The combination of primary sclerosing cholangitis and CCR5-Δ32 in recipients is strongly associated with the development of nonanastomotic biliary strictures after liver transplantation

Background: The role of the immune system in the pathogenesis of nonanastomotic biliary strictures (NAS) after orthotopic liver transplantation (OLT) is unclear. A loss-of-function mutation in the CC chemokine receptor 5 (CCR5-Δ32) leads to changes in the immune system, including impaired chemotaxis of regulatory T cells. Aim: To investigate the impact of the CCR5-Δ32 mutation on the development of NAS. Methods: In 384 OLTs, we assessed the CCR5 genotype in donors and recipients and correlated this with the occurrence of NAS. Results: The CCR5-Δ32 allele was found in 65 (16.9%) recipients. The cumulative incidence of NAS at 5 years was 6.5% in wild-type (Wt) recipients vs 17.2% for carriers of the CCR5-Δ32 allele (P<0.01). In recipients with CCR5-Δ32, 50% of all NAS occurred >2 years after OLT, compared with 10% in the Wt group. In multivariate regression analysis, the adjusted risk of developing NAS was four-fold higher in recipients with CCR5-Δ32 (P<0.01). The highest risk of NAS was seen in patients transplanted for primary sclerosing cholangitis (PSC), who also carried CCR5-Δ32 (relative risk 5.4, 95% confidence interval 2.2-12.9; P<0.01). Donor CCR5 genotype had no impact on the occurrence of NAS. Conclusions: Patients with the CCR5-Δ32 mutation have a four-fold higher risk of developing NAS, compared with Wt recipients. This risk is even higher in patients with CCR5-Δ32 transplanted for PSC. Late development of NAS is significantly more present in patients with CCR5-Δ32. These data suggest that the immune system plays a critical role in the development of NAS after OLT.