A case report of pembrolizumab-induced liver injury: The implication of CD8-positive lymphocytes in the immune-related adverse event

Abstract

A 76-year-old man with advanced non-small cell lung cancer (cT4N3M1a, stage IV A) received pembrolizumab treatment. At 8 days after the administration of pembrolizumab, he developed acute liver injury that worsened over time. Thus, liver biopsy was performed. Pathological examination revealed severe inflammation and focal necrosis in the central venous region; periportal inflammation was also detected. No remarkable fibrotic changes were observed. The infiltrating cells mainly comprised lymphocytes, and most of them were positive for CD8 staining. Based on this finding, an immune-related adverse event caused by pembrolizumab was suspected, and corticosteroid therapy was initiated, which immediately reduced liver injury. To our knowledge, this is the first report to describe the pathological features of pembrolizumab-induced liver injury, and our findings suggest that cytotoxic T cells play a crucial role in pembrolizumab-induced liver injury.