Immunoreactive anionic and cationic trypsins in serum after experimental porcine pancreatic transplantation.

Immunoreactive anionic and cationic trypsins (irAT and irCT) were measured in blood samples taken daily from 20 pigs during 60 days after whole organ pancreatic transplantation. Immunosuppression was discontinued on the twenty-eighth day after transplantation. IrAT concentrations showed three distinct peaks, the first immediately after operation, the second around the seventh day after operation, and the third irAT peak was seen 2 to 9 days after discontinuation of immunosuppression therapy. IrCT levels paralleled the irAT levels only in the first peak immediately after transplantation. After this there was a dissociation between the concentrations of the two immunoreactive trypsins, with low irCT levels and high irAT levels. Increased irAT levels heralded rejection of the pancreatic allograft by 4 to 30 days (median 20 days) in 13 of the 16 rejecting animals (80%). In addition, low irCT levels preceded hyperglycemia in 13 of the 16 rejecting pigs by 2 to 47 days (median 21 days). The first postoperative peak of immunoreactive trypsins is thought to be related to the operative and storage trauma, whereas the second and third peaks are thought to reflect a rejection process. The results suggest that immunoreactive trypsins can be used as markers for pancreatic allograft rejection.