IL2 and chronic graft versus host disease: Recent clinical trials using low-dose recombinant human IL2 (Proleukin, aldeskeukin) have shown preliminary success in selectively expanding Tregs in chronic graft-versus-host-disease (Koreth et al, 2011;, Hartemann et al, 2013;, Kennedy-Nasser et al, 2014) and in steroid-refractory moderate-to-severe systemic lupus erythematosus patients (von Spee-Mayer et al, 2016).