It was found that MSCs downregulated the activation of 26 out of the 41 T cell subsets identified within CD4+, CD8+, CD4+CD8+, CD4−CD8−, and γδ T cells in SSc patients (HC: 29/42) and affected the polarization of 13 out of 58 T cell subsets in SSc patients (HC: 22/64). This evidence concerns the gene CD4 and systemic sclerosis.