Islet Cell Autoantibody Formation and Its Effect on Insulin Requirement after Total Pancreatectomy with Islet Autotransplantation (TPIAT)

Introduction: Long term insulin requirements following TPIAT range from insulin independence to full (high) dose daily insulin (>0.5 units/kg/day). Markers of islet cell autoimmunity are used in children to predict type 1 diabetes risk. However, no studies have explored whether an association exists between islet cell autoimmunity and insulin requirement following TPIAT in children. We hypothesized that children with islet cell autoantibody formation were more likely to have a persistent insulin requirement following TPIAT. Methods: All children who underwent TPIAT between 2015 and 2021 at our institution were eligible for inclusion. Islet cell autoimmunity was defined as positive islet cell autoantibody screen for one or more of the following types of autoantibodies: Glutamic Acid Decarboxylase (GAD), Islet Antigen-2 (IA-2), Insulin (IAA), or Zinc Transporter 8 (ZnT8). Patients were screened prior to TPIAT and every six months following TPIAT for up to three years. In all, 73 patients were included in the analysis. Total daily insulin dose was determined for each patient at each time interval. Chi-square or Fisher’s exact tests were used to compare proportions. Results: Of patients with 12-month data (n=38), 47% of islet cell autoantibody negative patients were off insulin vs 26% of antibody positive patients (p=0.19). This trend was significant at 18, 24, and 36 months after TPIAT. At 18 months, 90% (9/10) of antibody negative patients were off insulin vs 29% (4/14) of antibody positive patients (p=0.005). At 24 months, 73% (8/11) of antibody negative patients were off insulin vs 23% (3/13) of antibody positive patients (p=0.04). At 36 months, 100% (8/8) of antibody negative patients were off insulin compared to 0% (0/9) of antibody positive patients (p<0.0001). Conclusions: The presence of pancreatic islet cell antibodies was associated with persistent insulin requirement after TPIAT. Disclosure A.R.Lavik: None. C.M.O.Lowe: None. S.E.Tellez: None. L.Hornung: None. C.Heinzman: None. J.D.Nathan: None. M.Abu-el-haija: None. D.A.Elder: None.