Amgen’s AMG-592, an IL-2 mutein with increased regulatory T cell selectivity, is in phase I/II trials in systemic lupus erythematosus and graft-versus-host disease, which also showed enhanced Treg cell expansion after low-dose IL-2 infusion in patients with SLE and type 1 diabetes (76) However, the limitations of IL-2 therapy include its short half-life, the necessity for repeated injections, and the potential for anti-drug immune responses. This evidence concerns the gene IL2 and graft versus host disease.