CD4 and systemic lupus erythematosus: Specifically, miRNA-148a and miRNA-21 were robustly up-regulated in CD4+ T cells from SLE patients lupus-prone MRL/lpr mice, giving rise to DNA hypomethylation via suppressing DNMT1 expression;223 and miRNA-126 inhibited DNA methylation in CD4+ T cells of SLE patients by binding to the 3’ untranslated region (3’ UTR) of DNMT1.179 In addition, defective ERK pathway in T cells negatively affected DNMT1 expression and enhanced the development of anti-dsDNA antibodies in transgenic mice,228 suggesting the involvement of suppressed ERK signaling in priming DNA hypomethylation among SLE carriers.