MBD2 and systemic lupus erythematosus: HERV-E clone 4–1 3’LTR could positively regulate MBD2 expression by acting as a ceRNA of MBD2 via miR-302d and HERV-E clone 4–1 3’LTR could induce DNA hypomethylation and IL-17 release via miR-302d/MBD2 in CD4+T cells of SLE.