The role of leukotriene inhibitors in allergic rhinitis and paranasal sinusitis

Abstract

Leukotrienes (LTs) have been known in the field of immunology since the 1930s. At that time they were referred to as the slow reacting substance of anaphylaxis. However, they were not characterised until the 1980s, when they were noted to be formed during the breakdown of arachidonic acid (AA) by the enzyme 5-lipoxygenase (5-LO). There are 5 types of LT: LTA₄, LTB₄, LTC₄, LTD₄ and LTE₄. LTs are so called because the molecules were originally isolated from leukocytes and their carbon backbones contain 3 double bonds in series (a trion). This structural information provided the key to the oxidative pathway of lipometabolism, known as the 5-LO pathway. LTs are classified as inflammatory mediators. They are produced by a number of cell types, particularly mast cells, eosinophils, basophils, macrophages and monocytes. With the identification disorders associated with inflammatory pathways, such as asthma, allergic rhinitis and paranasal sinusitis, the LTs have been implicated in the pathogenesis of these conditions and have become targets for therapeutic modulation. In this review we will look at the biological effects of LTs, how they are formed, their role in asthma patients, the first therapeutic use of LT inhibitors and finally LTs with reference to the paranasal sinus areas [1,2].

• 5-lipoxygenase
• allergic rhinitis
• asthma
• leukotrienes
• nasal polyposis
• sinusitis