CD4 and systemic lupus erythematosus: Co-culture of HD-PBMCs or SLE-PBMCs with CD4+CD25+CD127low UCB-Tregs increased IL-10 production on day 3 (7,995 ± 182 pg/ml and 7,802 ± 372 pg/ml, respectively) and day 7 (8,086 ± 86 pg/ml and 6,466 ± 152 pg/ml) (two-way ANOVA p < 0.0001).