IL4 and tuberculosis: Figure 7 shows a decline in the mean regulatory T cell frequency with an increasing mean IFN-γ/IL-4 cytokine ratio in both CD4+ and CD8+ T cells during the intensive phase of TB treatment. A significant negative correlation between CD25hi FoxP3+ CD4+ T cells and IFN-γ/IL-4 cytokine ratios was observed for CD4+ T cells (Spearman r = -0.47, P = 0.0032) and CD8+ T cells (Spearman r = -0.34, P = 0.0378).