Clinical significance of respiratory virus detection in patients with acute exacerbation of interstitial lung diseases

Abstract Background The impact of viral infections on acute exacerbations in idiopathic pulmonary fibrosis (IPF) and/or non-IPF interstitial lung disease (ILDs) has been scarcely described. Objectives To elucidate the frequency of virus infections in patients with IPF or non-IPF ILDs including idiopathic interstitial pneumonia (IIP) or connective tissue disease (CTD)-associated pneumonia, and its influence on their short-term mortality. Methods We prospectively enrolled adult patients with acute exacerbation of IPF and non-IPF ILDs who were admitted to the hospital during the last 3 years, and examined the respiratory samples obtained from nasopharyngeal, sputum, and bronchoalveolar lavage fluid. Results A total of 78 patients were identified, consisting of 27 patients with acute exacerbation of IPF and 51 patients with non-IPF ILDs (IIP: n = 27, CTD-associated IP: n = 24). Of all patients, 15 (19.2%) had viruses detected in their respiratory samples including the human herpesvirus 7 (HHV7; n = 4) and cytomegalovirus (CMV) plus HHV7 (n = 3). The proportion of virus infections in the IPF and non-IPF ILDs groups was comparable. The Kaplan-Meier survival curves over 60 days revealed a lower survival probability in the virus positive group (n = 15, 60%) than in the virus negative group (n = 60, 83.3%, p  Conclusions Viral infections, mostly CMV or HHV7, were identified in both patients with acute exacerbation of IPF and non-IPF ILDs, but the clinical significance on short-term mortality or isolation itself from respiratory samples remains to be determined.