Airway eosinophilia in remission and progression of asthma: Accumulation with a fast decline of FEV1

Summary Background As it is unknown whether complete asthma remission or progression of asthma is associated with airway inflammation and remodeling, we assessed these characteristics in bronchial biopsies of relevant subsets of asthma patients. Methods Sputum and bronchial biopsies were obtained from asthma patients in remission (PC20 histamine > 32 mg/ml, PC20 AMP > 320 mg/ml) and from those with either a slow FEV1 decline (30 ml/year). Inflammatory cells and mediators were determined in sputum, inflammatory cells and aspects of airway remodeling in bronchial biopsies. Results Asthmatics in remission and asthma patients with a slow FEV1 decline had a similar extent of airway inflammation and remodeling in sputum and bronchial biopsies. Asthma patients with a fast FEV1 decline had high sputum eosinophil numbers. Moreover, FEV1 decline (ml/year) correlated with sputum eosinophil numbers (Rs = 0.51, p = 0.003) and ECP levels (Rs = 0.57, p = 0.001). Airway remodeling, i.e. basement membrane thickness, correlated with sputum eosinophils (Rs = 0.69, p < 0.001), sputum ECP (Rs = 0.46, p = 0.018) and airway wall eosinophil numbers (Rs = 0.49, p = 0.002). Conclusions Asthma, even when in remission, is accompanied by airway inflammation and remodeling. Data suggest that eosinophils are important in a subset of asthma patients by association to accelerated FEV1 decline and change of basement membrane thickness.