CD4 and systemic lupus erythematosus: Addition of CD4+CD25+CD127low UCB-Tregs to the proliferating SLE-PBMCs significantly decreased the secreted IP-10 levels to 1,068 ± 77 pg/ml at 3 days (p < 0.0001) and 1,340 ± 35 pg/ml IP-10 at 7 days (p < 0.0001, Figure 2C).