The incidence was also significantly higher in patients exposed to an ART regimen containing ZDV (p <10−4), starting ART with a CD4 count <350 cells/mm3 (p <10−4), at clinical stage CDC 3 or WHO 4 (p <10−3) and in patients with neutropenia of grade 1 or 2 (p <10−4). This evidence concerns the gene CD4 and neutropenia.