Re‐exposure to beta cell autoantigens in pancreatic allograft recipients with preexisting beta cell autoantibodies

Re‐exposure to beta cell autoantigens and its relevance in the presence of donor‐specific antibodies (DSA) in pancreatic allograft recipients is not well known. Thirty‐three patients requiring a pancreas transplant were enrolled in an IRB approved study. They underwent prospective monitoring for DSA and beta cell autoantibody (BCAA) levels to GAD65, insulinoma‐associated antigen 2 (IA‐2), insulin (micro‐IAA mIAA]), and islet‐specific zinc transporter isoform‐8 (ZnT8). Twenty‐five (75.7%) had pre‐transplant BCAA. Twenty had a single antibody (mIAA n = 15, GAD65 n = 5); five had two or more BCAA (GAD65 + mIAA n = 2, GAD65 + mIAA+IA‐2 n = 2, GA65 + mIAA+IA‐2 + ZnT8 = 1). No changes in GAD65 (p > 0.29), IA‐2 (>0.16), and ZnT8 (p > 0.07) were observed between pre‐transplant and post‐transplant at 6 or 12 months. A decrease in mIAA from pre‐ to post‐6 months (p < 0.0001), 12 months (p < 0.0001), and from post‐6 to post‐12 months (p = 0.0002) was seen. No new BCAA was observed at one yr. Seven (21.0%) developed de novo DSA. The incidence of DSA was 24% in patients with BCAA vs. 25% in patients without BCAA (p = 0.69). Pancreatic allograft function of patients with vs. without BCAA, and with and without BCAA + DSA was comparable until last follow‐up (three yr). Re‐exposure to beta cell autoantigens by pancreas transplant may not lead to increased levels or development of new BCAA or pancreatic allograft dysfunction.