IFNG and tuberculosis: Within the CD4-positive lymphocytes, the percentage of Th1 cells, defined as lymphocytes positive for both CD4 and IFN-γ, was comparable between the two groups (21.1% vs. 18.0%, p = 0.686) while the percentage of Th2 cells, defined as those positive for both CD4 and IL-4, was higher in the TB group (0.83% vs. 0.51%, p = 0.041) (Fig. 1).