Since IL-4 is a multifunctional cytokine that acts on various allergy-related cells, several attempts have been made to develop an anti-IL-4 therapy whilst the successful inhibition of airway inflammation in a murine model of asthma [73] has led to clinical trials of soluble IL-4 receptors (IL-4R) for treating asthma. This evidence concerns the gene IL4 and asthma.