We examined the sociodemographic, including age, gender, nationality, marital status, partner HIV status, education, number of sexual partners, probable transmission route of HIV and syphilis infections, years of HIV seropositivity, clinical stage of syphilis and HIV/AIDS, use of ART and laboratory parameters such as results of CD4 +  T lymphocyte count and HIV viral load, quantative venereal diseases laboratory (VDRL) and T. Pallidum haemagglutination assay (TPHA) results and neurosyphilis association. This evidence concerns the gene CD4 and sexually transmitted disease.