The role of mast cell-derived secreted phospholipases A2 in respiratory allergy.
Secreted phospholipases A(2) (sPLA(2)s) are molecules released in plasma and biological fluids of patients with systemic inflammatory, autoimmune and allergic diseases. These molecules exert proinflammatory effects by either enzymatic-mechanisms or through binding to surface molecules expressed on inflammatory cells. sPLA(2)s are released at low levels in the normal airways and tend to increase during respiratory allergies (e.g., rhinitis and bronchial asthma) as the result of local secretion. Several sPLA(2) isoforms are expressed in the human lung and some of them (e.g., group IIA and group X) are released in the airways of patients with rhinitis or asthma. Mast cells play a major role in the pathogenesis of respiratory allergies and other chronic inflammatory lung diseases. Recent evidence indicates that mast cells purified from human lung express most of the sPLA(2) isoforms so far described. IgE-mediated activation of these cells induce the release of sPLA(2)s suggesting that mast cells are a main source of extracellular sPLA(2)s during allergic reactions. Once released, sPLA(2)s may contribute to the generation of eicosanoids (e.g., PGD(2) and LTC(4)) and to the release of preformed mediators (e.g., histamine) by an autocrine loop involving the interaction of sPLA(2)s with surface molecules such as heparan sulphate proteoglycans or the M-type receptor. Thus, mast cell-derived sPLA(2)s may play an important role in the initiation and amplification of the inflammatory reactions in patients with allergic rhinitis and bronchial asthma.
Granata
Francescopaolo
F
Department of Clinical Immunology and Allergy and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, 80131 Naples, Via Pansini 5, Italy.
Staiano
Rosaria Ilaria
RI
Loffredo
Stefania
S
Petraroli
Angelica
A
Genovese
Arturo
A
Marone
Gianni
G
Triggiani
Massimo
M
D000818:Animals; D001249:Asthma / Q000201:enzymology / Q000276:immunology; D006801:Humans; D008168:Lung / Q000276:immunology; D008407:Mast Cells / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D008954:Models, Biological; D054497:Phospholipases A2, Secretory / Q000378:metabolism*; D012130:Respiratory Hypersensitivity / Q000201:enzymology*; D012137:Respiratory System / Q000276:immunology
D054497:Phospholipases A2, Secretory