Sputum interleukin-17 is increased and associated with airway neutrophilia in patients with severe asthma

Asthma is a chronic inflammatory airway disease characterized by the involvement of many cells( including eosinophils, mast cells, T cells,neutrophils and airway epithelial cells ) and their cellular components. 1 While airway eosinophilic inflammation is considered as a characteristic ofasthma, our previous reports and other recent studies have demonstrated that neutrophils may play important roles in airway inflammation,