The negative impact of CD4+ cell count <200 cells/mm3 on PCS is likely attributable to the greater burden of the disease associated with CD4+ cell counts <200 cells/mm3, including the fact these individuals are more likely to have had HIV-infection for a longer period, be older and may have more associated comorbidities as was the case in our cohort (data not shown). This evidence concerns the gene CD4 and HIV infectious disease.