It is also possible that a novel peripheral Th2 cell subset, which originates from Foxp3+ progenitors after Hpb infection, participates in Th2-driven regulation of GVHD because these novel Th2 cells, unlike conventional Th2 lymphocytes, regain the expression of Foxp3 after exposure to TGF-β (53). The gene discussed is TGFB1; the disease is graft versus host disease.