Comparison of interferon-gamma production between TB1 and TB2 tubes of QuantiFERON-TB Gold Plus: a meta-analysis

Objectives: CD8 T-cells play an important role in interferon-gamma (IFN-gamma) production as a host defense against tuberculosis (TB) infection. Therefore, QuantiFERON-TB Gold Plus (QFT-Plus) was developed by adding a TB2 tube beside the TB1 tube. This study aimed to compare and analyze the difference in IFN-gamma production between the two tubes in general and specific populations. Content: PubMed, Web of Science, and EBSCO were searched for studies reporting IFN-gamma production levels in the TB1 and TB2 tubes. Statistical analysis was performed using RevMan 5.3. Summary: A total of 17 studies met the inclusion criteria. The IFN-gamma production in the TB2 tube was statistically higher than that in the TB1 tube (mean difference (MD)=0.02, 95 % confidence interval (95 % CI): 0.01-0.03). Further subgroup analysis in specific populations revealed that the MD of IFN-gamma production between the TB2 and TB1 tubes was significantly higher in active TB subjects than in latent TB infection (LTBI) subjects (MD=1.13, 95 % CI: 0.49-1.77, and MD=0.30, 95 % CI: 0.00-0.60, respectively). A similar finding was found in immune-mediated inflammatory disease subjects, but not statistically significant. Interestingly, IFN-gamma production capacity was lower in active TB subjects than in LTBI subjects in each of the TB1 and TB2 tubes. Outlook: This study is the first to systematically compare IFN-gamma production between the TB1 and TB2 tubes. The IFN-gamma production was higher in the TB2 tube than in the TB1 tube, representing the host's CD8 T-cell response magnitude to TB infection.