Unsuitability of exhaled breath condensate for the detection of Herpesviruses DNA in the respiratory tract

Exhaled breath condensate is a non-invasive method for detecting a wide number of molecules as well as genomic DNA in the airways. No study investigated the detection of viral DNA in exhaled breath condensate, while only one study excluded its usefulness for detection of influenza virus RNA. In this study, the suitability of exhaled breath condensate for detecting erpesviruses infection or reactivation in the respiratory tract of lung transplant recipients was evaluated. Twenty-four matched samples (exhaled breath condensate, bronchoalveolar lavage, whole blood, transbronchial biopsy) were evaluated for the detection of human cytomegalovirus (HCMV), human herpesvirus (HHV-6 and -7), Epstein-Barr virus (EBV) DNA by real-time PCR. Eighteen bronchoalveolar lavages (75%), six whole blood samples (25%), and two transbronchial biopsies (8.3%) were positive for at least one herpesvirus. Only one exhaled breath condensate specimen was positive for HCMV DNA (and positive also in the bronchoalveolar lavage, with low viral load in both specimens); while no other patient, irrespective of the viral load in any specimen or the presence of clinical symptoms and signs, had a positive exhaled breath condensate. These findings seem to exclude the suitability of exhaled breath condensate for non-invasive detection of viral DNA in the respiratory tract of lung transplant recipients.