IL17A and interstitial lung disease: Interestingly, a study on IL17-23 pathway observed that IL-17 and IL-23 were reduced and IL-21 was elevated in SSc as compared to sera of healthy controls.11 However, in exhaled breath of SSc-ILD patients, there was increased TNF-α, TGF-β, IL-17 and IL-23; possibly implying a possible local role of this axis in the pathogenesis of fibrosis.12