The cumulative data showed a significantly higher IL-2+ and IL-4/IL-5/IL-13+Mtb-specific memory CD4 T-cell frequencies in TB patients from TZ compared with TB patients from SA (P<0.05), while the frequencies of IFN-γ and TNF-α producing Mtb-specific memory CD4 T cells were not significantly different between TB patients from TZ and from SA (P>0.05; Fig 1B). This evidence concerns the gene IFNG and tuberculosis.