DNMT1 and systemic lupus erythematosus: Decreased global DNA methylation has been observed in immune cells from SLE patients [102], in PBMC and CD4+ T cells of psoriasis patients [42,103] whereas in Sjögren Syndrome, in epithelial cell of the salivary gland and minor salivary glands hypomethylation and reduced DNA methyltransferase (DNMT) level was observed [47,104].