Owing to previously described differences between murine and human T cell molecular interactions, notably in the costimulation family of molecules [28], [46] and further considering the current clinical development of CD28 and CD80/86 antagonists to control autoimmunity and transplant rejection [29], [47], we aimed at studying the impact of costimulatory molecules interacting with CD80/86 [4] on human Teff and Treg functions. Here, CD28 is linked to Autoimmunity.