IgG anticardiolipin antibody titer > 40 GPL and the risk of subsequent thrombo-occlusive events and death. A prospective cohort study

Antiphospholipid antibody testing

Antiphospholipid antibodies (aPL) are a family of autoantibodies targeting phospholipid-binding proteins and are associated with several clinical settings, and most notably define the antiphospholipid syndrome (APS). These antibodies can be identified using a variety of laboratory tests, which include both solid-phase immunological assays and functional clotting assays that detect lupus anticoagulants (LA). aPLs are linked to a range of adverse medical conditions, such as thrombosis and complications affecting the placenta and fetus, potentially leading to morbidity and mortality. The specific aPL identified, along with the pattern of reactivity, correlates with the severity of these conditions. Therefore, laboratory testing for aPL is crucial for evaluating the risk of complications and for fulfilling certain classification criteria for APS, which are also applied as diagnostic markers in medical practice. This review provides an overview of the available laboratory tests currently for measuring aPL and discusses their clinical implications.

Reporting and Establishment of Reference Intervals for Antiphospholipid Antibody Immunoassays: A Survey of Participants in the College of American Pathologists Proficiency Testing Program

CONTEXT.—

Misdiagnosis of antiphospholipid syndrome can occur owing to the wide diversity of antiphospholipid (aPL) assays and a lack of international calibrators and harmonized reference intervals.

OBJECTIVE.—

To assess laboratory practices regarding reporting and establishing reference intervals for immunoglobulin (Ig) G/IgM anti-cardiolipin (aCL) and anti-beta-2 glycoprotein I (anti-β2GPI) assays.

DESIGN.—

Supplemental questions related to reporting and establishing reference ranges for aPL assays were sent as part of the Antiphospholipid Antibody (ACL)-B 2019 College of American Pathologists (CAP) proficiency testing survey. The response rate and methods assessment details were determined, as well as qualitative and quantitative results for 3 test samples.

RESULTS.—

The number of participants reporting results for IgG aCL (n = 489), IgM aCL (n = 476), IgG anti-β2GPI (n = 354), and IgM anti-β2GPI (n = 331) varied by antibody type. The enzyme-linked immunosorbent assay (ELISA) (up to 58.6%, 260 of 444) was the most used method; others included multiplex (from 18.9% to 23.9%), fluorescence enzyme immunoassay (14.4%-17.6%), and chemiluminescence immunoassay (6.5%-9.0%). More respondents reported quantitative than qualitative results, and manufacturer cutoff ranges were used by 92.9% and 94.2% of respondents for aCL and anti-β2GPI, respectively. Despite variation in the use of semiquantitative ranges, qualitative negative/positive reporting of the test samples achieved almost 100% consensus. Qualitative consensus was met in contrast to the wide range of quantitative results obtained for each analyte across different kits.

CONCLUSIONS.—

ELISA remains the most used method for detecting aPL antibodies, with most laboratories reporting quantitative results based on manufacturers' suggested reference ranges. The categorization of quantitative results as equivocal, weak positive, or positive for responders using kits from the same manufacturer was variable.

Therapeutische Aspekte beim Antiphospholipidsyndrom

Das Antiphospholipidsyndrom (APS) wird klinisch durch venöse oder arterielle Thrombosen sowie Schwangerschaftskomplikationen gekennzeichnet und serologisch durch den Nachweis von Antiphospholipidantikörpern (aPL) bzw. eines Lupusantikoagulans (LA). In den letzten Jahren wurde evident, dass insbesondere bei Vorliegen aller drei serologischen Kriterien, Antikörper gegen Cardiolipin (aCL), gegen ß2-Glykoprotein-1 (aß2-GP1) und ein positives Lupusantikoagulans, die sog. Triple-Positivität, das Risiko für (weitere) thromboembolische und geburtshilfliche Komplikationen deutlich erhöht ist. Therapeutisch werden Thrombozytenaggregationshemmer (ASS), Heparin und Vitamin K Antagonisten eingesetzt. Von der Verwendung direkter oraler Antikoagulantien beim APS wird abgeraten. Eine Immunsuppression ist für die Vermeidung weiterer thromboembolischer Komplikationen eines APS nicht wirksam.

Laboratory Diagnosis of Antiphospholipid Syndrome: Insights and Hindrances

Diagnosis of antiphospholipid syndrome (APS) requires the presence of a clinical criterion (thrombosis and/or pregnancy morbidity), combined with persistently circulating antiphospholipid antibodies (aPL). Currently, laboratory criteria aPL consist of lupus anticoagulant (LAC), anticardiolipin antibodies (aCL) IgG/IgM, and anti-β2 glycoprotein I antibodies (aβ2GPI) IgG/IgM. Diagnosis and risk stratification of APS are complex and efforts to standardize and optimize laboratory tests have been ongoing since the initial description of the syndrome. LAC detection is based on functional coagulation assays, while aCL and aβ2GPI are measured with immunological solid-phase assays. LAC assays are especially prone to interference by anticoagulation therapy, but strategies to circumvent this interference are promising. Alternative techniques such as thrombin generation for LAC detection and to estimate LAC pathogenicity have been suggested, but are not applicable yet in routine setting. For aCL and aβ2GPI, a lot of different assays and detection techniques such as enzyme-linked immunosorbent and chemiluminescent assays are available. Furthermore, a lack of universal calibrators or standards results in high variability between the different solid-phase assays. Other non-criteria aPL such as anti-domain I β2 glycoprotein I and antiphosphatidylserine/prothrombin antibodies have been suggested for risk stratification purposes in APS, while their added value to diagnostic criteria seems limited. In this review, we will describe laboratory assays for diagnostic and risk evaluation in APS, integrating applicable guidelines and classification criteria. Current insights and hindrances are addressed with respect to both laboratory and clinical implications.

Semiquantitative interpretation of anticardiolipin and antiβ2glycoprotein I antibodies measured with various analytical platforms: Communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies

BACKGROUND

Antiβ2glycoprotein I (aβ2GPI) and anticardiolipin (aCL) IgG/IgM show differences in positive/negative agreement and titers between solid phase platforms. Method-specific semiquantitative categorization of titers could improve and harmonize the interpretation across platforms.

AIM

To evaluate the traditional 40/80-unit thresholds used for aCL and aβ2GPI for categorization into moderate/high positivity with different analytical systems, and to compare with alternative thresholds.

MATERIAL AND METHODS

aCL and aβ2GPI thresholds were calculated for two automated systems (chemiluminescent immunoassay [CLIA] and multiplex flow immunoassay [MFI]) by receiver operating characteristic curve analysis on 1108 patient samples, including patients with and without antiphospholipid syndrome (APS), and confirmed on a second population (n = 279). Alternatively, regression analysis on diluted standard material was applied to identify thresholds. Thresholds were compared to 40/80 threshold measured by an enzyme-linked immunosorbent assay (ELISA). Additionally, likelihood ratios (LR) were calculated.

RESULTS

Threshold levels of 40/80 units show poor agreement between ELISA and automated platforms for classification into low/moderate/high positivity, especially for aCL/aβ2GPI IgG. Agreement for semiquantitative interpretation of antiphospholipid antibodies (aPL) IgG between ELISA and CLIA/MFI improves with alternative thresholds. LR for aPL IgG increase for thrombotic and obstetric APS based on 40/80 thresholds for ELISA and adapted thresholds for the other systems, but not for IgM.

CONCLUSION

Use of 40/80 units as medium/high thresholds is acceptable for aCL/aβ2GPI IgG ELISA, but not for CLIA and MFI. Alternative semiquantitative thresholds for non-ELISA platforms can be determined by a clinical approach or by using monoclonal antibodies. Semiquantitative reporting of aPL IgM has less impact on increasing probability for APS.

Neuropsychiatric Manifestations of Antiphospholipid Syndrome—A Narrative Review

Antiphospholipid syndrome (APS) is a common autoimmune pro-thrombotic condition characterised by thrombosis and pregnancy morbidity. There are a broad range of neuropsychiatric manifestations associated with APS, from focal symptoms to more global dysfunction. Patients commonly present with transient ischaemic attacks and ischaemic strokes, with identifiable lesions on brain imaging. However, the underlying pathogenesis remains uncertain in other manifestations, such as cognitive dysfunction, seizures, headache and chorea. The aim is to provide a comprehensive review of the various neuropsychiatric manifestations associated with APS. A detailed literature search was applied to PubMed, including citations from 1983 to December 2021.

Obstetric anti-phospholipid syndrome: from pathogenesis to treatment

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by clinical manifestations such as thrombosis and obstetric complications with documented persistence of antiphospholipid antibodies (aPLs). Recent studies have revealed that the cause of aPL-related obstetric complications is dysfunction of placental trophoblasts and inflammation of the maternal-fetal interface induced by aPLs, not thrombosis. Although aPLs are associated with recurrence of serious complications during pregnancy, appropriate combination therapy with heparin and low-dose aspirin can improve the course of 70-80% of subsequent pregnancies. Preconception counseling and patient-tailored treatment are fundamental to improving maternal and fetal outcomes. Non-anticoagulant treatments such as hydroxychloroquine and statins are being developed for cases refractory to conventional treatment. Risk factors for thrombosis after pregnancy complications were identified based on the analysis of large databases of obstetric APS.

Antiphospholipid Antibody Profile Stability Over Time: Prospective Results From the APS ACTION Clinical Database and Repository

OBJECTIVE

The APS ACTION Registry studies long-term outcomes in persistently antiphospholipid antibody (aPL)-positive patients. Our primary objective was to determine whether clinically meaningful aPL profiles at baseline remain stable over time. Our secondary objectives were to determine (1) whether baseline characteristics differ between patients with stable and unstable aPL profiles, and (2) predictors of unstable aPL profiles over time.

METHODS

A clinically meaningful aPL profile was defined as positive lupus anticoagulant (LAC) test and/or anticardiolipin (aCL)/anti-β2 glycoprotein-I (anti-β2-GPI) IgG/M ≥ 40 U. Stable aPL profile was defined as a clinically meaningful aPL profile in at least two-thirds of follow-up measurements. Generalized linear mixed models with logit link were used for primary objective analysis.

RESULTS

Of 472 patients with clinically meaningful aPL profile at baseline (median follow-up 5.1 yrs), 366/472 (78%) patients had stable aPL profiles over time, 54 (11%) unstable, and 52 (11%) inconclusive. Time did not significantly affect odds of maintaining a clinically meaningful aPL profile at follow-up in univariate (P = 0.906) and multivariable analysis (P = 0.790). Baseline triple aPL positivity decreased (OR 0.25, 95% CI 0.10-0.64, P = 0.004) and isolated LAC test positivity increased (OR 3.3, 95% CI 1.53-7.13, P = 0.002) the odds of an unstable aPL profile over time.

CONCLUSION

Approximately 80% of our international cohort patients with clinically meaningful aPL profiles at baseline remain stable at a median follow-up of 5 years; triple aPL-positivity increase the odds of a stable aPL profile. These results will guide future validation studies of stored blood samples through APS ACTION Core Laboratories.

Hypercoagulability predicts worse outcomes in young patients undergoing lower extremity revascularization

OBJECTIVE

Although we know that young patients with peripheral artery disease (PAD) have worse outcomes than older patients, there is a scarcity of information about the incidence of hypercoagulability in this population. Our aim was to analyze outcomes of young patients diagnosed with a hypercoagulable state (unusual tendency toward thrombosis) after lower extremity revascularization compared with similar patients without hypercoagulability.

METHODS

All patients 50 years of age or younger undergoing an initial procedure for lower extremity PAD from 2000 to 2015 at the Cleveland Clinic were retrospectively analyzed. Patients with a hypercoagulability panel were included and classified into groups as hypercoagulable positive (HP) or hypercoagulable negative (HN). Demographics, preoperative risk factors, form of presentation, level of disease, and type of intervention were analyzed in addition to perioperative complications, early failure, and length of stay. Primary outcomes were limb loss and primary, primary assisted, and secondary patencies. Outcomes were analyzed and Kaplan-Meier curves generated.

RESULTS

Ninety-one patients were included for a total of 118 limbs. Mean follow-up was 32 months; 55% of patients had a hypercoagulable disorder, with 59% having lupus anticoagulant and 32% hyperhomocysteinemia. In the HP group, 71% were men; 49% were men in the HN group. Patients overall had a high prevalence of smoking (86%), hypertension (36%), and hyperlipidemia (33%). Acute limb ischemia was the most common form of presentation for both groups (50% HP, 38% HN). The aortoiliac segment was the most commonly affected (38% HP, 50% HN). The most frequent operation in the HN group was endarterectomy or bypass (32%); in the HP group, it was an endovascular intervention (29%). Perioperative occlusion or failure was 18% in the HN group vs 30% in the HP group (P > .05). Primary patency, primary assisted patency, and secondary patency at 36 months were all better for the HN group (no statistical significance) in all treatment groups. Major amputation at 36 months was significantly worse for the HP group (40% vs 10% in the HN group; P < .005). There was no difference in perioperative complications or length of stay.

CONCLUSIONS

Young patients undergoing lower extremity revascularization for PAD have worse outcomes when associated with hypercoagulability. There are trends to decreased patency of revascularization in these patients, with significantly more major amputations. No clear differences between modalities of treatment were demonstrated.

Antiphospholipid antibodies in epilepsy: A systematic review and meta-analysis

BACKGROUND

Autoimmunity is believed to play an important causative role in the pathogenesis of epilepsy. There are evidences for the presence of autoantibodies in patients with epilepsy. To date, many studies have assessed the presence of antiphospholipid antibodies (aPLs) in epilepsy patients, though the relationship has been inconclusive.

AIMS

The aim of this systematic review and meta-analysis was to evaluate the presence of aPLs in epileptic patients as compared to healthy controls.

METHODS

Five electronic databases (PubMed, Web of Science, Embase, Scopus and Google Scholar) were searched systematically. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. Quality assessment was carried out by using the modified 9-star Newcastle-Ottawa Scale (NOS). L'Abbé plots were generated to visually inspect heterogeneity while publication bias was evaluated via visualization of contour- enhanced funnel plots, and Begg's and Egger's tests.

RESULTS

Based on the inclusion criteria, 14 studies were selected involving 1248 epilepsy patients and 800 healthy controls. The majority of epilepsy was categorised as generalised or partial and none had comorbidity with autoimmune diseases. Significant presence of both anticardiolipin (aCL) antibodies (OR: 5.16, 95% CI: 3.21-8.28, p < 0.00001) and anti-β2- glycoprotein I (anti-β2-GPI) antibodies (OR: 2.95, 95% CI: 1.07-8.11, p = 0.04) exhibited comorbid association with epilepsy patients as compared to healthy controls. Subgroup analyses revealed that presence of aCL antibodies was more specifically observed in paediatrics (OR: 4.57, 95% CI: 2.57-8.15, p < 0.00001) than adults (OR: 4.24, 95% CI: 1.80-10.01, p = 0.001). The odds of aCL antibody presence was higher in partial epilepsy patients (OR: 7.88, 95% CI: 3.23-19.24, p < 0.00001) than that of generalised (OR: 3.76, 95% CI: 2.15-6.59, p < 0.00001) and in Asian epileptic patients (OR: 9.56, 95% CI: 2.69-33.95, p = 0.0005) than Europeans (OR: 4.35, 95% CI: 2.74-6.92, p < 0.00001). The presence of anti-β2-GPI antibodies was significant in paediatric (OR: 6.44, 95% CI: 1.39-29.89, p = 0.02) and African population with epilepsies (OR: 10.59, 95% CI: 1.22-92.25, p = 0.03). NOS of the majority of the studies (11/14) indicated a high methodological quality. No substantial heterogeneity was observed either from the quantitative analysis or from the L'Abbé plots while no significant publication bias was detected from funnel plots; Begg's and Egger's tests.

CONCLUSION

Since none of the epilepsy subjects exhibited any comorbid autoimmune disorders, significant presence of aCL and anti-β2-GPI antibodies indicate towards their contribution in immune-mediated general pathogenesis of epilepsy.

Performance Evaluation and Clinical Associations of Immunoassays That Detect Antibodies to Negatively Charged Phospholipids Other Than Cardiolipin

OBJECTIVES

We evaluate the performance characteristics of antiphosphatidylserine (anti-PS), antiphosphatidylinositol (anti-PI), and antiphospholipid mixture (APhL) enzyme-linked immunosorbent assays (ELISAs) compared with anticardiolipin (aCL) and anti-β2 glycoprotein I (anti-β2GPI) in a large group of patients with antiphospholipid (aPL)-related diseases.

METHODS

Serum samples from 548 patients from the Hopkins and Jamaican systemic lupus erythematosus cohorts, the PROMISSE cohort, and the Antiphospholipid Standardization Laboratory were examined for immunoglobulin G (IgG)/immunoglobulin M (IgM) positivity in aCL, anti-β2GPI, anti-PS, anti-PI, and APhL ELISA assays.

RESULTS

All IgG assays were associated with one or more thrombotic and/or obstetric manifestations, with an increased risk associated with higher antibody titers. Analytical performance was similar among assays, but IgG assays performed better than IgM counterparts.

CONCLUSIONS

Increasing titers of APhL, anti-PS, and anti-PI antibodies could indicate an increased risk of thrombotic and/or obstetric aPL-related manifestations. These assays may be promising biomarkers for particular APS manifestations.

Subsequent Thrombotic Outcomes in Patients with Ischemic Stroke with Antiphospholipid Antibody Positivity

PURPOSE

International consensus criteria for antiphospholipid syndrome (APS) require persistently positive antiphospholipid antibodies (aPL) and medium or high titers in association with clinical manifestations. However, the clinical relevance of persistence and titers of aPL in patients with stroke has not been identified. We aimed to investigate the risk of subsequent thrombotic events in patients with ischemic stroke with aPL positivity in terms of aPL status.

MATERIALS AND METHODS

We reviewed the medical records of 99 patients with ischemic stroke with at least one or more aPL-positivity (i.e., positivity for aCL, anti-β2-glycoprotein-1, and/or lupus anticoagulants). The patients were divided into two groups: "definite APS" who fulfilled the laboratory criteria and "indefinite APS" who fell short of the criteria. We compared the risk of subsequent thrombotic events between the two groups. Cox proportional hazards model and Kaplan-Meier survival curves were used for the analyses.

RESULTS

Of the 99 patients, 46 (46%) were classified as having definite APS and 53 (54%) as having indefinite APS. The mean follow-up was 51.6 months. Overall event numbers were 14 (30.4%) in definite APS and 16 (30.2%) in indefinite APS. Increased subsequent thrombotic events (hazard ratio 1.039; 95% confidence interval 0.449-2.404; p=0.930) and decreased time to thrombotic events (log-rank p=0.321) were not associated with aPL status.

CONCLUSION

There was no increased risk of subsequent thrombotic events in ischemic stroke patients with definite APS, compared with those with indefinite APS.

Laboratory diagnosis and management challenges in the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is characterized by recurrent arterial and/or venous thrombosis and pregnancy morbidity manifested by early or late losses. Laboratory diagnosis of APS relies on the demonstration of a positive test for antiphospholipid antibodies (aPL). In clinical practice, the gold standard tests are those that detect anticardiolipin antibodies (aCL) and/or the lupus anticoagulant (LA). Although other specificities for aPL have been described their clinical utility and standardization has still to be established. Persistence of aPL positive tests must be demonstrated, and other causes and underlying factors considered. Although it is universally recognized that the routine screening tests (aCL and/or LA) might miss some cases, careful differential diagnosis and repeat testing are mandatory before the diagnosis of ‘seronegative APS’ can be made. Correct identification of patients with APS is important, because prophylactic anticoagulant therapy can prevent thrombosis from recurring, and treatment of affected women during pregnancy can improve fetal and maternal outcome.

Myocardial infarction in young patients (≤35 years of age) with systemic lupus erythematosus: a case report and clinical analysis of the literature

The present study aims to report a-20-year old girl with systemic lupus erythematosus (SLE) who developed myocardial infarction (MI) and also aims to review acute myocardial infarction (AMI) in young SLE cases (≤35 years) reported in the literature. We conducted a comprehensive review of the English literature from 1975 to 2006 to analyse data on MI in SLE patients who had developed AMI either at 35 or earlier. In 32 English articles, we identified 49 SLE patients, plus our case, with AMI. They consist of 41 female and nine male patients, their mean age being 24 ± 6.4 years (range of 5—35). Disease duration varied between 0 and 13 years. The lag time between the onset of the SLE manifestations and development of AMI was 7.7 ± 5.4 year (range of 1 month to 20.5 years). We divided the patients into three subgroups according to their coronary involvement type (Group I: normal coronary artery or coronary thrombosis ( n = 16); Group II: coronary aneurysm/arteritis ( n = 12); Group III: coronary atherosclerosis ( n = 22)). The lag time between the onset of the SLE manifestations and development of MI in the subgroups showed variations: Group I < Group II < Group III. Both prevalence of renal involvement and steroid therapy were higher in patients with coronary atherosclerosis than were in Group I. There were one or more risk factors for atherosclerosis in 39 SLE patients. AMI in young SLE patients may be seen, albeit rare. We suggest that clinicians should have a low threshold for cardiac evaluation in patients with SLE. Also, traditional risk factors could be managed through preventive measures. Lupus (2007) 16, 289—297.

The antiphospholipid syndrome: from pathophysiology to treatment

Antiphospholipid antibody syndrome (APS) is an autoimmune acquired thrombophilia characterized by recurrent thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). APS can be primary, if it occurs in the absence of any underlying disease, or secondary, if it is associated with another autoimmune disorder, most commonly systemic lupus erythematosus. The exact pathogenetic mechanism of APS is unknown, but different, not mutually exclusive, models have been proposed to explain how anti-PL autoantibodies might lead to thrombosis and pregnancy morbidity. Diagnosis of APS requires that a patient has both a clinical manifestation (arterial or venous thrombosis and/or pregnancy morbidity) and persistently positive aPL, but the clinical spectrum of the disease encompasses additional manifestations which may affect every organ and cannot be explained exclusively by a prothrombotic state. Treatment for aPL-positive patients is based on the patient's clinical status, presence of an underlying autoimmune disease, and history of thrombotic events. In case of aPL positivity without previous thrombotic events, the treatment is mainly focused on reduction of additional vascular risk factors, while treatment of patients with definite APS is based on long-term anticoagulation. Pregnancy complications are usually managed with low-dose aspirin in association with low molecular weight heparin. Refractory forms of APS could benefit from adding hydroxychloroquine and/or intravenous immunoglobulin to anticoagulation therapy. Promising novel treatments include anti-B cell monoclonal antibodies, new-generation anticoagulants, and complement cascade inhibitors. The objective of this review paper is to summarize the recent literature on APS from pathogenesis to current therapeutic options.

Frequency of vascular and pregnancy morbidity in patients with low vs. moderate-to-high titers of antiphospholipid antibodies

Antiphospholipid syndrome (APLS) is an autoimmune hypercoagulable syndrome characterized by thrombotic and obstetric manifestations. We sought to determine the rate of APLS feature in patients tested positive for antiphospholipid antibodies (APLA) regardless of the serum level of anticardiolipin (ACL) and/or anti-β2-glycoprotein I (β2GPI) antibodies. An inception cohort of individuals who were tested positive for ACL and/or β2GPI IgG/IgM antibody, and/or lupus anticoagulant (LAC) on two occasions of at least 12 weeks apart. A total of 243 patients were included; their mean age was 40.1 ± 15.9 years. Thrombotic vascular events occurred in 118 patients (48.5%) of the entire cohort, of which 62 patients (25.5%) suffered from an arterial event and 56 patients (23%) from thrombotic venous events. Obstetrical morbidity occurred in 106 female patients (43.6%). In our cohort, we found no difference in the frequency of thrombotic or obstetric manifestations of APLS between patients with ACL IgG/IgM of low serum antibody level (<40 U) and medium-to-high level (≥40 U) and/or anti-β2GPI IgG, IgM higher than the 99th percentile vs. lower (>20 U). We suggest that in 'real life' the diagnosis of APLS should not be excluded because of low titer of APLA.

Antiphospholipid antibodies correlate with stroke severity and outcome in patients with antiphospholipid syndrome

BACKGROUND

Our goal was to analyze the association of the level of antiphospholipid antibodies (aPLs) with stroke severity and outcome in patients with antiphospholipid syndrome (APS).

METHODS

Observational study included consecutive patients with ischemic stroke younger than 55 years (2007-2012). We analyzed serum levels of aPLs, including anticardiolipin (aCL) antibodies, anti-β2-glycoprotein I antibodies (anti-β2GPI) and antiprothrombin antibodies (aPS/PT) within the first 48 h after admission, and again, in the case of a positive result, at least 12 weeks after the first measurement. Stroke severity was measured by the National Institutes of Health Stroke Scale (NIHSS), and the three-month stroke outcome by the modified Rankin Scale (mRS). Multiple linear regression models were used to analyze the correlation between the aPLs and stroke severity and outcome.

RESULTS

Overall 255 stroke patients were included, 22 (8.6%) with APS. Among them, a positive correlation was found between immunoglobulin M (IgM) aCL levels within 48 h and NIHSS (rho = 0.471; p = 0.027), as well as a tendency toward a positive correlation between immunoglobulin G (IgG) anti-β2GPI levels within 48 h and three-month mRS (rho = 0.364; p = 0.096). Multiple linear regression analyses showed a positive correlation between levels of IgM aCL < 48 h and the NIHSS (β-coefficient [standard error; SE] = 0.127 [0.044]), as well as the levels of IgG anti-β2GPIwithin 48 h and the three-month mRS (β-coefficient [SE] = 0.034 [0.011]).

CONCLUSIONS

In young stroke patients with APS, serum levels of IgM aCL within 48 h are correlated with stroke severity and levels of IgG anti-β2GPI within 48 h are correlated with three-month outcomes.

A new Eu(3+)-labeled method for anticardiolipin antibody IgM

BACKGROUND

The anticardiolipin antibodies (aCL) test has become a laboratory standard for the clinical diagnosis of antiphospholipid syndrome (APS). To better the quantitative detection of aCL-IgM so as to classify patients correctly and timely as APS positive, we established herein a new immunoassay based on a time-resolved fluoroimmunoassay (TRFIA).

METHODS

The complex of cardiolipin plus bovine anti-β2 glycoprotein-I was used as antigen fixed on microtiter plates to detect serum aCL-IgM, and Eu(3+) -labeled rabbit antihuman IgM was used as conjugate. The precision, sensitivity, specificity, coefficient of recovery, and stability of the assay were evaluated, and comparison with the traditional, classical enzyme-linked immunosorbent assay (ELISA) was also made.

RESULTS

The detection limit of the aCL-IgM TRFIA kit we established was 0.1 MPL U/ml, with a wider detectable range than commercial ELISA ones when a strong-positive specimen was diluted from 2,630.9 to 0.08 MPL U/ml. There was a good liner range within 0.16 to 2,630.9 MPL U/ml, whereas it was within 5.14 to 328.86 MPL U/ml when using three commercial ELISA ones. The average intra- and interassay variability was 3.19 and 3.70%, respectively. The mean recovery rate was 101.95%. The clinical diagnostic specificity was 98%. Additionally, the established assay kit presented good characteristics of stability and correlated well with the ELISA, and the correlation coefficient was 0.955.

CONCLUSION

The aCL-IgM TRFIA provides an approach to a more sensitive and reliable diagnosis of APS. Further validation of its use is required.

Should the presence of an antiphospholipid antibody affect the duration of anticoagulant treatment in patients with venous thromboembolism?

A 44-year-old otherwise healthy woman has completed 3 months of anticoagulation therapy for a first episode of unprovoked pulmonary embolism. At the time of diagnosis and before the initiation of anticoagulation, she was found to have an elevated IgG anticardiolipin antibody (ACLA), which was measured at 42 IgG phospholipid (GPL) units (reference range, < 15 GPL units) with negative lupus anticoagulant (LAC) testing. Should this laboratory finding affect the recommended duration of anticoagulant therapy?

Transient ischemic attack and stroke in systemic lupus erythematosus

Ischemic stroke is increased in systemic lupus erythematosus (SLE) patients. The differential diagnosis of stroke in SLE is complex. Transient ischemic attack and ischemic stroke share pathophysiologic mechanisms, but prognosis may vary depending on severity and cause, and definitions are dependent on the timing and extent of the diagnostic evaluation. In SLE patients with a history of transient ischemic attacks, stroke occurred in 57%. Cerebrovascular events account for 20% to 30% of deaths in patients with SLE. In SLE, both disease-specific and traditional stroke risk factors are important.

Auto-antibodies as emergent prognostic markers and possible mediators of ischemic cardiovascular diseases

During the last 15 years, a growing body of evidence supported the fact that auto-antibodies represent not only emergent markers but also active mediators of cardiovascular disease (CVD), clinically represented mostly by acute coronary syndrome (ACS) and stroke. There is a contrasted relationship between auto-antibodies and CVD, some being protective, while others acting as potential risk factors. Therefore, we performed a review of the literature on the respective cardiovascular prognostic value of the most relevant auto-antibodies in ACS and stroke, and their putative pathophysiological properties in atherogenesis. This review highlights auto-antibodies as active modulators of the innate immune system in atherogenesis (either toward a pro- or anti-inflammatory response), or by affecting basal heart rate regulation (anti-apoA-1 IgG). Given their apparent prognostic independency towards traditional cardiovascular risk factors, the data available in the literature indicates that some of those auto-antibodies could be of valuable help for cardiovascular risk stratification in the future, especially because their deleterious effects have been shown to be potentially abrogated in vivo and in vitro by existing therapeutic modalities. Although evidence in humans is currently lacking, these studies may open innovative therapeutic perspectives for CVD in the future.

Th1/Th2/Th17/Treg expression in cultured PBMCs with antiphospholipid antibodies

The aim of this study was to evaluate the expression of T-helper cell subtypes Th1, Th2, Th17 and Treg in antiphospholipid syndrome (APS), and whether they are related to anti-cardiolipin antibody (aPL) titers. Peripheral mononuclear cells (PBMCs) were isolated from healthy donors, and incubated with aPLs. Subsequent to a 48‑h incubation, PBMCs were collected and detected by flow cytometry. The results revealed that aPLs at higher concentrations may induce a significant increase in Th2 and Th17 frequencies, as opposed to a significant decrease in Th1 and Treg frequencies and the Th1/Th2 ratio. These results indicate that there is a Th1/Th2 imbalance, a Th17 upregulation and a Treg downregulation present in APS, and that these factors are positively correlated with aPL titers, suggesting a potential role of Th cells in the pathogenesis of APS.

Detection of anticardiolipin antibody IgG by time-resolved fluoroimmunoassay

In an effort to improve the quantitative detection of anticardiolipin antibodies (aCL) IgG so as to classify patients correctly as antiphospholipid syndrome (APS) positive, we developed a new immunoassay based on a sandwich time-resolved fluoroimmunoassay (TRFIA) using the complex of cardiolipin plus bovine β(2)GPI as antigen and Eu(3+)-labeled rabbit antihuman IgG as conjugate. The precision, sensitivity, specificity, and stability of the assay were evaluated, and comparison with the classical ELISA was also made. The aCL IgG TRFIA kit we established had a wider detectable range than three commercial ELISA ones from different manufacturers when a specimen was diluted, with strong positive result from 1:12.5 to 1:204,800. The average intra-assay and inter-assay CVs detected by the aCL IgG TRFIA was 3.14 and 3.70 %, respectively. The sensitivity was 0.1 GPL U/ml, and the clinical diagnostic specificity was 98 %. The established assay kit also behaved better in stability than the commercial ELISA ones. Additionally, the immunoassay we established correlated well with the ELISA, and the correlation coefficient was 0.975. We thus conclude that the TRFIA we developed for aCL IgG detection gives promise to a more sensitive and reliable diagnosis of APS and has potential value for large-scale screening programs.

The management of stroke in antiphospholipid syndrome

Ischemic stroke is one of the most common complications of the antiphospholipid syndrome (APS). Because of the relative lack of definitive prospective studies, there is still some debate as to whether the persistent presence of antiphospholipid antibodies (aPLs) increases the risk of recurrent stroke. There is more evidence for aPLs as a risk factor for first stroke. The mechanisms of ischemic stroke are considered to be thrombotic and embolic. APS patients with thrombotic stroke frequently have other, often conventional vascular risk factors. Transesophageal echocardiogram is strongly recommended in APS patients with ischemic stroke because of the high yield of valvular abnormalities. The appropriate management of thrombosis in patients with APS is still controversial because of limited randomized clinical trial data. This review discusses the current evidence for antithrombotic therapy in patients who are aPL positive but do not fulfill criteria for APS, and in APS patients. Alternative and emerging therapies including low molecular weight heparin, new oral anticoagulants (including direct thrombin inhibitors), hydroxychloroquine, statins, and rituximab, are also addressed.

A patient with bipolar disorder and antiphospholipid syndrome

Antiphospholipidsyndrome (APS) is an autoimmune disorder which causes a hyper-coagulable state characterized by recurrent thrombosis. It has a diverse range of central nervous system manifestations. We describe a case of a 61 year old man with bipolar disorder and APS, and we compare this to a previously reported case. Additionally, we reviewed literature regarding APS-related markers and the relationship of APS to other psychiatric and neurologic illnesses. We discuss possible mechanisms for an association between APS and bipolar disorder. We encourage clinicians to be aware of this possible relationship and have proposed research strategies.

Beta2-glycoprotein I gene polymorphisms Val247Leu and Trp316Ser in Spanish patients with primary antiphospholipid syndrome

The significance of beta2-glycoprotein I (β2GPI) polymorphisms in the production of anti-β2GPI and other antiphospholipid autoantibodies (aPL) and in the pathogenesis of primary antiphospholipid syndrome (PAPS) is not well understood. We performed a study comparing the distribution of polymorphisms at codons 247 (Val247Leu) and 316 (Trp316Ser) of the β2GPI gene in a Caucasian Spanish population of PAPS patients and healthy controls, and then making correlations with the development of anti-β2GPI antibodies and other aPL and associated clinical manifestations. A total of 57 PAPS patients and 100 control subjects were included. In the analysis of Val247Leu polymorphism, alleles (V and L) and genotypes (V/V, V/L, L/L) were similarly distributed in PAPS patients and controls (P = 0.66 and P = 0.22, respectively). Regarding Trp316Ser polymorphism, we found a higher percentage of patients with respect to controls expressing S allele (11.4 vs. 5%, P = 0.02) and T/S genotype (22.8 vs. 10%, P = 0.02). However, when we compared T/T and T/S genotypes in PAPS patients, we found no differences regarding generation of anti-β2GPI, other aPL and clinical manifestations favoring any genotype. Our findings suggest that among Spanish Caucasians, polymorphisms at codon 247 (Val247Leu) do not seem to influence PAPS pathogenesis. On the contrary, polymorphisms at codon 316 (Trp316Ser), by means of an increased S allele and T/S genotype presence in Spanish Caucasian patients, might play a role in the pathogenic development of PAPS, although mechanism would not involve an increased production of anti-β2GPI and other aPL.

The use of laboratory methods in differential diagnosis and treatment of SLE and antiphospholipid syndrome

The detection of autoantibodies has become an important component in the diagnosis and management of systemic lupus erythematosus (SLE) and antiphospholipid syndrome. Their importance lies in the fact that they are not only markers of the disease and used as part of a diagnostic panel, but many of them also show correlation with disease activity. All antibody testing should be interpreted in the context of the clinical features. The antinuclear antibodies test is an effective screening assay in patients with clinical features of SLE. The combination of antinuclear antibodies test, dsDNA and ENA (Ro, La, Sm, RNP) antibodies help to establish the diagnosis of most patients with SLE. New antibodies, such as antinucleosomes and anti-C1q, appear to be useful for SLE diagnosis, monitoring disease activity and predicting renal flares, particularly in dsDNA-negative patients. Anticardiolipin antibodies and lupus anticoagulant are the tests most commonly used in the diagnosis of antiphospholipid syndrome. However, the use of anti-beta(2)-glycoprotein I as a routine diagnostic test remains controversial.

Moderate versus high-titer persistently anticardiolipin antibody positive patients: are they clinically different and does high-titer anti-beta 2-glycoprotein-I antibody positivity offer additional predictive information?

The association between antiphospholipid antibodies (aPL) and clinical events is stronger with a positive lupus anticoagulant (LA) test, higher anticardiolipin antibody (aCL) titers, and/or higher anti-beta(2)-glycoprotein-I antibody (abeta( 2)GPI) titers. The objective of this study was to determine the clinical characteristics of persistently high-titer (> or =80 U) aCL-positive patients compared with those with persistent moderate aCL titers (40-79 U). Second, we analyzed whether high-titer abeta(2)GPI test adds predictive information in persistently moderate-to-high titer aCL-positive patients. In this cross-sectional study, the primary analysis compared the clinical and aPL characteristics of 58 patients with at least two moderate-titer aCL results to another 85 patients with at least two high-titer aCL results. In the secondary analysis of patients with at least two abeta(2)GPI test results, we compared 29 patients with 'aCL 40-79 U and abeta( 2)GPI < 80 U' profiles with 8 patients with 'aCL 40-79U and abeta(2)GPI > or = 80 U', and also compared 27 patients with 'aCL > 80 U and abeta(2)GPI < 80 U' with 32 patients with 'aCL > 80 U and abeta(2)GPI > or = 80 U'. Although aPL-related vascular and pregnancy events were similar between the moderate- and high-titer aCL groups, the number of patients with positive LA tests (RR 2.06, CI 1.38-3.08, p < 0.01) and with at least one non-criteria aPL manifestation (RR 1.66, CI 1.20-2.30, p = 0.0005) were significantly higher in the high-titer aCL group. While magnetic resonance imaging (MRI) white matter changes were statistically more common in the high-titer aCL group (RR 2.03, CI 1.04-3.94, p = 0.02), there was a trend towards increased prevalence of livedo reticularis, cardiac valve disease, and cognitive dysfunction occurring in the high-titer aCL group. The secondary analysis showed that MRI white matter changes, cardiac valve disease, and cognitive dysfunction were proportionally more common in the high-titer abeta( 2)GPI groups, suggesting a linear relationship between non-criteria aPL manifestations and aPL titers. Our results suggest that patients with high aCL titers, compared with those with moderate titers, are more likely to have a positive LA test and a higher prevalence of non-criteria aPL manifestations. Furthermore, high-titer abeta(2)GPI positivity may further increase the prevalence of non-criteria aPL manifestations in moderate- or high-titer aCL-positive patients.

Circulating osteoprotegerin levels are elevated and correlated with antiphospholipid antibodies in patients with systemic lupus erythematosus

Patients with antiphospholipid syndrome (APS) have an increased risk for the development of thrombotic complications. Recent studies indicate that osteoprotegerin (OPG) acts as an important molecule in the development of vascular diseases. The aim of the present study was to examine the association between serum OPG levels and APS manifestations in patients with SLE. Seventy-nine patients with SLE and ninety-two healthy controls, matched for age and sex, were included in this study. Serum levels of OPG, monocyte chemoattractant protein(MCP)-1 and soluble E-selectin were determined by ELISA. At the time of serum sampling, various clinical and laboratory parameters were assessed. We found that serum levels of OPG were significantly higher in patients with SLE than in healthy controls (1236 ± 82 vs 967 ± 37 pg/mL, P = 0.003). Particularly, serum OPG levels were significantly higher in SLE patients with APS than those without (1615 ± 191 vs 1171 ± 91 pg/mL, P = 0.006). Serum OPG levels correlated with titres of IgG anti-cardiolipin antibody ( P = 0.026) and anti-β2-glycoprotein I antibody ( P < 0.001). Moreover, serum OPG also correlated with serum levels of sE-selectin ( P = 0.002), which is an endothelial cell activation marker, and MCP-1 ( P = 0.003), a well known chemokine implicated in thrombogenesis. Collectively, serum OPG levels were increased in SLE patients with APS and correlated with titres of antiphospholipid antibodies, suggesting that OPG might be linked to the development of APS.