Bacterial load and inflammatory response in sputum of alpha-1 antitrypsin deficiency patients with COPD

Abstract

Bruno Balbi,1 Claudia Sangiorgi,1 Isabella Gnemmi,1 Ilaria Ferrarotti,2 Davide Vallese,1 Elena Paracchini,1 Lorena Delle Donne,1 Luciano Corda,3 Paolo Baderna,4 Angelo Corsico,2 Mauro Carone,1 Paola Brun,5 Francesco Cappello,6,7 Fabio LM Ricciardolo,8 Paolo Ruggeri,9 Sharon Mumby,10 Ian M Adcock,10 Gaetano Caramori,9 Antonino Di Stefano11Istituti Clinici Scientifici Maugeri, IRCCS, Division of Pneumology and Laboratory of Cytoimmunopathology of the Heart and Lung, Veruno, Italy; 2Department of Internal Medicine and Medical Therapy, University of Pavia, Pavia, Italy; 3Medicina Respiratoria, Seconda Medicina Interna, Spedali Civili, Brescia, Italy; 4Division of Pneumology, Aosta Hospital, Aosta, Italy; 5Department of Molecular Medicine, University of Padova, Padova, Italy; 6Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, Sezione di Anatomia Umana, Università di Palermo, Palermo, Italy; 7Euro-mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy; 8Department of Clinical and Biological Sciences, A.O.U., San Luigi Gonzaga, Orbassano, University of Turin, Turin, Italy; 9UOC Di Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e Delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy; 10Airways Disease Section, National Heart and Lung Institute, Imperial College London, UKCorrespondence: Antonino Di StefanoIstituti Clinici Scientifici Maugeri Irccs, Via Maugeri, 4, Pavia 27100, ItalyTel [phone]Fax [phone]Email [email protected]: Airway inflammation may drive the progression of chronic obstructive pulmonary disease (COPD) associated with alpha-1 antitrypsin deficiency (AATD), but the relationship between airway microbiota and inflammation has not been investigated.Methods: We studied 21 non-treated AATD (AATD-noT) patients, 20 AATD-COPD patients under augmentation therapy (AATD-AT), 20 cigarette smoke-associated COPD patients, 20 control healthy smokers (CS) and 21 non-smokers (CON) with normal lung function. We quantified sputum inflammatory cells and inflammatory markers (IL-27, CCL3, CCL5, CXCL8, LTB4, MPO) by ELISA, total bacterial load (16S) and pathogenic bacteria by qRT-PCR.Results: AATD-AT patients were younger but had similar spirometric and DLCO values compared to cigarette smoke-associated COPD, despite a lower burden of smoking history. Compared to cigarette smoke-associated COPD, AATD-noT and AATD-AT patients had lower sputum neutrophil levels (p=0.0446, p=0.0135), total bacterial load (16S) (p=0.0081, p=0.0223), M. catarrhalis (p=0.0115, p=0.0127) and S. pneumoniae (p=0.0013, p=0.0001). Sputum IL-27 was significantly elevated in CS and cigarette smoke-associated COPD. AATD-AT, but not AATD-noT patients, had IL-27 sputum levels (pg/ml) significantly lower than COPD (p=0.0297) and these positively correlated with FEV1% predicted values (r=0.578, p=0.0307).Conclusions: Compared to cigarette smoke-associated COPD, AATD-AT (COPD) patients have a distinct airway inflammatory and microbiological profile. The decreased sputum bacterial load and IL-27 levels in AATD-AT patients suggests that augmentation therapy play a role in these changes.Keywords: alpha-1 antitrypsin deficiency, COPD, chronic airway inflammation, respiratory disability, sputum

Keywords

• Alpha-1 antitrypsin deficiency
• COPD
• chronic airway inflammation
• respiratory disability
• sputum