Bacterial–viral load and the immune response in stable and exacerbated COPD: significance and therapeutic prospects

D’Anna, Silvestro Ennio; Balbi, Bruno; Cappello, Francesco; Carone, Mauro; Di Stefano, Antonino

Microbiome and immune response in COPD exacerbation episode were correlated with a shorter time to the next exacerbation. Moreover, frequent exacerbators had higher serum levels of IL-6 and CRP in comparison to infrequent exacerbators. The authors suggested that these higher inflammatory indices in frequent exacerbators could be related to the faster forced expiratory volume in 1 second decline and increased mortality seen in this subgroup of patients. 58 Nonrespiratory viruses such as human immunodeficiency virus can change the lung microbiome facilitating colonization by pathogenic gastrointestinal bacteria in infected patients. 59, 60 There are relatively few data available concerning viral infections in COPD patients caused by influenza virus A, coronavirus, Respiratory syncytial virus, and rhinovirus. [35] [36] [37] 39 Among nonrespiratory viruses involved in COPD exacerbations and lung microbiome alterations, data are limited only to human immunodeficiency virus infections. 59, 60 Moreover, these studies included only patients with mild COPD. [35] [36] [37] 39 As a consequence, further studies investigating the host immune response in relation to different stages and phenotypes of COPD patients are needed.