Because IL-5 is a pro-inflammatory cytokinethat increases the recruitment, activation, and survival of eosinophils, it isconsidered of pivotal importance in the pathophysiology of asthma.(40) Ying et al.(41) showed that IL-5 is highly expressed in T cells, eosinophils, and mastcells in bronchial biopsy specimens collected from patients with asthma. The gene discussed is IL5; the disease is asthma.