TSLP and asthma: IL-22 could induce antimicrobial protein, Reg3γ, produced by signal transducer and activator of transcription (STAT)3 activation, which then reduced the secretion of IL-33 and thymic stromal lymphopoietin (TSLP) of the lung epithelial cells, and inhibited the eosinophilic airway inflammation [20]; IL-22 could also suppress proinflammatory cytokine interferon-γ (IFN-γ)-induced secretion of proinflammatory chemokines in human bronchial epithelial cells in vitro [21], demonstrating that it may have a potential protective role in asthma.