Abstract
Aim The pattern of rejection of vascularized pancreas allografts in presensitized recipients was studied among congeneic and recombinant rat strains in order to establish the time frame of rejection. Donors and recipients differed either in their entire MHC or in class I or class II MHC antigens. Material and methods Streptozotocin diabetic (55 mg/kg bone weight) recipients underwent an intra-abdominal heterotopic pancreas whole organ transplantation. The exocrine secretion of the pancreas was suppressed by ligation of the duct. Rejection was defined as recurrence of diabetic hyperglycemia exceeding 14 mmol/L, which was subsequently confirmed by histologic examination. The pancreas recipients were presensitized by repetitive donor-specific skin transplants performed 12, 8, and 4 weeks prior to pancreas grafting. Results The results shown accelerated rejection in all instances. Animals with incompatibility for the entire MHC showed a median rejection time in naive recipients of 12.5 days and in presensitized recipients of 8 days. Class I MHC incompatible native recipients rejected the allografts after 16.5 days (median) and presensitized recipients after 9 days (median). Concerning class II MHC incompatibility rejection appeared in naive recipients after 16 days (median) and in presensitized recipients after 7 days (median). Hyperacute rejection, however, was not observed. Discussion These results show an accelerated pattern of rejection in all instances caused by donor MHC antigens. Hyperacute rejection, however, was not observed. The effect is slightly pronounced in class II MHC incompatibility. Acceleration of rejection may be caused by stimulation of the humoral as well as the cellular pathway of the immune response. The underlying mechanisms concerning the different MHC incompatibilities, however, remains speculative.
Published Version
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