Human Herpesvirus 6 Infection of the Gastroduodenal Mucosa

Abstract

Human herpesvirus 6 (HHV-6) infections are usually asymptomatic reactivations in adult liver transplant recipients, but they may also cause fever or graft dysfunction. HHV-6 infection can also present symptoms of gastroenteritis. In this study, we investigated the presence of HHV-6 in the gastroduodenal mucosa of liver transplant recipients and in immunocompetent patients undergoing gastroscopic examination because of dyspeptic symptoms. HHV-6 and cytomegalovirus (CMV) examinations were performed on gastroduodenal biopsy specimens obtained during upper gastrointestinal endoscopic examinations from 90 liver transplant recipients and from 31 immunocompetent patients with upper gastrointestinal symptoms. In the gastroduodenal mucosa, HHV-6 and CMV was demonstrated by immunohistochemistry in frozen sections using monoclonal antibodies against HHV-6- and CMV-specific antigens. HHV-6-positive cells were found in biopsy specimens from 21 (23%) of the liver transplant recipients and 6 (19%) of the immunocompetent patients, CMV-positive cells were found in specimens from 55 (61%) of the transplant recipients and 7 (23%) of the immunocompetent patients, and 12 transplant recipients were found to have both HHV-6 and CMV infection. Fifteen transplant recipients with positive HHV-6 findings in the gastroduodenal mucosa also had HHV-6 antigenemia, whereas 30 patients with HHV-6 antigenemia did not have gastroduodenal involvement. Endoscopic findings in these patients included biliary complications in 10 patients and gastritis in 2 patients. Histopathological findings were nonspecific and included very mild inflammation. A total of 30 (94%) of the transplant recipients with biliary complications also had HHV-6 or CMV detected in the duodenal mucosa. HHV-6-positive cells and CMV-positive cells were frequently found in the gastroduodenal mucosa of liver transplant recipients and of immunocompetent patients undergoing gastroscopic examination because of dyspeptic symptoms.