Mechanisms of asthma.

Understanding of the mechanisms of asthma has progressed in three areas: the genetics of asthma, the role of nitric oxide in asthma, and the role of neurokinins in asthma. Genes encoding for the high affinity IgE receptor, the beta 2-adrenergic receptor, and interleukin-4 have been linked to clinical characteristics of asthma. Exhaled nitric oxide may be a useful clinical marker for airway inflammation in asthma. Tachykinin receptors are present in human lung and may be differentially expressed in individuals with asthma.