In QFT-negative CCs, helminth infection resulted in decreased frequency of IFN-γ+CD4+ T cells in unstimulated, PPD as well as SEB stimulated PBMCs compared to helminth negative QFT-negative CCs, and Ascaris, S. mansoni, and hookworm infections all showed a similar impact with more than a 50% reduction. This evidence concerns the gene CD4 and helminthiasis.