[Sulfidopeptide leukotrienes and asthma]

The role of sulfidopeptide leukotrienes in asthma alone or in association with other mediators is still debated. Sulfidopeptide leukotrienes (s-LT) C4, D4 and E4 are 5-lipoxygenase derivatives of membrane arachidonic acid. All s-LT contract bronchial smooth muscle in vitro and provoke an acute bronchial obstruction in vivo in both healthy and asthmatic subjects. Numerous cells, including mast cells, alveolar macrophages, polynuclear basophils and eosinophils, are capable of secreting s-LT following such diverse stimuli as allergen exposure, platelet activating factor and calcium ionophore A 23187. In addition to constricting bronchial smooth muscle, s-LT promote the occurrence of mucosal oedema increase micro-vascular permeability in the bronchial wall, and cause hypersecretion of mucus by tracheo-bronchial glands. These effects lead to worsening of airways obstruction. s-LT increase non specific bronchial hyper-responsiveness. Clinical trials aiming to test the efficacy of new anti-leukotrienes are currently under way. In general these products have a real antagonistic effect on exogenous s-LT. Their efficacy vis-a-vis other types of stimulus such as allergens, histamine and exercise does not seem to be constant and depends largely on the composition and perhaps the route of administration (inhaled versus oral). The contribution of s-LT as part of the therapeutic arsenal for the long term treatment of asthma remains to be established.