Progressive Fibrosis is Driven by Genetic Predisposition, Allo-Immunity, and Inflammation in Pediatric Liver Transplant Recipients

Abstract Aim To determine predisposing factors of idiopathic allograft fibrosis among pediatric liver transplant recipients. Background Protocol biopsies (PB) from stable liver transplant (LT) recipient children frequently exhibit idiopathic fibrosis. The relation between allograft inflammation, humoral immune response and fibrosis is uncertain. Also the role of HLA-DRB1 genotype has not been evaluated, though it's associated with fibrosis in autoimmune hepatitis. Patients and Methods This observational study, included 89 stable LT recipient transplanted between 2004–2012 with mean follow-up of 4.3years, 281 serial PBs (3.1 biopsy/child) and human leukocyte antigen (HLA) antibody data. PBs were taken 1–2, 2–3, 3–5, 5–7, and 7–10years post-LT, and evaluated for inflammation and fibrosis using liver allograft fibrosis score (LAFSc). The evolution of fibrosis, inflammation and related predisposing factors were analysed. Findings HLA-DRB1*03/04 allele and Class II DSA were significantly associated with portal fibrosis (p=0.03; p=0.03, respectively). Portal inflammation was predisposed by Class II DSA (p=0.02) and non-HLA antibody presence (p=0.01). Non-portal fibrosis wasn't predisposed by inflammation. Lobular inflammation was associated with non-HLA antibodies. Interpretation We conclusively demonstrated that allograft inflammation results in fibrosis and is associated with post-LT Class II DSA and non-HLA antibodies. The HLA-DRB1*03/04 allele caused genetic predisposition for fibrosis. Funding None.