Abstract
Background: Severe refractory asthma (SRA) is characterized by amplified inflammatory/remodeling process. CC16 is associated with Th2 modulation. SPD plays an important role in surfactant homeostasis & eosinophil chemotaxis.
Aim: Measurement of CC16 & SPD levels in sputum supernatants of SRA patients, comparison with mild to moderate asthma and controls and investigation of inflammatory/remodelling mediator or cell associations.
Methods: 31 optimally treated SRA patients, 33 mild to moderate asthmatics and 12 controls were studied. All underwent lung function tests, bronchial hyperresponsiveness and Exhaled Nitric Oxide (FeNO) assessment, sputum induction for differential cell count and CC16, SPD, Il-8, IL-13, TGF-β & ECP measurement in sputum supernatants.
Results: CC16 [median (interquartile range) ng/ml] was significantly elevated in SRA compared to mild-moderate asthma and controls [214 (59-900) vs 58 (38-95) vs 33 (21-53), p<0.001].
SPD [ng/ml] was significantly elevated in SRA compared to mild to moderate asthma and controls [28.5 (18-45) vs 6.1 (4-9) vs 4.8 (3.4-7), p<0.001]. No difference was observed between mild to moderate asthmatics and controls for either CC16 or SPD. Regression analysis did not reveal significant associations between CC16 or SPD and sputum differential count, inflammatory/remodeling mediators, FeNO or lung function tests. A significant but moderate positive association was observed between CC16 and SPD [r2=0.2].
Conclusions: SPD & CC16 levels are upregulated in SRA compared to mild to moderate asthmatics and controls, being consistent with the hypothesis that epithelium injury & repair play an important role in this phenotype.
- © 2012 ERS
