 Leukotrienes are produced from arachidonic acid by 5-lipoxygenase (which is made from phospholipids in the cell membrane) and other various enzymes.The cells of the immune system that release leukotrienes are basophils, eosinophils, mast cells and macrophages following various stimuli for example allergens.They bind to cysteinyl leukotriene receptors (CysLT).