Background: Patients with established liver grafts may receive excessive immune suppression. Liver biopsies were analyzed in those with normal liver biochemistry to identify parameters that might identify such cases.
Methods: Patients with established grafts (>3 years from engraftment) and normal liver biochemistry (normal alanine transaminase, alkaline phosphatase, and bilirubin) were invited to undergo liver biopsy. Liver tissue was assessed by routine histopathology, a modified Ishak score, and immunohistochemistry for lymphocyte and cell-cycle markers. Circulating and intrahepatic lymphocytes were subjected to flow cytometry. Data were subjected to principal component analysis.
Results: Two hundred twenty-five (40%) patients under regular review had an established graft with normal liver biochemistry; liver tissue was obtained in 55. Liver histology was normal in eight cases (14.5%). The most common abnormalities were mild nonspecific hepatitis in 25 (45.4%) and disease recurrence in 14 (25.4%). Principal component analysis identified a cluster of variables that accounted for a significant degree of variation within the dataset. These were lobular inflammation, portal inflammation, interface hepatitis, and fibrosis.
Conclusions: Inflammation persisted in established grafted livers in most patients with normal liver biochemistry. Systematic histological and lymphocyte phenotype analysis generated an index that distinguished patient groups. Those with least inflammation and the lowest alanine transaminase may have a reduced requirement for immune suppression.