On this matter, no significant differences were obtained on the IFN-γ released in QFN-G-IT or SFCs (overall RD1 response) counted in T-SPOT.TB between unexposed and individuals exposed to SHS with LTBI [median and IQR for IFN-γ released in QFN-G-IT (IU/mL): 2.29 (0.96–14.58) for unexposed and 3.55 (1.02–9.57) for SHS; for SFCs in T-SPOT.TB: 46.00 (20.00–94.00) for unexposed and 42.50 (21.00–82.50) for SHS]. This evidence concerns the gene IFNG and tuberculosis.