IL17A and dry eye syndrome: Research demonstrates that KC-derived S100A9 induces dendritic cells to produce IL-23, driving the IL-23/IL-17 axis, while IL-17A further stimulates KCs to express IL-25 (also termed IL-17E), which mediates proinflammatory phenotypes and hyperproliferation through signal transducer and activator of transcription (STAT) 3 activation [86].