THE EFFECT OF HLA-DR MATCH ON THE INCIDENCE OF NON-ANASTOMOTIC BILIARY STRICTURES AFTER LIVER TRANSPLANTATION.

142 Background: Non-anastomotic biliary strictures (NAS) after orthotopic liver transplantation (OLT) result from microcirculatory insufficiency or direct destruction of bile ducts. Human leukocyte associated antigen (HLA) disparity may lead to an immune response resulting in endothelial and biliary epithelial damage. Aim: To determine the relationship between NAS after OLT and HLA antigen disparity. Methods: After exclusion of patients with other causes for biliary strictures (ABO incompatibility, pediatric recipients, arterial complications, prolonged ischemic time (≥ 11 hr) and patients with short graft survival (< 21 days), 394 consecutive patients with primary OLT's since 7/17/1988 (UW-era) were studied. In 80 patients, the diagnosis was primary sclerosing cholangitis (PSC), leaving 314 patients with other indications (Non-PSC). NAS was diagnosed by cholangiography using indwelling biliary tubes, by ERCP or PTC. Results: The incidence of NAS in the Non-PSC group was 5.7% (18/314) and in the PSC group was 16.3% (13/80) (p<0.002). In the Non-PSC group, the incidence of NAS in patients with a partial/complete HLA-DR match was found to be significantly different compared to patients with a complete HLA-DR mismatch (0.8% vs. 10.7%, p<0.0001), while no difference in NAS was found with HLA A, B, DRw, DQ matching. (Table)TableIn PSC patients, HLA match had no effect on the incidence of NAS. Conclusions: In Non-PSC patients, a partial or complete HLA-DR match diminishes the risk of NAS after OLT. These data suggest that immunological mechanisms may play a role in the pathogenesis of NAS after OLT.