Anticardiolipin antibodies in patients with pregnancy loss induce factor Xa production in the presence of beta 2-glycoprotein I.
OBJECTIVE
Anticardiolipin antibodies (aCL) are commonly associated with recurrent pregnancy loss, though the mechanism is uncertain. Some investigators have indicated that aCL may be directed at a complex made up of cardiolipin and a blood anticoagulant, beta 2-glycoprotein I (beta 2GPI). We therefore investigated the effects of beta 2GPI-dependent aCL IgG enriched fractions, isolated from sera of patients with pregnancy losses, on blood coagulation.


METHODS
beta 2GPI-dependent aCL were prepared from sera of three women with second trimester pregnancy losses, by cardiolipin affinity column chromography, following by anti-beta 2GPI affinity column chromatography. The effects of beta 2GPI and beta 2GPI-dependent aCL on the activation of factor X in vitro were examined.


RESULTS
beta 2GPI inhibited the activation of factor X and beta 2GPI-dependent aCL blocked this inhibitory effect in a dose dependent manner.


CONCLUSIONS
These results imply the possibility of beta 2GPI-dependent aCL induce hypercoagulation or thrombus by blocking the inhibitory effect of beta 2GPI on activation of factor X, which may result in pregnancy loss.
Ogasawara
M
M
Department of Obstetrics and Gynecology, Nagoya City University Medical School, Japan.
Aoki
K
K
Matsuura
E
E
Kunimatsu
M
M
Ohkubo
I
I
Galli
M
M
Sasaki
M
M
Yagami
Y
Y
D000026:Abortion, Habitual / Q000097:blood / Q000209:etiology / Q000276:immunology*; D017153:Antibodies, Anticardiolipin / Q000302:isolation & purification / Q000502:physiology*; D001053:Apolipoproteins / Q000502:physiology*; D001777:Blood Coagulation / Q000187:drug effects / Q000276:immunology; D015951:Factor Xa / Q000096:biosynthesis* / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D053482:beta 2-Glycoprotein I
D017153:Antibodies, Anticardiolipin; D001053:Apolipoproteins; D006023:Glycoproteins; D053482:beta 2-Glycoprotein I; D015951:Factor Xa