Anti beta 2glycoprotein I antibodies and lupus anticoagulant in patients with recurrent pregnancy loss: prevalence and clinical significance.

Anticardiolipin antibodies (aCL) were found to recognize beta 2glycoprotein I (beta 2GPI) structure altered by its interaction with an oxygen modified solid phase surface by gamma-ray radiation. Lupus anticoagulant (LA) has been reported to comprise anti prothrombin antibodies, anti factor X antibodies and anti beta 2GPI antibodies. The present study focuses on the possible association between antibodies against the altered beta 2GPI structure (anti beta 2GPI antibodies) and LA in patients with recurrent pregnancy loss. Moreover, the clinical significance of both subgroups of so-called antiphospholipid antibodies were investigated to cast light on the controversy of whether aCL and LA are risk factors for pregnancy losses. One hundred and ninety five women with a history of two or more unexplained consecutive miscarriages and 100 control pregnant women were tested. Lupus anticoagulant was detected by the dilute phospholipid activated partial thromboplastin time. Anti beta 2GPI antibodies were measured by the ELISA method using commercially oxygenated microtiter plates. Twenty two (11.3%) and 19 (9.7%) of the 195 recurrent aborters were, respectively, positive for LA and anti beta 2GPI antibodies. Seven (3.6%) of the aborters had both of them. None of the control pregnant women had LA. Three of the control pregnant women had anti beta 2GPI antibodies. Nine (40.9%) of 22 aborters with positive-LA had a history of miscarriages in the second trimester as compared to 8 (4.6%) of 173 aborters with negative-LA. (P = 0.000007, Odds ratio = 14.3). None of the 12 aborters with anti beta 2GPI antibodies but no LA had a history of second trimester-fetal loss. These results support the hypothesis that aCL and LA define two distinct but partly related populations and that aCL include two subtypes of antibodies, with and without LA activity. LA and anti beta 2GPI antibodies appear to be associated with pregnancy loss, with LA being linked not only to abortions in the first trimester but also to miscarriages in the second trimester.