Treg function in ADA-SCID patients after different treatments. (A) Representative autologous and allogeneic suppression assays for a PEG-ADA–treated patient compared with an HD. E* indicates effector cells stimulated with allogeneic accessory cells (APCs) and soluble anti-CD3. Percentages of suppression are indicated. Data are intraexperimental mean ± SD. (B) Representative autologous and allogeneic suppression assays for a GT-treated patient compared with an HD. Percentages of suppression are indicated. (C-D) Stimulated Tregs (Treg*) of the same PEG-ADA-treated (C) and GT-treated (D) patients with their respective HDs and reversion of Treg anergy by IL-2. (E-F) Summarized percentages for autologous (E) and allogeneic (F) suppression assays in PEG-ADA– and GT-treated patients compared with healthy controls. Data are interexperimental mean ± SD. ***P < .0005 (Mann-Whitney test). **P < .005 (Mann-Whitney test). *P < .05 (Mann-Whitney test).