Late Acute Liver Allograft Rejection; A Study of Its Natural History and Graft Survival in the Current Era

Background. Late acute rejection (LAR) after liver transplantation is often associated with poor clinical outcomes. We reviewed our experience of managing LAR in the current era to determine its natural history. Methods. A database of 970 consecutive adult liver transplants was reviewed retrospectively. LAR was defined as histologically proven acute cellular rejection occurring more than 90 days after transplantation. Results. The incidence of LAR was 11%, with a mean time of 565 days (median, 311 days; range, 90-2922 days) after transplantation. The highest rates for LAR were in seronegative hepatitis (17%), primary biliary cirrhosis (16%), and primary sclerosing cholangitis (13%) with an odds ratio of 2.3, 2.1, and 1.8, respectively. Logistic regression showed that younger recipients, primary biliary cirrhosis, and previous graft loss were independent predictors of LAR (P<0.001). Mean trough whole blood tacrolimus levels were at their lowest levels 1 week before the diagnosis of rejection (5.5 ng/mL; SD, 2.6) compared with levels of 7.7 ng/mL 4 weeks before rejection, showing a clear temporal relation. Graft survival was worse in those with LAR (P<0.01), whereas the best graft survival was among early acute rejection cases (85% 10-year survival; P<0.01). Poor response to treatment correlated with the development of ductopenic rejection (r=0.3; P<0.01). Approximately half with early ductopenic rejection eventually died (n=15). Conclusion. LAR continues to provide a risk to patient and graft survival: understanding risk factors may allow an improvement in monitoring and early intervention and so prevent early graft loss.