At baseline, education, prior psychiatric illness and co-existing moderate depression (PHQ-9 > 9), but not HIV-specific parameters (HIV-1 RNA level and CD4+ T-lymphocytes nadir) [2, 4, 21] or co-infections (syphilis and HCV) [22, 23], tended to be independently associated with poor IHDS performance. This evidence concerns the gene CD4 and syphilis.