Toward harmonized interpretation of anticardiolipin and anti-ß2-glycoprotein I antibody detection for diagnosis of antiphospholipid syndrome using defined level intervals and likelihood ratios: communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies.

BACKGROUND: Improving harmonization of the clinical interpretation of anticardiolipin (aCL) and anti-ß2-glycoprotein I (aß2GPI) antibodies immunoglobulin G (IgG)/immunoglobulin M (IgM) in the diagnosis of antiphospholipid syndrome (APS) is desirable. Likelihood ratios (LRs) with corresponding test-result intervals can identify the power of a test to discriminate between a diseased and nondiseased patient and may be useful for the semiquantitative interpretation of aCL/aß2GPI results. OBJECTIVES: To determine moderate and high thresholds for aCL and aß2GPI IgG/IgM measured with chemiluminescent immunoassay, enzyme-linked immunosorbent assay, fluorescence enzyme immunoassay, and multiplex flow immunoassay. METHODS: aCL and aß2GPI antibodies IgG/IgM were determined with 4 solid-phase systems in a case-control study population including 381 APS patients and 727 controls. Interval-specific LRs (IS-LR) were calculated for ranges determined by prespecified specificity and sensitivity levels. Three methods were used for determining thresholds that separated low, moderate, and high positive antibody levels. Interassay agreement was checked with Cohen's kappa statistics. RESULTS: Assay- and antibody-specific thresholds demonstrated increasing IS-LR, reflecting different clinical significance for low, moderate, and high levels, especially for IgG aCL and aß2GPI and in thrombotic APS. IS-LRs per antibody and unit range were comparable across solid-phase platforms resulting in enhanced harmonization of result interpretation. Agreement between assays for identifying high levels was improved by semiquantitative interpretation compared with that by quantitative reporting. CONCLUSION: aCL and aß2GPI IgG/IgM moderate and high thresholds were determined for 4 analytical platforms. Thresholds improve harmonized interpretation of aCL/aß2GPI levels across platforms. The proposed thresholds should be verified in an independent case-control study to check interlaboratory transferability.

NEUT-RI, a surrogate marker of NETosis is lower in patients with strong IgM antiphospholipid antibodies.

BACKGROUND: Antiphospholipid antibody syndrome (APS) is an acquired autoimmune disorder characterized by recurrent venous or arterial thrombosis and/or pregnancy complications. Recently, thrombotic APS was linked to increased neutrophil extracellular traps (NET) formation, suggesting an association between NETs and the severity of APS-related thrombosis. METHODS: We performed a retrospective study on patients tested for presence of antiphospholipid antibodies (990 negative and 374 positive) to evaluate the association between the neutrophil activation state, estimated by the neutrophil reactive index (NEU-RI), a parameter routinely available from some haematology analysers, and antiphospholipid antibodies. RESULTS: We do not observe a difference in NEU-RI values between positive and negative patients globally. However, interestingly, we highlight an association between high titers of IgM and low NEU-RI values indicating a lower neutrophil activation. CONCLUSION: Our data are in line with the recent questioning about the putative clinical consistency of positive solid-phase aPL IgM.

Corrigendum: Serum D-dimer is not predictive of placenta-mediated complications in pregnancy at high risk: the multicentric prospective cohort AngioPred study.

[This corrects the article DOI: 10.3389/fcell.2023.1115622.].

Catastrophic Antiphospholipid Syndrome.

Unlike classic APS, CAPS causes multiple microthrombosis due to an increased inflammatory response, known as a "thrombotic storm". CAPS typically develops after infection, trauma, or surgery and begins with the following symptoms: fever, thrombocytopenia, muscle weakness, visual and cognitive disturbances, abdominal pain, renal failure, and disseminated intravascular coagulation. Although the presence of antiphospholipid antibodies in the blood is one of the diagnostic criteria, the level of these antibodies can fluctuate significantly, which complicates the diagnostic process and can lead to erroneous interpretation of rapidly developing symptoms. Triple therapy is often used to treat CAPS, which includes the use of anticoagulants, plasmapheresis, and high doses of glucocorticosteroids and, in some cases, additional intravenous immunoglobulins. The use of LMWH is recommended as the drug of choice due to its anti-inflammatory and anticoagulant properties. CAPS is a multifactorial disease that requires not only an interdisciplinary approach but also highly qualified medical care, adequate and timely diagnosis, and appropriate prevention in the context of relapse or occurrence of the disease. Improved new clinical protocols and education of medical personnel regarding CAPS can significantly improve the therapeutic approach and reduce mortality rates.

Intimate partner violence as a risk factor for venous thromboembolism in women on combined oral contraceptives: An international matched case-control study.

BACKGROUND: Intimate partner violence (IPV) targeting women is probably underestimated during a woman's lifetime. Venous thromboembolism (VTE) is a multifactorial disease associated with haemostasis-activating conditions. Minor injuries can trigger VTE. OBJECTIVES: We aimed to look for an association between VTE and IPV in women taking combined oral contraceptives (COCs) METHODS: We performed a multicentric, international, matched case-control study. Patients were women with a first VTE associated with COC intake. Controls were women taking COCs undergoing regular gynaecological check-ups. Patients and Controls were matched for country, age, length of COC intake and type (997 pairs). IPV was evaluated using the WAST self-administrated questionnaire. RESULTS: IPV, defined as a WAST score value at least 5, was diagnosed in 33 Controls (3.3 %) and 109 patients (10.9 %), conditional odds ratio (OR): 3.586, 95 % confidence interval (2.404-5.549), p < 0.0001. After multivariate analysis, the adjusted OR was 3.720 (2.438-5.677), p < 0.0001. Sensitivity analysis using increasing WAST score thresholds confirmed the association. CONCLUSIONS: A first VTE in women taking COCs is associated with IPV. This association can have strong human consequences but also raises significant medical issues, for instance on the haemorrhagic risk of anticoagulant treatments in abused women. Pathophysiological studies are warranted.

New erythrocyte parameters derived from the Coulter principle relate with red blood cell properties-A pilot study in diabetes mellitus.

In routine hematological instruments, blood cells are counted and sized by monitoring the impedance signals induced during their passage through a Coulter orifice. However, only signals associated with centered paths in the aperture are considered for analysis, while the rejected measurements, caused by near-wall trajectories, can provide additional information on red blood cells (RBC), as recent publications suggest. To assess usefulness of two new parameters in describing alterations in RBC properties, we performed a pilot study to compare blood samples from patients with diabetes mellitus (DM), frequent pathological condition associated with impairment in RBC deformability, versus controls. A total of 345 blood samples were analyzed: 225 in the DM group and 120 in the control group. A diagram of [Formula: see text] and [Formula: see text], the two new parameters derived from the analysis of impedancemetry pulses, was used to compare distribution of RBC subpopulations between groups. To discriminate RBC from DM and control individuals, based on our multiparametric analysis, we built a score from variables derived from [Formula: see text] matrix which showed good performances: area under the receiving operating characteristic curve 0.948 (0.920-0.970), p<0.0001; best discriminating value: negative predictive value 94.7%, positive predictive value was 78.4%. These results seem promising to approach RBC alterations in routine laboratory practice. The related potential clinically relevant outcomes remain to be investigated.

The 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria.

OBJECTIVE: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR. METHODS: This international multidisciplinary initiative included 4 phases: 1) Phase I, criteria generation by surveys and literature review; 2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; 3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and 4) Phase IV, validation using independent adjudicators' consensus as the gold standard. RESULTS: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into 6 clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and 2 laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-ß2 -glycoprotein I antibodies). Patients accumulating at least 3 points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria versus the 2006 revised Sapporo classification criteria had a specificity of 99% versus 86%, and a sensitivity of 84% versus 99%. CONCLUSION: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.

2023 ACR/EULAR antiphospholipid syndrome classification criteria.

OBJECTIVE: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR. METHODS: This international multidisciplinary initiative included four phases: (1) Phase I, criteria generation by surveys and literature review; (2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; (3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and (4) Phase IV, validation using independent adjudicators' consensus as the gold standard. RESULTS: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-ß2-glycoprotein I antibodies). Patients accumulating at least three points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria vs the 2006 revised Sapporo classification criteria had a specificity of 99% vs 86%, and a sensitivity of 84% vs 99%. CONCLUSION: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.

Is intimate partner abuse underestimated as a precipitating factor for venous thromboembolism in women?

Major and minor trauma increase the risk of venous thromboembolism (VTE), but violence against young women is not reported as a precipitating factor for thrombosis. Here, we report 20 cases of first VTE events in women of childbearing age after evidence of intimate partner violence. Other risk factors for VTE were often associated. In most cases, women did not report this state of violence at the first consultation and their doctors did not suspect it. We imagine that it is an underdiagnosed situation and should call for a systematic evaluation. Screening for intimate partner abuse could have significant consequences, both on protecting women who are affected by it and better evaluating the risk of bleeding with anticoagulant treatment in this situation.

Inflammation and Immune Reactions in the Fetus as a Response to COVID-19 in the Mother.

Background: Contracting COVID-19 during pregnancy can harm both the mother and the unborn child. Pregnant women are highly likely to develop respiratory viral infection complications with critical conditions caused by physiological changes in the immune and cardiopulmonary systems. Asymptomatic COVID-19 in pregnant women may be accompanied by fetal inflammatory response syndrome, which has adverse consequences for the newborn's life and health. Purpose: To conduct an inflammatory response assessment of the fetus due to the effects of COVID-19 on the mother during pregnancy by determining pro-inflammatory cytokines, cell markers, T regulatory cells, T cell response, evaluation of cardiac function, and thymus size. Materials and methods: A prospective study included pregnant women (n = 92). The main group consisted of 62 pregnant women with COVID-19 infection: subgroup 1-SARS-CoV-2 PCR-positive pregnant women 4-6 weeks before delivery (n = 30); subgroup 2-SARS-CoV-2 PCR-positive earlier during pregnancy (n = 32). The control group consisted of 30 healthy pregnant women. In all pregnant women, the levels of circulating cytokines and chemokines (IL-1α, IL-6, IL-8, IL-10, GM-CSF, TNF-α, IFN-γ, MIP-1ß, and CXCL-10) were determined in the peripheral blood and after delivery in the umbilical cord blood, and an analysis was performed of the cell markers on dendritic cells, quantitative and functional characteristics of T regulatory cells, and specific T cell responses. The levels of thyroxine and thyroid-stimulating hormone were determined in the newborns of the studied groups, and ultrasound examinations of the thymus and echocardiography of the heart were also performed. Results: The cord blood dendritic cells of newborns born to mothers who suffered from COVID-19 4-6 weeks before delivery (subgroup 1) showed a significant increase in CD80 and CD86 expression compared to the control group (p = 0.023). In the umbilical cord blood samples of children whose mothers tested positive for COVID-19 4-6 weeks before delivery (subgroup 1), the CD4+CCR7+ T cells increased with a concomitant decrease in the proportion of naive CD4+ T cells compared with the control group (p = 0.016). Significantly higher levels of pro-inflammatory cytokines and chemokines were detected in the newborns of subgroup 1 compared to the control group. In the newborns of subgroup 1, the functional activity of T regulatory cells was suppressed, compared with the newborns of the control group (p < 0.001). In all pregnant women with a severe coronavirus infection, a weak T cell response was detected in them as well as in their newborns. In newborns whose mothers suffered a coronavirus infection, a decrease in thymus size, transient hypothyroxinemia, and changes in functional parameters according to echocardiography were revealed compared with the newborns of the control group. Conclusions: Fetal inflammatory response syndrome can occur in infants whose mothers suffered from a COVID-19 infection during pregnancy and is characterized by the activation of the fetal immune system and increased production of pro-inflammatory cytokines. The disease severity in a pregnant woman does not correlate with SIRS severity in the neonatal period. It can vary from minimal laboratory parameter changes to the development of complications in the organs and systems of the fetus and newborn.

Clonal haematopoiesis of indeterminate potential in patients with venous thromboembolism.

Over the last decade, the concept of Clonal haematopoiesis of undetermined potential (CHIP) has emerged. Low frequency somatic mutations in hematopoietic cells can occur with age and might allow formation of clones in individuals with no characterized haematological pathology. These CHIP mutations are associated with an increased risk of cancer or atherothrombosis, and their prevalence are more and more studied in pathologies with an inflammatory component. In our study, we analysed, by next generation sequencing, the prevalence of CHIP mutation in 94 patients with deep venous thrombosis (DVT), distinguishing two clinical phenotypes: provoked distal and non-provoked proximal DVTs. We show that there is no difference in CHIP prevalence between these two groups, nor with a matched-aged control group. The number of mutation per patients and the affected genes remain also the same between the three groups. Consequently and despite the relative small number of patients in each cohort, it seems that CHIP is not a strong concern in venous thromboembolism.

Assessment-based management of placenta-mediated pregnancy complications: Pragmatism until a precision medicine approach evolves.

The management of pregnant women with thrombophilia and a history of gestational vascular complications remains debatable. Treatment of the latter is often based on clinical outcome rather than disease mechanism. While the use of venous thromboembolism prophylaxis in pregnancy is recommended for those at increased risk, the ability of anticoagulant and/or antiplatelet agents to lower the risk of placenta-mediated complications in this clinical setting remains controversial. The available guidelines are inconsistent in some situations, which reflects the limited evidence base. This review critically discusses risk assessment models (RAMs) and management strategies of women with thrombophilia and pregnancy complications, using clinical vignettes. RAMs, taking into account obstetric and thrombotic history as well as thrombophilia status, could drive a precision medicine approach, based on disease mechanism, and guide individual therapeutic interventions in high-risk clinical settings.

Added value of antiphosphatidylserine/prothrombin antibodies in the workup of obstetric antiphospholipid syndrome: communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies.

BACKGROUND: The added value of antiphosphatidylserine/prothrombin antibodies (aPS/PT) in the diagnostic workup of antiphospholipid syndrome (APS) is unclear. Currently, diagnosis of thrombotic APS (TAPS) and obstetric APS (OAPS) requires persistent presence of lupus anticoagulant (LAC), anticardiolipin (aCL) immunoglobulin (Ig) G/IgM, or anti-ß2-glycoprotein I (aß2GPI) IgG/IgM antibodies. OBJECTIVES: To evaluate the role of aPS/PT IgG and IgM in OAPS. METHODS: aPS/PT IgG/IgM, aCL IgG/IgM, aß2GPI IgG/IgM, and LAC were determined in 653 patients (OAPS, TAPS, and controls). In-house aPS/PT cut-off values were calculated, titers and prevalence were compared between OAPS, TAPS, and controls and type of pregnancy morbidity. Sensitivity, specificity, likelihood ratios, and odds ratios (OR) with 95% CI were calculated. RESULTS: In OAPS, aPS/PT IgG and IgM showed an OR of 4.32 (95% CI, 2.54-7.36) and 3.37 (95% CI, 1.93-5.89), respectively, but the association was not independent of LAC. Prevalence and titers of aPS/PT IgG and IgM were lower in OAPS than in patients with TAPS. aPS/PT were more prevalent and showed higher titers in patients with late pregnancy loss than in patients with early pregnancy loss with a positivity of 86.4% and 39.3%, respectively. Higher aPS/PT titers did not increase the likelihood of having OAPS. CONCLUSION: The added value of aPS/PT testing in the current diagnostic workup of OAPS seems limited compared with LAC, aCL, and aß2GPI. aPS/PT might be useful in specific subsets of patients with OAPS. However, future multicentric studies are needed to elucidate the risk of less frequent and most severe obstetrical manifestations.

Serum D-dimer is not predictive of placenta-mediated complications in pregnancy at high risk: The multicentric prospective cohort AngioPred study.

Background: The theory that D-dimer level might has a predictive or diagnostic role in preeclampsia needs to be explored. Aim of the study was to evaluate the association between serum D-dimer level and the occurrence of placenta-mediated complications (PMC) in a pregnant population at high risk. Methods: A prospective multicenter cohort study including 200 pregnant women was conducted. Results: Serum D-dimer increases throughout pregnancy, with the highest levels at the end of gestation. Serum D-dimer level was similar for women with PMC and with no complication. Serum D-dimer level was not different in women with preeclampsia versus uncomplicated women. Serum D-dimer level was not different in women with early or late preeclampsia versus uncomplicated women. Conclusion: This result suggests that serum D-dimer level was not predictive of the PMC occurrence. This corroborates the fact that the origin of PMC based more on immunity than in hemostasis.

Prognostic value of an automated thrombin generation assay in COVID-19 patients entering hospital: A multicentric, prospective observational study.

INTRODUCTION: The prognostic significance of the thrombin generation assay (TGA) with a thrombomodulin (TM) challenge in patients entering hospital with severe COVID-19 is uncertain. METHODS: We prospectively evaluated an automated TGA (aTGA) using the ST-ThromboScreen® assay and ST-Genesia® analyser in 179 patients with severe COVID-19 during their admission to 2 university hospitals. The primary outcome was early survival at Day 28 (D28). Secondary outcomes were late survival at Day 90 (D90), later transfer to an intensive care unit (ICU), and occurrence of any thrombotic complications during hospitalisation. RESULTS: Among the 174 patients, 50 were initially admitted to ICUs. Forty-two were transferred to ICUs before D28. Fourteen patients, all in ICUs, died before D28, and 20 before D90, all but 1 in ICUs. None of the aTGA-derived results were associated with vital status either at D28 or D90. Nine patients had a thrombotic event with no association with the aTGA results. Later transfer to the ICU was associated with higher velocity index, thrombin peak height and endogenous thrombin potential (ETP) values of the aTGA performed with TM, and mainly with a lower TM-induced decrease in ETP (odds ratio 15.5 (2.15-132), p = 0.009). CONCLUSIONS: aTGA, a global assay supposed to evidence coagulopathy, could predict neither early or late survival, nor thrombotic events, in hospitalised COVID-19 patients. Its clinical justification in that setting is thus unlikely. A relative resistance of the ETP to TM was associated with later transfer to the ICU and deserves further investigation.

Antiphospholipid Antibodies in Pregnancy: Maternal and Neonatal Implications.

Antiphospholipid antibodies (aPL Abs) have long been associated with the occurrence of certain specific pregnancy morbidities, affecting both mother and fetus. Antithrombotic-based prophylactic regimens are the standard of care. Their intensity is modulated by the thrombotic history and has greatly improved the prognosis related to spontaneous morbidity. Observational studies show that this treatment is still associated with the persistence of excess of late-pregnancy placental diseases, calling for new or complementary developments, yet to be validated. Rigorous prospective multicentric validation of clinical and laboratory parameters capable of identifying those women and fetuses at a risk of pejorative evolution, thus early prognosis, is a priority issue. These will make it possible to develop customized treatments and test them. Furthermore, there are still concerns, particularly neurodevelopmental ones, about children born to aPL Ab-positive mothers, and clarification based on regular, more systematic evaluations is required. Even after pregnancy, women with a pure obstetrical antiphospholipid syndrome are at a greater risk of venous and arterial thrombosis over time, and prevention needs to be improved. These women also appear to develop more psychiatric and mood disorders. Central nervous system imaging using high-resolution techniques has shown subtle impairments in the white matter, associated with the most pathogenic aPL Abs and the clinical significance of this is under investigation. These mothers also seem to develop an excess of cancers. The systemic impact of aPL Abs is gradually being suspected, although this requires further evidence, and prevention should be envisaged.

Combined oral contraceptive-associated venous thromboembolism revealing an antiphospholipid syndrome: International retrospective study of outcomes.

INTRODUCTION: Limitations in the data used to define thromboprophylaxis for patients with antiphospholipid antibodies (aPLAbs) and thrombosis include uncertainties after an initial provoked venous thromboembolic event (VTE). We aimed to study such cases associated with combined oral contraceptive (COC) intake. METHODS: We retrospectively analysed thrombotic outcomes after a first COC-associated VTE and positive aPLAbs, with a low risk HERDOO2 score, on low-dose aspirin (LDA) secondary thromboprophylaxis, seen from 2010 to 2021 in 3 tertiary referral centres, one in France and 2 in Russia. Data from 264 patients (distal deep vein thrombosis DVT: 62.9 %), cumulating in 1327.7 patient-years of observation, were collected. RESULTS: There were 22 cases of thrombosis: 16 distal DVTs, 3 proximal, 1 pulmonary embolism (PE) and 2 transient ischemic attacks. Recurrence rate was 1.66 per 100 patient-years (p-y; 95 % CI: 0.96-2.33). No major bleeding occurred. Risk factors affecting recurrence-free survival were the time between first COC intake and VTE (p < 0.0001; the shortest, the lower), proximal DVT (p = 0.021), active smoking (p = 0.039), an associated systemic disease (p = 0.043) and circulating monocyte counts (p = 0.001). CONCLUSIONS: We observed a low risk of recurrence which was modulated by classical risk factors for VTE. These observational data may provide clues for future randomized controlled trials.

The Risk of Thrombosis Around Pregnancy: Where Do We Stand?

Pregnancy and puerperium increase the relative risk of venous thromboembolism (VTE) and the absolute risk remains low, around 1 per 1,000, with induced mortality of around 1 per 100,000. Analysis of large databases has helped specify the modes of presentation and risk factors (RF) whose impact is greater after than before childbirth, since VTE during pregnancy and post-partum obey different RFs. The evolution of the population concerned (mostly women over 35, obese, of multi-ethnicity undergoing medically assisted reproduction) affects the frequency of these RFs. Pulmonary embolism (PE) is over-represented after childbirth, but 30% of PE in pregnancy occurs without any RFs. Recommendations for prevention, mainly from expert groups, are heterogeneous and often discordant. Low molecular weight heparins (LMWH) are the mainstay of pharmacological thromboprophylaxis, in a field where randomized controlled studies are definitely lacking. VTE risk assessment in pregnancy must be systematic and repetitive. Risk assessment methods and scores are beginning to emerge to guide thromboprophylaxis and should be used more systematically. In the future, analyzing observational data from huge, nationwide registries and prospective cluster clinical trials may bring to light clinically relevant outcomes likely to feed comprehensive guidelines.

Soluble CD146 is increased in preeclampsia and interacts with galectin-1 to regulate trophoblast migration through VEGFR2 receptor.

OBJECTIVE: To explore the regulatory role of soluble CD146 (sCD146) and its interaction with galectin-1 (Gal1) in placenta-mediated complications of pregnancy. DESIGN: Prospective pilot and experimental studies. SETTING: University-affiliated hospital and academic research laboratory. PATIENT(S): One hundred fifteen women divided into three groups: 30 healthy, nonpregnant women, 50 women with normal pregnancies, and 35 with placenta-mediated pregnancy complications. INTERVENTION(S): Wound-healing experiments were conducted to study trophoblast migration. MAIN OUTCOME MEASURE(S): Quantification of sCD146 and Gal1 by enzyme-linked immunosorbent assay. Analysis of trophoblast migration by wound closure. RESULT(S): Concomitant detection of sCD146 and Gal1 showed lower sCD146 and higher Gal1 concentrations in women with normal pregnancies compared with nonpregnant women. In addition, follow-up of these women revealed a decrease in sCD146 associated with an increase in Gal1 throughout pregnancy. In contrast, in women with preeclampsia, we found significantly higher sCD146 concentrations compared with women with normal pregnancies and no modification of Gal1. We emphasize the opposing effects of sCD146 and Gal, since, unlike Gal1, sCD146 inhibits trophoblast migration. Moreover, the migratory effect of Gal1 was abrogated with the use of an anti-CD146 blocking antibody or the use of small interfering RNA to silence VEGFR2 expression. This suggests that trophoblast migration is mediated though the interaction of Gal1 with CD146, further activating the VEGFR2 signaling pathway. Significantly, sCD146 blocked the migratory effects of Gal1 on trophoblasts and inhibited its secretion, suggesting that sCD146 acts as a ligand trap. CONCLUSION(S): Soluble CD146 could be proposed as a biomarker in preeclampsia and a potential therapeutic target. CLINICAL TRIAL REGISTRATION NUMBER: NCT 01736826.