Furthermore, compared to HIV-1-infected patients, AIDS patients had a higher level of blood viral load (40 vs. 21,366.5 copies/mL, p < 0.001) and tear viral load (0 vs. 20 copies/mL, p = 0.011), but a much lower CD4 + T cell count and CD4 +/CD8 + T cell count (542 vs. 75 cells/μL, 0.51 vs. 0.13, p < 0.001). Here, CD4 is linked to AIDS.