The older sibling received marrow from a matched related donor and is alive and stable at 5 years of follow-up, with sustained donor chimerism and resolution of autoimmunity, complicated only by transient mild chronic graft-versus-host disease.<h4>Discussion</h4>The two cases expand the mutational and clinical spectrum of <i>IL2RA</i> deficiency and provide long-term evidence that HSCT can cure immune dysregulation and susceptibility to infection. This evidence concerns the gene IL2RA and infection.