HAVCR2 and type 2 diabetes mellitus: L-15R mRNA relative levels in Tregs exposed to no stimulation, 10 ng/mL of IL-15 stimulation, or 100 ng/mL of IL-15 stimulation did not differ significantly between groups (p > 0.05, Figure 4A). mRNA expressions of immune checkpoint molecules, including CTLA-4, LAG-3, PD-1, and TIM-3, were significantly increased in the T2DM, CHB, and CHB + T2DM group compared with control group (p < 0.05).