HOW TO DIAGNOSE CHRONIC REJECTION - A STUDY IN PORCINE INTESTINAL ALLOGRAFTS

Porcine small bowel allografts were followed for 18 weeks during immun osuppression with cyclosporine-A (CyA), azatioprine and prednisone. Th e mucosal alterations noted at the 12th week were epithelial vacuolati on and loss of Goblet cells, Moderate infiltration of inflammatory cel ls, mainly lymphocytes, was found in the lamina propria. In addition, a few grafts exhibited oedema and fibrosis. Vessels already showed end othelial swelling and intimal proliferation at the 12th week, In the s ubmucosa, the infiltration of inflammatory cells was not present till the 18th week. Further changes in the mucosa at the 18th week were the blunting of villi, cuboidal epithelium, crypt abscesses and epithelia l atrophy. The histological alterations of mucosa and lamina propria e xisting in the full thickness biopsies were mostly also detectable in mucosal biopsies, provided that multiple biopsies were taken. Thus the se parameters analyzed from mucosal biopsy material are suitable for t he diagnosis and monitoring of chronic small bowel rejection, In autop sy, the most prominent features were in the mesenterial arteries: inti mal proliferation, vasculitis, proliferation of media and endothelial alterations. The activity of the mucosal disaccharidases maltase and s ucrase remained near the initial level till the 12th week and had decr eased markedly by the 18th week.