TLR8 signaling induces inflammatory cytokines and IFN-I–driven response in pDCs of patients with SSc. (A–F) Purified pDCs from SSc patients (n = 4) were stimulated with ORN-8L, or left Unstim for 6 h. The RNA was harvested for RNA-seq. (A) PCA of transcriptome in Unstim or TLR8L-stimulated SSc pDCs. (B) Volcano plot comparing gene expression between TLR8L-stimulated and Unstim SSc pDCs. IFN-Is, ISGs, cytokines, and other upregulated genes are labeled in red, purple, green, and grey, respectively. Genes with down-, not significant (NS), and upregulation are shaped by a triangle, square, and circle, respectively. (C and D) Heatmap (LogCPM) comparing TLR8L-stimulated and Unstim SSc pDCs of differentially expressed (C) IFN-Is and (D) inflammatory cytokines with a threshold at Log₂FC > 1 and adjusted P value <0.05. (E) Gene set enrichment of Reactome subset of the MSigDB canonical pathways collection of differentially expressed genes of TLR8L versus Unstim condition. (F) Gene set enrichment analysis of genes correlated with top three upregulated pathways by TLR8L stimulation.