CD4 and systemic lupus erythematosus: All-trans retinoic acid has been shown to increase the CD4+ and CD8+ regulatory T Cells, which have therapeutic potential in the treatment of SLE and other autoimmune diseases (78) Furthermore, a nucleosomal histone peptide could improve human CD8+CD25+FoxP3+ T cells to decrease the production of pathogenic autoantibody via TGF-β/ALK-5/pSmad 2/3 signaling pathway (41) (Table 2C).