Anti-microbial immunity is impaired in COPD patients with frequent exacerbations

Aran Singanayagam; Su-Ling Loo; Maria Calderazzo; Lydia J Finney; Maria-Belen Trujillo Torralbo; Eteri Bakhsoliani; Jason Girkin; Punnam Veerati; Prabuddha S Pathinayake; Kristy S Nichol; Andrew Reid; Joseph Foottit; Sebastian L Johnston; Nathan W Bartlett; Patrick Mallia

A cohort of 40 COPD subjects was recruited to a longitudinal study carried out at St Mary's Hospital, London UK between June 2011 to December 2013 investigating the pathogenesis of naturallyoccurring COPD exacerbations. The study protocol was approved by the East London Research Ethics Committee (study number 11/LO/0229) and all subjects gave informed written consent. The subjects all had a clinical diagnosis of COPD that was confirmed with spirometry. All subjects had an initial visit at baseline when clinically stable for clinical assessment, spirometry (forced expiratory volume in 1 second (FEV 1 ), forced vital capacity (FVC) and peak expiratory flow (PEF)) and clinical sample collection including spontaneous or induced sputum, taken and processed as previously described 8, 15 . At the baseline visit, all subjects were asked about the number of exacerbations experienced in the previous year and were grouped into two groups -frequent exacerbators (≥2 exacerbations in preceding year) and infrequent exacerbators (0 -1 exacerbations in the previous year), as previously described 16 .