IFNG and infection: In general, TB diseased children had significantly higher background IFN-γ responses (whole blood stimulated with medium alone) compared to the other children without TB disease (irrespective of their infection status) (medium (IQR) 52.6 (42.0–78.4) pg/mL versus 18.6 (0.0–41.7) pg/mL, P = 0.0003) (Fig. 2).