Based on the aberrant expansion of NKG2D+CD4+ T cells and its negative correlation with Treg cells, we purified Treg cells from HCs and induced the NKG2DL ULBP1-3 expression by stimulation with SLE serum for 18 h in vitro (Fig. 3A). The gene discussed is CD4; the disease is systemic lupus erythematosus.