Risk factors of silent allograft fibrosis 10 years post-pediatric liver transplantation.

This study analyzed factors related to allograft fibrosis in clinically stable pediatric liver transplantation patients. Pediatric patients who underwent liver transplantation from January 1997 to January 2008 and further underwent 10-year protocol biopsies were examined. Grades of inflammation and fibrosis were classified based on Banff criteria and the Liver Allograft Scoring (LAF) system, respectively. Risk factors for fibrosis were analyzed using logistic regression. Sixty-six patients with no clinical signs of chronic liver disease were included. Forty-one patients out of 66 (62.1%) had certain stage of allograft fibrosis. More than five events with aminotransferase >50 U/L was a risk factor for a LAF score 1-2 portal fibrosis (OR = 3.156, CI 1.059-9.410, P = 0.039). More than five events with aminotransferase >100 U/L was a risk factor for LAF score 2 portal fibrosis (OR = 13.978, CI 2.025-97.460, P = 0.007) and LAF score 1-2 sinusoidal fibrosis (OR = 4.897, CI 1.167-20.548, P = 0.030). Positive autoantibody (OR = 3.298, CI 1.039-10.473, P = 0.043) and gamma-glutamyl transferase  60 U/L (OR = 6.201, CI 1.096-35.097, P = 0.039) were related to sinusoidal fibrosis with LAF score of 1-2 and 2, respectively. Experience of post-transplantation lymphoproliferative disease was related to LAF score 1-2 portal fibrosis (OR = 7.371, CI 1.320-41,170, P = 0.023) and LAF score 1-2 centrolobular fibrosis (OR = 8.822, CI = 1.378-56.455, P = 0.022). Our results indicate that liver fibrosis is common in patients with no clinical signs of graft deterioration and repeated elevation of aminotransferases, positive autoantibodies, elevated gamma-glutamyl transferase and experience of post-transplantation lymphoproliferative disease are suspicious signs for fibrosis.