Prevalence of human herpesvirus 6 in lung tissue from children with pneumonitis.

AIMS/BACKGROUND Human herpesvirus type 6 (HHV-6) is the aetiological agent of exanthem subitum, and has also been linked with a variety of other diseases. The aim of this study was to investigate the role of HHV-6 in pneumonitis in children. METHODS Formalin fixed, paraffin wax embedded lung tissue from 33 children (age range two months to 16 years) who died with pneumonitis was subjected to immunohistochemical staining for HHV-6 using an avidin-biotin method. RESULTS Active HHV-6 infection was demonstrated in four children: a bone marrow transplant recipient with concomitant adenovirus infection, a patient with hepatitis of unknown aetiology, a patient with congenital anomalies, and a patient with congenital immunodeficiency. CONCLUSION Accurate localisation of HHV-6 is possible in postmortem lung tissue. HHV-6 either alone or in combination with other pathogens may play a role in the development of pneumonitis.