IL17A and tuberculosis: The results of our study are consistent with these findings; the median response of IL-17 in response to ESAT-6 was relatively lower in TB patients compared with ESAT-6 responsive TB contacts (S2) and the difference in responses between TB patients and the S2 spouses was emphasised by the ratio of IFN-γ/IL-17 in response to PPD with significantly higher median response in TB patients than the S2 spouses (P<0.01; Figure 4B).