Detection by PCR of adenovirus and human herpes virus 6 in peripheral blood monocyte from young children who were hospitalized with lower respiratory tract infection

There are reports that the second most causative viral agent which causes lower respiratory tract infection (LRTI) in young children is adenovirus (ADV). Human herpes virus 6 (HHV-6) is also reported as a rare agent of LRTI in young children. But there is no report of simultaneous detection of ADV and HHV-6 in LRTI using the same peripheral blood monocyte (PBM) by nested-polymerase chain reaction (PCR) or PCR. Firstly, we detected ADV antigen (Ag) and HHV-6 Ag in serum by each monoclonal antibody with enzyme immunoassay (EIA). Secondly we tested two viruses in peripheral blood monocyte by nested-PCR or PCR. Twenty nine cases of young hospitalized children with LRTI (mean age 11.3 months, mean hospitalization period 5.7 days) had bronchiolitis or viral pneumonia and were confirmed by X-ray findings. Positivity of ADV Ag in serum by EIA was 75% (21/28) and positivity of HHV-6 Ag in serum by EIA was 10.7% (3/28). ADV in PBM by nested-PCR positivity was 89.7% (26/29) and HHV-6 in PBM by PCR positivity was 42.9% (12/28). ADV and HHV-6 dual infection in PBM by PCR was 11/29 (37.9%). Young children with dual infection were hospitalized (mean 6.3 days) with severe bronchiolitis.