The therapy of biological agents in severe asthma.

Bronchial asthma is a heterogeneous disease characterized by airway hyperresponsiveness, smooth muscle contraction and airway inflammation. Multiple factors such as genetic back- ground and environmental factors are involved in the pathogenesis of asthma. Allergic asthma is a Th2-driven eosinophilic inflammatory disease, in which may cytokines including IL- 4, IL-5, and IL-13 play important roles. Monoclonal antibody therapies target specific mole- cules in severe asthma. Omalizumab, an IgE antibody, reduces symptoms and acute exac- erbations in severe asthma, and mepolizumab, a more recent monoclonal antibody against IL-5, is also efficacious in similar group of patients. In order to improve clinical ability and to achieve optimal health and economical benefit of biologics, further studies on clinical fac- tors and biomarkers which predict the drug efficacy are required.