aPL Profile Research Articles

Antiphospholipid antibody positivity is associated with maturation failure and thrombosis of native arteriovenous fistula: a retrospective study in HD patients.

The prevalence of antiphospholipid antibody (aPL) is high among hemodialysis (HD) patients compared to the general population and is inconsistently associated with arteriovenous fistula (AVF) thrombosis or stenosis. The association with maturation failure has never been investigated. This study aims to evaluate native AVF complications (thrombosis, stenosis, and maturation failure) and primary patency in aPL positive HD patients. We retrospectively identified 116 HD patients with native AVF. We collected the aPL profiles, the clinical and biological data potentially involved in AVF maturation failure, thrombosis, and stenosis, and investigated the association of these complications and aPL positivity. Kaplan-Meier survival analysis was performed. In our cohort, the prevalence of aPL persistent positivity was 32.7% and this was strongly associated with AVF maturation failure defined by ultrasound. aPL persistent positivity was a strong predictor in multivariate analysis and this association was independent of AVF stenosis or thrombosis during maturation process. There was no association with primary and functional primary patency, and stenosis. However, aPL persistent positivity according to ACR/EULAR classification criteria was associated with thrombosis when compared to strictly negative aPL patients. In our cohort, aPL persistent positivity was significantly associated with AVF maturation failure and thrombosis but not with AVF stenosis. To our knowledge, we report for the first time, a statistically significant association between aPL positivity and delay or absence of native AVF maturation.

Cell-bound complement activation products in antiphospholipid antibody-positive patients without other systemic autoimmune rheumatic diseases.

The objective of this study was to analyze complement activation in antiphospholipid antibody (aPL)-positive patients without other systemic autoimmune rheumatic diseases, using C3/C4 and cell-bound complement activation products (CB-CAPs) (B-lymphocytes [BC4d], erythrocytes [EC4d], and platelets [PC4d]). Persistently aPL-positive patients with or without aPL-related clinical manifestations (thrombotic APS [TAPS], microvascular APS [MAPS], obstetric APS, thrombocytopenia [TP], and/or hemolytic anemia [HA]) were enrolled in a single center study. Blood and clinical data were collected at baseline; a subgroup of patients completed 6- or 12-month follow-up. At baseline, 4/31 (13%) patients had decreased C3/C4, while 7/29 (24%) had elevated BC4d, 11/33 (33%) EC4d, and 12/32 (38%) PC4d. Based on different aPL profiles, all patients with decreased C3/C4 or elevated BC4d, EC4d, and PC4d had triple aPL or isolated lupus anticoagulant positivity. Based on different aPL clinical phenotypes, the number of patients with strongly positive EC4d and PC4d were proportionally higher in those with MAPS/TP/HA, compared to TAPS or no APS. Compared to baseline, the frequencies of BC4d, EC4d, and PC4d positivity were not significantly different in the subgroup of patients during their 6- or 12-month follow-up. There was a weak correlation between C3/C4 and CB-CAPs, especially for PC4d. In summary, complement activation in aPL-positive patients varies based on aPL profiles and clinical phenotypes. Given the higher percentage of aPL-positive patients with abnormal CB-CAPs, compared to C3/C4, and the poor inverse correlation between CB-CAPs and C3/C4, our study generates the hypothesis that CB-CAPs have a role in assessing disease activity and thrombosis risk in aPL-positive patients.

Phosphatidylserine-Dependent Anti-prothrombin Antibodies as a Key Predictor for Systemic Lupus Erythematosus in Patients with Primary Antiphospholipid Syndrome: A retrospective longitudinal cohort study.

Primary antiphospholipid syndrome (PAPS) is an autoimmune disorder characterized by thrombosis and pregnancy morbidity. Although PAPS is distinct from systemic lupus erythematosus (SLE), the two conditions share clinical features and susceptibility genes. Progression from PAPS to SLE is well-recognized. However, risk factors for this transition are poorly understood. We aimed to identify predictors of progression to SLE in patients with PAPS. A longitudinal single-center study was conducted at Hokkaido University Hospital from 1990 to 2021. Baseline characteristics including clinical features, laboratory data, aPL profiles were compared between patients who progressed to SLE (SLE group) and those who did not (non-SLE group). Among 64 patients diagnosed with PAPS at baseline, nine (13.8%) progressed to SLE over a mean follow-up of 9 years (incidence rate, 1.61 per 100 person-years). At the diagnosis of PAPS, the SLE group had a higher prevalence of anti-phosphatidylserine/prothrombin antibodies (aPS/PT) and anti-dsDNA antibodies compared to the non-SLE group. Other clinical findings, autoantibody profiles, and serum complement levels were similar between the two groups. Multivariate Cox analysis showed that IgG aPS/PT was significantly associated with SLE development (Hazard ratio: 10.3, 95% CI: 1.13-92.6, p=0.04). IgG aPS/PT may be a predictive factor for new-onset SLE in patients with PAPS, suggesting its utility in guiding risk stratification and monitoring strategies for these patients.

The clinical relevance of different antiphospholipid antibody profiles in pediatric rheumatology patients

BackgroundThe clinical relevance of different antiphospholipid antibody (aPL) profiles, including low level anticardiolipin (aCL) and anti-β2-glycoprotein-I (aβ2GPI) antibodies, is ill-defined in the pediatric population. Our purpose is to describe the demographic, clinical, and laboratory characteristics of aPL positive pediatric patients based on different aPL profiles.FindingsIn this single center retrospective cohort study, based on the screening of our pediatric (age ≤ 18) rheumatology electronic medical records (2016–2022), we identified patients who had at least one “positive” aPL (lupus anticoagulant [LA], aCL IgG/M, or aβ2GPI IgG/M) result. Patients were grouped into high- (LA positive and/or aCL/aβ2GPI IgG/M > 40U [ELISA]) and low-risk (LA negative and aCL/aβ2GPI IgG/M 20-39U) aPL profiles; those with persistently positive aPL were descriptively analyzed for demographic and clinical characteristics. Of 57 included patients, 34 (59%) had initial high- and 23 (40%) had initial low-risk profiles. Based on subsequent aPL results available in 42/57 (74%) patients, 25/27 (93%) in the high-, and 7/15 (47%) in the low-risk groups remained still positive. Of these 32 patients with persistently positive aPL, moderate-to-large vessel or microvascular thrombosis occurred in nine (28%) patients with high-risk and in none with low-risk aPL profiles; non-thrombotic aPL-related manifestations were reported in 15 (47%) patients with persistent aPL positivity.ConclusionAn initial high-risk aPL profile was persistent in approximately 90% of our cohort, a third of whom had thrombosis, and half had non-thrombotic aPL manifestations. Our results underscore the need for a large-scale effort to better characterize aPL-related manifestations in pediatric patients with persistent high-risk aPL-profiles.

Laboratory assessment of antiphospholipid syndrome: Laboratory data.

Thorough assessment of the antiphospholipid syndrome (APS) includes retesting of positive antiphospholipid antibody (aPL) tests after at least 12 weeks, and a full antiphospholipid antibody profile. To what extent this work-up is done in clinical practice is unknown. Data on 25 116 in- and out-hospital patients tested for the presence of lupus anticoagulant (LA), the aPL which most strongly correlates with thrombosis, was extracted from the laboratory information system of the only laboratory that performs LA tests in the Capital Region, Denmark. We estimated fraction of repeated tests, tests repeated within the recommended time span, and fraction with a full aPL profile. Out of 25 116 patients, 843 were positive for LA (3.3%), and 3948 results were inconclusive (16%). Only 51% (95% CI of the proportion: 48%-54%) (n = 431) of positive tests were repeated. The proportion of inconclusive LA test results increased from 13% (12%-15%) in 2009 to 20% (19%-22%) in 2020. Out of the positive tests repeated within the first year, only 60/353 (17%; 13%-21%) were repeated within 12-16 weeks; 177/353 (50%; 45%-55%) were re-tested within the first 12 weeks of first positive test result. The proportion of patients with a full antiphospholipid antibody profile increased from 161/1978 (8%) in 2010 to 1041/1978 (43%) in 2020. We found several issues with the laboratory workup of APS. This indicates a need for increased awareness of comprehensive laboratory assessment of possible APS as well as a closer collaboration between the laboratory and clinicians.

2023 ACR/EULAR classification criteria in existing research cohorts: an international study.

To assess the impact of the updated ACR/EULAR APS classification criteria on two large research cohorts. Consecutive patients who tested persistently positive for at least one aPL in the last three years were enrolled. The first APS Sydney index event was considered and computed for the comparison between Sydney and 2023 APS criteria. When computing the 2023 APS criteria, additional manifestations were also considered. The cohort comprised 249 patients (185 with APS and 64 aPL carriers according to Sydney criteria). The 185 patients had as first index event venous thrombosis in 55 cases (29.8%), arterial thrombosis in 63 (34%) and pregnancy morbidity in 67 (36.2%). When applying the updated criteria, 90 subjects (48.7%) failed to reach the composite score of the new criteria. The percentage of thrombotic APS per Sydney criteria decreased from 47.3% to 34.9% because of high cardiovascular risk in 23 cases, IgM aPL profile in six cases and in two patients for both reasons. Patients with pregnancy morbidity decreased from 26.9% to 3.2% (39 cases of recurrent early pregnancy loss and 20 of fetal losses). Consequently, the percentage of aPL carriers increased from 26% to 61%. When looking at the disease evolution at follow-up, 32 additional patients out of 90 (35.6%) fulfilled the new APS criteria, after developing additional clinical manifestation following index event. When applying the new APS criteria to our research cohorts, not-negligible differences exist in patients' classification. A multidisciplinary approach will be mandatory to assess the impact of the new criteria on research and, ultimately, patients' care.

Cardiovascular risk in rare autoimmune diseases, lessons from a primary antiphospholipid syndrome patients

Abstract Background Antiphospholipid syndrome is a thrombo-inflammatory disease driven by circulating autoantibodies (aPL) that recognize cell surface phospholipids and phospholipid-binding proteins. In the absence of an underlying connective tissue disorder, the persistent presence of these antibodies associated with recurrent fetal losses and arterial or venous thrombosis is defined as a primary antiphospholipid syndrome (PAPS) with a prevalence of 1/2000 people, predominantly female. Purpose Estimation of cardiovascular risk presence based on markers of subclinical cardiovascular impairment. Methods 100 PAPS patients, with an average age of 47.70±13.14y, 93.7% females, were included in the study. Anticardiolipin antibodies (aCL IgG/IgM), anti-ß2 glycoprotein-I (anti-ß2GPI IgG/IgM), and lupus anticoagulant (LAC) were determined. Abnormal cut-off values used for left ventricular diastolic dysfunction (LVDD) were septal E ́<7 cm/sec, lateral E ́ <10 cm/sec, average E/E ́ ratio >14, LA volume index (LAVI) >34 mL/m2, and peak tricuspid regurgitation velocity >2.8 m/sec. LVDD was present if more than half parameters were with abnormal values. Endothelial dysfunction was assessed through ultrasound measurement of brachial artery flow-mediated dilation (FMD) and atherosclerosis progression by ultrasound assessment of intima-media thickness (cIMT) on carotid arteries (common carotid artery, CCA, internal carotid artery, ICA). The results were compared to 90 healthy, age and sex-matched controls. Results LVDD was significantly more prevalent in PAPS patients compared to healthy controls (24.8% vs. 2.2%, p=0.001). FMD was significantly lower in PAPS patients (10.76±5.15% vs. 14.20±6.76%, p=0.0001) and cIMT values were significantly higher (left ICA 0.80±0.29mm vs 0.56±0.20mm, p=0.001). All markers of subclinical atherosclerosis were significantly related to age and standard atherosclerotic risk factors present. Regarding aPL profile, anti-ß2GPI IgG positive PAPS patients had higher levels of cIMT ICA left (p=0.049) and LAC positive higher prevalence of LVDD (p=0.047) CONCLUSIONS: PAPS patients impose significantly higher prevalence of subclinical cardiovascular involvement compare to healthy population. Timely recognition, along with vigorous control of standard atherosclerotic risk factors and a proper therapeutic (antithrombotic and/or anticoagulant) regime, is of great importance.

Descriptive analysis of patients positive for anti-phospholipid antibodies included in two Italian registries

The definite diagnosis of antiphospholipid syndrome (APS) depends on the laboratory performance and clinicians’ interpre- tation. Results from two Italian inception cohort studies of anti- phospholipid antibodies (aPL)-positive subjects, the Italian Survey on ANtiphoSpholipid antibody Positive Individuals Reg- istry (INSPIRE) and the Survey on AnTicoagulated Patients- Reg- isTry (START) have been compared. Data from INSPIRE were collected by rheumatologists of the FIRMA group while those of START by physicians working in Italian thrombosis centers. Ev- idence on several, still unraveled, clinical and methodological as- pects of ‘real life’ aPL testing and APS diagnosis was collected. In this paper, we report the characteristics of 123 cases enrolled in INSPIRE and 229 in START registries, with particular refer- ence to the reasons why these tests were requested, the obtained aPL profile, and consequent treatment. Laboratory testing for aPL in the absence of clinical criteria defining APS was more frequent in INSPIRE (p<0.0001). The rate of patients in classification cat- egory I (more than one aPL test positive) was significantly higher in START (p<0.0001) as well as the use of warfarin. A wide va- riety of treatments has been observed in patients in classification category II (single aPL positivity). These data indicate that there is a need to harmonize many aspects among the various specialists dealing with APS.

Association of anti-β2-glycoprotein I/HLA-DR complex antibody with arterial thrombosis in female patients with systemic rheumatic diseases

Backgroundβ2-glycoprotein I (β2GPI) complexed with human leukocyte antigen DR (β2GPI/HLA-DR) was found to be a major autoantibody target in antiphospholipid syndrome (APS). This study aimed to reveal the association between anti-β2GPI/HLA-DR antibodies and vascular thromboses in women with systemic rheumatic diseases.MethodsWe conducted a retrospective longitudinal study. We measured anti-β2GPI/HLA-DR antibodies and compared them with anti-phospholipid antibody (aPL) profiles and the adjusted global antiphospholipid syndrome score (aGAPSS). Using receiver operating characteristic (ROC) analysis, we determined the best cut-off value for arterial thrombosis. We also evaluated the validity of anti-β2GPI/HLA-DR antibodies by adding to conventional cardiovascular risk factors in multivariate logistic analysis.ResultsWe evaluated 704 patients, including 66 (obstetric or thrombotic) APS, 13 primary APS, and 78 asymptomatic aPL carriers. Seventy-seven patients had a history of arterial thrombosis, and 14 patients had both arterial and venous thrombosis. These 14 patients, as well as patients with aGAPSS > 10 or triple-positive aPL profiles, displayed high anti-β2GPI/HLA-DR antibody titers. The ROC curve showed a sensitivity, specificity, and area under the curve (AUC) for arterial thrombosis of 33.8%, 91.4%, and 0.6009, respectively, with a cut-off value of 172.359 U/mL. The anti-β2GPI/HLA-DR antibody positivity using this cut-off value yielded an odds ratio of 5.13 (95%CI: 2.85–9.24), significantly improving the AUC from 0.677 to 0.730.ConclusionAnti-β2GPI/HLA-DR antibodies are associated with arterial thrombosis in female patients with systemic rheumatic diseases.

Damage measured by Damage Index for Antiphospholipid Syndrome (DIAPS) in antiphospholipid antibody-positive patients included in the APS ACTION registry.

Our primary objective was to quantify damage burden measured by Damage Index for Antiphospholipid Syndrome (DIAPS) in aPL-positive patients with or without a history of thrombosis in an international cohort (the APS ACTION cohort). Secondly, we aimed to identify clinical and laboratory characteristics associated with damage in aPL-positive patients. In this cross-sectional study, we analysed the baseline damage in aPL-positive patients with or without APS classification. We excluded patients with other autoimmune diseases. We analysed the demographic, clinical and laboratory characteristics based on two subgroups: (i) thrombotic APS patients with high vs low damage; and (ii) non-thrombotic aPL-positive patients with vs without damage. Of the 826 aPL-positive patients included in the registry as of April 2020, 586 with no other systemic autoimmune diseases were included in the analysis (412 thrombotic and 174 non-thrombotic). In the thrombotic group, hyperlipidaemia (odds ratio [OR] 1.82; 95% CI 1.05, 3.15; adjusted P = 0.032), obesity (OR 2.14; 95% CI 1.23, 3.71; adjusted P = 0.007), aβ2GPI high titres (OR 2.33; 95% CI 1.36, 4.02; adjusted P = 0.002) and corticosteroid use (ever) (OR 3.73; 95% CI 1.80, 7.75; adjusted P < 0.001) were independently associated with high damage at baseline. In the non-thrombotic group, hypertension (OR 4.55; 95% CI 1.82, 11.35; adjusted P = 0.001) and hyperlipidaemia (OR 4.32; 95% CI 1.37, 13.65; adjusted P = 0.013) were independent predictors of damage at baseline; conversely, single aPL positivity was inversely correlated with damage (OR 0.24; 95% CI 0.075, 0.77; adjusted P = 0.016). DIAPS indicates substantial damage in aPL-positive patients in the APS ACTION cohort. Selected traditional cardiovascular risk factors, steroids use and specific aPL profiles may help to identify patients more prone to present with a higher damage burden.

The ABCs of antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is a thromboinflammatory syndrome characterized by thrombotic, microvascular, obstetric, or non-thrombotic events in the setting of persistent antiphospholipid antibodies (aPL), namely anticardiolipin antibody (aCL), anti-β2 glycoprotein-I antibody (aβ2GPI), and lupus anticoagulant (LA). The diagnosis of APS requires careful assessment of the aPL profile, the clinical phenotype, and additional risk factors. The standard management of aPL-related thrombosis is anticoagulation, which is not effective for microvascular and non-thrombotic events. In parallel to our improved understanding of aPL-related mechanisms, the role of immunosuppression has been increasingly investigated. In this review, we summarize the basic concepts and future perspectives in APS.

High-throughput sequencing technology facilitates the discovery of novel biomarkers for antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis and/or morbid pregnancy, accompanied by persistent antiphospholipid antibody (aPL) positivity. However, due to the complex pathogenesis of APS and the large individual differences in the expression of aPL profiles of patients, the problem of APS diagnosis, prognosis judgment, and risk assessment may not be solved only from the antibody level. It is necessary to use new technologies and multiple dimensions to explore novel APS biomarkers. The application of next-generation sequencing (NGS) technology in diseases with a high incidence of somatic mutations, such as genetic diseases and tumors, has been very mature. Thus, we try to know the research and application progress of APS by NGS technology from genome, transcriptome, epigenome and other aspects. This review will describe the related research of NGS technology in APS and provide more reference for the deep understanding of APS-related screening markers and disease pathogenesis.

Anti-Neutrophil Extracellular Trap Antibodies in Antiphospholipid Antibody-Positive Patients: Results From the Antiphospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking Clinical Database and Repository.

This study aimed to elucidate the presence, antigen specificities, and potential clinical associations of anti-neutrophil extracellular trap (anti-NET) antibodies in a multinational cohort of antiphospholipid (aPL) antibody-positive patients who did not have lupus. Anti-NET IgG/IgM levels were measured in serum samples from 389 aPL-positive patients; 308 patients met the classification criteria for antiphospholipid syndrome. Multivariate logistic regression with best variable model selection was used to determine clinical associations. For a subset of the patients (n=214), we profiled autoantibodies using an autoantigen microarray platform. We found elevated levels of anti-NET IgG and/or IgM in 45% of the aPL-positive patients. High anti-NET antibody levels are associated with more circulating myeloperoxidase (MPO)-DNA complexes, which are a biomarker of NETs. When considering clinical manifestations, positive anti-NET IgG was associated with lesions affecting the white matter of the brain, even after adjusting for demographic variables and aPL profiles. Anti-NET IgM tracked with complement consumption after controlling for aPL profiles; furthermore, patient serum samples containing high levels of anti-NET IgM efficiently deposited complement C3d on NETs. As determined by autoantigen microarray, positive testing for anti-NET IgG was significantly associated with several autoantibodies, including those recognizing citrullinated histones, heparan sulfate proteoglycan, laminin, MPO-DNA complexes, and nucleosomes. Anti-NET IgM positivity was associated with autoantibodies targeting single-stranded DNA, double-stranded DNA, and proliferating cell nuclear antigen. These data reveal high levels of anti-NET antibodies in 45% of aPL-positive patients, where they potentially activate the complement cascade. While anti-NET IgM may especially recognize DNA in NETs, anti-NET IgG species appear to be more likely to target NET-associated protein antigens.

Associations Among Antiphospholipid Antibody Types, Isotypes, and Titers: An AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) Study

Several antiphospholipid antibody (aPL) profiles (“triple” and lupus anticoagulant [LA] positivity) are associated with a higher risk for clinical manifestations of antiphospholipid syndrome (APS). Further risk is correlated with higher levels of anticardiolipin antibody (aCL) and anti-β2 glycoprotein-I antibody (aβ2GPI), and with aPL persistence. Given that the 3 aPL tests detect partially overlapping sets of antibodies, the primary goal of this study was to characterize the associations among aPL tests using AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) core laboratory data. The APS ACTION Registry includes annually followed adult patients with positive aPL based on the Revised Sapporo Classification Criteria. We analyzed baseline and prospective core laboratory data of the registry for associations among aPL tests using the Spearman rank correlation with Bonferroni-adjusted significance level for multiple comparisons. An aPL Load was calculated based on 6 tests (aCL IgG/IgM/IgA and aβ2GPI IgG/IgM/IgA); a receiver operating characteristic curve was used to evaluate the diagnostic performance of the aPL Load in predicting LA positivity. In 351 patients simultaneously tested for LA, aCL, and aβ2GPI, the frequency of moderate-to-high (≥40 U) titers of aCL and aβ2GPI IgG/IgM/IgA was higher in patients who were positive for LA vs those who were negative. An aPL Load was calculated for each patient to assess the overall aPL burden. For every 1-point increase in the aPL Load, the possibility of a positive LA test increased by 32% (odds ratio, 1.32; 95% CI, 1.2-1.5; P < .001). Based on core laboratory data from a large international registry, most aPL enzyme-linked immunosorbent assay ≥40 U and a high calculated aPL Load combining 6 aPL enzyme-linked immunosorbent assays were predictive of a positive LA. These data suggest that the combined quantitative burden of aPL may provide a mechanistic explanation of a positive LA.

An Antiphospholipid Antibody Profile as a Biomarker for Thrombophilia in Systemic Lupus Erythematosus

Despite recent advances in treatment and significant improvements in prognosis, thrombosis remains the major cause of death in systemic lupus erythematosus (SLE). Antiphospholipid antibodies (aPL) are the main triggers of thrombosis in patients with SLE, with a frequency of approximately 30-40%. Lupus anticoagulant, anticardiolipin, and anti-β2-glycoprotein I antibodies, which are included in the criteria for antiphospholipid syndrome, and 'non-criteria' aPL such as anti-phosphatidylserine/prothrombin complex antibodies, are risk factors for thrombosis in patients with SLE. Multiple positivity for aPL is also associated with an increased risk of thrombosis, and scores calculated from aPL profiles can predict the risk of developing thrombosis. Although there is insufficient evidence for treatment, aPL-positive SLE patients should/may be treated with anticoagulants and/or low-dose aspirin as appropriate. This review summarises the evidence on the clinical significance of the aPL profile as a biomarker of thrombophilia in patients with SLE.

Evaluation of a gene signature related to thrombotic manifestations in antiphospholipid syndrome.

Thrombotic primary antiphospholipid syndrome (t-PAPS) is an acquired condition characterized by heterogeneous thrombotic manifestations, which is intriguing since venous and arterial thrombosis appear to have distinct pathogenesis. Gene expression analysis may constitute a new approach to evaluate potential similarities or differences between the clinical manifestations of t-PAPS. Recently, dysregulation of the ANXA3, TNFAIP6, TXK, BACH2, and SERPINB2 genes has been associated with both arterial and venous thrombosis in the general population. Therefore, the aim of this study was to examine whether ANXA3, TNFAIP6, TXK, BACH2, and SERPINB2 expression was associated with t-PAPS. Gene expression was quantified by qPCR of total leukocyte mRNA. In this case-control study, 102 t-PAPS patients, 17 asymptomatic antiphospholipid (aPL) carriers and 100 controls were evaluated. Increased expression of ANXA3 (P = 0.008) and TNFAIP6 (P = 0.001) and decreased expression of the TXK gene (P = 0.0001) were associated with an increased risk of t-PAPS compared to the control. ANXA3 upregulation was more evident in cases of arterial thrombosis and multiple thrombotic events. There was no difference in the expression of these genes between triple and non-triple aPL positivity. ANXA3, TNFAIP6, TXK, BACH2, and SERPINB2 expression levels were also similar between aPL carriers and controls (P = 0.77; P = 0.48; P = 0.08; P = 0.73, and P = 0.13, respectively). In conclusion, our results showed that genes related to hemostasis (ANXA3) and immunity (TNFAIP6, TXK) are dysregulated in t-PAPS compared to controls. Gene dysregulation was not detected in aPL carriers and was not related to the aPL profile, suggesting that this gene signature is related to thrombotic manifestations rather than to aPL burden. Our results suggest that innate immunity and hemostasis pathways are associated with t-PAPS at a molecular level and may play a role in disease severity.

Adjusted global antiphospholipid syndrome score (aGAPSS) is useful to predict relapses in patients with retinal vein occlusion

BackgroundA significant proportion of patients with retinal vein occlusion (RVO) are antiphospholipid antibodies (aPL) carriers. Relapsing disease occurs in nearly 10 % of cases and the role of aPL has not been established. The adjusted global antiphospholipid syndrome score (aGAPSS) was developed to assess the risk of clinical events in aPL carriers and its role in the management of RVO patients is unknown. ObjectiveTo analyze the values of aGAPSS in a large cohort of patients with RVO and population-based controls, and to assess its usefulness to predict RVO relapses. MethodsCase-control study of RVO patients and population-based controls of similar age and sex. We have assessed and compared the aPL profile and the aGAPSS score in patients with and without relapsing disease and controls. ResultsFour-hundred and seventy-two RVO patients and 346 controls were included. Fifty-seven RVO patients had antiphospholipid syndrome (RVO-APS). Of them, 75.4 % had a high-risk profile compared to 3 % in controls (p = 0.0001). The median aGAPSS values were 8 [7–13], 3 [1–4], and 3 [0–4], in RVO-APS, RVO no-APS, and controls. Nineteen patients had had a recurrence of RVO before inclusion and 8 during the follow-up. APS was more prevalent in relapsing patients. In the adjusted multivariable regression model, the best predictor for RVO recurrence during the follow-up was an aGAPSS score ≥6 (OR 5.5, CI95% 1.3–23.7; p = 0.023). ConclusionsIn patients with RVO, once the control of vascular risk factors has been optimized, the aGAPSS might help to identify those at risk of relapsing disease.

Neural Network Diagnoses the Antiphospholipid Syndrome without Interrupting Anticoagulant Therapy

Background The antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies (aPL) and is associated with an increased risk of thrombosis and pregnancy morbidity. The Laboratory diagnosis of APS is difficult because most patients already use anticoagulants due to a thrombotic event, resulting in interference with the clotting assays used for lupus anticoagulant (LAC) testing. Nevertheless, the aPL profile defines patient management, making aPL testing warranted during anticoagulant therapy. Sometimes, cessation of anticoagulant treatment is necessary to perform the lupus anticoagulant (LAC) test, which is unfavorable. The thrombin generation (TG) test is a functional and global hemostatic test. Clinical studies have shown that increased TG is associated with thrombosis, also in thrombotic APS patients. We have previously shown that the artificial intelligence method neural networks can be used to diagnose untreated APS patients from a group of healthy, auto-immune disease, and thrombosis controls with high accuracy. At the moment of aPL testing, many patients are already on anticoagulants, hampering the detection of LAC. Therefore, we developed a neural net (NN) for diagnoses APS in a cohort of anticoagulated subjects, based on the TG test. Methods Antiphospholipid antibodies positivity was diagnosed according to the Sapporo-Sydney guidelines. TG was measured using the calibrated automated thrombogram assay (CAT) on platelet poor plasma with PPP reagent (intermediate concentration of tissue factor) in 48 APS patients and 64 control non-APS patients, both treated with vitamin K antagonists (VKAs) TG was explored in more depth by quantifying parameters of prothrombin conversion and thrombin inactivation, using thrombin dynamics (TD) analysis, and assessing the sensitivity of the activated protein C pathway through the addition of thrombomodulin (TM). Five NNs were developed and the most accurate NN was selected for clinical validation based on its sensitivity and specificity. Input parameters for the NN were TG parameters lag time, peak, endogenous thrombin potential, time-to-peak, and velocity index, and TD parameters total prothrombin conversion, maximum prothrombin conversion rate, thrombin-antithrombin complex formation, and thrombin-α2-macroglobulin complex formation, and the inhibition of TG and TD by TM. The top performing NN was clinically validated using the TG and TD data acquired in the validation cohort, consisting of 33 APS patients and 62 controls, both on VKA therapy, 49 auto-immune disease controls, 38 thrombosis controls, 92 patients visiting the hospital for other indications and 37 healthy subjects. All control subjects were negative for aPL. Results TG was slightly increased in APS patients compared to controls. VKA therapy abolished the typical lag time prolongation seen in non-anticoagulated APS patients due to the LAC effect. The rate of prothrombin conversion was significantly increased in anticoagulated APS patients compared to controls, indicating a more prothrombotic phenotype. The selected NN classified APS patients with a sensitivity of 92% and a specificity of 95% in the developmental cohort consisting of APS patients and controls on VKA antagonists (ROCAUC = 0.9805; 0.9542-1.000; p<0.0001). On average, controls and APS patients were assigned an APS likelihood score of 12% and 89%, respectively. The NN was clinically validated in a separate validation cohort of 311 individuals, including 33 anticoagulated APS patients, 62 anticoagulated controls, 38 thrombosis patients, 49 auto-immune disease patients, 92 hospital controls, and 37 healthy controls. The sensitivity of the NN for the detection of APS was 85%. The overall specificity of the NN was 93%, and 100%, 96%, 96%, 92% and 76% respectively in healthy controls, auto-immune disease controls, hospital controls, anticoagulated controls, and thrombosis controls. Conclusions We developed a NN that accurately classifies APS under anticoagulant treatment. Therefore, this NN could be an alternative for diagnosing APS patients already treated with VKAs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Relevance of inflammatory and complement activation biomarkers profiling in antiphospholipid syndrome patients outside acute thrombosis.

To evaluate whether inflammatory and complement biomarkers are associated with specific characteristics of antiphospholipid syndrome (APS). Serum levels of interleukin (IL)-1β (IL-1β), IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, interferon-α (IFN)-α, IFN-γ, vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), E-selectin, and vascular cell adhesion molecule (VCAM)-1, and plasma levels of soluble C5b-9 (sC5b-9), C3a, C4a, Bb fragment were measured in unselected APS patients. Twenty-five healthy blood donors were included as controls. Between January 2020 and April 2021, 98 APS patients were included outside acute thrombosis (median time from the last APS manifestation: 60 (23;132) months). Levels of IL6, VCAM-1, sC5b-9, C3a, C4a, and Bb were significantly increased in APS patients compared to controls. A cluster analysis allowed to divide patients into two clusters: "inflammatory" (higher levels of IL-6 and VCAM-1) and "complement". In APS, elevated IL-6 was associated with hypertension, diabetes, BMI, and hypertriglyceridaemia. 85% of our APS patients had elevated levels of at least one complement biomarker. Elevated Bb (34%) was associated with aPL positivities, especially with triple aPL positivity (50% vs. 18%, p<0.001). 7/8 patients with history of catastrophic APS had elevated levels of complement biomarkers. Our findings suggested that APS patients outside acute thrombosis might be divided into two clusters: "inflammatory" and "complement". Elevated IL-6 was associated with cardiovascular risk factors and metabolic parameters, whereas Bb fragments, a marker of alternative pathway complement activation, was strongly associated with aPL profile at highest risk of severe disease.

Risk of livedo with antiphospholipid antibodies in patients with systemic lupus erythematosus: A systematic review and meta-analysis.

Livedo is a well-known skin condition in patients with systemic lupus erythematosus (SLE) which correspond to small vessels involvement. The influence of antiphospholipid antibodies (aPL) on the occurrence of livedo is controversial. The aim of our study was to estimate the risk of livedo associated with aPL in patients with SLE. We conducted a systematic review and meta-analysis of the literature from 1977 to 2021 to estimate the risk of livedo in SLE patients according to different aPL profiles. Data sources were PubMed, Embase, Cochrane Library, hand search, and reference lists of studies. Studies were selected if they included SLE patients with descriptions of the exposure to aPL and the outcome (livedo). Two independent investigators assessed study eligibility, quality, and extracted patient characteristics from each study as well as exposure (aPL) and outcome (livedo). Risk estimates were pooled using random effects models and sensitivity analyses. For all stages of the meta-analysis, we followed the PRISMA guidelines. PROSPERO registration number: CRD42015027377. Of the 2,355 articles identified, 27 were included with a total of 4,810 SLE patients. The frequency of livedo was 25.5% in aPL-positive patients and 13.3% in aPL-negative patients. The overall Odds Ratio (OR) for livedo in aPL-positive patients compared to aPL-negative patients was 2.91 (95% CI; 2.17-3.90). The risk of livedo was significantly increased for most of aPL subtypes, including lupus anticoagulant (LA) (OR = 4.45 [95% CI; 2.21-8.94]), IgG anticardiolipin (OR = 3.95 [95% CI; 2.34-6.65]), and IgG anti-β2-glycoprotein 1 (OR = 3.49 [95% CI; 1.68-7.27]). We demonstrated in this meta-analysis an excess risk of livedo in aPL-positive SLE patients compared to aPL-negative patients. For daily practice, in patients with SLE, livedo associated with aPL could correspond to a peculiar group of patients with small vessel disease. Livedo could be a good candidate for inclusion in future classification criteria for antiphospholipid syndrome.