Ultrastructural changes in human hepatocytes in acute non-A, non-B hepatitis

Ultrastructural findings in the liver of a 52-year-old man with acute non-A, non-B (NANB) post-transfusion hepatitis are described. Apart from non-specific alterations also known to occur in hepatocytes in hepatitis A and B--such as proliferation of membranes of smooth endoplasmic reticulum, formation of membrane-bound cytoplasmic vacuoles containing electron-dense material, and accumulation of distorted peroxisomes--unique cytoplasmic changes were observed that have not previously been described in man. A few hepatocytes contained in their cytoplasm tightly packed, bent, parallel structures and small clusters of virus-sized particles. No virus-like material was found in the nucleus of liver cells or in Kupffer and endothelial cells. Closely similar structures have been reported earlier in the acute-phase hepatocytic cytoplasm of chimpanzees with NANB hepatitis. These alterations may represent an ultrastructural hallmark of acute human NANB hepatitis.