Antiphospholipid antibodies in women with recurrent embryo implantation failure: A systematic review and meta-analysis

Innate and adaptive immune dysregulation in women with recurrent implantation failure

Recurrent implantation failure (RIF) is a condition where a woman fails to obtain pregnancy after multiple embryo transfer cycles, even with superior-quality blastocysts. There are various factors that can contribute to RIF, including immunologic disturbances. The immune system is extremely important during pregnancy. Immune cells such as T cells, B cells, natural killer (NK) cells, and macrophages (MQ) are present in the female reproductive tract and are accountable for regulating the immune response to invading pathogens and maintaining tissue homeostasis. Dysregulation of these immune cells can lead to inflammation, which can impair fertility. One of the most common immunological disturbances observed in RIF is an altered Th1/Th2 ratio, along with changes in NK cell and macrophage numbers. In addition, the presence of some antibodies, such as anti-ovarian antibodies, can also contribute to RIF. Interleukins have been implicated in the development of an inflammatory response that can interfere with successful embryo implantation. As a result, a comprehensive understanding of immunological compartments in RIF women could assist us in determining the immunological origins of this disease. We will discuss immunological factors that might contribute to RIF etiology, including cellular and molecular components.

Biological markers of high risk of thrombotic recurrence in patients with antiphospholipid syndrome: A literature review

OBJECTIVES

This review aims to identify biological markers associated with the risk of recurrence of thrombotic and/or obstetric events in patients with antiphospholipid syndrome (APS).

METHODS

A comprehensive review of literature was conducted to evaluate established and potential novel biological markers associated with thrombosis in APS. To this end, a PubMed literature search was conducted for the last twenty years using the following keywords or their combinations: thrombotic risk, recurrence of thrombosis, risk stratification, severity, predictive value.

RESULTS

Previous studies showed that multiple aPL positivity correlates with an increased risk of thrombosis in APS. Moreover, the analysis of N-glycosylation of antiphospholipid antibodies (aPL) revealed that low levels of IgG sialylation, fucosylation or galactosylation increases the pro-inflammatory activity of aPL, predisposing to thrombosis. In addition, quantification of neutrophil extracellular traps (NETs) and antibodies directed against NETs (anti-NETs) in serum demonstrates promising prognostic utility in assessing APS severity. Oxidative stress plays a role in the pathogenicity of APS and paraoxonase 1 (PON1) activity emerges as a promising biomarker of thrombotic risk in APS. Furthermore, identification of novel antigenic targets involved in the pathophysiology of APS, such as lysobisphosphatidic acid (LBPA), had led to the discovery of unconventional aPL, antibodies directed against the LBPA (aLBPA), whose clinical value could make it possible to identify APS patients at high risk of thrombotic recurrence.

CONCLUSION

The immunological profile of aPL, N-glycosylation of aPL, quantification of NETs and anti-NETs, analysis of biomarkers of oxidative stress and the discovery of aLBPA offer potential prognostic tools for risk stratification in APS patients.

Anti-phospholipid autoantibodies in human diseases

Anti-phospholipid autoantibodies are a group of antibodies that can specifically bind to anionic phospholipids and phospholipid protein complexes. Recent studies have reported elevated serum anti-phospholipid autoantibody levels in patients with antiphospholipid syndrome, systemic lupus erythematosus, rheumatoid arthritis, metabolic disorders, malaria, SARS-CoV-2 infection, obstetric diseases and cardiovascular diseases. However, the underlying mechanisms of anti-phospholipid autoantibodies in disease pathogenesis remain largely unclear. Emerging evidence indicate that anti-phospholipid autoantibodies modulate NETs formation, monocyte activation, blockade of apoptotic cell phagocytosis in macrophages, complement activation, dendritic cell activation and vascular endothelial cell activation. Herein, we provide an update on recent advances in elucidating the effector mechanisms of anti-phospholipid autoantibodies in the pathogenesis of various diseases, which may facilitate the development of potential therapeutic targets for the treatment of anti-phospholipid autoantibody-related disorders.

Identification of MARK2, CCDC71, GATA2, and KLRC3 as candidate diagnostic genes and potential therapeutic targets for repeated implantation failure with antiphospholipid syndrome by integrated bioinformatics analysis and machine learning

Background

Antiphospholipid syndrome (APS) is a group of clinical syndromes of thrombosis or adverse pregnancy outcomes caused by antiphospholipid antibodies, which increase the incidence of in vitro fertilization failure in patients with infertility. However, the common mechanism of repeated implantation failure (RIF) with APS is unclear. This study aimed to search for potential diagnostic genes and potential therapeutic targets for RIF with APS.

Methods

To obtain differentially expressed genes (DEGs), we downloaded the APS and RIF datasets separately from the public Gene Expression Omnibus database and performed differential expression analysis. We then identified the common DEGs of APS and RIF. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed, and we then generated protein-protein interaction. Furthermore, immune infiltration was investigated by using the CIBERSORT algorithm on the APS and RIF datasets. LASSO regression analysis was used to screen for candidate diagnostic genes. To evaluate the diagnostic value, we developed a nomogram and validated it with receiver operating characteristic curves, then analyzed these genes in the Comparative Toxicogenomics Database. Finally, the Drug Gene Interaction Database was searched for potential therapeutic drugs, and the interactions between drugs, genes, and immune cells were depicted with a Sankey diagram.

Results

There were 11 common DEGs identified: four downregulated and seven upregulated. The common DEG analysis suggested that an imbalance of immune system-related cells and molecules may be a common feature in the pathophysiology of APS and RIF. Following validation, MARK2, CCDC71, GATA2, and KLRC3 were identified as candidate diagnostic genes. Finally, Acetaminophen and Fasudil were predicted as two candidate drugs.

Conclusion

Four immune-associated candidate diagnostic genes (MARK2, CCDC71, GATA2, and KLRC3) were identified, and a nomogram for RIF with APS diagnosis was developed. Our findings may aid in the investigation of potential biological mechanisms linking APS and RIF, as well as potential targets for diagnosis and treatment.

The pathogenesis of obstetric APS: a 2023 update

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the persistent presence of antibodies directed against phospholipids and phospholipid-binding proteins that are associated with thrombosis and pregnancy-related morbidity. The latter includes fetal deaths, premature birth and maternal complications. In the early 1990s, a distinct set of autoantibodies, termed collectively antiphospholipid antibodies (aPL), were identified as the causative agents of this disorder. Subsequently histological analyses of the placenta from APS pregnancies revealed various abnormalities, including inflammation at maternal-fetal interface and poor placentation manifested by reduced trophoblast invasion and limited uterine spiral artery remodeling. Further preclinical investigations identified the molecular targets of aPL and the downstream intracellular pathways of key placental cell types. While these discoveries suggest potential therapeutics for this disorder, definitive clinical trials have not been completed. This concise review focuses on the recent developments in the field of basic and translational research pursuing novel mechanisms underlying obstetric APS.

Positive antiphospholipid antibodies: observation or treatment?

Antiphospholipid antibodies (APLAs) are  primarily directed toward phospholipid-binding proteins and are responsible for thrombotic events. APLAs include anti-β2Glycoprotein I (anti-β2GPI), anticardiolipin (anti-CL) antibodies, and lupus anticoagulant. These antibodies are typical markers of antiphospholipid syndrome (APS) and are a part of its diagnostic criteria. Many data underline the presence of APLAs in other rheumatic diseases (e.g., systemic lupus erythematosus, systemic sclerosis, Sjögren's syndrome, rheumatoid arthritis and Behçet's disease). However, they are also detected in patients with cancer, infection, and neurological disorders. Furthermore, healthy individuals may be carriers of APLAs. Chronic asymptomatic APLAs presence is most common in the elderly and subjects with chronic diseases (including malignancies). Specific kinds of APLAs are considered markers of oncological progression. These antibodies occur in 6% of pregnant women (without diagnosed APS) and are related to many pregnancy complications. Of worth, various types of APLAs are reported to have different prothrombotic properties. The risk of thrombotic events in APLA-positive but clinically naïve patients raises many questions in clinical practice. This manuscript analyses various clinical situations and consequences of the APLAs' presence, particularly in patients without diagnosed APS. The prevalence, etiology, molecular background, and prothrombotic properties of numerous APLAs are broadly discussed. The new management approach in different clinical conditions and organ complications is present in the context of recent recommendations. Discussed data underlines that adequate and timely introduced thromboprophylaxis can decrease the risk of thrombus formation and prevent increased morbidity.

Comparison of the conventional tube and erythrocyte-magnetized technology in titration of red blood cell alloantibodies

BACKGROUND

Erythrocyte alloantibodies are mainly produced after immune stimulation, such as blood transfusion, pregnancy, and transplantation, and are the leading causes of severe hemolytic transfusion reactions and difficulty in blood grouping and matching. Therefore, antibody screening is critical to prevent and improve red cell alloantibodies. Routine tube assay is the primary detection method of antibody screening. Recently, erythrocyte-magnetized technology (EMT) has been increasingly used in clinical practice. This study intends to probe the application and efficacy of the conventional tube and EMT in red blood cell alloantibody titration to provide a reference for clinical blood transfusion.

AIM

To investigate the application value of conventional tube and EMT in red blood cell alloantibody titration and enhance the safety of blood transfusion practice.

METHODS

A total of 1298 blood samples were harvested from blood donors at the Department of Blood Transfusion of our hospital from March 2021 to December 2022. A 5 mL blood sample was collected in tubing, which was then cut, and the whole blood was put into a test tube for centrifugation to separate the serum. Different red blood cell blood group antibody titers were simultaneously detected using the tube polybrene test, tube antiglobulin test (AGT), and EMT screening irregular antibody methods to determine the best test method.

RESULTS

Simultaneous detection was performed through the tube polybrene test, tube AGT and EMT screening irregular antibodies. It was discovered that the EMT screening irregular antibody method could detect all immunoglobulin G (IgG) and immunoglobulin M (IgM) irregular antibodies, and the results of manual tube AGT were satisfactory, but the operation time was lengthy, and the equipment had a large footprint. The EMT screening irregular antibody assay was also conducted to determine its activity against type O Rh (D) red blood cells, and the outcomes were satisfactory. Furthermore, compared to the conventional tube method, the EMT screening irregular antibody method was more cost-effective and had significantly higher detection efficiency.

CONCLUSION

With a higher detection rate, the EMT screening irregular antibody method can detect both IgG and IgM irregular antibodies faster and more effectively than the conventional tube method.

Pregnancy outcomes and adverse events in patients with recurrent miscarriage receiving fondaparinux versus low molecular-weight heparin: A meta-analysis

OBJECTIVE

Current opinion on the superiority of fondaparinux versus low molecular-weight heparin (LMWH) in treating recurrent miscarriage is controversial. This meta-analysis aimed to comprehensively compare the pregnancy outcomes and adverse events in patients with recurrent miscarriage receiving fondaparinux versus LMWH.

METHODS

EMBASE, PubMed, Cochrane, China National Knowledge Internet (CNKI), Wanfang Database, and China Science and Technology Journal Database (CQVIP) databases were searched for articles reporting fondaparinux versus LMWH in treating recurrent miscarriage till June 10, 2022. Inclusion criteria for study screening were: (i) randomized, controlled trials (RCT), non-randomized controlled studies, or observational studies; (ii) patients aged over 18 years; (iii) patients with recurrent miscarriage during gestation period; (iv) patients in the experimental/observational group who received FD, and patients in the control group who received LMWH; (v) studies involving at least one outcome of interest for the current analysis. Exclusion criteria were: (i) systematic reviews, meta-analyses, case reports, or animal studies; (ii) duplicated studies; (iii) incomplete or inconsistent data. Quality assessment was conducted with Newcastle-Ottawa Scale criteria or Cochrane Collaboration. Data of live birth, abortion, birth weight, fetal growth restriction (FGR), and adverse events were extracted and synthesized.

RESULTS

Six eligible studies (4 observational studies and 2 RCTs) with 321 patients receiving fondaparinux and 546 patients receiving LMWH were enrolled. Live birth (relative risks (RR) = 1.05, 95% confidence interval (CI) = 0.97 ∼ 1.14, P = 0.217), abortion (RR = 0.73, 95% CI = 0.50 ∼ 1.08, P = 0.113), birth weight (weighted mean difference = 167.20, 95% CI = -236.89 ∼ 571.30, P = 0.417), and FGR (RR = 0.95, 95% CI = 0.25 ∼ 3.59, P = 0.942) were of no difference between patients receiving fondaparinux and LMWH. Regarding adverse events, the incidence of ecchymosis (RR = 0.11, 95% CI = 0.03 ∼ 0.46, P = 0.002) and skin reaction at injection site (RR = 0.15 95% CI = 0.05 ∼ 0.44, P = 0.001) were lower in patients receiving fondaparinux compared with those receiving LMWH, while that of thrombocytopenia (RR = 0.45, 95% CI = 0.09 ∼ 2.14, P = 0.315), vagina bleeding (RR = 1.03, 95% CI = 0.62 ∼ 1.71, P = 0.646), and oral mucosa hemorrhage (RR = 1.08, 95% CI = 0.33 ∼ 3.51, P = 0.899) did not vary between these patients receiving these two treatments. However, most studies were conducted in China, which could induce regional and ethnic bias.

CONCLUSION

Fondaparinux is attributable to fewer adverse events and similar pregnancy outcomes compared with LMWH in patients with recurrent miscarriage.

Recurrent implantation failure: A comprehensive summary from etiology to treatment

Implantation is the first step in human reproduction. Successful implantation depends on the crosstalk between embryo and endometrium. Recurrent implantation failure (RIF) is a clinical phenomenon characterized by a lack of implantation after the transfer of several embryos and disturbs approximately 10% couples undergoing in vitro fertilization and embryo transfer. Despite increasing literature on RIF, there is still no widely accepted definition or standard protocol for the diagnosis and treatment of RIF. Progress in predicting and preventing RIF has been hampered by a lack of widely accepted definitions. Most couples with RIF can become pregnant after clinical intervention. The prognosis for couples with RIF is related to maternal age. RIF can be caused by immunology, thrombophilias, endometrial receptivity, microbiome, anatomical abnormalities, male factors, and embryo aneuploidy. It is important to determine the most possible etiologies, and individualized treatment aimed at the primary cause seems to be an effective method for increasing the implantation rate. Couples with RIF require psychological support and appropriate clinical intervention. Further studies are required to evaluate diagnostic method and he effectiveness of each therapy, and guide clinical treatment.

Impact of nitric oxide synthesis modulators on the state of humoral immune system in experimental antiphospholipid syndrome

Background: Antiphospholipid syndrome is an autoimmune disease of multiple venous and/or arterial thrombosis and/or pregnancy loss. Oxidative stress only enhances the body’s immune response. In pathological conditions, the formation of nitric oxide is disrupted, which can be manifested by vasoconstriction, increased coagulation, and endothelial dysfunction.

Objective: The aim of the research was to study the level of immunoglobulins and circulating immune complexes (CICs) in experimental antiphospholipid syndrome and its correction with L-arginine and aminoguanidine.

Materials and methods: Antiphospholipid syndrome was modeled on white female BALB/c mice. L-arginine (25 mg/kg) and aminoguanidine (10 mg/kg) were used for its correction. The content of immunoglobulins and CICs was studied.

Results: It was established that the level of immunoglobulins (Ig) and circulating immune complexes increased in the group of animals with antiphospholipid syndrome compare to the control. The levels of IgA and CICs decreased significantly, and the levels of IgM and IgG did not change in the mice with antiphospholipid syndrome and L-arginine correction. In cases of aminoguanidine administration, decreased IgM and IgG levels and no significant decrease in IgA and CICs was evidenced compare to the animals with antiphospholipid syndrome. In cases of using a combination of L-arginine and aminoguanidine agents, only IgM did not change, all other parameters decreased compare to the animals with APS.

Conclusion: The parameters of the humoral immunity in female mice with experimental antiphospholipid syndrome increase. The level of immunoglobulins and circulating immune complexes decrease depending on the chosen correction agents or their complex administration. Thus, L-arginine and aminoguanidine has a positive effect on various immunity responses by decreasing the negative impact of pathobiochemical alterations.

The ART of Thromboprophylaxis in the Prevention of Gestational Venous Thromboembolism

Assisted reproductive techniques (ART) allow infertile couples to conceive. Use of hormones to obtain a controlled ovarian stimulation and an adequate growth of the endometrium preparatory for embryo implantation are not riskless. Among others, thrombotic events can occur during the ovulation induction or pregnancy following ART. As the number of women approaching ART to conceive is steadily increasing, the issue of thrombotic risk in this setting is relevant. Data on the weight of each risk factor and on potential benefit of thromboprophylaxis are largely lacking. In this review, we discuss risk of venous thromboembolism during pregnancy following ART, with a focus on general (i.e.: age, body mass index, thrombophilia, bed rest, transfusions) and ART-specific (i.e., polycystic ovarian syndrome, ovarian hyperstimulation syndrome) risk factors. We also attempt to provide some suggestions to guide clinical practice, based on available data and studies performed outside ART.