A study by Kellar et al. failed to show IFN-γ response in culture-confirmed TB patients, but other cytokines, i.e., IL-2, IL-6, IL-8, IP-10, and MIP-1β showed greater responses to ESAT-6, CFP-10, and TB7.7 Mtb Ags, suggesting that other cytokines or chemokines are potentially useful for the diagnosis of TB [49]. This evidence concerns the gene IL2 and tuberculosis.