title: Autoantibodies to contact proteins in patients with recurrent pregnancy losses.
abstract: The kallikrein-kinin system or plasma contact system consists of three essential plasma proteins. These are coagulation factor XII, prekallikrein and high molecular weight kininogen. Deficiencies of these proteins are not associated with clinical bleeding despite marked prolongation of in vitro surface-activated coagulation time. Paradoxically, studies suggest that contact proteins have anticoagulant, profibrinolytic functions in a physiologic millieu, on endothelial cells. Recently, evidence has accumulated for the presence of the kallikrein-kinin system or plasma contact system in the fetoplacental unit. Kinins which are released within the placenta may play a role in regulating placental blood flow. This suggests that the plasma contact system may also have an important role in pregnancy. Several studies have reported the presence of autoantibodies to the contact proteins in patients with recurrent early pregnancy losses. Disruption of this system may be a risk factor for early gestational losses.
authors.affiliation: Department of Obstetrics and Gynecology, Center for Growth and Reproductive Medicine, Tokai University School of Medicine, Bohseidai, Isehara Kanagawa 259-1193, Japan. sugi@is.icc.u-tokai.ac.jp
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Sugi
authors.forename: Tsunehisa
authors.initials: T
authors.lastname: Makino
mesh_terms: D000026:Abortion, Habitual / Q000097:blood* / Q000209:etiology / Q000276:immunology*; D017152:Antibodies, Antiphospholipid / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D005174:Factor XII / Q000276:immunology*; D005175:Factor XII Deficiency / Q000276:immunology; D005260:Female; D006801:Humans; D016234:Kallikrein-Kinin System / Q000276:immunology; D019679:Kininogen, High-Molecular-Weight / Q000276:immunology*; D011247:Pregnancy; D011288:Prekallikrein / Q000276:immunology*; D012307:Risk Factors
chemical_list: D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies; D019679:Kininogen, High-Molecular-Weight; D005174:Factor XII; D011288:Prekallikrein