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

Utokaparch et al 35 with qPCR in frozen lung tissue from 20 GOLD stage 1 COPD patients in stable state and 20 healthy smoker controls, detected viral nucleic acid in 18/40 patients. The two most common viruses detected were influenza virus A and coronavirus 229E, each isolated in 10/40 samples. 35 Influenza virus was more prevalent in COPD patients than in control subjects (40% vs 10%). COPD patients had a greater total viral load and a greater number of viruses per patient compared with healthy controls. 37 Mallia et al 37 also showed a significant inverse relationship between the forced expiratory volume in 1 second/forced vital capacity ratio and the number of macrophages and neutrophils in the small airways, and a direct relationship between inflammatory cells and total viral load. The authors postulated that viruses might act as a pathogen reservoir in COPD. COPD patients are considered more susceptible to virus infection and persistence of infection.