CD4 and systemic lupus erythematosus: Next, we used flow cytometry to analyze the DDIT3 expression in immune cells in SLE patients and HC (Fig. S1) and found that there was no significant difference in the mean fluorescence intensity (MFI) of DDIT3 in CD4+ T cells, CD8+ T cells, regulatory T cells (Tregs), and monocytes between patients and HC (Fig. 1B).