QFT-GIT contains a TB antigen tube, whereas QFT-Plus contains two TB antigen tubes (TB1 and TB2): the TB1 antigen tube contains long peptides derived from ESAT-6 and CFP-10 (TB 7.7, which was included in the previous QFT-GIT version, has been removed) and is designed to induce a specific CD4 T-cell response; the TB2 antigen tube contains not only the long peptides of TB1 but also shorter peptides from ESAT-6 and CFP-10 to detect both CD4 and CD8 T-cell responses. This evidence concerns the gene CD4 and tuberculosis.