A new tracheal bioartificial organ: evaluation of a tracheal allograft with minimal antigenicity after treatment by detergent.

The aim of this study was to reduce the antigenicity of tracheal allografts by detergent treatment. We attempted to apply these grafts to tracheal immunosuppressant-free allotransplantation. Fresh tracheal grafts were harvested from donor beagle dogs and treated with a detergent at 4 degrees C for 48 hours. By using treated grafts, we have performed tracheal immunosuppressant-free transplantation in six dogs at an intrathoracic five-ring defect. Implanted grafts were covered with an omental pedicle. In five of the six grafts, complete removal of the epithelium and mixed glands was recognized with both light microscopy and scanning electron microscopy. The appearance of the cartilage cells in the grafts was similar to those in fresh trachea. Five dogs that received detergent treated grafts survived uneventfully. The grafts had been incorporated by the host trachea without stenosis. On the one tracheal graft in which removal of the epithelium was incomplete (noted after implantation), moderate stenosis occurred 1 month after placement. These results suggest that removal of the tracheal epithelium and mixed glands can remarkably reduce tracheal antigenicity. A tracheal graft that has its epithelium and mixed glands removed can be used in tracheal immunosuppressant-free allotransplantation.