P180 Post-liver transplant outcomes in PSC and PSC-AIH overlap syndrome: insights from an international cohort study

<h3>Background</h3> Primary sclerosing cholangitis (PSC) is a progressive cholestatic liver disease that often requires liver transplantation (LT). It is complicated by PSC recurrence (rPSC) in up to 27% of cases which increases the risk of graft failure and need for re-transplantation. A subset of patients present with PSC-autoimmune hepatitis (AIH) overlap syndrome, characterized by features of both biliary stricturing and hepatocellular inflammation. Outcomes after LT for PSC-AIH remain poorly defined. The aim of this study was to compare long-term post-transplant outcomes between patients with PSC and PSC-AIH overlap syndrome. <h3>Methods</h3> This retrospective cohort study included adult patients who underwent their first LT for PSC or PSC-AIH between 2000–2018 at three transplant centers: Austin Hospital (Melbourne, Australia), King’s College Hospital (London, United Kingdom) and Leiden University Medical Centre (LUMC)(Leiden, Netherlands). Patients with early post-LT mortality, early retransplantation (&lt;3 months from LT) or cholangiocarcinoma on explant were excluded. Data collected included demographics, liver disease characteristics, transplant details, immunosuppression, and post-LT outcomes including rPSC, graft rejection, retransplantation, and survival. <h3>Results</h3> A total of 265 patients were included in the analysis (218 PSC; 47 PSC-AIH)(84 Austin Hospital; 138 King’s College; 43 LUMC) with mean follow-up of 9.9 years (no difference between groups). PSC-AIH patients were significantly younger at diagnosis (mean 25.1 vs. 38.3 years) and more frequently female (49% vs. 33%). Donor graft features were comparable as were cold and warm ischaemia times. Hepaticojejunostomies were more common in PSC patients than PSC-AIH patients (66% vs. 40%; P=0.001). Post-LT immunosuppression were similar in each group. There was no significant difference in rates of rPSC (34.8% PSC-AIH vs. 41.3% PSC), P=0.46), rejection after 12 months (26% vs. 17%, P=0.15) and retransplantation (10.6% vs. 12%, P=0.79). However, PSC-AIH patients had lower overall mortality (26.2% vs. 10.6%, P=0.023). After multivariate adjustment for confounders, this trended towards but did not remain significant (P= 0.078). Hepaticojejunostomy emerged as an independent risk factor for rPSC (HR: 2.087 (1.136–3.833),P=0.018) and retransplantation (HR: 10.582 (2.353–47.588), P=0.002) in the overall cohort. <h3>Conclusion</h3> Patients with PSC-AIH overlap have comparable rates of rPSC, graft rejection, retransplantation tand survival to those with isolated PSC following LT. These findings suggest that LT outcomes in PSC-AIH are at least equivalent to PSC, supporting similar management and surveillance strategies post-transplant.