ER antagonists saved DNMT1 and DNA hypomethylation down-regulated by estrogen, suggesting that estrogen seemed to play an important role in systemic lupus erythematosus development by regulating DNA hypomethylation.394 The decrease of DNA methylation at the X promoter site may lead to dose abnormality of X-linked genes in immune cells. This evidence concerns the gene DNMT1 and systemic lupus erythematosus.