Introduction: Since the nationwide adoption of enteric drainage as the preferred method of pancreas allograft implantation, immunological monitoring is largely limited to indirect measures such as serum amylase/lipase or blood glucose. Image-guided percutaneous is seldom performed because of concerns about complications and feasibility.
Methods: Single centre retrospective study of all pancreatic allograft biopsies performed from 2009 to 2015 were analysed. Radiological, histological and clinical data were correlated to assess the safety, histological adequacy, and incidence of complications.
Results:
91 pancreas transplants were performed using enteric/iliac drainage technique in this period. 72 biopsies (71 ultrasound-guided and 1 CT-guided) were performed in a total of 42 patients; 69 were indication biopsies, 3 were surveillance. Biopsy indications included: elevated amylase in 38 (55%), deranged sugars in 8 (12%), 7 (10%) for both, low c-peptide and insulin in 1 (1.4%) and 15 (22%) were for graft dysfunction.  31 biopsies (43%) were performed as day cases, 41 (57%) during inpatient stays.  21 (29.2%) of 72 showed rejection, 15 (20.8%) sclerosis or fibrosis, 11 (15.3%) showed other features such as hyalinosis and 14 (19.4%) were normal. 10 (13.9%) samples were insufficient. One patient developed bleeding immediately post-biopsy bleeding requiring transfusion – no further intervention was needed. 3 patients (4.2%) had hyperamylasemia following biopsy. Based on histology, 19 (26.4%) received enhanced immunosuppression - IVIg, steroids, or plasma exchange; 7 patients (9.7%) received IV antibiotics for presumed pancreatitis, and 5 (6.9%) patients received all the above. No allografts were lost to biopsy related complications. 
Discussion:
Pancreatic allograft biopsies may be performed with low risk of complications, and provide useful diagnostic information. Technical feasibility of percutaneous biopsy needs to be considered in planning biopsy-based immunological monitoring of these grafts.

Ultrasound-guided pancreas allograft biopsies: safety and diagnostic use