CD8A and systemic sclerosis: Besides Th2, several other T cell subsets are implicated in the pathogenesis of SSc, such as CD4+CD8+ T cells, CD8+ T cells, cytotoxic CD4+ T cells, follicular helper T (Tfh) cells, Treg, Th17, Th9, Th22, γδ T cells, and angiogenic T cells (Tang) cells, which are identified as CD3+CD31+CXCR4+.