LEUKOTRIENES AND LIPOXINS - NEW POTENTIAL PERFORMERS IN THE REGULATION OF HUMAN MYELOPOIESIS

Leukotrienes and lipoxins are bioactive lipoxygenase products formed b y leukocytes alone or in collaboration with other cells. While the phy siological role of lipoxins remains to be clarified, accumulating evid ence shows that leukotrienes are important mediators in asthma and inf lammation. Consequently, recent clinical trials with leukotriene D-4 r eceptor antagonists and 5-lipoxygenase inhibitors have demonstrated ma rked reduction of airway symptoms in asthmatic patients. In addition, both leukotrienes and lipoxins have been indicated as modulators of ce ll proliferation. This article reviews recent findings suggesting that these compounds may also participate in the regulation of human myelo poiesis. Such a role is conceivable since leukotrienes and lipoxins ca n be produced by bone marrow cells and potently modulate GM-CSF-induce d myeloid stem cell proliferation.