P2RX7 and graft versus host disease: Finally, bone marrow chimeras with a host P2rx7−/− haematopoietic system including P2rx7−/− DCs had reduced disease compared to mice with a host P2rx7−/− haematopoietic system but wt DCs, indicating that P2X7 on host DCs is contributing to GVHD development [72].