Six liver biopsies from previously healthy adult patients with cytomegalovirus (CMV) mononucleosis were studied by routine light microscopy and by the immunoperoxidase technique for CMV antigen. Light microscopical findings consisting of a mononuclear portal and sinusoidal infiltrate, increased hepatocellular mitotic activity and minimal hepatocellular necrosis were consistently found. Less common features were granuloma formation and bile duct epithelial damage. Typical CMV nuclear inclusions and CMV antigen were identified in only one case, a patient with marked leukopenia secondary to CMV who had received corticosteroid therapy. The other five cases contained no inclusions and CMV antigen could not be identified by immunoperoxidase staining. This data suggests that, as with hepatitis B, viral antigen is not identifiable in acute CMV hepatitis in the immunocompetent host, perhaps due to active destruction of infected cells. The immunoperoxidase technique for CMV appears to be of little value in the diagnosis of acute CMV hepatitis.
Hepatic involvement as defined by abnormal serum liver function tests is commonly encountered in the heterophile-negative mononucleosis-like illness caused by cytomegalovirus (CMV) (1, 2). Abnormalities usually consist of mild elevation of SGOT and SGPT, with no or minimal elevation of alkaline phosphatase and bilirubin (1-3). Histologically, the liver is characterized by infiltration of both portal tracts and sinusoids by mononuclear cells. Focal necrosis, increased mitotic activity within hepatocytes, and granulomatous inflammation may be seen as well (1,(4)(5)(6). While these changes are characteristic, they are not diagnostic; identical lesions are found, for example, in Epstein-Barr virus (EBV)induced mononucleosis (7, 8) and with some drugs, e.g., diphenylhydantoin (9). The finding of typical CMV inclusions, while diagnostic, is extremely unusual in CMV hepatitis in the nonimmunocompromised host. In this report we have utilized the immunoperoxidase technique to look for CMV-associated antigens in liver biopsy specimens from six previously healthy patients with CMV mononucleosis. Such antigens, if present, would