Long-term survival of heart grafts in the presence of donor-specific cytotoxic T-cell precursors (CTLp) in the peripheral blood.

To monitor their immunological status we determined donor and third-party-specific cytotoxic T-cell precursor frequencies (CTLpf) in the peripheral blood of 15 heart transplant recipients. PBL samples were obtained at different time points before and after transplantation. Donor-specific CTLpf and third-party-specific CTLpf were within the same range for all samples (1-1489/10(6) cells). The donor-specific CTLpf were not different between patients who had never had an acute rejection (AR) and patients who had an acute rejection as diagnosed by endomyocardial biopsy (EMB). No difference was observed between donor-specific CTLpf of samples taken on the day of transplantation and those obtained between 3 months and 3 years after transplantation. There was also no relationship between the donor-specific CTLpf in the PBL and the culturing success of lymphocytes from EMB taken at the same time. CTLpf were in the same range both when cultures could be propagated from the graft and when no cells grew out. We conclude that long-term graft survival is possible in the presence of CTLpf in peripheral blood.