CD4 and syphilis: CSF assessment is indicated in patients with: -clinical evidence of neurological, ocular, and auricular involvement, whatever the stage of the disease; tertiary syphilis (cardiovascular, gummatous). Some experts still recommend CSF assessment in ANS patients: HIV-positive patients with late syphilis and CD4 cells ≤ 350/mm3 and/or a serum VDRL/RPR titer >1:32; in those who have serological failure or are serofast; in those given alternative treatment for late syphilis.