Enhanced suppressive function of regulatory T cells from patients with immune-mediated diseases following successful ex vivo expansion

Recent studies and our current data demonstrated the deficits in the numbers and/or functions of the CD4⁺CD25⁺Foxp3⁺ Treg cells in the patients with autoimmune diseases, indicating that restoration of Treg cells in these patients could be a potential therapeutic approach. Here, we demonstrated that CD4⁺CD25⁺Foxp3⁺ Treg cells can be purified, activated and expanded from peripheral blood of patients with immune-mediated diseases, to a similar degree to those from healthy donors. Within 3weeks, Treg cells from most patients could be expanded ex vivo 100-2000 fold and maintained their phenotypic characteristics. Furthermore, ex vivo expanded Treg cells displayed potent and enhanced in vitro suppressive activities inhibiting T effector cell proliferation compared to Treg cells freshly purified from the same patients. The expanded Treg cells with enhanced biological function may provide an opportunity to restore the proper balance of immunity and tolerance, suggesting the potential of using Treg cell therapy for treatment of immune-mediated diseases.