title: [Platelet antigens: immunology and immuno-allergology].
abstract: Platelet immunology allows the understanding of clinical findings in a genetic and serologic basis. Blood platelets bear common antigens and same specific antigens, classified in five groups (HPA 1 to 5), that are localized on membrane glycoproteins Ia, Ib alpha, IIb and IIIa. Antiplatelet autoimmunization is generally due to IgG antibodies against membrane complexes IIb/IIIa or Ib/lX. Antiplatelet alloimmunization, clinically resulting in Posttransfusion Purpura and Neonatal Thrombocytopenia is more frequently associated with anti-IIb/IIIa antibodies, either anti-HPA-1a or HPA-1b. Finally, platelet participation in immunoallergic reactions is discussed, focusing both platelet activation by allergen itself and platelet recruitment by other inflammatory cells.
authors.affiliation: Servico de Medicina III, Hospital de Santa Maria, Propedêutica Médica, Faculdade de Medicina de Lisboa, Centro de Immunologia e Hematologia da Universidade de Lisboa, Portugal.
authors.forename: J C
authors.initials: JC
authors.lastname: de Sousa
authors.forename: A G
authors.initials: AG
authors.lastname: Palma-Carlos
mesh_terms: D000328:Adult; D016824:Antigens, Human Platelet / Q000145:classification / Q000276:immunology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D011247:Pregnancy
chemical_list: D016824:Antigens, Human Platelet; D010980:Platelet Membrane Glycoproteins
vernacular_title: Les antigènes plaquettaires: immunologie et immunoallergologie.