Anti-beta(2)-glycoprotein-I and anti-phosphatidylserine antibodies in women with spontaneous pregnancy loss

How I diagnose and treat antiphospholipid syndrome in pregnancy

ABSTRACT

Antiphospholipid syndrome (APS) is a rare autoimmune disease characterized by arterial, venous, or microvascular thrombosis, pregnancy morbidities, or nonthrombotic manifestations in patients with persistently positive antiphospholipid antibodies. These antibodies bind cellular phospholipids and phospholipid-protein complexes resulting in cellular activation and inflammation that lead to the clinical features of APS. Our evolving understanding of APS has resulted in more specific classification criteria. Patients meeting these criteria should be treated during pregnancy according to current guidelines. Yet, despite treatment, those positive for lupus anticoagulant have at least a 30% likelihood of adverse pregnancy outcomes. Patients with recurrent early miscarriage or fetal death in the absence of preeclampsia or placental insufficiency may not meet current classification criteria for APS. Patients with only low titer anticardiolipin or anti-β(2)-glycoprotein I antibodies or immunoglobulin M isotype antibodies will not meet current classification criteria. In such cases, clinicians should implement management plans that balance potential risks and benefits, some of which involve emotional concerns surrounding the patient's reproductive future. Finally, APS may present in pregnancy or postpartum as a thrombotic microangiopathy, a life-threatening condition that may initially mimic preeclampsia with severe features but requires a very different treatment approach.

Effect of COVID-19 inactivated vaccine on peripheral blood anti-β2-GPI antibody and outcomes in vitro fertilization-embryo transplantation

Corona Virus Disease 2019 (COVID-19) is an acute respiratory infection and a global public health event. The level of aβ2GPI is significantly up-regulated in COVID-19 patients. The impact of inactivated vaccination against COVID-19 on aβ2GPI and in vitro fertilization and embryo transfer (IVF-ET) remains unknown amidst the universal administration of COVID-19 vaccines. We conducted a retrospective study to assess the impact of COVID-19 inactivated vaccination on aβ2GPI levels and its effect on superovulation and pregnancy outcomes. We found aβ2GPI level is significantly up-regulated after vaccination. There was no statistical difference in mature egg rate, 2PN fertilization rate, day 3 high-quality embryo rate, blastocyst formation rate, embryo implantation rate and miscarriage rate between the vaccine group and control group. Our findings showed vaccination with COVID-19 inactivated vaccine can elevate the level of aβ2GPI in peripheral blood but have no effect on the outcomes of controlled ovarian hyperstimulation and pregnancy in IVF-ET.

Factors associated with spontaneous abortion: a systematic review

Abstract Objectives: to compile studies produced regardinggenetic and non-genetic risks factors associated with occurrence of spontaneous abortion. Methods: it talks about a systematic review article, with studies between January of 2008 to November of 2018 according to SciELO, PubMed, Lilacs and BVS. Results: in total, 567 articles were found. After applying the definedeligibility criteria, 44 articles made part of the review, being the majority published on Asia between 2008 and 2011, and 10 articles published on Brazil. Not genetic causes like sociodemographic factors and healthy state were among the most associated conditions of spontaneous abortion. Asiatic continent had predominance about the correlation of spontaneous abortion with factors related to life style like obesity, smoking and labor activities, on the other hand, in the Americas, causes related to sociodemographics factors like low pay and low studies are high-lighted. Conclusions: the risk factors change about the occurrence region, being important to make local studies capable of subsidize the implantation of public politics and to reduce abortions.

Recommendations of the Spanish Rheumatology Society for Primary Antiphospholipid Syndrome. Part I: Diagnosis, Evaluation and Treatment

OBJECTIVE

The difficulty in diagnosis and the spectrum of clinical manifestations that can determine the choice of treatment for primary antiphospholipid syndrome (APS) has fostered the development of recommendations by the Spanish Society of Rheumatology (SER), based on the best possible evidence. These recommendations can serve as a reference for rheumatologists and other specialists involved in the management of APS.

METHODS

A panel of four rheumatologists, a gynaecologist and a haematologist with expertise in APS was created, previously selected by the SER through an open call or based on professional merits. The stages of the work were: identification of the key areas for drafting the document, analysis and synthesis of the scientific evidence (using the Scottish Intercollegiate Guidelines Network [SIGN] levels of evidence) and formulation of recommendations based on this evidence and formal assessment or reasoned judgement techniques (consensus techniques).

RESULTS

46 recommendations were drawn up, addressing five main areas: diagnosis and evaluation, measurement of primary thromboprophylaxis, treatment for APS or secondary thromboprophylaxis, treatment for obstetric APS and special situations. These recommendations also include the role of novel oral anticoagulants, the problem of recurrences or the key risk factors identified in these subjects. This document reflects the first 21, referring to the areas of: diagnosis, evaluation and treatment of primary APS. The document provides a table of recommendations and treatment algorithms.

CONCLUSIONS

An update of the SER recommendations on APS is presented. This document corresponds to partI, related to diagnosis, evaluation and treatment. These recommendations are considered tools for decision-making for clinicians, taking into consideration both the decision of the physician experienced in APS and the patient. A partII has also been prepared, which addresses aspects related to obstetric SAF and special situations.

Detection of non-criteria autoantibodies in women without apparent causes for pregnancy loss

Background

Some of the non‐criteria autoantibodies, especially non‐conventional antiphospholipid (aPL) antibodies, were present with high prevalence in sporadic miscarriages and recurrent pregnant loss. However, whether these autoantibodies are associated with miscarriage patients without apparent causes remain unclear.

Methods

The subjects were recruited from the female patients visiting the Infertility Center at the Beijing Obstetrics and Gynecology Hospital from January 2017 to March 2018. The women who experienced one sporadic miscarriage (n = 89) or recurrent pregnancy loss (n = 125) were enrolled. The control participants (n = 59) were those women with normal pregnancy history and with no miscarriage or thrombosis experience. The collected serum specimens from above patients and controls were subjected to the 13 non‐criteria autoantibody examinations, targeting non‐conventional phospholipids, thyroid, sperm, endometrial, and anti‐nuclear antigens.

Results

When compared with the controls, the following non‐criteria antibodies stood out in present study with significantly increased frequency and were listed in the order of decreasing positive rates: aPE IgM (40.0%), ANA (15.2%), aEM IgG (13.6%), aPE IgG (12.8%), and aPT IgM (10.4%). Except for ANA, the presence of aPE IgM, aEM IgG, aPE IgG, and aPT IgM was not associated with positivity of LA tests. In receiver operating characteristic analyses, the combined aPE IgG and aEM IgG biomarker panel had the best discriminating power between miscarriage patients and healthy controls.

Conclusion

Our findings suggested that the non‐criteria could be included as part of the pregnancy loss evaluation when apparent causes are absent, and the conventional aPLs tests failed to provide interpretations.

Antibodies to phosphatidylserine/prothrombin (aPS/PT) enhanced the diagnostic performance in Chinese patients with antiphospholipid syndrome

Background:

Increasing evidence has highlighted the role of non-criteria antiphospholipid antibodies (aPLs) as important supplements to the current criteria aPLs for the diagnosis of antiphospholipid syndrome (APS). In this retrospective study, we evaluated the clinical relevance of antibodies to phosphatidylserine/prothrombin (aPS/PT) in Chinese patients with APS.

Methods:

A total of 441 subjects were tested, including 101 patients with primary APS (PAPS), 140 patients with secondary APS (SAPS), 161 disease controls (DCs) and 39 healthy controls (HCs). Serum IgG/IgM aPS/PT was determined by ELISA.

Results:

The levels of IgG/IgM aPS/PT were significantly increased in patients with APS compared with DCs and HCs. IgG and IgM aPS/PT were present in 29.7% and 54.5% of PAPS, and 42.1% and 53.6% of SAPS, respectively. For diagnosis of APS, IgG aCL exhibited the highest positive likelihood ratio (LR+) of 21.60, followed by LA (13.84), IgG aβ2GP1 (9.19) and IgG aPS/PT (8.49). aPS/PT was detected in 13.3% of seronegative PAPS patients and 31.3% of seronegative SAPS patients. LA exhibited the highest OR of 3.64 in identifying patients with thrombosis, followed by IgG aCL (OR, 2.63), IgG aPS/PT (OR, 2.55) and IgG aβ2GP1 (OR, 2.33). LA and IgG aCL were correlated with both arterial and venous thrombosis, whereas IgG aPS/PT and IgG aβ2GP1 correlated with venous or arterial thrombosis, respectively.

Conclusions:

Our findings suggest that the inclusion of IgG/IgM aPS/PT may enhance the diagnostic performance for APS, especially in those in whom APS is highly suspected, but conventional aPLs are repeatedly negative. In addition, IgG aPS/PT may contribute to identify patients at risk of thrombosis.

Antiphospholipid syndrome and recurrent miscarriage: A systematic review and meta-analysis

Antiphospholipid syndrome (APS) is an autoimmune condition that is associated with thrombosis and morbidity in pregnancy. The exact mechanisms by which these associations occur appear to be heterogeneous and are not yet well understood. The aim of this study was to identify and analyze publications in recent years to better understand the diagnosis and its contribution to monitoring APS among women with recurrent miscarriage (RM). This systematic review and meta-analysis was conducted using the PubMed and Web of Knowledge databases, with articles published between 2010 and 2014, according to the PRISMA statement. Of the 85 identified studies, nine were selected. Most of the studies reported an association between recurrent miscarriage and specific antiphospholipid antibodies, as anticardiolipin antibodies (aCL), lupus anticoagulant (LA), anti-β2-glycoprotein I antibodies (aβ2GPI) and antiphosphatidylserine (aPS), which showed a relationship with RM. The main result of the meta-analysis revealed association between antiphospholipid antibodies (aPLs) and/or APS compared to the patients with RM (OR: 0.279; 95% CI: 0.212-0.366) and APS cases compared to the patients with RM (OR: 0.083; 95% CI: 0.036-0.189). High heterogeneity among these studies (I²=100.0%, p <0.001) was observed. In addition, there was no significant publication bias across studies according to Begg's test (p=0.230), although Egger's test (p=0.037) suggests significant publication bias. The funnel plot was slightly asymmetrical. Systematic review and meta-analysis demonstrated a positive association between antiphospholipid antibodies and/or antiphospholipid syndrome in patients with recurrent miscarriage.

Antiphospholipid syndrome: A diagnostic challenge

The antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilic disorder that is characterized by thrombosis (venous, arterial and microvascular) and obstetric morbidity due to a diverse family of antibodies against phospholipid-binding proteins present in plasma. The term antiphospholipid antibody is actually a misnomer as the antibodies are not against the phospholipid per se, but target the plasma protein co-factors, which bind to anionic PLs. The exact etiology has not been elucidated and is multifactorial. The initial guidelines for the diagnosis of APS were laid down in Sapporo, 1999, which were subsequently revised as the Sydney Consensus Conference criteria in 2006. Major changes were the inclusion of β2GPI as independent laboratory criteria, addition of ischemic stroke and transient cerebral ischemia as established clinical criteria and the requirement of repeating the test after 12 weeks. The laboratory tests recommended are coagulation assays, which study the effect of lupus anticoagulant on the clotting time and immunological assays, mostly ELISAs to detect IgG and IgM antibodies against cardiolipin and/or β2 glycoprotein I. For the diagnosis of APS, at least one clinical criterion and one laboratory criterion should be present. Limitations pertaining to the standardization, reproducibility and robustness of the currently recommended diagnostic tests still remain. Despite elaborate guidelines and syndrome defining criteria, the diagnosis of APS still remains a challenge. A greater interaction between the clinicians and the laboratory professionals is necessary for arriving at the correct diagnosis as a misdiagnosis of APS can have grave consequences.

Both IgG and IgM anti-beta2 glycoprotein I antibodies assays are clinically useful to the antiphospholipid syndrome diagnosis

OBJECTIVES

The aim of our study was to evaluate the clinical values of anti-beta2 glycoprotein I antibodies (anti-beta2GPI) IgG and IgM comparing with lupus anticoagulant (LA), anticardiolipin antibodies (aCL) in the two clinical groups of antiphospholipid syndrome (APS), vascular thrombosis (VT) and pregnancy morbidity (PM).

METHODS

Eighty patients who fulfilled the APS clinical criteria, VT n = 34; PM n = 40, both VT and PM n = 6 were included. LA, aCL and three anti-beta2GPI ELISA kits were tested.

RESULTS

Sensitivities of LA, aCL and anti-beta2GPI assays were found respectively 62, 26 and 41% in VT, and 28, 28 and 30% in PM. The sensitivity for the APS diagnosis could reach to 63% using triple tests. The presence of LA (P<0·01, OR = 4·3) or anti-beta2GPI IgG alone (P<0·05, OR = 8·4) was significantly associated with VT. IgM isotype was found more frequent in PM (92%) than in VT (57%) among all positive anti-beta2GPI cases.

CONCLUSION

Both IgG and IgM anti-beta2GPI assays were useful when clinical features of APS presented, even its standardization is ongoing. A decreased by half sensitivity of LA in PM compared with that in VT underlines the importance of adding anti-beta2GPI in PM of APS, especially IgM isotype although recent review questioned its significance.

Spectrum of antibodies to reproductive hormones in threatened abortion

The spectrum of antibodies to reproductive hormones and the diagnostic significance of their measurements in threatened abortion during trimester I were studied. Enhanced production of antibodies to hormones was detected by ELISA in patients with threatened abortion (N=44) in comparison with women with normal gestation (N=30). These antibodies were detected more often than antiphospholipid antibodies (p<0.05). Antibodies to chorionic gonadotropin (IgM, IgG) and gonadotropin-releasing hormone (IgG) were associated with threatened abortion. According to ROC analysis, their measurements were diagnostically significant in this pathology (AUC>0.8). Subclasses IgG1 and IgG2 predominated among IgG to chorionic gonadotropin. Presumably, antibodies to chorionic gonadotropin and gonadotropin-releasing hormone could serve as independent factors of threatened abortion risk during trimester I.

Bouquet variety of antiphospholipid antibodies in recurrent pregnancy loss

Seventy-six female patients with two or more recurrent pregnancy losses (RPL) during the 1(st) trimester were studied. Based on the results of the aCL and aB2GPI antibodies testing, patients were divided in two groups: 22 patients with RPL and elevated immunoglobulin (Ig) G/IgM aCL and/or aB2GPI [RPL + antiphospholipid syndrome (APS)] and 54 patients with RPL alone (without high antibodies). Immunoglobulin G aPS and IgG a-AnV in patients with RPL + APS were higher than in controls and IgG aPS were higher in RPL + APS than in RPL alone. Additionally IgG a-AnV and IgM aPE are higher in RPL alone than in controls. In 18/22 (81%) patients with RPL + APS and 29/54 (54%) patients with RPL alone, there were one or more positive antibodies: aPS, aPT, a-AnV or aPE. These results raise a question whether or not these antiphospholipid antibodies should be routinely tested in women with RPL and especially in the context of the so-called "seronegative APS".

Recurrent early pregnancy loss and antiphospholipid antibodies: where do we stand?

Evidence from basic science studies supports a causative relationship between antiphospholipid antibodies (aPL) and recurrent early miscarriage (REM) (prior to 10 weeks of gestation). However, human studies have not consistently found a relationship between aPL and REM. Members of the Obstetric Task Force of the 14th International Congress on Antiphospholipid Antibodies performed a literature review of the association of aPL and REM and searched for clinical trials in women with REM who tested positive for aPL. Of the 46 studies that investigated the relationship between aPL and REM, 27 found a positive association, seven found no association, and the remaining 12 papers could not report an association (lack of control group). The main identified problems for such conflicting results were varying definitions of REM (two or three abortions, not necessarily consecutive; different gestational age at which pregnancy losses occurred); analysis of patients with previous fetal death (>10 weeks) in the same group of REM; and different definitions of “positive aPL” (cutoffs not following international recommendations; small number of studies confirmed persistence of positive aPL after six to 12 weeks). The 10 identified randomized trials with proposed treatments for women with REM who test positive for aPL also had heterogeneous inclusion criteria, with only one trial limited to subjects who would meet the current criteria for antiphospholipid syndrome (APS) by both clinical and laboratory criteria. Against this background, we conclude that the association between REM and aPL remains inconclusive and that the findings of treatment trials are at best inconsistent and at worst misleading. More convincing data are critically needed. Studies that identify, or at least stratify, according to international consensus criteria and include standardized core laboratory testing results are crucial if we are to establish an evidence-based association between aPL and REM and treatment recommendations.

Anti-β2-glycoprotein I paratopes and β2-glycoprotein I epitopes characterization using random peptide libraries

Studies concerning interactions between anti-β2-glycoprotein I antibodies (anti-β2GPI) and β2-glycoprotein I (β2GPI) suggest relevance of charge interactions and hydrogen bonds. However, paratope of diagnostically and clinically relevant anti-β2GPI and epitope characteristics of β2GPI, still remain unclear. The aim of our study was to determine paratope characteristics of various anti-β2GPI antibodies and epitope characteristics of β2GPI using phage display. Monoclonal IgG anti-β2GPI, purified polyclonal high avidity and low avidity IgG anti-β2GPI derived from plasma of APS patients were used to screen phage display libraries. The affinity and competition ability of selected clones were evaluated. Various heptapeptides presenting putative paratopes of anti-β2GPI and specific heptapeptides presenting putative epitopes of β2GPI were determined. Epitope presenting peptides bind to the respective anti-β2GPI and consequently interrupt antibody-antigen interaction. The amino acid composition of selected peptides confirmed the importance of hydrogen bonds and charge interactions in the binding of anti-β2GPI to the antigen. Epitopes recognized by high avidity anti-β2GPI predominately contain hydrogen bond forming side chains, while in low avidity anti-β2GPI epitope the charged side chains prevail. The alignment of selected sequences to three-dimensional antigen structure revealed that polyclonal high avidity anti-β2GPI recognize native epitopes that are accessible regardless of β2GPI's conformation whereas the epitope recognized by low avidity anti-β2GPI is cryptic and cannot be accessed when β2GPI takes the closed plasma conformation.

Study on the pathogenesis of autoimmune-type recurrent spontaneous abortion by establishing a new mouse model

OBJECTIVE

To establish a new mouse model for autoimmune-type recurrent spontaneous abortion (AI-RSA) and demonstrate the potential role of intrauterine immunization with β2GP-1-like antigen in AI-RSA, we performed an intrauterine injection of human β2GP-1 in BALB/c mice and unrelated protein, adjuvants, and normal saline (NS) as controls. The mean number of embryos implanted (MNEI), embryo loss rate (ELR), mean embryo bulk (MEB), and mean placental weight (MPW) were analyzed. Compared with the control mice, BALB/c mice injected with human β2GP-1 showed increased anti-β2GP-1 and MPW. Moreover, BALB/c mice immunized with human β2GP-1 exhibited hypercoagulability and vascular thrombus formation in the placenta. Electron microscopy confirmed the existence of platelet aggregation, mitochondrial swelling, and endothelial cell necrosis in the placentas of BALB/c mice immunized with human β2GP-1. These finding indicated that intrauterine immunization with β2GP-1 successfully induced AI-RSA in mice. Increased anti-β2GP-1 antibody could independently induce hypercoagulability, vascular endothelial injury, and vascular thrombus formation in the placenta, which led to AI-RSA.

Top 10 clinical research developments in antiphospholipid syndrome

Persistently positive antiphospholipid antibodies (aPL) with thrombosis and/or pregnancy morbidity are a characteristic of antiphospholipid syndrome (APS). Although many challenges and controversies exist regarding APS diagnosis and management, there has been significant progress in APS clinical research in parallel with increased understanding of the pathogenesis. The purpose of this review is to discuss the "top ten" recent clinical developments in APS, including the magnitude of the problem, standardization of aPL tests, predictors of clinical events, diagnostic algorithms, new clinical research collaboration, and potential future treatments, e.g., new anticoagulants and immunosuppressive agents.

14th International Congress on Antiphospholipid Antibodies Task Force report on obstetric antiphospholipid syndrome

Pregnancy morbidity is one of the clinical manifestations used for classification criteria of antiphospholipid syndrome (APS). During the 14th International Congress on Antiphospholipid Antibodies (aPL), a Task Force with internationally-known experts was created to carry out a critical appraisal of the literature available regarding the association of aPL with obstetric manifestations present in actual classification criteria (recurrent early miscarriage, fetal death, preeclampsia and placental insufficiency) and the quality of the evidence that treatment(s) provide benefit in terms of avoiding recurrent adverse obstetric outcomes. The association of infertility with aPL and the effectiveness of the treatment of patients with infertility and positive aPL was also investigated. This report presents current knowledge and limitations of published studies regarding pregnancy morbidity, infertility and aPL, identifying areas that need better investigative efforts and proposing how critical flaws could be avoided in future studies, as suggested by participants of the Task Force. Except for fetal death, there are limitations in the quality of the data supporting the association of aPL with obstetric complications included in the current APS classification criteria. Recommended treatments for all pregnancy morbidity associated to APS also lack well-designed studies to confirm its efficacy. APL does not seem to be associated with infertility and treatment does not improve the outcomes in infertile patients with aPL. In another section of the Task Force, Dr. Jane Salmon reviewed complement-mediated inflammation in reproductive failure in APS, considering new therapeutic targets to obstetric APS (Ob APS).

Management of women with recurrent pregnancy losses and antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) have been associated with recurrent pregnancy losses (RPL) and other obstetrical complications. The diagnostic criteria for the classical antiphospholipid antibody syndrome (APS) have been utilized for the detection of obstetrical APS in women with RPL. However, laboratory findings and immunopathology of obstetrical APS are significantly different from those of classical APS. In addition, many women with RPL who have positive aPL do not have symptoms consistent with the current APS criteria. The induction of a proinflammatory immune response from trophoblasts and complement activation by aPL rather than thromboembolic changes has been reported as a major immunopathological feature of obstetrical APS. Heparin treatment has been reported to be effective in prevention of early pregnancy loss with APS but not for the late pregnancy loss or complications. The complex effects of heparin may explain the limited efficacy of heparin treatment in RPL. New diagnostic criteria for obstetrical APS are needed urgently, and new therapeutic approaches should be explored further.

Protein Z variants associated with protein Z plasma levels and with risk of idiopathic recurrent miscarriage

Protein Z (PZ) deficiency due to anti-PZ autoantibodies and/or mutations in PZgene was linked with adverse pregnancy outcomes, including idiopathic recurrent miscarriage (IRM). We investigated the association of rs3024718, rs3024719, rs3024731, rs3024778, rs3024772, and rs3024735 (G79A) PZ variants and changes in PZ levels in 287 women with IRM, and 308 control women. Of the 6 single nucleotide polymorphisms (SNPs) analyzed, higher minor allele frequency of rs3024735 (G79A) and rs3024731 were seen in IRM cases than in control women. Significantly higher frequencies of rs3024735/G79A G/A and A/A (P< .001), rs3024719 G/A (P= .009), and rs3024731 A/A (P = .012), but not rs3024718 (P= .12), rs3024778 (P = .76), or rs3024772 (P= .27) genotype carriers were seen between IRM cases versus control women, respectively, and was linked with reduced PZ levels. Six-locus (rs3024718/rs3024719/rs3024778/rs3024731/rs3024735/rs3024772) PZhaplotypes analysis demonstrated increased frequency of GAGAAG and AGGTAG and reduced frequency of AGGTGC haplotypes in IRM cases, thereby conferring disease susceptibility and protective nature to these haplotypes, respectively. These results demonstrate that specific PZSNPs and haplotypes are significantly associated with IRM.

Prediction of adverse pregnancy outcome by the presence of lupus anticoagulant, but not anticardiolipin antibody, in patients with antiphospholipid antibodies

OBJECTIVE

To investigate which serologic and clinical findings predict adverse pregnancy outcome in patients with antiphospholipid antibody (aPL) and to test the hypothesis that a pattern of clinical and serologic variables can identify women at highest risk of adverse pregnancy outcome.

METHODS

Women enrolled in a multicenter prospective observational study of risk factors for adverse pregnancy outcome in patients with aPL (lupus anticoagulant [LAC], anticardiolipin antibody [aCL], and/or antibody to β2-glycoprotein I [anti-β2 GPI]) and/or systemic lupus erythematosus (SLE) were recruited for the present prospective study. Demographic, clinical, serologic, and treatment data were recorded at the time of the first study visit. The relationship between individual and combined variables and adverse pregnancy outcome was assessed by bivariate and multivariate analysis.

RESULTS

Between 2003 and 2011 we enrolled 144 pregnant patients, of whom 28 had adverse pregnancy outcome. Thirty-nine percent of the patients with LAC had adverse pregnancy outcome, compared to 3% of those who did not have LAC (P<0.0001). Among women with IgG aCL at a level of ≥40 units/ml, only 8% of those who were LAC negative had adverse pregnancy outcome, compared to 43% of those who were LAC positive (P=0.002). IgM aCL, IgG anti-β2 GPI, and IgM anti-β2 GPI did not predict adverse pregnancy outcome. In bivariate analysis, adverse pregnancy outcome occurred in 52% of patients with and 13% of patients without prior thrombosis (P=0.00005), and in 23% with SLE versus 17% without SLE (not significant); SLE was a predictor in multivariate analysis. Prior pregnancy loss did not predict adverse pregnancy outcome. Simultaneous positivity for aCL, anti-β2 GPI, and LAC did not predict adverse pregnancy outcome better than did positivity for LAC alone.

CONCLUSION

LAC is the primary predictor of adverse pregnancy outcome after 12 weeks' gestation in aPL-associated pregnancies. Anticardiolipin antibody and anti-β2 GPI, if LAC is not also present, do not predict adverse pregnancy outcome.

Antiphospholipid syndrome: laboratory testing and diagnostic strategies

The antiphospholipid syndrome (APS) is diagnosed in patients with recurrent thromboembolic events and/or pregnancy loss in the presence of persistent laboratory evidence for antiphospholipid antibodies. Diagnostic tests for the detection of antiphospholipid antibodies include laboratory assays that detect anticardiolipin antibodies, lupus anticoagulants, and anti-β(2)-glycoprotein I antibodies. These assays have their origins beginning >60 years ago, with the identification of the biologic false positive test for syphilis, the observation of "circulating anticoagulants" in certain patients with systemic lupus erythematosus, the identification of cardiolipin as a key component in the serologic test for syphilis, and the recognition and characterization of a "cofactor" for antibody binding to phospholipids. Although these assays have been used clinically for many years, there are still problems with the accurate diagnosis of patients with this syndrome. For example, lupus anticoagulant testing can be difficult to interpret in patients receiving anticoagulant therapy, but most patients with a thromboembolic event will already be anticoagulated before the decision to perform the tests has been made. In addition to understanding limitations of the assays, clinicians also need to be aware of which patients should be tested and not obtain testing on patients unlikely to have APS. New tests and diagnostic strategies are in various stages of development and should help improve our ability to accurately diagnose this important clinical disorder.