Different antiphospholipid antibody specificities are found in association with early repeated pregnancy loss versus recurrent IVF-failure patients

The positive impact of targeted modulating food intolerance on immune-related recurrent pregnancy loss

BACKGROUND

It has been proven that immune disorders are one of the vital risk factors of recurrent pregnancy loss (RPL), and the presence of food intolerance seems to play an essential role in this. However, the impact of immune status induced by food intolerance on RPL has not been reported. This study utilized a targeted diet avoiding food intolerance as much as possible for each participant to investigate their effects on pregnancy outcomes in RPL patients with positive autoimmune markers.

METHODS

From January 2020 to May 2021, fifty-eight patients with RPL were enrolled. They were divided into two groups based on the presence of autoantibodies: the autoantibody-positive group (AP, n = 29) and the autoantibody-negative group (AN, n = 29). Their food-specific immunoglobulin (Ig) G antibodies for 90 foods were tested using enzyme-linked immunosorbent assay (ELISA). The levels of immune parameters and the presence of gastrointestinal discomforts (diarrhea or constipation, eczema, and mouth ulcers) were recorded before and after dietary conditioning, followed by the analysis of pregnancy outcomes.

RESULTS

Compared to the AN group, the patients in the AP group showed immune disorders at baseline, such as reduced levels of IL-4 and complement C3, and increased levels of IL-2 and total B cells. These parameters within the AP group were significantly improved after dietary conditioning that avoided food intolerance, while no significant changes were observed in the AN group. Patients in the AP group had significantly higher food-specific IgG antibodies for cow's milk (89.66% vs. 48.28%, p < .001), yolk (86.21% vs. 27.59%, p < .001), bamboo shoots (86.21% vs. 44.83%, p < .001) compared to those in the AN group. Additionally, gastrointestinal discomforts including diarrhea or constipation, eczema, and mouth ulcers were more common in the AP group than in the AN group. After 3-month dietary conditioning, these significantly improved characteristics were only observed in the AP group (p < .001). Finally, the baby-holding rate was higher in the AP group compared to the AN group (p < .05).

CONCLUSIONS

The RPL patients in the AN group did not exhibit immune disorders, whereas those in the AP group experienced immune disorders and gastrointestinal discomforts. For patient with positive autoantibodies, dietary intervention may mitigate immune disorders and gastrointestinal discomforts, presenting a promising approach to enhance pregnancy outcomes.

Non-criteria and criteria antiphospholipid antibodies and their association with pregnancy outcomes in women with a history of miscarriage: A retrospective study

INTRODUCTION

The objective of this study was to investigate both antiphospholipid antibodies (aPLs) and non-criteria aPLs (NC-aPLs) in relation with pregnancy outcomes.

METHODS

We retrospectively analyzed 1574 pregnant women with experienced at least one miscarriage who were tested for aPLs and NC-aPLs, and compared their clinical characteristics, immune biomarkers, and pregnancy outcomes. The χ2 test or Fisher's exact test compared pregnancy outcomes among patients negative for all aPLs, positive for NC‑aPLs subtypes, and positive for criteria aPLs subtypes.

RESULTS

Multivariate logistic regression analysis indicated that positive aPLs (OR = 2.216, 95 % CI 1.381-3.558), and positive NC-aPLs (OR = 1.619, 95 % CI 1.245-2.106) are linked to adverse outcomes. For fetal loss, positive aPLs (OR = 2.354, 95 % CI 1.448-3.829), NC-aPLs (OR = 1.443, 95 % CI 1.076-1.936) were significant. Premature delivery was associated with positive NC-aPLs (OR = 2.102, 95 % CI 1.452-3.043). In the NC-aPLs positive group, the rate of adverse outcomes was higher in the multiple-positive subgroup (77.8 %) compared to the double-positive (52.3 %) and single-positive (37.0 %) subgroups. The rates of fetal loss and premature delivery were also higher in the multiple-positive NC-aPLs subgroup compared to the single-positive subgroup (48.1 % vs. 22.6 % for fetal loss and 57.1 % vs. 16.5 % for premature delivery).

DISCUSSION

Our findings suggest that both aPLs and NC-aPLs are associated with an increased incidence of adverse pregnancy outcomes, and patients presenting with multiple NC-aPLs positivity were found to have a higher incidence of adverse outcomes compared to their single-positive counterparts.

Association between antinuclear antibody and female infertility: A meta-analysis

Autoimmunity is reported involving in reproductive failures, and antinuclear antibody (ANA) positivity has been regarded as a typical feature of autoimmunity. Published studies on the association of ANA with reproductive failures including infertility are controversial. The aim of this meta-analysis was to analyse whether the presence of ANA positivity increases the risk of infertility in women. We searched the PubMed and Embase databases for relevant literature without any restrictions prior to April 28, 2021. All analyses were performed using the RevMan 5.3 software. Twelve studies with 2734 participants, including 1482 patients with infertility, met the inclusion and exclusion criteria. The total positivity rate of ANA was 23.8% (353/1482) in all infertile patients and 8.5% (107/1252) in the control group. Infertile females had a significantly higher ANA positivity rate than the control group (odds ratio [OR] = 2.90, 95% confidence interval [CI]: 1.72-4.87, I2 = 65%, P < .0001). Several subgroup analyses were performed to reduce the heterogeneity. ANA positivity was associated with female infertility in studies either performed by indirect immunofluorescence (OR = 2.26, 95% CI:1.67-3.06, P < .00001) or by ELISA (OR = 10.76, 95% CI:1.82-63.64, P < .00001). ANA was significantly associated with increased risk of women infertility either after the definite exclusion of individuals with autoimmune diseases (AID) or without exclusion [(OR = 1.99, 95% CI:1.29-3.06, P = .002), (OR = 2.76, 95% CI:1.56-4.88, P = .0005), respectively]. This meta-analysis provides a comprehensive overview of the prevalence of antinuclear antibodies (ANA) in infertile women and suggests that ANA positivity increases the risk of infertility.

Antinuclear antibodies positivity in women in reproductive age: From infertility to adverse obstetrical outcomes - A meta-analysis

This systematic review and meta-analysis were designed to identify possible correlations between isolated serum antinuclear antibody (ANA) and (i) infertility in the context of in-vitro fertilization (IVF), (ii) idiopathic recurrent pregnancy losses (RPL), and (iii) second/ third trimester pregnancy complications. We performed a systematic review and meta-analysis of the literature in PubMed Library database from inception to March 2022 following PRISMA guidelines. Our pooled results showed a lower pregnancy rate among ANA-positive women undergoing IVF/ICSI compared to ANA-negative women undergoing the same procedures (279/908 versus 1136/2347, random effect, odds ratio -OR- 0.50, 95% confidence interval -CI- 0.38-0.67, p 0.00001, I² = 58%). We also reported a higher miscarriage rate among ANA-positive compared to ANA-negative women (48/223 versus 109/999, random effect, OR: 3.25 95% CI: 1.57-6.76, p = 0.002, I² = 61%) and a lower implantation rate (320/1489 versus 1437/4205, random effect, OR: 0.51, 95% CI: 0.36-0.72, p = 0.0001, I² = 78%). Regarding RPL, pooled results demonstrated a higher prevalence of ANA-positivity in RPL women compared to controls (698/2947 versus 240/3145, random effect, OR: 3.22, 95% CI: 2.12-4.88, p 0.00001, I² 77%), either using > 2 or > 3 pregnancy losses threshold for defining RPL. Heterogeneity of reporting outcome did not allow a quantitative analysis and led to no clear demonstration of an effect of serum ANA on the incidence of stillbirth, preeclampsia and hypertensive disorders. In conclusion, the unfavorable effect of serum ANA was observed in women following IVF. Similarly, ANA were associated with the risk of RPL, while data were unconclusive in terms of late pregnancy complications.

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

OBJECTIVE

Antiphospholipid antibodies (aPL) are related to poor pregnancy outcomes, but their effect on embryo implantation is unclear. We aimed to assess the prevalence of different aPL in women with recurrent implantation failure (RIF).

METHODS

We searched studies in PubMed (MEDLINE), Scopus and Cochrane Library. Quality of studies was scored by the Newcastle-Ottawa Scale and risk of bias assessment by items described in RevMan5 software. Statistical analyses were made using random-effects model and presented as pooled Odds Ratio (OR), 95% confidence interval (CI). Heterogeneity was assessed by I²% and D²%.

RESULTS

This systematic review and meta-analysis included 17 studies and showed a high degree of variability in aPL positivity in RIF. In the latter, the risk of bias assessment suggested unclear bias on study performance with a median sample size and interquartile range for RIF patients and fertile women of 96 (57-417) and 100 (60.5-202.5), respectively. Among the criteria aPL, IgG anticardiolipin autoantibodies (OR 5.02, 95% CI [1.95, 12.93]) were associated with RIF. Within the non-criteria aPL, anti-β2 glycoprotein I-IgA (OR 64.8, 95% CI [9.74, 431.0]), and antiphosphatidylglycerol-IgG and IgM (OR 10.74, 95% CI [5.25, 22.0]; OR 4.26, 95% CI [1.76,10.31]; respectively) were associated with RIF, too.

CONCLUSIONS

Anticardiolipin-IgG is a prevalent autoantibody in women with RIF. Three other non-criteria aPL, aβ2GP I-IgA, aPG-IgG and aPG-IgM also present a positive rate in RIF. Overall, these results advise about testing them as indicators of RIF risk in women seeking IVF treatment.

Correlation Between the Presence of Antinuclear Antibodies and Recurrent Pregnancy Loss: A Mini Review

In the past decade, the incidence of recurrent pregnancy loss (RPL) has increased significantly, and immunological disorders have been considered as one of the possible causes contributing to RPL. The presence of antinuclear antibodies (ANAs) is regarded as a typical antibody of autoimmunity. However, the relationship between the presence of ANAs and RPL, the underlying mechanism, and the possible role of immunotherapy is still controversial. The aim of this mini review is to assess the association between ANAs and RPL and the effects of immunotherapy on pregnancy outcomes in women with positive ANAs and a history of RPL from the available data and to provide a relevant reference basis for clinical application in this group of women.

Antinuclear antibodies positivity is a risk factor of recurrent pregnancy loss: A meta-analysis

OBJECTIVE

Immunologic mechanisms have been proposed as part of the pathogenesis mechanisms involved in recurrent pregnancy loss (RPL). Presence of positive antinuclear antibodies (ANA) is regarded as a typical feature of autoimmunity. Many studies had tried to clarify the association of ANA with RPL, but the conclusions were controversial. The aim of this meta-analysis was to assess whether ANA was positively associated with increased RPL risk.

METHODS

We searched PubMed and Embase databases for relevant literatures on the association between ANA positivity and RPL. The odds ratios (OR) with 95% confidence intervals (95%CI) were pooled using meta-analysis, and either fixed-effect or random-effect model was used based on heterogeneity across the included studies.

RESULTS

Twenty-one studies with 5038 participants (including 2683 RPL patients and 2355 controls) met the inclusion criteria were included. The total positive rate of ANA was 22.0% (591/2683) in RPL group, and 8.3% (196/2355) in the control group. RPL patients had a significantly higher ANA positive rate than controls (OR = 2.97, 95%CI 1.91-4.64, P<0.00001; I² = 75%), and a significant association between positive ANA and unexplained RPL was also observed (OR = 3.27, 95%CI 2.01-5.31, P<0.00001; I² = 70%). ANA positivity was also significantly associated with increased risk of RPL in women without defined autoimmune diseases (OR = 2.23, 95%CI 1.40-3.55, P=0.0007). Subgroup analysis demonstrated low titers of ANA (1:40≤ANA≤1: 80) were not associated with RPL (OR = 2.44, 95%CI 0.42-14.06, P=0.32), while higher ANA titer (≥1:160) had a significant association with RPL (OR = 45.89, 95%CI 8.44-249.45, P<0.00001). A higher rate of homogenous pattern in RPL patients was observed (OR = 4.89, 95%CI 2.20-10.87, P<0.001), and no significant difference in speckled pattern or nucleolar pattern was found.

CONCLUSIONS

This study demonstrated that ANA positivity was positively associated with increased RPL risk. ANA positivity is an important risk factor for RPL which needed to be screened among women with RPL.

Vitamin D Effects on the Immune System from Periconception through Pregnancy

Vitamin D is a well-known secosteroid and guardian of bone health and calcium homeostasis. Studies on its role in immunomodulatory functions have expanded its field in recent years. In addition to its impact on human physiology, vitamin D influences the differentiation and proliferation of immune system modulators, interleukin expression and antimicrobial responses. Furthermore, it has been shown that vitamin D is synthesized in female reproductive tissues and, by modulating the immune system, affects the periconception period and reproductive outcomes. B cells, T cells, macrophages and dendritic cells can all synthesize active vitamin D and are involved in processes which occur from fertilization, implantation and maintenance of pregnancy. Components of vitamin D synthesis are expressed in the ovary, decidua, endometrium and placenta. An inadequate vitamin D level has been associated with recurrent implantation failure and pregnancy loss and is associated with pregnancy-related disorders like preeclampsia. This paper reviews the most important data on immunomodulatory vitamin D effects in relation to the immune system from periconception to pregnancy and provides an insight into the possible consequences of vitamin D deficiency before and during pregnancy.

Uterine and placental blood flow indexes and antinuclear autoantibodies in unexplained recurrent pregnancy loss: should they be investigated in pregnancy as correlated potential factors? A retrospective study

BACKGROUND

The potential role of antinuclear antibodies (ANA) in recurrent pregnancy loss (RPL) pathogenesis is still debated, although some evidences suggest that they could affect pregnancy outcome, leading to a higher miscarriage rate in these patients. A hypothesized mechanism is through changes in uterine flow in pre-conceptional stage, by modifying endometrial receptivity in RPL. However, scant data are available, in pregnancy, about their role in RPL placental perfusion, also in relation to its potential treatments, such as low molecular weight heparin (LMWH). The aim of this study is to retrospectively further investigate the correlation between two-dimensional (2D) and three-dimensional (3D) uterine and placental flow indexes and the presence or the absence of ANA in women with unexplained RPL (uRPL), treated or not treated with LMWH.

METHODS

2D Doppler measurement of pulsatility index (PI) of the uterine arteries and 3D ultrasonography determination of vascularization index (VI), flow index (FI) and vascularization flow index (VFI) was carried out with the aid of the virtual organ computer-aided analysis (VOCAL) technique in LMWH treated (n 24) and not treated-uRPL patients (n 20) and in the relative control group (n 27), each group divided in ANA+ and ANA- subgroups. Serum assay for the presence of ANA was performed in all women.

RESULTS

No differences were found in PI, VFI and VI values, by comparing the different groups. A difference in VI values was found for ANA- patients between RPL women not treated with LMWH and the treated ones (p = 0,01), which have lower VI values and similar to controls. By considering only ANA- treated and not treated RPL patients, the ROC curve shows an area of 0,80 and at the VI cut-off of 11,08 a sensitivity of 85% and a specificity of 67%.

CONCLUSIONS

LMWH could exert a potential beneficial effect in restoring the physiological blood flow supply in terms of VI in uRPL ANA- status, suggesting to include ANA and VI investigations in the RPL diagnostic algorithm in a research context, since further studies are needed to clarify this challenging hypothesis in order to try to ameliorate ANA and abnormal placental vascularization negative influence on RPL pregnancy outcome .

The pathogenic role of autoantibodies in recurrent pregnancy loss

In the present manuscript, we review the recent research investigating the pathogenic association between most studied autoantibodies and recurrent pregnancy loss. Pregnancy loss represents a common obstetric complication occurring in about 15%-25% of all clinically recognized pregnancies. The recurrence of pregnancy loss identifies a distinct clinical entity, that is recurrent pregnancy loss (RPL), affecting about 2%-4% of couples. Several factors, including age, chromosomal abnormalities, uterine anomalies, thrombophilic disorders, endocrinopathies, hormonal and metabolic disorders, infections, sperm quality, and lifestyle issues, are involved in RPL. The role of autoantibodies in RPL is only partially determined. In some cases (antiphospholipid antibodies [aPL]), their involvement is well established. In other cases (anti-thyroid autoantibodies, antinuclear, anti-transglutaminase, and anti-endomysial antibodies), it is still debated, despite multiple, although not fully conclusive, evidences strongly suggest a possible involvement in RPL. Further extensive research is needed to definitively confirm or exclude their actual role.

Preconception antiphospholipid antibodies and risk of subsequent early pregnancy loss

Objectives To prospectively estimate the association of preconception antiphospholipid antibodies (aPL) with subsequent pregnancy loss using a cohort design. aPL have been associated with recurrent early pregnancy loss (EPL) prior to 10 weeks in previous case-control studies. Prospective ascertainment of pregnancy loss is challenging, as most women do not seek care prior to EPL. Methods Secondary analysis of the Effects of Aspirin in Gestation and Reproduction trial of preconception low-dose aspirin. Preconception anticardiolipin (aCL) and anti-β2-glycoprotein-I (a-β2-I) were assessed in 1208 women with one or two prior pregnancy losses and no more than two prior live births. Comparison cohorts were defined by positive aPL (+aPL) or negative aPL (-aPL) status. All women were followed for six menstrual cycles while trying to conceive; if successful, they underwent an ultrasound at 6-7 weeks' gestation. EPL was defined as loss prior to 10 weeks' gestation; embryonic loss was loss after visualization of an embryo but prior to 10 weeks; clinical loss was any loss after visualization of an embryo (with or without fetal cardiac activity detected). Results In total, 14/1208 (1%) tested positive for +aPL. 786/1208 (65%) women had positive human chorionic gonadotropin during the study period, of which 9/786 (1%) had +aPL. Of the 786 pregnant women, 589 (75%) had live births and 24% had pregnancy losses. Women with +aPL experienced EPL at similar rates as women with -aPL, 44% vs 21% (aRR 2.4, 95% confidence interval (CI) 0.5-10.9). Embryonic loss was more common in women with +aCL IgM (aRR 4.8, 95% CI 1.0-23.0) and in women with two positive aPL. Clinical pregnancy loss was more common in women with positive a-β2-I IgM (50% vs 16.5%, aRR 3.7, 95% CI 1.3-10.8). Conclusion Positive levels of aPL are rare in women with one or two prior pregnancy losses and are not clearly associated with an increased rate of subsequent loss. Clinical trial registration The original source study was registered at ClinicalTrials.gov (#NCT00467363).

Recurrent Miscarriage: Diagnostic and Therapeutic Procedures. Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry Number 015/050)

Purpose

Official guideline of the German Society of Gynecology and Obstetrics (DGGG), the Austrian Society of Gynecology and Obstetrics (ÖGGG) and the Swiss Society of Gynecology and Obstetrics (SGGG). The aim of this guideline was to standardize the diagnosis and treatment of couples with recurrent miscarriage (RM). Recommendations were based on the current literature and the views of the involved committee members.

Methods

Based on the current literature, the committee members developed the statements and recommendations of this guideline in a formalized process which included DELPHI rounds and a formal consensus meeting.

Recommendations

Recommendations for the diagnosis and treatment of patients with RM were compiled based on the international literature. Specific established risk factors such as chromosomal, anatomical, endocrine, hemostatic, psychological, infectious and immunological disorders were taken into consideration.

ESHRE guideline: recurrent pregnancy loss

STUDY QUESTION

What is the recommended management of women with recurrent pregnancy loss (RPL) based on the best available evidence in the literature?

SUMMARY ANSWER

The guideline development group formulated 77 recommendations answering 18 key questions on investigations and treatments for RPL, and on how care should be organized.

WHAT IS KNOWN ALREADY

A previous guideline for the investigation and medical treatment of recurrent miscarriage was published in 2006 and is in need of an update.

STUDY DESIGN, SIZE, DURATION

The guideline was developed according to the structured methodology for development of ESHRE guidelines. After formulation of key questions by a group of experts, literature searches and assessments were performed. Papers published up to 31 March 2017 and written in English were included. Cumulative live birth rate, live birth rate and pregnancy loss rate (or miscarriage rate) were considered the critical outcomes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Based on the collected evidence, recommendations were formulated and discussed until consensus was reached within the guideline group. A stakeholder review was organized after finalization of the draft. The final version was approved by the guideline group and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

The guideline provides 38 recommendations on risk factors, prevention and investigations in couples with RPL, and 39 recommendations on treatments. These include 60 evidence-based recommendations – of which 31 were formulated as strong recommendations and 29 as conditional – and 17 good practice points. The evidence supporting investigations and treatment of couples with RPL is limited and of moderate quality. Of the evidence-based recommendations, only 10 (16.3%) were supported by moderate quality evidence. The remaining recommendations were supported by low (35 recommendations: 57.4%), or very low quality evidence (16 recommendations: 26.2%). There were no recommendations based on high quality evidence. Owing to the lack of evidence-based investigations and treatments in RPL care, the guideline also clearly mentions investigations and treatments that should not be used for couples with RPL.

LIMITATIONS, REASONS FOR CAUTION

Several investigations and treatments are offered to couples with RPL, but most of them are not well studied. For most of these investigations and treatments, a recommendation against the intervention or treatment was formulated based on insufficient evidence. Future studies may require these recommendations to be revised.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in RPL, based on the best evidence available. In addition, a list of research recommendations is provided to stimulate further studies in RPL. One of the most important consequences of the limited evidence is the absence of evidence for a definition of RPL.

STUDY FUNDING/COMPETING INTEREST(S)

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive payment. J.E. reports position funding from CARE Fertility. S.L. reports position funding from SpermComet Ltd. S.M. reports research grants, consulting and speaker’s fees from GSK, BMS/Pfizer, Sanquin, Aspen, Bayer and Daiichi Sankyo. S.Q. reports speaker’s fees from Ferring. The other authors report no conflicts of interest.

ESHRE Pages are not externally peer reviewed. This article has been approved by the Executive Committee of ESHRE.

The outcome of ELISA for antiphosphatidylethanolamine antibodies is dependent on the composition of phosphatidylethanolamine

OBJECTIVE

The presence of circulating autoantibodies against phosphatidylethanolamine (PE) has been shown to be positively associated with symptoms of antiphospholipid syndromes (APS). However, the current ELISA-based tests for antiphosphatidylethanolamine (aPE) antibodies remain inconsistent and controversial. The term PE refers to a collection of phospholipids that have phosphorylethanolamine head group as a common structural feature, but can vary in fatty acids with diverse physicochemical properties. The present study was to investigate, using synthetic positionally symmetrical PE species as a model system, the impact of PE structural variations on aPE ELISA.

METHODS

Single and combinations of synthetic PE species, including 16:0 (fatty acid length:degree of unsaturation), 18:0, 18:1, 20:4 and 22:6, were screened with ELISA using serum samples from aPE patients and compared with chicken egg PE. There were a total of 37 aPE patient serum samples, including 11 cofactor-independent IgM, 14 ABP-independent IgG and 12 ABP-dependent aPE serum samples (3 IgM, 8 IgG and 1 IgA). The ELISA conditions were investigated for different isotypes and cofactor dependence. Based on the initial screening, adjustments in phospholipid compositions were made for achieving optimal OD readings. Finally, we isolated total IgG from aPE sera to validate different antigenic preferences.

RESULTS

The antigenic preference was different among immunoglobulin isotypes and between cofactor-dependent versus cofactor-independent aPE antibodies. More specifically, 18:1 PE was a preferred antigen for cofactor-dependent aPE, whereas 20:4 PE was the preferred antigen for cofactor-independent IgG aPE. In contrast, cofactor-independent IgM aPE appeared to have a general preference for a more complex PE combination with longer fatty acids and a higher degree of unsaturation.

CONCLUSION

The present data indicated that the outcome of aPE ELISA was dependent on the composition and physicochemical properties of PE antigens. The discovery that aPE antibodies may have different antigenic preferences could shed light on the nature of their binding interactions.

Antiphosphatidylserine antibodies and reproductive failure

Some cases of reproductive failure with autoimmune background are characterized by the involvement of autoantibodies. This occurs mainly in patients having systemic lupus erythematosus or antiphospholipid syndrome. The autoantibodies associated with reproductive failure include: a) antibodies which directly bind phospholipid (e.g., cardiolipin, phosphatidylserine, phosphatidylethanolamine); b) antiphospholipid Abs which bind the phospholipid via phospholipid-binding glycoproteins such as b2glycoprotein-I, annexin V and prothrombin; c) autoantibodies directed to laminin-I, actin, thromboplastin, the corpus luteum, prolactin, poly (ADP-ribose), thyroglobulin and mitochondrial antibodies of the M5 type. This paper will focus on the association of antiphosphatidylserine autoantibodies and reproductive failure. Future studies are likely to help to identify peptides resembling the epitope specificities associated with the specific clinical manifestations.

The European Registry on Obstetric Antiphospholipid Syndrome (EUROAPS): A survey of 247 consecutive cases

AIM

To analyse the clinical features, laboratory data, foetal-maternal outcomes, and follow-up in a cohort of 247 women with obstetric antiphospholipid syndrome (OAPS).

METHODS

The European Registry on APS became a Registry within the framework of the European Forum on Antiphospholipid Antibody projects and placed on a website in June 2010. Cases with obstetric complaints related to aPL who tested positive for aPL prospectively and retrospectively were included. The three-year survey results are reported.

RESULTS

338 women with 1253 pregnancy episodes were included; 915 were historical and 338 were latest episodes. All these women tested positive for aPL. 247 of the 338 fulfilled the Sydney criteria. According to the laboratory categories, 84/247 were in category I, 42 in IIa, 66 in IIb and 55 in IIc. Obstetric complications other than foetal losses, appeared in 129 cases (52.2%). 192 (77.7%) had a live birth and 55 (22.3%) did not. The latter group of only 38 cases (69%) received adequate treatment and 17 (31%) did not. 177/247 (72%) women were put on heparin plus LDA. Thrombosis appeared in two during pregnancy and in 14 during the puerperium. 7 (3%) women evolved to complete SLE.

CONCLUSIONS

OAPS shows differential characteristics than classical APS. All laboratory test categories are needed to avoid false-negative diagnoses. In some cases, complement levels could act as a serological marker. OAPS has very good foetal-maternal outcomes when treated. Thrombosis and progression to SLE in mothers with OAPS are scarce compared with "classical APS", suggesting that they have different aPL-mediated pathogenic mechanisms.

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.

14th International Congress on Antiphospholipid Antibodies Task Force. Report on antiphospholipid syndrome laboratory diagnostics and trends

Current classification criteria for definite Antiphospholipid Syndrome (APS) require the use of three laboratory assays to detect antiphospholipid antibodies (aCL, anti-β2GPI and LA) in the presence of at least one of the two major clinical manifestations (i.e. thrombosis or pregnancy morbidity) of the syndrome. However, several other autoantibodies shown to be directed to other proteins or their complex with phospholipids have been proposed to be relevant to APS but their clinical utility and their diagnostic value remains elusive. This report summarizes the findings, conclusions and recommendations of the "APS Task Force 3-Laboratory Diagnostics and Trends" meeting that took place during the 14th International Congress on Antiphospholipid Antibodies (APLA 2013, September 18-21, Rio de Janeiro, RJ, Brazil).

Obstetric antiphospholipid syndrome: a recent classification for an old defined disorder

Obstetric antiphospholipid syndrome (APS) is now being recognized as a distinct entity from vascular APS. Pregnancy morbidity includes >3 consecutive and spontaneous early miscarriages before 10weeks of gestation; at least one unexplained fetal death after the 10th week of gestation of a morphologically normal fetus; a premature birth before the 34th week of gestation of a normal neonate due to eclampsia or severe pre-eclampsia or placental insufficiency. It is not well understood how antiphospholipid antibodies (aPLs), beyond their diagnostic and prognostic role, contribute to pregnancy manifestations. Indeed aPL-mediated thrombotic events cannot explain the obstetric manifestations and additional pathogenic mechanisms, such as a placental aPL mediated complement activation and a direct effect of aPLs on placental development, have been reported. Still debated is the possible association between aPLs and infertility and the effect of maternal autoantibodies on non-vascular manifestations in the babies. Combination of low dose aspirin and unfractionated or low molecular weight heparin is the effective treatment in most of the cases. However, pregnancy complications, in spite of this therapy, can occur in up to 20% of the patients. Novel alternative therapies able to abrogate the aPL pathogenic action either by interfering with aPL binding at the placental level or by inhibiting the aPL-mediated detrimental effect are under active investigation.

Immunological modes of pregnancy loss: inflammation, immune effectors, and stress

Inflammatory immune response plays a key role in reproductive failures such as multiple implantation failures (MIF), early pregnancy loss, and recurrent pregnancy losses (RPL). Cellular immune responses particularly mediated by natural killer (NK), and T cells are often dysregulated in these conditions. Excessive or inappropriate recruitment of peripheral blood NK cells to the uterus may lead to cytotoxic environment in utero, in which proliferation and differentiation of trophoblast is hampered. In addition, inadequate angiogenesis by uterine NK cells often leads to abnormal vascular development and blood flow patterns, which, in turn, leads to increased oxidative stress or ischemic changes in the invading trophoblast. T-cell abnormalities with increased Th1 and Th17 immunity, and decreased Th2 and T regulatory immune responses may play important roles in RPL and MIF. A possible role of stress in inflammatory immune response is also reviewed.

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).

Low circulating CD4(+) CD25(+) Foxp3(+) T regulatory cell levels predict miscarriage risk in newly pregnant women with a history of failure

PROBLEM  The purpose of this study was to determine whether quantification of peripheral blood Treg cell levels could be used as an indicator of miscarriage risk in newly pregnant women with a history of immunologic reproductive failure. METHOD OF STUDY  Fifty-four pregnant women with a history of immunologic infertility and/or pregnancy loss were retrospectively evaluated (mean age: 36.7 ± 4.9 years, 2.8 ± 2.5 previous miscarriages; 1.5 ± 1.9 previous IVF failures). Twenty-three of these women experienced another first trimester miscarriage, and 31 of these women continued their current pregnancies past 12 weeks ('pregnancy success'). The following immunologic parameters were assessed in the first trimester: NK cell 50:1 cytotoxicity, CD56(+)  16(+)  CD3(-) (NK), CD56(+)  CD3(+) (NKT), TNFα/IL-10, IFNγ/IL-10, CD4(+)  CD25(-) Foxp3(+) , total CD4(+)  Foxp3(+) (CD4(+ ) CD25(+)  Foxp3 plus CD25(- ) Foxp3(+) ), and CD4(+)  CD25(+)  Foxp3(+) levels. RESULTS  Patients with successful ongoing pregnancies experienced a mean (CD4(+)  CD25(+)  Foxp3(+) ) 'Treg' level of 0.72 ± 0.52%, while those that miscarried in the first trimester experienced a mean Treg level of 0.37 ± 0.29% (P = 0.005). Markers not significantly different between the loss and success groups were NK 50:1 cytotoxicity (P = 0.63), CD56(+)  16(+)  3(+) NK cells (P = 0.63), CD56(+)  3(+)   NKT (P = 0.30), TNFα(+) IL-10(+) (P = 0.13), IFNg(+) IL-10(+) (P = 0.63), and CD4(+)  25(-)  Foxp3(+) cells (P = 0.10), although total CD4(+)  Foxp3(+) levels remained significant (P = 0.02) and CD4(+)  25(+) Foxp3(+) showed the most significant difference (P = 0.005). Mean day of blood draw was 49.2 ± 36.1 days pregnant (median 39.0 days). In addition, patients with a low Treg level (<0.7%) in the first trimester experienced a significantly lower ongoing pregnancy rate than those with a higher Treg level (>0.7%) in the first trimester [44% (15/34) versus 80% (16/20); P = 0.01]. Of the 18 successful pregnancies with sequential Treg results, 85% (11/13) showed a T-regulatory-cell-level increase (mean Treg change 0.33 ± 0.32), while only 40% (2/5) of the failed pregnancies showed a Treg increase (mean Treg change -0.08 ± 0.28; P = 0.02). CONCLUSIONS  From these data, we propose that CD4(+)  CD25(+)  Foxp3(+) T regulatory cells may serve as a superior pregnancy marker for assessing miscarriage risk in newly pregnant women. Larger follow-up studies are needed for confirmation.

Antiphospholipid antibody-mediated reproductive failure in antiphospholipid syndrome

The association of elevated titers of circulating antiphospholipid (anti-PL) Abs in antiphospholipid syndrome (APS) and reproductive failure is well established in the literature. The clinical features include recurrent abortions at various stages, including implantation, placentation in the first trimester, miscarriages in the second and third trimesters, intrauterine growth retardation, preeclampsia with placental insufficiency and growth restrictions, arterial and venous thrombosis, and possibly also infertility. APS-mediated recurrent pregnancy loss and other features of reproductive failure might result from diverse autoimmune factors, inflammation, involving different mechanisms, which encompass pathogenic anti-PL Abs. Herein, we discuss the association of anti-PL Abs with reproductive failure with special emphasis on antiphospholipid autoantibodies characterizing APS. This association is evident from either human studies or murine models.

Fetal rejection: infertility and immunity

Defective reaction toward fetal alloantigens could result in both recurrent spontaneous abortions (RSAs) and recurrent early pregnancy failures (REPFs), the latter existing in couples with unexplained infertility and multiple failures of implantation after in vitro fertilization embryo transfer. Immunological mechanisms leading to RSA and REPF seem to be different, although both syndromes probably have a genetic background that has not been identified so far. Despite the fact that antiphospholipid syndrome is a well-established cause of repeated pregnancy loss, the role of different autoantibodies existing in RSA and REPF patients needs to be elucidated. Immunotherapy is believed to correct the detrimental immune reactions; however, its real effectiveness and safety for the treatment of distinct forms of pregnancy loss need to be reconsidered.

Autoantibodies and coagulation in reproductive medicine

Management of recurrent pregnancy loss (RPL) is considered to be difficult, in part because of cunfusion between autoantibodies and coagulation disorders. Autoantibodies and coagulation are related; two groups of multicenter studies concerning autoantibodies and coagulation reported that factor XII deficiency, hypofibrinolysis, anti-phosphatidylethanolamine (aPE), anti-beta2-glycoprotein I, anti-annexin A5, and lupus anticoagulant (LA) were found to be frequent risk factors in RPL women. Therefore, discrimination of autoantibodies and coagulation is important in understanding RPL well. We propose three types of pathways regarding reproduction, which are different and independent: (1) Negatively charged-phospholipid related antibodies (anti-phosphatidylserine; aPS, anti-cardiolipin; aCL, lupus anticoagulant; LA, anti-annexin A5; aANX), (2) factor XII-aPE-fibrinolysis: suppression of fibrinolysis, (3) protein C-protein S-factor V: loss of inactivation against activated factor V. Women with RPL and infertility showed similar findings in terms of the above clinical tests. Available data, however, is not enough to conclude whether these are pathogenic to infertile women.

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

OBJECTIVE

To evaluate the role of anti-beta(2)-glycoprotein-I (anti-beta(2)GPI-ab) and anti-phosphatidylserine (aPS-ab) antibodies as a risk factor in both recurrent miscarriage (RM) and unexplained fetal losses (UFL).

DESIGN

Retrospective, cohort study.

SETTING

Vall d'Hebron University Hospital, Barcelona, Spain.

PATIENT(S)

122 pregnant women divided in two groups: study group of 54 women with RM and/or UFL and control group of 68 pregnant without RM history.

INTERVENTION(S)

Analysis of lupus anticoagulant, anticardiolipin antibodies, and anti-beta(2)GP1 and aPS antibodies.

MAIN OUTCOME MEASURE(S)

Comparison of aPL antibody between groups.

RESULT(S)

The prevalence of aPL positive results was 8 out of 54 (14.8%) in the study group and 3 out of 68 (4.41%) in the controls. In the RM subgroup, the prevalence was 3 out of 25 (12%) versus 3 out of 68 (4.4%), and 7 out of 34 (20.6%) versus 3 out of 68 (4.4%) in UFL subgroup. As a whole, the prevalence of anti-beta(2)GP1-ab in the RM/UFL group showed a difference compared with controls but not aPS-ab. In the RM women, anti-beta(2)GP1-ab was positive in 3 out of 25 (12%) versus 1 out of 68 (1.5%) in controls and in 4 out of 34 versus 0 out of 68 cases in women with UFL. In the RM subgroup, aPS-ab was positive in 1 out of 25 (4%) versus 2 out of 68 (2.9%) in control group and in 3 out of 34 versus 2 out of 68 cases in women with UFL.

CONCLUSION(S)

Our results suggest that anti-beta(2)GP1-ab but not aPS-ab is related to RM/UFL and should be considered as a pregnancy-loss risk factor.

Antigenic profile, prevalence, and clinical significance of antiphospholipid antibodies in women referred for in vitro fertilization

The aim of this prospective study was to assess the prevalence of antiphospholipid antibodies (aPL) in women who had undergone in vitro fertilization (IVF) and the relationship between aPL and IVF outcome. A total of 101 infertile women with at least three unsuccessful IVF attempts were consecutively included in this study. Samples were collected in the follicular phase of a spontaneous ovarian cycle 2 months after the last ovulation induction treatment. Age-matched healthy fertile women (n = 160) were included as controls. All were evaluated for the presence of lupus anticoagulant (LA), antibodies (IgG, IgA, IgM) to cardiolipin (aCL), beta2-glycoprotein I (abeta2GPI), and phosphatidylethanolamine (aPE). Out of the 101 infertile women, 40 were persistently positive for aPL, showing a prevalence significantly higher than in controls (39.6% versus 5%, P < 0.0001). Among aPL, aPE were found with a significantly higher prevalence compared with LA, aCL, and aP2GPI (67.5% versus 0%, 15%, and 40%, respectively). Interestingly, aPE were found in 70% of the cases in the absence of the other aPL. The predominant isotype of aPL was IgA, in particular for abeta2GPI. Finally, no significant association was found between the presence of aPL and IVF outcome. This prospective study shows aPE as the most prevalent aPL in infertile women and IgA as more common than IgG and IgM. However, our results do not support an association between aPL and IVF outcome.

IgG-antiphospholipid antibodies in follicular fluid of IVF-ET patients are related to low fertilization rate of their oocytes

PROBLEM

Patients undergoing in vitro fertilization and embryo transfer (IVF-ET) failures show an increased incidence of antiphospholipid antibodies (aPL) in their blood. The physiological manifestations of aPL in this patient group are nonetheless controversial. Pathological effects of aPL on embryos in vitro have been documented. We questioned whether aPL if found in follicular fluids (FFs) could result in embryonic damage.

METHOD OF STUDY

Blood from 44 patients with three or more IVF-ET failures were tested by enzyme-linked immunosorbent assays (ELISA) for the presence of immunoglobulin (Ig)G, IgM and IgA aPL. Both the 29 aPL-positive and 15 aPL-negative patients gave permission for FF collection during their next IVF-ET attempt for additional aPL determinations.

RESULTS

Patients with no aPL in their blood, had no aPL in their FFs. Patients with IgG and/or IgM aPL in their blood had IgG but not IgM in their respective FFs.

CONCLUSIONS

The presence of IgG aPL in FFs and increased infertility length were significantly related to lower fertilization rates, independently. Follicular fluid IgG aPL appears as a risk factor in association with successful IVF-ET outcomes.

Preconception Peripheral Natural Killer Cell Activity as a Predictor of Pregnancy Outcome in Patients with Unexplained Infertility

PROBLEM

Preconception high peripheral natural killer (NK) cell activity in women with recurrent spontaneous abortion can predict subsequent miscarriages. We have examined prospectively, for the first time, the pregnancy rate in patients with unexplained infertility by measuring the peripheral NK activity.

METHOD OF STUDY

We tested the peripheral NK activity of 94 infertile women who despite treatment were unable to conceive for 6 or more months (mean; 2.4 years). Peripheral NK activity was measured by a chromium-51 release cytotoxicity assay. Women were followed for 2 years and assessed.

RESULTS

In 77 patients who were followed for 2 years, 28 had conceived but 49 did not. The peripheral NK activity of the group that became pregnant (mean +/- S.D.; 34.5 +/- 13.8%) was significantly lower than that of non-conception group (42.3 +/- 13.3%, P = 0.017).

CONCLUSIONS

Our finding suggests that elevated peripheral NK activity in patients with unexplained infertility is a risk factor for attaining pregnancy success.

Thrombophilias and recurrent pregnancy loss: a critical appraisal of the literature

Thrombophilias are suggested to play a role in recurrent miscarriage. The aim of this study was to evaluate the literature of the past 10 years regarding the association between thrombophilias and recurrent miscarriage. We concluded that there is a large variety in applied study methodology. Therefore, we defined criteria for an adequate study on the relationship of thrombophilias on recurrent pregnancy loss: (i) no exclusion criteria for patients or at least the same criteria for patients and controls; (ii) a clear definition of the gestational age at previous losses; (iii) a well-described control group; (iv) clear description of the test methods and moment of testing; and (v) a clear description of the (non) significant differences or odds ratio between cases and controls. Eleven out of 69 studies fulfilled these criteria. Their results show significant higher serum homocysteine levels among women with a history of recurrent miscarriage. No relation was found between recurrent miscarriage and the methylenetetrahydrofolate reductase C667T mutation. No relation was observed for the levels of antithrombin, protein C and protein S. Seven studies on the association of factor V Leiden (FVL) and/or pathologic activated protein C ratio (pAPCR) showed that FVL may play a role in second trimester losses, as do antiphospholipid antibodies. Studies on the prothrombin gene mutation yielded conflicting results. Consequently, large prospective studies according to the aforementioned criteria are needed to establish if there is a relationship between thrombophilias and recurrent miscarriage at all. At present, there is only justification for testing for homocysteine levels, antiphospholipid antibodies and FVL in women with a history of recurrent miscarriage.

Association of anticardiolipin antibody and C677T in methylenetetrahydrofolate reductase mutation in women with recurrent spontaneous abortions: a new path to thrombophilia?

CONTEXT

Recurrent spontaneous abortion (RSA) has been associated with venous thrombosis in the mother. Acquired and inherited thrombophilia factors are possible causes.

OBJECTIVE

To evaluate the association between thrombogenic factors and recurrent spontaneous abortion.

TYPE OF STUDY

Case-control study.

SETTING

Centro de Atenção Integral à Saúde da Mulher, Universidade Estadual de Campinas.

METHODS

40 ml of blood was collected from 88 women attending an RSA clinic and 88 fertile women attending a family planning clinic, to evaluate the presence of acquired and inherited thrombophilia factors. Anticardiolipin antibodies (ACA), lupus anticoagulant and deficiencies of proteins C and S and antithrombin III were evaluated by enzyme-linked immunosorbent assay (ELISA), dilute Russell Viper Venom time (dRVVT), coagulometric and chromogenic methods. DNA was amplified by the polymerase chain reaction (PCR) to study factor V Leiden and G20210A mutations in the prothrombin gene and C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. Data were analyzed using odds ratios and a regression model for age adjustment. Fishers exact test was used to evaluate statistical relationships between associated factors and RSA.

RESULTS

ACA was detected in 11 women with RSA and one fertile woman. Heterozygous C677T was detected in 59 women with RSA and 35 fertile women. Concomitant presence of ACA and C677T was found in eight women with RSA and no fertile women (p < 0.01).

DISCUSSION

The meaning of the association between C677T mutation in the MTHFR gene and ACA is still not clear. It is possible that an inherited factor that alone would not strongly predispose a woman to thrombosis could, when associated with an acquired factor, start the process and increase the likelihood of thrombosis expression.

CONCLUSIONS

ACA and C677T in the MTHFR gene are statistically associated with RSA. The association of these two conditions is a new finding in thrombogenic factors and RSA.

Recurrent implantation failure in assisted reproduction: how to counsel and manage. B. Treatment options that have not been proven to benefit the couple

The success of assisted reproduction, although gradually increasing over the years, is still less than satisfactory. Many couples have benefited from this treatment; however, many have also been left frustrated following multiple failed attempts. Couples who fail to conceive after multiple IVF/intracytoplasmic sperm injection (ICSI) treatments often seek treatment options that are new and that have not been offered before. Some of these include immunological testing and treatment, allogenic lymphocyte therapy, intratubal transfer of zygotes and embryos, blastocyst transfer, sequential embryo transfer, assisted hatching, co-cultures, and preimplantation genetic screening for aneuploidy. Although the evidence behind some of these is more robust, most suffer from lack of well designed randomized trials comparing them with other treatment options. Randomized studies are extremely difficult to conduct, as couples will resist being randomized into a treatment group where previously failed procedures will be repeated. In the mean time, assisted reproduction programmes should resist offering treatment options that are not evidence based, or at least they should share with the couple the information that is available and should stress that none of these is a panacea for their problem.

Anti-annexin A5 Antibodies in Reproductive Failures in Relation to Antiphospholipid Antibodies and Phosphatidylserine

PROBLEM

The presence of IgG anti-annexin A5 (IgGalphaA5) and/or antiphospholipid antibodies (aPL) are risk factors associated with recurrent spontaneous abortion. Problems are whether IgA antiannexin A5 (IgAalphaA5) is pathogenic, and how IgGalphaA5 works.

METHOD OF STUDY

Blood samples from 238 patients with early recurrent spontaneous abortion, 48 patients with recurrent in vitro fertilization-embryo transfer failure, 179 non-pregnant women and 120 pregnant controls were tested for IgAalphaA5 by enzyme-linked immunosorbent assay. We also determined if IgGalphaA5 appeared coincident with aPL. The antigenic epitope(s) recognized by IgGalphaA5 was investigated.

RESULTS

We observed no difference between patients and controls for IgAalphaA5. The prevalence of IgGalphaA5 was not different statistically between patient samples with or without aPL. Patient IgGalphaA5 bound annexin A5 when the latter was free/unbound but not when annexin A5 was associated with phospholipid.

CONCLUSIONS

The IgAalphaA5 does not appear to be pathogenic. IgGalphaA5 works to make a complex with annexin A5 without relation to aPLs, which may reduce annexin A5 available for binding to trophoblast.

Antiphospholipid antibodies in implantation failures

PROBLEM

The amino phospholipids (PL), phosphatidylserine (PS) and phosphatidylethanolamine (PE) are distributed asymmetrically in the plasma membranes of eucaryotic cells. This arrangement involves active transport of PS and PE from the outer to inner membrane leaflet by an aminophospholipid translocase (flipase). Cell activation, injury and programmed cell death (apoptosis) cause collapse of the PS/PE asymmetry by activation of another enzyme system, scramblase. Unlike other cells, the developing trophoblast exteriorizes PS during its differentiation.

METHODS OF STUDY

An analysis of published and unpublished data.

RESULTS

The trophoblast is targeted by antiphospholipid antibodies (aPL), especially to PS (aPS). Cardiolipin is not present in the trophoblast plasma membrane, nonetheless, anticardiolipin (aCL) has been implicated in trophoblast pathology. The aPS and aCL are often crossreactive. Both animal and in vitro experimental models have shown monoclonal and polyclonal aPS and aCL to specifically destroy trophoblast, inhibit syncytium formation, halt human chorionic gonadatropin (hCG) production, and limit trophoblast invasion. Antibodies to PE (aPE) have not been well characterized, however, recent reports from several independent laboratories document that aPE are associated significantly with very early (embryonic) recurrent pregnancy loss (RPL). Umeda and coworkers have shown that during cytokinesis (late telophase) of Chinese hamster ovary (CHO) cells, formation of PE rafts in cleavage furrows is required for completion of cell division and formation of daughter cells. This raises the question whether aPE might interfere with implantation and cell division during embryogenesis.

CONCLUSIONS

A role for aPL in implantation failure and occult pregnancy loss constitutes the basis of this overview.