Reduced Treg numbers have been positively correlated with disease activity in SLE patients and were associated with an impaired capacity of T cells to produce IL-2 (Humrich et al. 2010; Alcocer-Varela and Alarcon-Segovia 1982; Von Spee-Mayer et al. 2016), which is indispensable for peripheral Treg survival and expansion (Fontenot et al. 2005; D’Cruz and Klein 2005; Setoguchi et al. 2005). The gene discussed is IL2; the disease is systemic lupus erythematosus.