Donor Brain Death Inhibits Tolerance Induction in Miniature Swine Recipients of Fully MHC‐Disparate Pulmonary Allografts

We have previously shown that a short course of high‐dose tacrolimus induces long‐term tolerance to fully mismatched lung allografts procured from healthy MHC‐inbred miniature swine. Here, we investigate whether donor brain death affects tolerance induction. Four recipient swine were transplanted with fully mismatched lung grafts from donors that were rendered brain dead and mechanically ventilated for 4 h before procurement (Group 1). These recipients were compared to two control groups (Group 2: 4 h of donor ventilation without brain death [n = 5]; and Group 3: no donor brain death with <1 h of ventilation [n = 6]). All recipients were treated with a 12‐day course of tacrolimus. In contrast to both groups of control animals, the swine transplanted with lung allografts from brain dead donors all rejected their grafts by postoperative day 45 and showed persistent responsiveness to donor antigen by MLR. Several additional swine underwent brain death induction and/or mechanical ventilation alone to determine the effects of these procedures on the expression of proinflammatory molecules. Significant increases in serum concentrations of IL‐1, TNF‐α and IL‐10 were seen after brain death. Upregulation of IL‐1 and IL‐6 gene expression was also observed.