ESR1 and systemic lupus erythematosus: Besides, the times of HERV-E clone 4–1 mRNA upregulation were higher in CD4+ T cells from SLE patients than that of HCs when NFAT1 or ER-α was overexpressed (Fig. 4e and f), and the times of HERV-E clone 4–1 mRNA upregulation were higher in CD4+ T cells from HCs than that of SLE patients when 5-aza C was used (Fig. 4g).