Histopathological Spectrum of Liver Allograft Biopsies and Association with Clinical and Pathological Parameters in Transplant Patients: A Cross-sectional Study

Abstract

Introduction: Transplantation is vital for acute and terminal irreversible liver conditions. While imaging and functional measurements are valuable for evaluating post-transplant hepatocellular or biliary issues, liver allograft biopsies are used to determine the underlying causes of these changes. Long-term Immunosuppression (IMS), complex clinical circumstances, and de novo complications present challenges in transplant pathology, necessitating a multidisciplinary approach. Aim: To conduct a histopathological assessment of allograft liver biopsies for differential diagnosis, timing (postoperative day), and prevalence of post-transplantation complications, including identifying the causes of graft damage. Materials and Methods: This retrospective cross-sectional study was conducted between January 2019 and June 2022 at Vayalil Parambath Shamsheer (VPS) Lakeshore Hospital, Kochi, Kerala, India. A total of 45 post-transplant needle biopsy samples were analysed, examining histological characteristics and clinical data extracted from hospital records. Over 3.5 years, 45 post-liver transplant biopsies were performed. All clinical records and biopsy findings were examined using staining, and immunohistochemical analysis was performed. The Banff Working Group’s criteria were used to grade rejection based on a semiquantitative index, the Rejection Activity Index (RAI), into indeterminate (Score 1, 2); mild (Score 3, 4); moderate (Score 5, 6); and severe (>6). The classic histologic findings are characterised by predominant portal-based lesions, including a classical triad of mixed inflammatory cell infiltrates, venous endothelial inflammation, and inflammatory infiltration of bile ducts. Results: Among 38 patients, a total of 45 needle biopsies were performed. The first specimen was collected within a few hours of transplantation, and the final specimen was collected after 770 days. Notably, T-Cell-Mediated Rejection (TCMR) was diagnosed in 9 out of 45 (20.00%) specimens. Other complications included Intrahepatic Cholestasis (IHC) in 11 out of 45 (24.44%) cases, biliary obstruction in 5 out of 45 (11.11%) patients, Herpes Simplex Virus (HSV) hepatitis in 3 out of 45 (6.67%) specimens, Plasma Cell-Rich Rejection (PCRR) in 2 out of 45 (4.44%), and Isolated Central Perivenulitis (ICP), Dengue Haemorrhagic Fever (DHF), and veno-occlusive-like disease in 2 out of 45 (4.44% each) specimens. One patient had ethanolinduced liver injury (1 out of 45, 2.22%). Conclusion: Post-transplant liver biopsies are essential for accurate and timely diagnosis of rejection and other complications, guiding therapeutic interventions. This study offers insights into the types, prevalence, and timing of critical complications following liver transplantation (LTx).