CD4 and systemic lupus erythematosus: Many studies have identified that the expression of above-mentioned ncRNAs, such as miR-21, miR-155, miR-31, miR-29a, miR-126, miR-142-3p/5p, and miR-183C, as well as several newly discovered lncRNAs and circRNAs, are markedly altered in the CD4+ T cells or peripheral blood mononuclear cells (PBMCs) of SLE, and are involved in SLE development by directly or indirectly regulating the aberrant activation and differentiation of CD4+ T cells.