Detection of viruses in pulmonary exacerbations in CF

Aims : To evaluate the involvement of viruses in CF pulmonary exacerbations and to identify the main viral pathogens.
Methods : Respiratory viruses were searched for, at the onset of any acute pulmonary exacerbation, in respiratory secretions obtained by nasal wash or broncho-alveolar lavage (BAL) using multiplex-PCR and culture, and potentially blood for viral serology.
Results : For 199 acute pulmonary exacerbations in 86 CF patients (median age = 11y4m; sex ratio : F/M = 42/44), a viral pathogen was detected in 64/199 (32,2%) episodes and in 3/64 episodes 2 viruses were found. The 3 main viral pathogens were influenza A virus, respiratory sincitial virus and human metapneumovirus, respectively found in 15, 15 and 8 episodes. In 56/64 (87,5%) episodes, the viral pathogen was detected on respiratory secretions (nasal wash: 52-BAL :4) and only in 9/30 (30%) by serology. Common viruses were found in all ages, however influenza A was mostly detected in adults (10 11/24=45,8%) whereas RSV was more present in the 0-2 yrs old (in 7/14=50%).
Conclusions : Common respiratory viruses seem to play a role in an unexpected high proportion (32%) of pulmonary exacerbations in CF patients of all age groups. PCR and culture on respiratory secretions obtained by nasal wash is a rapid, sensitive and non-invasive method for viral detection compared to serology.