003 Interleukin (IL)-26 drives pathogenic IL-17A responses through a TH17-keratinocyte crosstalk

Interleukin (IL)-26 is a TH17 cytokine with known antimicrobial and pro-inflammatory functions highly expressed in tissues of TH17-mediated inflammatory diseases including psoriasis. However, the expression IL-26 respect to IL-17A its precise function context pathogenic responses are still unclear. In this study, we used flow cytometry-based fluorescent situ hybridization blood cells along single-cell spatial transcriptomics psoriatic skin lesions analyze dynamic regulation cells. We show that contain large population IL-26-producing do not produce IL-17A. Unlike IL-17A-producing cells, these develop at early stages differentiation require TGF-β. when exposed TGF-β, transition into IL-17 producers, process also observed lesions, where TGF-β by basal keratinocytes close vicinity T cell-derived was able induce themselves, suggesting mechanism which control via IL-26. Thus, our study identifies as an stage can further differentiate producing upon infiltration paracrine loop involving