IFNA1 and systemic sclerosis: IFN appears to be the main target of tofacitinib in SSc, both in keratinocytes and fibroblasts, including the 2 major subsets: SFRP2 fibroblasts, progenitors of myofibroblasts, and MYOC/CCL19 fibroblasts, which include adventitial fibroblasts.