Notably, the levels of HLA-DR + CD8+/CD8 + % in the HIV/syphilis co-infection group were substantially elevated compared to those in the HIV mono-infection group at 3, 6 months, 2, 4, and 6 years, with p values of 0.018, 0.014, 0.044, 0.027, and 0.004, respectively (Figure 1E). Here, CD8A is linked to syphilis.