CD4 and systemic sclerosis: In FACS analysis, increases of Th17/CD4+ T cells in early SSc were found compared with late SSc (p < 0.001) and HC (p < 0.05). In RNA-seq, Treg genes were differentially expressed in early SSc compared with late SSc (False Discovery Rate < 0.05).Increases of “activated subpopulation” in Treg, calculated by deconvolution were found in early SSc compared with late SSc (p < 0.05) and HC (p < 0.05), and that was associated with OXPHOS pathway and TCR signaling.