Increased Plasma Concentrations of Antiprothrombin Antibodies in Women with Recurrent Spontaneous Abortions

Anti-Prothrombin Antibodies are Associated with Adverse Pregnancy Outcome

“…In our series, anti‐PT antibodies showed a strong association with unexplained late fetal death (OR, 95% CI: 10.80, 2.35–49.67; P < 0.001). The prevalence of anti‐PT antibodies in controls was similar to those previously reported in literature, 5,6 and we find it hard to believe that the highly significant difference between cases and controls is a chance finding. Although there has been controversy around how anti‐PT assays should be performed, the microplate for immunometric enzyme immunoassay used in our study is coated with highly purified prothrombin, and the native immunogenic structure of prothrombin, after immobilization on the solid phase, is guaranteed by the manufacturer.…”

“…Although the mechanisms, if any, by which anti‐PT antibodies might be involved in adverse pregnancy outcomes remain hypothetical, their thrombogenic effect may well play a prominent role 16–18 . It is known that anti‐PT antibodies are a risk factor for venous thrombosis, 3,4 and they have been found in women with recurrent spontaneous abortions either in association or not, with aPL 4–6 . It has been suggested that they may lead to pregnancy loss by the promotion of microvascular placental thrombosis; the association of placental thrombosis with pregnancy loss is supported by histological findings 19 .…”

“…Suggested thrombogenic effects of anti‐PT antibodies are the inhibition of prothrombin‐dependent pathways that control the rate of further thrombin production and the inhibition of thrombin‐mediated prostacyclin release and protein C activation on the vascular endothelial cells. Furthermore, high prevalence of anti‐PT was found in women with early pregnancy loss either associated with 5 or not associated with antiphospholipid syndrome 6 . Anti‐protein S (anti‐PS) and anti‐protein C (anti‐PC) antibodies may exert a procoagulant effect by inhibiting the protein C/protein S degradation of activated factor V 7 .…”

Anti-Phosphatidylserine/Prothrombin Antibodies Are Associated with Adverse Pregnancy Outcomes

“…We found 7% (11/169) of patients to be aPS/PT positive and negative for all other tested aPL and 63% (7/11) of them experienced early recurrent pregnancy loss. Only one published study also confirmed association of antiprothrombin antibodies to early pregnancy loss; however it differed from the current study in that they measured aPT-A and included patients whose pregnancies ended spontaneously within 20th WG [ 21 ]. Considering the Sydney revised laboratory criteria of APS, only 17.8% (30/169) of patients in our study were positive for LA or aCL and/or anti- β 2 GPI, but when aPS/PT was evaluated as an additional parameter, 24.8% (41/169) of patients were aPL positive.…”

“…Five studies tested only aPT-A antibodies, which are (according to newer data) less significant for APS [ 3 , 12 , 14 , 17 , 21 ]. Among five larger studies, recruiting more than 100 patients, three showed significant association of aPS/PT or aPT-A with obstetric complications [ 3 , 18 , 21 ]; one did not find any significant association; however they only measured aPT-A antibodies [ 14 ], and one was performed before 2006 and recruited patients with more than two recurrent miscarriages, instead of three [ 15 ]. Conflicting data in the literature and the lack of studies investigating the role of antiprothrombin antibodies in obstetric APS led us to study the occurrence of these antibodies in different early and late adverse pregnancy outcomes.…”