Discovered in 1984, lipoxins ( LXS ) form , together with other metabolites of arachidonic acid autakoidów large group collectively eicosanoids . Of the three best known biosynthetic pathways lipoxins ( LXA4 and LXB4 ) , catalyzed by a two sequentially acting 12/15-lipoksygenazę 5 -i and the third initiated by aspirin acetylated cyclooxygenase- 2 and generates a 15- epimers of lipoxins ( 15R - LXA4 and B4) . Unlike other eicosanoids , lipoxins are mainly produced by two cooperating with each cell , such as neutrophils and platelets . Two types of receptors have been characterized for lipoxins : lipoxin -specific receptor A4, subject expression in monocytes and granulocytes and enterocytes present in cells other than neutrophils peptidoleukotriene receptor for which LXA4 is a partial agonist . In the current study shows that in vitro lipoxins have immunomodulatory properties , but it is difficult to say what is their role in immune reactions in vivo , involving other eicosanoids . It is believed that lipoxins are mediators of inflammation , act in opposition to the leukotrienes (stop Charles Serhan signaling hypothesis ) in an autocrine and inhibit the activity of neutrophils.