The recent reports describing the beneficial effect of intrathymic (IT) inoculation of donor antigen on subsequent allograft survival prompted us to study this phenomenon in the high responder WAG to BN rat strain combination as well as in the low-responder BN to WAG combination. Previously in the WAG to BN model, we found that a donor-specific blood transfusion (DST) given 1 week before the heterotopic heart transplantation led to accelerated rejection in 5 days, whereas in the reverse model, a DST consistently led to marked prolongation of graft survival. These opposing phenomena led us to determine whether the effects of DST in the two rat strain combinations mentioned above would also occur after IT injection of donor type cells.[...]In conclusion we demonstrated that, similarly as following DST, the ability to induce prolonged acceptance of heart allografts by IT injection of donor-type cells is highly dependent on the donor-host combination used. The remarkable finding that IT injection can also lead to sensitization and even hyperacute rejection indicates that caution should be exercised with this ambiguous procedure
