Detection of human cytomegalovirus in bronchoalveolar lavage fluid of lung transplant recipients reflects local virus replication and not contamination from the throat

Whether bronchoalveolar lavage (BAL) fluid may be contaminated with oropharyngeal cytomegalovirus (CMV) has never been investigated. In an analysis of CMV DNA loads in 76 simultaneously obtained BAL fluid and throat wash samples from lung transplant recipients, we show that such contamination is unlikely and that detection of CMV DNA in BAL fluid reflects virus replication in the lung.