Down-regulation of MBD4 contributes to hypomethylation and overexpression of CD70 in CD4+ T cells in systemic lupus erythematosus

Background Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterized by lymphocytic infiltration and overproduction of autoantibodies, leading to significant morbidity and mortality. However, the pathogenesis of this disorder has not yet been completely elucidated. It has been reported that CD70, a B cell costimulatory molecule encoded by the gene TNFSF7 (tumor necrosis factor ligand superfamily member 7), is overexpressed in CD4+ T cells from patients with SLE due to the demethylation of its promoter. We aimed to investigate the expression patterns of MBD4 (methyl-CpG binding domain protein 4) in CD4+ T cells and its contribution to the pathogenesis of SLE by increasing CD70 expression through epigenetic regulation.