In type1 diabetics undergoing pancreas transplant the significance of re-exposure to pancreatic auto-antigens in the context of DSA and new alloimmunity is not well known.

Twenty patients (pts) with pancreas-transplant (PTA 6, SPK 13, and PAK 2) undergoing prospective luminex single antigen bead testing (expressed as MFI) at regular time intervals were enrolled. AA titers to auto-antigens GAD65, Insulinoma-associated-antigen 2 (IA-2), insulin (mIAA), and islet-specific zinc transporter isoform-8 (ZnT8) were tested pre- and 6 months after transplant. Median follow up is 29 months. All pts underwent thymoglobulin induction with addition of anti-CD 20 for PTA. Thirteen (65%) pts were found to have AA. No difference was observed in the pre and 6 month post transplant AA titers of anti-GAD65,IA-2 and ZnT8 whereas the titers of mIAA dropped (p=0.00). Eight pts (40%) developed denovo DSA at median of 76 days, 1 pt had pre-formed DSA. Seven pts had both class I and class II DSA, one with class I and one with class II only. Mean class I DSA-MFI was 3529 (±1456); class II DSA-MFI was 5734 (±3204) whereas cumulative DSA MFI (CI + CII) was 9264 (±4233). Pts were divided based on the presence of DSA.

Incidence of any AA in pts with DSA was 66% vs. 63% in pts without DSA (p=0.97). In the DSA group 5(55%) pts had one AA and 1pt (11%) had 2 AAs. In non DSA group 5 (45%) pts had 1 AA while 2 (20%) >1 AAs. No difference was noted in the DSA MFI of pts with and without AA. No denovo AA were detected. Fasting blood glucose levels, C-peptide, A1C, and serum lipase were comparable in both groups.

Conclusion: Presence of one or more of the pancreatic AA's after a pancreas transplant is not associated with the DSA, new alloimmunity and pancreatic allograft dysfunction.

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