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.