Biopsy of the Pancreas Allograft for Diagosis of Rejection

Introduction: The early diagnosis of pancreas allograft rejection after single pancreas or simultaneous pancreas/kidney transplantation is essential for adequate anti-rejection therapy and long term graft survival. In simultaneous pancreas/kidney transplantation it has been shown that the absence of histological rejection in kidney biopsies is not always indicative for absence of rejection in the pancreas. Due to the potential spectrum of complications, pancreas allograft biopsies are performed reluctantly. Here, we report on our results on cause-biopsies of the pancreas and kidney allografts. Methods: All allografts were monitored during follow up after transplantation by contrast-enhanced ultrasound using a Acuson Sequoia (Siemens Medical Solutions) and 1ml of SonoVue® (BRACCO). The indication to biopsy was given if organ function deteriorated (elevated fasting blood-glucose and/or increased pancreas enzymes or impaired kidney function) and no other underlying cause was detected. Causebiospies of the pancreas graft were performed under ultrasound- or computertomography (CT) guidance. The kidney graft was biopsized exclusively by ultrasound due to its easy accessibility. Histopathologic evaluation was performed at an external reference center. Results: A total of 13 pancreas transplantations have been performed at our center since 2008, thereof 1 patient with pancreoprive diabetes and 12 patients with type 1 diabetes and end-stage renal disease (10 simultaneous pancreas/kidney, 1 pancreas after kidney and 1 pancreas re-transplantation). During follow up 12 cause-biopsies of pancreasallografts were indicated in 7 patients due to elevated fasting blood glucose or increased pancreas enzymes. In 5 patients biopsies were performed under ultrasound guidance, in 2 patients via CT-monitoring. Two biopsies resulted in insufficient material and had to be repeated. By histopathological examination, 5 rejection episodes of different degree (BANFF III, IIa, II, I) were found in 4 patients and treatment with Predisone- or Thymoglobulin pulse-therapy was initiated. An exclusive kidney-allograft rejection was diagnosed in 1 patient that was previously treated for pancreas-allograft rejection. No complications occured, neither after ultrasound- nor computertomography guidance occurred. Conclusion: Cause-biospies of pancreas-allografts can be performed safely under contrast-enhanced ultrasound or computertomography guidance. Especially contrast-enhanced ultrasound appears to be an excellent method for pancreas allograft surveillance and biopsy in experienced hands. Even though the cohort is relatively small, our results suggest that a simultaneous rejection of the pancreas and kidney allograft is a rare event.