Peng Z, et al. – In this study, researchers investigate explore interleukin (IL)–9 plays a role in the development of Vogt–Koyanagi–Harada (VKH) disease. These outcomes propose that IL–9 is involved in the pathogenesis of VKH disease and that IL–9 could also enhance the inflammatory response by increasing the secretion of IL–17, an established proinflammatory cytokine in VKH disease. Manipulation of IL–9 could represent a novel alternative for the treatment of VKH disease.