In two small, placebo-controlled, double-blind, crossover studies of patients with corticosteroid refractory asthma, treatment with anti-TNF-α antibody (etanercept) resulted in clinical improvement in PC20, quality-of-life scores, and lung function [38] and improvement in asthma control questionnaire scores with reductions in the use of nebulized β2 agonists [39]. Here, TNF is linked to asthma.