Lupus Anticoagulant Positive Patients Research Articles

PB0411 Platelet Glycoprotein IIb- and IIIa Levels are Altered in Persistently Lupus Anticoagulant Positive Patients with a History of Thrombosis

PB0411 Platelet Glycoprotein IIb- and IIIa Levels are Altered in Persistently Lupus Anticoagulant Positive Patients with a History of Thrombosis

Evaluation of acquired and hereditary risk factors for the development of thromboembolism in patients with systemic lupus erythematosus.

Although the contribution of antiphospholipid antibodies (aPL) to thrombolembolism in systemic lupus erythematosus (SLE) is well known, there is not enough data on the contribution of various hereditary thrombophilic factors. In this study, we aimed to determine acquired and hereditary thrombophilic factors in adult patients with SLE. A total of 93 SLE patients (87 women and 6 men) were included. Data on clinical, demographic and laboratory characteristics, and disease activity scores (SLEDAI) of the patients were evaluated. The patients were analyzed with a screen, including lupus anticoagulant, anticardiolipin antibodies (aCL), antithrombin III, protein C, protein S, and homocysteine levels; factor V Leiden ( FVL ), methylenetetrahydrofolate reductase ( MTHFR ) and prothrombin G20210A gene mutations. A total of 23 thromboembolic events were reported in 17 (18.3%) of the patients. The frequency of pregnancy complications and SLEDAI scores were significantly higher in SLE patients who had a thromboembolism event ( P < 0.05). Thromboembolism was detected in 12 (32.4%) of 37 patients with positive aPL antibody and 5 (8.9%) of 56 patients with negative aPL antibody ( P = 0.006). In addition, thromboembolism developed in 11 (32.3%) of 34 lupus anticoagulant-positive patients and 6 (10.1%) of 59 lupus anticoagulant-negative patients ( P = 0.012). Moreover, protein C levels were significantly lower in patients who developed thromboembolism ( P < 0.05). Patients with and without thromboembolism were similar in terms of genetic thrombophilia factors ( MTHFR A1298C, MTHFR C677T, FVL and Prothrombin G20210A ) ( P > 0.05). In conclusion, in the current study, some acquired (aPL, lupus anticoagulant and cCL IGG) and hereditary (protein C deficiency) thrombophilic factors were shown to be associated with the development of thrombosis in SLE patients. However, the effect of other hereditary factors on the development of thromboembolism could not be demonstrated. According to the data of this study, genetic screening seems inappropriate in terms of the risk of thromboembolism in patients with SLE.

Prevalence and Impact of Lupus Anticoagulant in Patients Receiving Extracorporeal Membrane Oxygenation.

Monitoring of blood coagulation is essential in ECMO patients. We investigated the prevalence of lupus anticoagulant (LA) and its association with coagulation testing and hemostaseologic complications in patients treated with ECMO. This is a retrospective analysis including adult patients who received ECMO at a medical intensive care unit at the Medical University of Vienna. The primary outcome was the prevalence of LA. Secondary outcomes included conditions associated with LA positivity, rates of bleeding and thromboembolic events, as well as the proportions of aPTT and antiXa measurements within the target range. Between 2013 and 2021 193 patients received ECMO, in 62 (32%) of whom LA diagnostics were performed. Twenty-two (35%) patients tested positive. LA positive patients had more frequently received VV ECMO (77.3% vs 34.3%; p = 0.002), were more frequently diagnosed with viral respiratory infections (SARS-CoV2: 45.5% vs 20%; p = 0.041, influenza virus: 22.7% vs 0%; p = 0.003), had a longer ECMO treatment duration (25 vs 10 days; p = 0.011) and a longer ICU stay (48 vs 25 days; p = 0.022), but similar rates of bleeding and thromboembolic events.

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

BackgroundDiagnosis of antiphospholipid syndrome (APS) requires persistent presence of lupus anticoagulant (LAC), anticardiolipin (aCL) IgG/IgM, or anti‐β2 glycoprotein I (aβ2GPI) IgG/IgM antibodies. Other antiphospholipid antibodies (aPL) such as antiphosphatidylserine/prothrombin antibodies (aPS/PT) are promising in assessment of thrombotic APS (TAPS). AimTo evaluate the added value of aPS/PT IgG and IgM in TAPS. Material and MethodsaPS/PT IgG/IgM, aCL IgG/IgM, aβ2GPI IgG/IgM, and LAC were determined in 757 patients (TAPS and controls). aPS/PT cut‐off values were calculated, and aPS/PT titers and positivity were compared between TAPS and controls, type of thrombosis, and antibody profiles. Likelihood ratios (LR), odds ratios (OR), and aPL score were determined. ResultsaPS/PT IgG and IgM were associated with TAPS and triple positivity. In‐house calculated cut‐offs were higher for IgM (43 units), compared to manufacturer’s cut‐off (30 units). Thresholds of 90 (IgG) and 200 (IgM) units were determined as high‐titer cut‐off. Higher aPS/PT titers were observed in triple positive patients and showed higher LR and OR for TAPS. aPS/PT was independently associated with TAPS when adjusted for aCL/aβ2GPI, but not when adjusted for LAC. In isolated LAC positive patients, aPS/PT was positive in 27.1% TAPS patients and in 77.3% patients with autoimmune disease. Diagnostic value of aPL score did not differ with and without including aPS/PT. ConclusionaPS/PT positivity, especially with high antibody titer, is associated with TAPS diagnosis. Analysis on top of current laboratory criteria is not essential in TAPS diagnosis, but aPS/PT could be useful in patients with thrombosis and a double positive aPL profile (aCL+/aβ2GPI+).

Renal Function and Risk of Arterial Thrombotic Events in Patients Positive for Lupus Anticoagulant

Background: Patients with lupus anticoagulant (LA) are at risk for arterial and venous thromboembolic events. Recent work suggests that LA positive patients who experience thrombotic events in different vascular beds constitute distinct subgroups. To risk stratify patients, further work is needed to better characterize predictors for thromboembolic events in these subgroups.Aims: The aim of this study was to identify baseline characteristics and laboratory parameters associated with the development of arterial or venous thrombotic events.Methods: Patients with at least 2 previous positive LA tests were serially monitored for thrombotic events within the prospective Vienna Lupus Anticoagulant and Thrombosis Study (LATS). Patients without clinical follow-up were excluded from this analysis. Statistical analysis was performed with RStudio (Version 1.1.442).Results: One-hundred-eighty-seven patients were followed (Table 1) for a median of 11.4 years and 1865 follow-up visits (median visit/patient=9). Fifty-seven prospective thrombotic events (TE), including 27 arterial thrombotic events (ATE) and 30 venous thrombotic events (VTE), were observed. This corresponded to 10-year prospective ATE, VTE and overall thrombosis incidences of 13.9% [95%CI: 8.3, 19.6], 18.8% [12.2, 25.4], and 32.0% [24.1, 39.8], respectively. (Figure 1). Thirty-seven of the 57 events occurred in patients with a prior history of thrombosis (“recurrent thrombosis”).In univariable competing risk analysis, age (subdistribution hazard ratio (SHR) = 1.02, 95% CI: 1.00-1.05, p=0.019), body mass index (BMI, 1.05, 1.00-1.11, p=0.042), history of ATE (3.14, 1.45-6.81, p=0.0038), active smoking (2.16, 1.00-4.62, p=0.049), diabetes (4.16, 1.47-11.8, p=0.0073), VKA use at baseline (0.42, 0.18-0.97, p=0.042), aCL IgM positivity (2.48, 1.05-5.83, p=0.038), aβ 2GPI IgM positivity (2.86, 1.18-6.93, p=0.020), mean platelet volume (1.17, 1.06- 1.30, p=0.0024), creatinine (3.76, 1.32- 10.7, p=0.013), and estimate glomerular filtration rate (eGFR, 0.98, 0.96-0.99, p=0.0011) were associated with prospective risk of ATE (Table 2). Conversely, the prospective risk of VTE was univariably associated only with prior history of VTE (3.26, 1.40-7.68, p=0.0061).After adjusting for traditional arterial thrombotic risk factors (age, sex, BMI, active smoking, diabetes,), history of ATE (SHR = 3.97, 95% CI: 1.71-9.025, p=0.0014), prior history of both ATE and VTE (3.87, 1.06-14.16, p=0.041), creatinine (3.93, 1.22-12.66, p=0.022), and eGFR (CKD-EPI, 0.96, 0.96-0.99, p=0.0037) remained independently associated with prospective risk of ATE (Table 2).In detail, the 10-year cumulative risk of ATE was 24.9% [95%CI: 8.8, 41.0], 15.0% [5.8, 24.2], and 6.7% [2.2, 13.8] in patients with a baseline eGFR less than 60 mL/min/1.73m 2, between 60 and 89 mL/min/1.73m 2, and greater than or equal to 90 mL/min/1.73m 2, respectively (Gray's test, p=0.019, Figure 2).Conclusion: Approximately 14% of patients persistently positive for LA experienced an ATE over 10 years. After adjusting for traditional arterial risk factors, decreased renal function was associated with an increased prospective risk of ATE. Notably, decreased renal function was not associated with development of VTE and the association with ATE was also independent of underlying SLE, LLD, or rheumatic disease (data not shown). Clinically, LA positive patients with decreased renal function may represent a subgroup that might benefit from more aggressive anti-thrombotic therapy or anti-thrombotic prophylaxis. [Display omitted] DisclosuresPabinger: Bayer: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Daiichi Sanchyo: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; NovoNordisk: Consultancy, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding.

Evaluation of the Determination of Dabigatran, Rivaroxaban, and Apixaban in Lupus Anticoagulant-Positive Patients.

Background: The effect of direct oral anticoagulants (DOAC) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa, is a well-known problem and can cause both false positive and negative results. In particular, the situation in patients who develop lupus anticoagulant (LA) antibodies is highly complex. To evaluate the effectiveness of DOAC therapy in lupus-positive patients, 31 samples were enrolled in this retrospective study. All patient samples were spiked with three types of DOAC (dabigatran, DABI; rivaroxaban, RIVA; and apixaban, API) in a concentration that significantly influenced the screening test for LA and thus can mask the presence of LA. Subsequently, the DOAC was always unbound by the DOAC-Stop procedure. DOAC levels before and after binding were determined by functional assays, followed by liquid chromatography coupled with mass spectrometry (LC-MS) analysis. Methods: The determination of DOAC levels was performed by direct thrombin assay and determination of anti-Xa activity with specific calibration as functional tests for DABI and xabans (API and RIVA). To determine concentration levels of API, DABI, and RIVA, our in-house LC-MS method was used. Results: The results of LA-positive samples show significant differences between functional tests and the LC-MS method both before and after DOAC binding. Conclusions: The acute findings of the presence of LA-type antibodies fundamentally affects the determination of DOAC by functional tests, and in this case, it is necessary to use LC-MS analysis to determine the true value. If patients treated with DOAC develop LA of medium and higher titers, we do not recommend checking DOAC levels with functional tests.

Anti-domain 1 of beta2-glycoprotein I aids risk stratification in lupus anticoagulant-positive patients.

Lupus anticoagulant (LA) is considered a risk factor for thromboembolism (TE) and adverse pregnancy outcomes (APOs). However, quite a few patients diagnosed with LA positivity do not suffer these adverse events. Further testing of anticardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI) or anti-domain 1 of β2GPI (anti-D1) may help to assess the occurrence risk of TE and APOs. Therefore, we aimed to study how to stratify LA-positive patients. In our study, 167 LA-positive patients were consecutively enrolled from January 2015 to December 2016. Serum aCL and anti-β2GPI (IgG, IgM and IgA) and anti-D1 IgG were simultaneously measured. Among these patients, 114 (68.3%) were followed for an average of 36.5months for TE and APOs. The outcomes showed that 105 patients experienced TE and/or APOs, and 62 patients were LA carriers. Anti-D1 had good consistency with triple positivity (LA+, aCL+, anti-β2GPI+) (kappa = 0.742). Elevated anti-D1 was related to increased risks for TE [odds ratio (OR) 29.87, 95% confidence interval (CI) 8.05-110.74] and APOs (OR 8.73, 95% CI 3.41-22.31). Area under curve showed that the diagnostic power of anti-D1 for TE and APOs was 0.856 (95% CI 0.743-0.970) and 0.682 (95% CI 0.599-0.765), respectively. Survival analysis revealed that patients with high anti-D1 titres had a high cumulative incidence of APOs (hazard ratio 4.66, 95% CI 1.46-14.87). In conclusion, anti-D1, based on good consistency with triple positivity in LA-positive patients, has a stronger association with TE and APOs and, to some degree, could predict pregnancy outcomes. Therefore, anti-D1 may aid risk stratification in LA-positive patients.

Andexanet Alfa Corrects the Interference of Direct Factor Xa Inhibitors on Lupus Anticoagulant Testing

BackgroundDirect Factor Xa (FXa) inhibitors (e.g. rivaroxaban or apixaban) are widely used oral anticoagulants and are known to interfere with dilute Russell's viper venom time (dRVVT) and aPTT-based lupus anticoagulant (LA) testing, often yielding false-positive LA results. A false positive LA result might incorrectly diagnose a patient with the anti-phospholipid antibody syndrome and lead to a wrong decision for long-term anticoagulation to prevent recurrent thrombosis.Andexanet alfa is a recombinant modified human FXa decoy protein that has been specifically designed as an antidote to neutralise the effect of the direct and indirect FXa inhibitors.AimTo determine whether the addition of andexanet alfa can overcome the interference of rivaroxaban and apixaban on LA testing in plasma samples from both LA positive and LA negative patients.MethodsAfter written informed consent, citrated blood (20mL) was collected from 12 patients on therapeutic doses of rivaroxaban (n=6) or apixaban (n=6) with previously known LA status (3/6 LA positive in each group). Samples were double centrifuged at 3,000 x g for 10 minutes and aliquots were frozen at -40oC until analysed. Normal pooled plasma and rivaroxaban and apixaban calibrated plasma was obtained from a commercial source (Diagnostica Stago) or control plasma from healthy volunteers, prepared as above. IgG was purified by a Protein G column from a known LA positive patient and a control healthy volunteer.Rivaroxaban (Bayer) and apixaban (Bristol-Myers Squibb) tablets were crushed and dissolved in DMSO. Andexanet alfa (Portola Pharmaceuticals, Inc.) was dissolved in distilled water and aliquots were frozen at -40oC until used. Plasma samples were spiked with varying concentrations of FXa inhibitors and andexanet alfa.LA-sensitive aPTT, PT, TCT, dRVVT (Siemens Healthcare Diagnostics) and anti-FXa level (Diagnostica Stago) were performed with and without andexanet alfa on the Sysmex CS5100 analyser.Andexanet alfa (at a final concentration of 250µg/mL) was added to LA positive and LA negative plasma samples to assess the impact on the dRVVT normalised ratio.ResultsAndexanet alfa demonstrated a concentration-dependent increase in LA sensitive aPTT and dRVVT clotting times, with negligible impact on PT or TCT. Andexanet alfa was capable of reversing FXa inhibition in a concentration-dependent manner in plasma samples containing rivaroxaban or apixaban.When rivaroxaban is added to normal plasma it significantly prolongs the dRVVT without phospholipid more than with excess phospholipid leading to a false-positive LA ratio at final concentrations >100ng/mL. This level of rivaroxaban is in the therapeutic range. The addition of andexanet alfa reduced the measurable anti-FXa level and returned the normalised dRVVT ratio to LA negative result (<1.25). In contrast, apixaban and andexanet alfa proportionately prolongs the dRVVT with or without excess phospholipid and even at high concentrations, the normalised LA ratio remains negative (<1.25).Andexanet alfa converted the false positive dRVVT rivaroxaban patient plasmas LA ratio to negative. True LA positive patients remained positive after the addition of andexanet alfa. These results were confirmed by adding LA positive and control purified IgG to known concentrations of rivaroxaban and apixaban (200ng/ml) in normal plasma.ConclusionAndexanet alfa corrects the false positive LA ratio in patients on rivaroxaban without affecting the true diagnosis in LA positive patients. Apixaban and andexanet alfa proportionately prolong the dRVVT with and without phospholipid, so the LA ratio remains negative. For this reason true LA positive patients can be diagnosed whilst on apixaban at therapeutic concentrations without the addition of andexanet alfa. DisclosuresBaker:Biogen Idec: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Other: Conference travel support; Astellas and CSL Behring: Research Funding; Bristol-Myers Squibb: Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shire: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support, Research Funding; Daiichi Sankyo: Research Funding; Portola Pharmaceuticals: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support; Biogen Idec: Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support, Research Funding; Roche: Other: Conference travel support. McGregor:Gilead: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Equity Ownership, Other: Conference travel support; Pfizer: Other: Conference travel support; Roche: Honoraria; Abbvie: Equity Ownership; Portola Pharmaceuticals: Equity Ownership.

Exogenous Magnesium Chloride Reduces the Activated Partial Thromboplastin Times of Lupus Anticoagulant-Positive Patients.

The activated partial thromboplastin time (APTT) assay is a basic hemostatic assay based on the time it takes for clots to form in plasma samples after the addition of calcium chloride. It is used to screen for various coagulation disorders. Several previous reports have suggested that magnesium (Mg) might contribute to coagulation reactions by binding to specific coagulation proteins. We investigated the effects of Mg on the APTT. In healthy controls, the APTT was significantly prolonged in proportion to the increase in the concentration of magnesium chloride in the range from 2.1 to 16.7 mmol/L. Among eight samples from patients with various disorders that exhibited prolonged APTT, two samples demonstrated shorter APTT when Mg was added, both of which were from patients that were positive for lupus anticoagulant. When we examined 206 clinical APTT samples, we found that Mg shortened the APTT of two samples. These two samples were also from lupus anticoagulant-positive patients (p-value: <0.003). Our findings regarding the unique effects of exogenous Mg on the APTT of lupus anticoagulant-positive patients might shed light on the role of Mg in APTT assays and lead to the development of a novel screening method for lupus anticoagulant.

Dilute Russell's viper venom and activated partial thromboplastin time in lupus anticoagulant diagnosis: is mixing essential?

Dilute Russell's viper venom (DRVV) testing and activated partial thromboplastin time (APTT) have been effectively used in combination for lupus anticoagulant testing. The purpose of our study was to evaluate the role of mixing in activated partial thromboplastin and dilute Russell's viper venom testing for evaluation of lupus anticoagulants. Citrated blood from patients who were not on oral anticoagulant therapy was studied. Mixing study with 1 : 1 normal plasma for elevated APTT and also few samples with elevated screen time was carried out. Elevated APTT was seen in only 48.1% of patients with lupus anticoagulant. Correction of APTT was seen in 27.8% of lupus anticoagulant-positive patients. DRVV test on mixing resulted in 83.8% false-negative values. Integrated DRVV test could be a standalone test for testing lupus anticoagulant. Mixing study may be restricted for patients on oral anticoagulants or patients with strong lupus anticoagulant.

Annexin A5 Resistance Is Associated with Thrombotic Risk in Patients with the Lupus Anticoagulant: The Vienna Lupus Anticoagulant and Thrombosis Study (LATS)

INTRODUCTIONAntiphospholipid (aPL) antibody mediated interference with the anticoagulant effect of annexin A5 (A5) - designated "annexin A5 resistance" (A5R) - has been implicated in adverse clinical outcomes. In this study, we ask whether A5R is associated with anamnestic thrombotic complications and adverse pregnancy outcomes in patients with the lupus anticoagulant (LA).PATIENTS & METHODS: We conducted a cross-sectional study including 143 patients (median age: 40.5 years, interquartile range (IQR): 31.8-60.0; female: n=119) who tested persistently positive for LA according to ISTH criteria (Miyakis et al. J Thromb Haemost 2006; 4: 295). Thrombotic complications were defined as a composite of arterial and/or venous thromboembolic events. Pregnancy complications were defined according to the modified Sapporo criteria. Out of the 143 patients, 94 (65.7%) had a history of a thrombembolic event (arterial: n=21, venous: n=80, both: n=7). Ninety-three women had at least one pregnancy, and 40 (43.0%) out of these women had at least one pregnancy complication as defined by the above mentioned criteria. It is important to mention that on average, these pregnancy complications had occurred more than ten years before study inclusion. A5R assays were done using phospholipid that was first exposed to patient plasmas as previously described; A5R results were expressed as the ratio of coagulation times with and without annexin A5. In a subsample (n=109), a blinded external validation using two separate measurements of the A5R was performed. RESULTSIn blinded analysis, the concordance between the two A5R measurements was very high (Liu's concordance correlation coefficient=0.83, average difference=12.2 units (95% limits of agreement from Bland-Altman analysis: -37.0 - 61.3). The A5R was inversely correlated with levels of antibodies against cardiolipin (Spearman's rho for IgG and IgM: -0.65 and -0.24, respectively), and against beta2-glycoprotein I (Spearman's rho for IgG and IgM: -0.57 and -0.28). The median A5R level was 205 units (IQR: 205-250, range: 130-336). Patients with a prior history of a thrombotic complications had significantly lower median levels of A5R (193.1 vs. 238.7 units, mean difference: 26.7 units (95% CI: 11.0-42.4), p=0.001). This difference was independent of both IgG and IgM isotype antibody levels against cardiolipin and beta2-glycoprotein I (adjusted mean difference: 20.7 units (95% CI: 6.4-35.0), p=0.005), and of whether patients were on anticoagulation or not (adjusted mean difference: 24.8 units (95% CI: 4.3 - 45.2), p=0.018). In the 95 women with at least one pregnancy, average A5R were lower in women with (n=40) compared to those without (n=53) at least one pregnancy complication (median: 200.9 vs. 231.9 units), however, this difference was not statistically significant (t-test p=0.255). CONCLUSIONA5R is associated with a history of thromboembolic complications in LA positive patients, suggesting that the ex vivo measurement of the A5R may reflect a prothrombotic phenotype in this patient population. Interestingly, we found no clear association between the A5R and anamnestic pregnancy complications was observed, however, the generalizability of this finding is hampered by the long time interval between anamnestic pregnancy complications and inclusion in this study. DisclosuresNo relevant conflicts of interest to declare.

Thrombotic Events in Lupus Anticoagulant Positive Patients Prospectively Correlate with Clinical Risk Factors - the Vienna Lupus Anticoagulant and Thrombosis Study (LATS)

INTRODUCTIONPatients with the lupus anticoagulant (LA) are at an increased risk of thrombotic events (TE), which in turn increase the risk of death (Gebhart J et al. Blood. 2015. 125:3477). Understanding the determinants of thrombotic risk in LA patients may pave the way towards targeted thromboprophylaxis. To date, several retrospective studies have investigated the association between anamnestic thrombosis and certain factors, such as antibodies against cardiolipin and beta2-glycoprotein I. However, robust prospective evidence is still limited. We aimed to investigate clinical and laboratory risk factors for development of TE in patients with a persistently positive LA.PATIENTS & METHODS: In this prospective, observational cohort study with a baseline biobank we followed 150 patients (median age: 41.3 years, interquartile range (IQR): 32.3-60.2, female gender: n=122 (81.3%)), who tested repeatedly positive for the LA until the development of TE, death, or censoring. The primary endpoint was the time-to-TE during the observation period, defined as a composite of arterial or venous, independently-adjudicated thrombotic complications. Ninety-eight (65.3%) of the 150 patients had a history of at least one TE event (arterial TE: n=21, venous TE: n=84, both: n=7), and 70 (46.7%) were on oral anticoagulation at baseline. Sixty-five (43.3%) patients also had IgM and/or IgG isotype antibodies against cardiolipin and beta2-glycoprotein I ("Triple positivity"). For investigation of the LA, lupus-sensitive aPTT reagents were used (aPTT-LA, Diagnostica Stago, Asnieres, France). Prospective associations were analyzed using competing risk analysis treating death-from-any-cause as the competing event. Evaluated risk factors included (1) the lupus-sensitive activated partial thromboplastin time (aPTT-LA), (2) antibodies against cardiolipin, beta2-glycoprotein I, domain 1 of beta2-glycoprotein I, prothrombin, and "triple positivity", (3) general cardiovascular risk factors (diabetes, hypertension, smoking, and hypertriglyceridemia, body mass index), and (4) AnnexinA5 resistance (A5R). RESULTSDuring a median follow-up period of 8.7 years (range: 12 days - 12.4 years), 30 TE events occurred (arterial TE: n=14, venous TE: n=16), and 20 patients died. The cumulative incidence of TE at 1, 5, and 10 years of follow-up were 4.0% (95% Confidence Interval (CI): 1.7-8.1), 12.8% (95% CI: 7.9-18.9), and 24.4% (95% CI: 16.8-32.8), respectively. In univariable analysis, a prolonged aPTT-LA (Subhazard ratio (SHR) for aPTT≥118 seconds (i.e. 75th percentile of the aPTT-LA distribution)=2.59, 95%CI: 1.27-5.31, p=0.009), diabetes (SHR=4.36, 95%CI: 1.44-13.19, p=0.009), active smoking (SHR=2.35, 95%CI: 1.16-4.77, p=0.018), and elevated triglycerides (SHR per 50mg/dL increase=1.14, 95%CI: 1.09-1.18, p<0.001) were associated with a higher risk of TE events. In multivariable analysis, the only independent predictors of a higher thrombotic risk were a prolonged aPTT-LA (adjusted SHR=2.33, 95%CI: 1.06-5.13, p=0.035), diabetes (adjusted SHR=3.79, 95%CI: 1.12-12.89, p=0.033), and active smoking (adjusted SHR=2.62, 95%CI: 1.24-5.52, p=0.012). These results prevailed after adjusting for anticoagulation at baseline. Using these three parameters allowed identification of clinical subgroups with a very high and a low risk of TE events (cumulative risk of TE after 5 years 43.3% in the high risk group and 5.6% in the low risk group, respectively, Figure 1). The other risk factors did neither in univariable nor in multivariable analysis emerge as predictors of thrombotic risk in this large cohort. CONCLUSIONDiabetes and smoking, which are established risk factors for vascular events in the general population, turned out to be relevant also in patients with the LA. Moreover, a very long lupus sensitive aPTT was as well predictive for occurrence of TE in these patients. This effect was independent of anticoagulation. Interestingly, disease defining antibodies, such as those against cardiolipin or beta2-glycoprotein I (including those against domain I) were not associated with future occurrence of TE in this LA positive patient population. These data suggest that above standard anticoagulation, interventions to control and improve metabolic status and smoking habits might influence the rates of future TE in patients with known persistent LA. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Lupus anticoagulant and thrombosis in splenic marginal zone lymphoma

IntroductionSplenic marginal zone lymphoma (SMZL) is a rare low-malignant Non-Hodgkin lymphoma (NHL), in which immune mediated paraneoplastic phenomena such as autoimmune hemolytic anemia (AIHA), autoimmune thrombocytopenia (ITP) and C1 esterase inhibitor deficiency are relatively common. Materials and MethodsWe performed a multicenter retrospective study in 70 patients on the prevalence and clinical features of antiphospholipid antibodies (aPLA) in SMZL. Results and ConclusionsNine patients (13%) had the diagnosis of a lupus anticoagulant (LA). The occurrence of venous thromboembolic events was significantly higher in LA positive patients compared to LA negative patients (4/9 [44%] vs 5/61 [8%], p=0.002), especially within 12months after splenectomy (3/6 [50%] vs 2/28 [7%], p=0.007). None of the patients with LA had a persistent complete remission of LA after splenectomy, but complete remission of LA was achieved in 2/2 patients after rituximab-bendamustine immuno-chemotherapy. In conclusion, our data show a relatively high prevalence of aPLA in SMZL and an increased risk of postsplenectomy thrombosis in these patients. The fact that rituximab-bendamustine was effective for eradicating LA may be considered as an argument for using immuno-chemotherapy as first line therapy in SMZL patients with LA.

The introduction of anti-phosphatidylserine/prothrombin autoantibodies in the laboratory diagnostic process of anti-phospholipid antibody syndrome: 6months of observation.

PurposeTo evaluate the impact of the introduction of the anti-phosphatidylserine/prothrombin autoantibodies (aPS/PT) in the laboratory diagnostic process of anti-phospholipid antibody syndrome (APS).MethodsFour hundred and twenty-one patients (71.5 % females; 53 ± 15 years) presenting a medical prescription for aPS/PT antibodies were consecutively enrolled in the study from March 2013 to August 2013. During the same period, aPS/PT were additionally investigated in a selected series of 62 patients characterized by difficult lupus anticoagulant (LA) tests interpretation and in a retrospective series of 52 LA positive cases with available data about anti-prothrombin (aPT) antibodies. The aPS/PT antibodies, as well as the anti-cardiolipin (aCL), the anti-β2 glycoprotein I (aβ2GPI) and the aPT antibodies were analyzed by ELISA. LA was tested according to the recommended criteria, performing both the screen and the confirm steps.ResultsOverall, aPS/PT IgM positive (>30 U/ml) and/or IgG frankly positive (>40 U/ml) antibodies were found in 49/421 (11.6 %) cases. Among the LA positive patients, we found 56.1 % aPS/PT positive versus 31.7 % aCL and/or aβ2GPI positive cases, with limited (17.1 %) simultaneous positivity. The PS/PT complex resulted the newly recognized specificity in about 27 % of patients recruited from the subset with difficult LA test interpretation. Compared to aPT antibodies, the aPS/PT antibodies displayed a much higher sensitivity (55.8 versus 15.4 %) in LA positive patients.ConclusionsThe introduction of aPS/PT antibodies in the diagnostic process of APS is highly recommended, since they disclose a notable diagnostic performance and a high correlation with LA activity, such that they can be a viable alternative.

THU0029 Inflammation is Strongly Associated with Lupus Anticoagulant Positivity, Independent of Known Autoimmune Disease and Recent Venous or Arterial Thrombosis

BackgroundThe antiphospholipid syndrome (APS) is an auto-immune disorder defined by presence of antiphospholipid antibodies and either thrombosis or obstetric complications (1). Laboratory part of the diagnosis of APS comprise of...

The role of soluble P selectin in the diagnosis of venous thromboembolism

Soluble P selectin (sPsel), a member of the selectin family of cell adhesion receptors, has been proposed as a key molecule in hemostasis and thrombosis mediating platelet rolling, generating procoagulant microparticles and enhancing fibrin deposition. The aim of this study was to examine the role of sPsel in the diagnosis of venous thromboembolism (VTE). We performed a systematic review and we used meta-analysis to synthesize data from published studies reporting sPsel levels in patients with i) VTE (deep venous thrombosis; DVT or DVT and pulmonary embolism; PE) and ii) DVT only. Pooled Odds Ratios (ORs) with 95% Confidence Intervals (CIs) were appropriately calculated among patients and controls. Diagnostic performance of sPsel was tested with pooled sensitivity, specificity, Diagnostic Odds Ratio (DOR) and summary receiver operator characteristic (SROC) curve. Eleven studies, comprising of 586 VTE patients and 1,843 controls were deemed eligible. The sPsel was significantly increased after VTE (OR=2.89, 95%CI=2.31-3.61, p<0.001), or DVT only (OR=2.64, 95%CI=1.95-3.56, p<0.001). Subgroup analysis evidenced that sPsel was also increased after VTE when evaluating only studies with patients that had no prior medical history (OR=2.88, 95%CI=1.98-4.19, p<0.001). Exclusion of studies including patients with solid organ tumor, HIV or lupus anticoagulants positive patients did not alter findings. Pooled sensitivity and specificity of sPsel was 0.57 (95%CI=0.30-082, p<0.001) and 0.73 (95%CI=0.51-0.90, p<0.001), respectively and DOR was 4.31 (95%CI=2.22-8.37, p<0.01). SROC curve yielded in significant accuracy of sPsel performance (AUC=0.74, p=0.05). The sPsel was significantly elevated in patients with DVT, both uncomplicated and complicated with PE and presented with high levels of diagnostic performance. sPsel is a plasma biomarker that may help in the diagnosis of VTE.

AB0695 Anti-prothrombin/phosphatidyl-serine complex autoantibodies in antiphospholipid syndrome: Preliminary data using a new ELISA method

BackgroundNew emerging anti-phospholipid (aPL) assays could improve our ability in diagnosing anti-phospholipid syndrome (APS). However, the availability of aPL assays in routine laboratory practice is limited and present available assays...

Clinical significance of IgG and IgM autoantibodies that target the complex of phosphatidylserine and prothrombin (PS/PT)

Objective Determine the performance characteristics and clinical utility of an ELISA for detecting autoantibodies against a complex of phosphatidylserine and prothrombin (PS/PT). Method 71 patients with anti-phospholipid syndrome (APS), 24 with lupus anticoagulant (LAC), 167 normal blood donors and 52 disease controls were tested for IgG and IgM antibodies to PS/PT. The new assays were compared to traditional anti-B2GPI and LAC assays. Matched serum and citrated plasma samples were tested. Results All LAC positive patients were found to be positive for either IgG or IgM PS/PT antibodies, or both. Forty-eight of the 71 APS patients (68%) were PS/PT positive, and many of these individuals were negative for anti-B2GPI and LAC. Only three of 167 blood donors and one of 52 disease controls were positive on either assay, for a combined specificity of 98% (4/219). The assays had high inter- and intra-run precision. Equivalent results are obtained with serum or citrated plasma. Conclusion IgG and IgM autoantibodies that react with a complex of PS/PT are sensitive markers for APS. Unlike LAC, these antibodies can be detected in people treated with anticoagulants, and anti-PS/PT antibodies should be considered as additional new markers for diagnosing patients with APS.

Diagnostic test combinations associated with thrombosis in lupus anticoagulant positive patients

Diagnostic test combinations associated with thrombosis in lupus anticoagulant positive patients -

Antiphospholipid-associated thrombocytopenia or autoimmune hemolytic anemia in patients with or without definite primary antiphospholipid syndrome according to the Sapporo revised classification criteria: a 6-year follow-up study

AbstractThe updated Sapporo classification criteria for antiphospholipid syndrome (APS) only include thrombosis or pregnancy morbidity as clinical criteria. To test this notion, we studied 55 patients (80% women) with hematologic manifestations. All fulfilled the laboratory criteria for primary APS. Thirty-five patients (64%) had thrombocytopenia, 14 (25%) had autoimmune hemolytic anemia, and 6 (11%) had both. Twenty-five patients (22 women, 88%) also fulfilled one clinical criterion for APS after a median follow-up of 13.2 years (range, 1.45-37 years), whereas the remaining 30 patients (22 women, 73%) have not had any thrombotic event nor pregnancy morbidity after a median follow-up of 5.4 years (range, 0.12-24 years). No patient developed systemic lupus erythematosus during follow-up. The hematologic manifestation was asynchronous with the APS onset in 84% of patients. The response to treatment was similar regardless of the APS status. Patients with definite APS were more frequently positive for the lupus anticoagulant (63%) than lupus anticoagulant-positive patients without APS (30%; odds ratio, 3.5; 95% confidence interval, 1.07-11.4; P < .02). Anticardiolipin or anti–β2-glycoprotein-I antibodies were highly prevalent among the study groups. Our study suggests that, depending upon their antiphospholipid profile, patients with hemocytopenias appear to comprise a peculiar subset of patients with APS; some develop thrombotic and/or obstetric APS whereas others continue with hematologic APS.