Its contribution to the output variability is balanced by four other parameters: p_eventCD4, the probability of CD4+ increase under viral suppression (7.7%); MortalityRateOnTreatment_3, the mortality rate while on ART, with CD4+ count between 50 and 100 cells/mm3 (6.5%); and the number of UIAI acts per month with the CD4+ count above 500 cells/mm3 (6.9%) and during the acute infection phase (6.4%). This evidence concerns the gene CD4 and infection.