Recipient cells form the proliferative lesion in the rat heterotopic tracheal allograft model of obliterative airway disease. 
To determine the nature of the proliferative lesion in obliterative airway disease, heterotopic tracheal allograft transplantation was performed between fully disparate Brown Norway and Lewis rat strains.  Four weeks after transplantation, the resulting lumenal occlusive lesion was stripped from the underlying tissue.  The lesion was probed using immunohistochemical analysis with monoclonal antibodies and for DNA using strain-specific primers for Brown Norway or Lewis major histocompatibility complex Class I alleles.  The lesions were alpha-actin positive, and polymerase chain reaction probing revealed only recipient DNA in the lesion tissue, regardless of the direction of transplantation, with no amplification of donor DNA.  From this, we conclude that the proliferative lesion in the rat heterotopic tracheal model is of recipient origin a finding with important implications for the pathobiology of obliterative airway disease.