CD4 and graft versus host disease: In a model of GVHD in mice, administration of IL‐2 antibody complexes and rapamycin was synergic to CD8+FOXP3+ Tregs increase up to 30‐fold whereas CD4+FOXP3+ Tregs increased 4‐fold.32 In other studies, in patients treated with low doses of IL‐2, CD8+ Tregs were not reported,108, 109 although only a few of them described extensive immunophenotyping.109