Open AccessImplication of IL‐18 in chronic inflammation of severe refractory asthma
Author(s) -
Roviikoletta,
Dima Efrosini,
Bakakos Petros,
Tseliou Eleni,
Kontogianni Konstantina,
Papiris Spiridon,
Koulouris Nikolaos,
Loukides Stylianos
Publication year - 2015
Publication title -
clinical and translational allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.979
H-Index - 37
ISSN - 2045-7022
DOI - 10.1186/2045-7022-5-s2-o10
Subject(s) - medicine , sputum , eosinophil , asthma , immunology , inflammation , proinflammatory cytokine , eosinophilic , methacholine , airway , pathophysiology of asthma , lung , respiratory disease , pathology , tuberculosis , surgery
In refractory asthma, where chronic inflammation and airway remodeling are key pathological features, it is suggested that the dysregulation of the Th1/Th2 cytokines production modifies airway inflammation and airway hyperrespnsiveness (AHR).Interleukin (IL)-18, a pleiotropic proinflammatory cytokine, contributes to the pathophysiology of asthma by modulating airway inflammation. Aim of this study was to investigate IL-18 levels in refractory asthma and its relation to eosinophilic airway inflammation and airway remodelling.IL-18 levels were measured in sputum supernatants obtained from patients with mild asthma (21 smokers and 24 non smokers), and patients with refractory asthma (n=18). Eosinophilic airway inflammation was assessed by measuring ECP, eosinophil counts in sputum and AHR to methacholine. Airway remodelling was assessed by measuring IL-13, VEGF and transforming growth factor (TGF)-b1 in induced sputum.Patients with refractory asthma had significantly lower IL-18 levels in sputum compared to smoking and non smoking asthmatics (pu003c0.001). IL-18 levels were correlated to the macrophagesu0027 percentage (r=0.635, p=0.026) and inversely correlated to neutrophilsu0027 percentage in sputum (r=-0.715, p=0.009). Furthermore, IL-18 levels in sputum correlated to FEV1 (% pred) (r=0.760, p=0.004), to FVC (% pred) (r=0.620, p=0.032), and to PD20Mch (r=0.733, p=0.007). No correlations were found between IL-18, ECP, TGF-β1, VEGF levels, and eosinophil counts in the sputum of refractory asthma.These findings suggest that in refractory asthma IL-18 is possibly involved in chronic airway inflammation and airway remodelling through an eosinophil independent pathway.