TGFB1 and asthma: However, as some studies have demonstrated a tissue-protective role of IL-22 in terms of reducing the expression of proinflammatory cytokines such as IFN-γ [35] and enhancing barrier function [36], it was important to evaluate the impact of IL-22 stimulation on airway epithelial cells, both alone and in the context of stimulation with TGF-β1, a cytokine that is closely associated with severe asthma and tissue remodeling due to its role in the induction of EMT.