P. Kuusanmaki et al., ACUTE REJECTION OF PORCINE SMALL-BOWEL ALLOGRAFT - AN EXTENDED HISTOLOGICAL SCORING SYSTEM, Transplantation, 58(7), 1994, pp. 757-763
Using nonimmunosuppressed piglet small bowel grafts, we performed a de
tailed histological study on acute rejection and analyzed altogether 4
5 different histological parameters throughout the bowel wall, in 10 a
llografts and 6 autografts. Heterotopic grafts were followed by full-t
hickness biopsies every other day beginning on the 3rd day after trans
plantation. The parameters were scored from 0 to 3 according to the se
verity of the change and the values of every variable were compared st
atistically between the 2 groups. The earliest significant changes, be
ginning on days 3-5, were infiltration of inflammatory cells and pyron
inophilia among these cells in lamina propria; edema, fibrosis, and in
flammation in submucosa and muscularis; vacuolar degeneration of myocy
tes; and endothelial and intimal changes in vessels. Villous blunting
and cuboidal epithelium were the other early markers. On day 7, the ep
ithelial and vascular changes became most significant. We want to emph
asize especially the vascular parameters: endothelial swelling and pro
liferation, intimal thickening, intramural inflammation, and obliterat
ion of the lumen. The dilatation of lymph vessels and changes of Peyer
's patches had no value in the estimation of rejection. All allografts
became necrotic by day 11 after transplantation.