The change in activity of three disaccharidase enzymes (maltase, sucra
se and lactase) was determined according to the method of Dahlqvist du
ring acute rejection in non-immunosuppressed piglet small bowel grafts
. In addition, two brush border enzymes, lactase and aminopeptidase, w
ere stained with monoclonal antibodies. Diminishing disaccharidase act
ivity was an early event during rejection. Diminution began 2 days bef
ore distinct morphological changes were seen in the mucosal biopsies,
Evaluation of disaccharidase activity can thus be used as a confirmato
ry method in detecting rejection. Reduction in immunohistological stai
ning of lactase and aminopeptidase with monoclonal antibodies and chan
ges in mucosal morphology were observed to progress simultaneously.