Haemophilus influenzae stimulation of alveolar macrophages from COPD patients; effects of corticosteroids

Haemophilus influenzae stimulation on alveolar macrophages from COPD patients; effects of corticosteroids R.Khalaf, S.Lea, H.Metcalfe & D.Singh. University of Manchester, NIHR Translational Research Facility, University Hospital Of South Manchester Foundation Trust, Southmoor Road, Manchester.Background: The lower airways of COPD patients are chronically colonized by bacteria in stable disease. Airway colonization is a dynamic process and believed to play an important role in disease progression and development of acute exacerbation. Non-typeable Haemophilus influenza (NTHI) has been identified as a common airway colonizer and common cause for COPD exacerbation. Corticosteroids, are the mainstay in treatment of COPD and its exacerbation, however corticosteroid resistance is an emerging problem in management.Study aim is to investigate the in vitro response of alveolar macrophage (AM) to NTHI infection in terms of cytokine release and to study the effect of corticosteroids on this response; furthermore we sought to follow the downstream signalling pathways of NTHI infection in AM. Methods: AM from 12 COPD patients and 9 smoking controls were infected with live NTHI (strain 12) at multiplicity of infection (MOI) of 100:1 (bacteria: AM) for 24 hours. AM were pre-treated with dexamethasone (1, 0. 1, 0.01, 0.001 and 0.0001 µM) for 1 hour. AM response was assessed by measuring TNF-α, IL-6, IL-8 and IL-10 by ELISA. AM protein was extracted for Western blot analysis of Nuclear Factor κB(NFκB), P38 and Extracellular regulated mitogen activated protein kinases(P38 and ERK) activation.Results: NTHI stimulates AM to release TNF-α, IL-6, IL-8 and IL-10 from AM after 24 hours of infection (p