group had significantly reduced levels of CD4⁺CD45RO^-CD186⁺CD183^- T lymphocytes (Z = -3.988, P < 0.001) and CD8⁺CD45RO⁺CD186⁺CD183^- T lymphocytes (Z = -2.428, P = 0.035). CD4⁺CD45RO^-CD186⁺CD183^- T lymphocytes had an AUC area of 0.978 (0.93, 1.00), 88.9 % sensitivity, and 100.0 % specificity. Additionally, the sensitivity of CD8⁺CD45RO⁺CD186⁺CD183^- was 55.6 %, and the specificity was 100.0 %, with an AUC area of 0.747 (0.522, 0.972). The levels of CD8⁺CD186⁺ (t = -3.198, P = 0.015), CD8⁺CD44⁺CD186⁺ (t = -2.706, P = 0.030), and CD8⁺CD44^-CD186⁺ (t = -2.915, P = 0.022) in BSK-db/db mice were significantly lower than in BSK-db/db homologous control mice. Taken together, CXCR6⁺T cells might play a role in T2D, and has the potential to become a biomarker for T2D patients.