CD28 and systemic lupus erythematosus: After stimulation with CD3/CD28 beads and IL-2 for 3 days, an increase in the percentage of the CD4+CD25+CD127low-expressing Treg cells was observed in SLE-PBMCs, whereas their distribution rearrangement was observed in CD4+CD25+CD127low UCB-Tregs where an overall decrease in the CD8+ only expressing T cells with an actual increase in the CD4+ and CD8+ co-expressing cells was observed in UCB-Tregs : SLE-PBMCs co-culture.