075 Cellular subsets and signaling pathways of IgA vasculitis revealed by single-cell RNA sequencing

IgA vasculitis (IgAV) is a systemic, immune complex–mediated, small-vessel leukocytoclastic vasculitis. In the cutaneous tissue, it characterized by nonthrombocytopenic palpable purpura. Increasing evidence suggests importance of host immunity in its contribution to IgAV. However, molecular mechanisms tissue damage IgAV remain largely unknown. We performed single-cell RNA sequencing on biopsied skin from one and two healthy control individuals reveal transcriptomic changes stromal/immune cells Stromal such as CXCL14+ fibroblasts MAP3K8+ lymphatic vessel endothelial were enriched lesion, suggesting their role cell activation or recruitment pathogenesis The relative number Th17 increased lesion. Upregulated genes TNF TGFB1 regulatory T CXCL8 monocytes. Inflammatory pathways, including IL-17 signaling, cells. As was reported positively correlate with clinical severity IgAV, our results suggest contributory monocytes signaling Th17, respectively, may explain accumulation neutrophils Altogether, we systematically analyzed events focusing stromal By uncovering distinct subpopulations inflammatory functional properties microenvironment, speculate cell-driven TNF/CXCL8 gene signature highly associated lesion