Tracheal allotransplantation in beagle dogs without immunosuppressants

Background. The antigenicity of tracheal grafts is still unclear. We invest igated the possibility of performing tracheal allotransplantation without i mmunosuppressants. Methods. Intrathoracic five-ring tracheal replacements were performed in be agle dogs without immunosuppressants (n = 18). The dogs were divided into 9 pairs, and grafts were exchanged within the pairs. In group 1 (n = 6), the paired dogs were blood relatives, whereas in group 2 (n = 12), the paired dogs were not related. Full-thickness skin transplantation was also perform ed in both groups. Results. In group 1, 5 animals survived uneventfully for more than 3 months . No stenosis was observed in any of the dogs. In group 2, the grafts were incorporated by the host trachea in 2 dogs. Four animals died of airway obs truction within 3 months. Moderate or slight airway stenosis was observed i n 6 dogs. Rejection was confirmed by histologic examination. In both groups , all of the skin allografts were destroyed within 2 weeks. Conclusions. After tracheal allotransplantation, longterm survival was achi eved, especially in recipient dogs that were blood relatives of donors. We conclude that it is possible to perform tracheal allotransplantation using histocompatible matched grafts without immunosuppressants. (C) 2001 by The Society of Thoracic Surgeons.