Donor-specific cellular immune response against human cardiac valve allografts

We studied the presence of donor-specific T lymphocytes in explanted human cardiac valve allografts in vivo. From five of seven explants we propagated lymphocyte cultures in an interleukin-2 conditioned medium. Phenotyping revealed the presence of T-cell receptors in more than 95% of the lymphocytes obtained in each culture. Donor-specific cytotoxicity was demonstrated in three patients with known HLA status of the donor. Cytotoxicity was directed against only HLA class I in one patient, and against class I and/or class II in the others. These results indicate that donor-specific cellular reactivity can be induced by transplantation of human cardiac valve allografts.