CD4 and systemic lupus erythematosus: In human LN patients, a substantial shrinkage of CD4+CD25high and CD4+CD25+FoxP3+ TReg cells was observed in the peripheral blood, and such reduction in TReg number was accompanied with lower serum TGF-β1 levels [83] Moreover, the increase of peripheral Th17 cells was coupled with a decrease in TReg in LN patients, suggesting that the importance of Th17/TReg imbalance in the pathogenesis of renal disease in SLE [84].