P-47 HISTOPATHOLOGICAL ANALYSIS OF 10-YEAR PROTOCOL LIVER ALLOGRAFT BIOPSY OF ASYMPTOMATIC PEDIATRIC RECIPIENTS FROM A SINGLE BRAZILIAN CENTER

Introduction: Liver transplant (LT) is the main therapeutic procedure for irreversible liver failure. Protocol liver biopsies during post-transplant follow-up in pediatric recipients with stable graft function have been done in order to identify structural changes. A more specific score, LAFSc, to analyze fibrosis and inflammation on liver allografts has been validated recently. Objectives: To describe the prevalence of histological liver abnormalities in asymptomatic pediatric patients after ten years following LT from a Brazilian single center comparing two different scoring methods. Methods: Cross-sectional study of analysis of protocol percutaneous liver biopsies performed in patients who underwent liver transplant before the age of 18 years, of both genders, asymptomatic, using Tacrolimus for immunosuppression and at least 10-years post-liver transplant. From 97 recipients, 21 met inclusion criteria and had stable liver graft function. A single experienced pathologist assessed histopathological features comparing METAVIR scoring system and LAFSc. Results: Mean follow-up was 12.8 (+/- 2.1) years after post-LT. TAC mean daily dose during biopsy time was 4mg (+/- 1.7) with mean serum level of 4.04. METAVIR scoring system pointed 10 recipients with any degree of fibrosis and 13 with inflammation findings in protocol biopsies. However, using LAFSc scoring system, 13 patients scored for abnormal findings in any of the three zones analysed, although 8 of these had total score of mild fibrosis (1-3). Of the three zones analysed in LAFSc, the highest scores were found in portal space. Centrilobular vein zone was the most affected, documented in 11 recipients. Conclusion: We observed a higher prevalence of abnormal findings using the new allograft fibrosis scoring system – LAFSc. It also showed more specifically the degree and location of fibrosis within hepatic lobule compared to METAVIR. Compared to other LT reports, we observed lower rates of chronic allograft hepatitis and fibrosis at 10 years.