CD4 and systemic lupus erythematosus: As shown Figure 2A, high levels of soluble IL-10 were detected in CD4+CD25+CD127low UCB-Tregs supernatant at days 3 and 7 (11,169 ± 118 pg/ml and 8,019 ± 221 pg/ml, respectively), whereas minimal IL-10 secretion was detected in HD-PBMC- or SLE-PBMC-alone supernatant at day 3 (223 ± 130 pg/ml and 1,010 ± 38 pg/ml, respectively) and day 7 (494 ± 59 pg/ml and 1,391 ± 111 pg/ml, respectively).