The Pathological Spectrum of Hepatic GVHD

Liver GVHD has declined in recent years but still remains a serious complication of HSCT. The characteristic features involve damaged small bile ducts and cholestasis. There are several different presentations of liver GVHD including those which present as acute GVHD with skin and especially gut involvement. Prolonged acute GVHD of the liver first targets and destroys bile ducts, leading to marked secondary changes of cholestasis. Another presentation of GVHD occurs later as a slowly progressing cholestatic injury without elevations of aminotransferases. Evaluation of liver GVHD involves cytokeratin immunostaining, which helps identify and quantify the bile ducts, and other stains including the periodic acid-Schiff (PAS) stain, which highlights the hepatic architecture and helps identify abnormal and damaged bile ducts. The interpretation of posttransplant liver biopsies must incorporate clinical factors including time posttransplant, exposure to immunosuppression, and other potential causes including drug-induced liver injury (DILI).