CD4 and neurosyphilis: An HIV viral load ≤ 400 copies/mm3 (OR = 0.20, 95 % CI 0.06‒0.65, p = 0.008) was an independently protective factor, while serum VDRL titer ≥ 1:32 (OR = 13.4, 95 % CI 1.6‒113.4, p = 0.017) and CD4 count ≤ 350 cells/mm3 (OR = 4.0, 95 % CI 1.23‒1289, p = 0.021) increased the risk for confirmed neurosyphilis.