Among 128 (77.1 %) of the 166 asymptomatic patients which had CD4+ ≤ 350 cells/mm3 or VDRL titer ≥ 1:32, 15 (11.7 %) had confirmed neurosyphilis: 11 with CSF VDRL positive titers and 4 due to cytologic criteria. This evidence concerns the gene CD4 and neurosyphilis.