IRF7 and systemic sclerosis: Studies on SSc plasmacytoid dendritic cells (pDCs), specialised antigen-presenting cells that may quickly release a large amount of type I IFN upon activation, were motivated by the distinctive type I IFN signature discovered in SSc.8 Most of our SSc subjects had hypomethylation in the IRF7 promoter region, consequently leading to its increased mRNA expression.