We have previously reported that the treatment of mice with poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) decorated with anti-CD2 antibodies and encapsulating IL-2 and TGF-β induced tolerogenic CD4+ and CD8+ pTregs that protected mice from fatal graft-versus-host disease (GvHD). Here, CD4 is linked to graft versus host disease.