We demonstrated in this study that very low dose clinical grade IL‐2 (Proleukin) induces STAT‐5 phosphorylation selectively in CD4+CD25+CD127– Treg from blood and liver of patients with AILD and is accompanied not only by a series of phenotypic and functional changes, but also up‐regulates Bcl‐2 to support Treg survival. The gene discussed is BCL2; the disease is angioimmunoblastic T-cell lymphoma.