The direct role of antiphospholipid antibodies (aPL) at maternal-fetal interface has not been fully investigated, especially whether they are involved in physiological and pathological implantation conditions, in an antiphospholipid syndrome (APS)-independent manner. In fact, trophoblast cells and placental endothelial cells at the implantation site express potential aPL targeted-phospholipid antigens (PL Ags); thus, the local production and presence of their specific antibodies, not related to APS (characterized by aPL presence in the peripheral blood), could be a potential marker of aberrant invasion, implantation and fetal-maternal immune tolerance processes. Anti-Beta2glycoprotein I (anti-β2GPI) and anticardiolipin (aCL Ab) antibodies (the most clinically relevant aPL) were detected by immunoenzymatic assay (ELISA), in the amniotic fluid (AF) of 167 women with physiological and complicated common pregnancy conditions, sharing an aberrant implantation process, such as recurrent pregnancy loss (RPL), autoimmune hypothyroidism (ahT) and smoking. All women included in the study were negative to peripheral blood aPL. aCL and anti-β2GPI antibodies were detectable in all the AF samples. RPL, ahT and smoking patients had higher level of anti-β2GPI Abs (IgM) compared to women with physiological pregnancies (p < 0.0001). Since IgM cannot cross the placenta, their local production in response to maternal-fetal interface stimuli, could be hypothesized. The presence of aPL in the AF (not related to APS) could reveal a potential clinical significance at maternal-fetal interface in selected pregnancy complications, in which an aberrant implantation process, and in turn an impaired fetal-maternal immune tolerance cross-talk, could occur.

中文翻译：

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羊水抗磷脂抗体：在抗磷脂综合征独立异常植入过程中的潜在作用

尚未充分研究抗磷脂抗体（aPL）在母胎界面上的直接作用，特别是它们是否以抗磷脂综合征（APS）独立的方式参与生理和病理植入条件。实际上，植入位点的滋养层细胞和胎盘内皮细胞表达潜在的aPL靶向磷脂抗原（PL Ags）。因此，与APS不相关的特异性抗体的局部产生和存在（以外周血中aPL的存在为特征）可能是异常侵袭，植入和胎儿-母亲免疫耐受过程的潜在标志。抗Beta2糖蛋白I（抗β2GPI）和抗心磷脂（aCL Ab）抗体（临床上最相关的aPL）通过免疫酶检测（ELISA）进行检测，167名患有生理和复杂的普通怀孕状况的妇女的羊水（AF）中，存在着异常的着床过程，例如反复流产（RPL），自身免疫性甲状腺功能低下（ahT）和吸烟。纳入研究的所有女性均对外周血aPL阴性。在所有AF样品中均检测到了aCL和抗β2GPI抗体。RPL，ahT和吸烟患者的抗β2GPIAbs（IgM）水平高于生理怀孕的女性（p <0.0001）。由于IgM不能穿过胎盘，因此可以假设它们是响应母胎界面刺激而产生的局部产物。AF中存在aPL（与APS不相关）可能会揭示某些妊娠并发症中母胎界面的潜在临床意义，其中异常的植入过程，