Veronica Murru

GAPSS: the Global Anti-Phospholipid Syndrome Score

OBJECTIVE To develop and validate a risk score [global APS score (GAPSS)] derived from the combination of independent risk for thrombosis and pregnancy loss (PL), taking into account the aPL profile, conventional cardiovascular risk factors and the autoimmune antibody profile. METHODS This cross-sectional study included 211 consecutive SLE patients. Data on clinical manifestations, conventional cardiovascular risk factors, aPL profile, ANAs, ENA and anti-dsDNA were collected. Long-term low-dose aspirin, oral anticoagulant and HCQ treatment were also included in the analysis. Patients were randomly divided into two sets by a computer-generated randomized list. We developed GAPSS in the first set of patients (n = 106), assigning the risk factors identified by multivariate analysis weighted points proportional to the β-regression coefficient values. GAPSS was validated in the second set of patients (n = 105). The relationship between GAPPS and thrombosis and/or PL was analysed. RESULTS In the first set, higher values of GAPSS were seen in patients who experienced thrombosis and/or PL compared with those without clinical events [GAPSS 9.3 (4.8) (range 1-19) and 5.3 (4) (range 0-16), P < 0.001]. Also taken separately, patients who experienced thrombosis or PL showed higher GAPSS compared with those without clinical events [GAPSS 9.6 (4.8) (range 1-19) vs 4.9 (5) (range 0-14), P = 0.027 for thrombosis; 7.3 (5) vs 3.9 (5.1) (range 0-16), P = 0.024 for PL, respectively]. In the second set, the results were similar, with statistically higher values of GAPSS in patients with a clinical history of thrombosis and/or PL compared with those without events [GAPSS 9.5 (5.6) (range 0-20) and 3.9 (4.1) (range 0-17), P < 0.001). Higher values were also seen when subclassifying the patients according to the clinical manifestation, thrombosis or PL [GAPSS 9.5 (5.6) (range 0-20) vs 4.8 (5.4) (range 0-17), P = 0.036 for thrombosis; 7.9 (3.3) vs 3.8 (5.4) (range 0-16), P = 0.037 for PL, respectively). CONCLUSION These data propose a substantial improvement in risk prediction of thrombosis or PL in SLE based on assessment of the GAPSS, a quantitative scoring system.

Anti-prothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies and the risk of thrombosis in the antiphospholipid syndrome. A systematic review.

Antibodies to prothrombin are detected by directly coating prothrombin on irradiated ELISA plates (aPT) or by using the phosphatidylserine/prothrombin complex as antigen (aPS/PT). Although these antibodies have both been associated with antiphospholipid syndrome (APS) and a correlation between the two assays have been reported, it seems that aPT and aPS/PT belong to different populations of autoantibodies. It was our objective to systematically review the available evidence on aPT and aPS/PT antibodies and the risk of thrombosis in APS. Medline-reports published between 1988 and 2013 investigating aPT and aPS/PT as a risk factor for thrombosis were included. Whenever possible, antibody isotype(s) and site of thrombosis were analysed. This systematic review is based on available data from more than 7,000 patients and controls from 38 studies analysing aPT and 10 aPS/PT. Antibodies to prothrombin (both aPT and aPS/PT) increased the risk of thrombosis (odds ratio [OR] 2.3; 95% confidence interval [CI] 1.72-3.5). aPS/PT seemed to represent a stronger risk factor for thrombosis, both arterial and/or venous than aPT (OR 5.11; 95%CI 4.2-6.3 and OR 1.82; 95%CI 1.44-2.75, respectively). In conclusion, routine measurement of aPS/PT (but not aPT) might be useful in establishing the thrombotic risk of patients with previous thrombosis and/or systemic lupus erythematosus. Their inclusion as laboratory criteria for the APS should be indisputably further explored.

Clinical accuracy for diagnosis of antiphospholipid syndrome in systemic lupus erythematosus: evaluation of 23 possible combinations of antiphospholipid antibody specificities.

Summary.  Objectives: To evaluate the clinical accuracy of antiphospholipid antibody (aPL) specificities both individually and/or in combination, in a wide cohort of systemic lupus erythematosus (SLE) patients in an attempt to identify a panel of tests that may provide the best accuracy for diagnosing antiphospholipid syndrome (APS). Patients and Methods: This study included 230 patients (218 women, mean age 42.7 ± 11.9 years, mean disease duration 12.2 ± 8.7 years), all fulfilling the 1982 criteria for SLE. All patients were tested for lupus anticoagulant (LA), anti‐cardiolipin (aCL), anti‐β2glycoprotein I (anti‐β2GPI), solid phase anti‐prothrombin (aPT), anti‐phosphatidylserine/prothrombin (aPS/PT), and anti‐phosphatidylethanolamine (aPE) antibodies. Sensitivity, specificity and predictive values were calculated. The diagnostic accuracy for each combination of tests was assessed by ROC and their area under the curve analysis as well as by the Youden’s index (YI). Results: Testing for six aPL derived 23 possible combinations of results. Among them, LA + anti‐β2GPI + aPS/PT had the best diagnostic accuracy for APS as a whole and individually for both thrombosis and pregnancy loss (AUC 0.712, OR 3.73 [95% CI 1.82–5.38], P = 0.0001, YI = 0.32 and AUC 0.709, OR 3.75 [95% CI 2.13–6.62], P = 0.0001, YI = 0.37 and AUC 0.677, OR 4.82 [95% CI 2.17–10.72], P = 0.0007, YI = 0.38, respectively) and the best specificity when compared with all the other obtainable combination of tests. Triple positivity for LA + anti‐β2GPI + aPS/PT was more strongly associated with clinical events (thrombosis and/or PL) when compared with double or single positivity (OR 23.2 [95% CI 2.57–46.2] vs. OR 7.3 [95% CI 2.21–25.97], OR 5.7 [95% CI 2.12–17.01] or OR 3.11 [95% CI 1.56–7.8] for single positivity for LA, aPS/PT and anti‐β2GPI, respectively). Conclusions: Combining LA, anti‐β2GPI and aPS/PT improves the diagnostic power and helps in stratifying the risk for each patient, according to their aPL profile.

Low-dose aspirin vs low-dose aspirin plus low-intensity warfarin in thromboprophylaxis: a prospective, multicentre, randomized, open, controlled trial in patients positive for antiphospholipid antibodies (ALIWAPAS)

OBJECTIVES The objectives of this study are to examine the efficacy and safety of low-dose aspirin (LDA) vs LDA plus low-intensity warfarin (LDA + W) in the primary thrombosis prevention of aPL-positive patients with SLE and/or obstetric morbidity and the role of clinical and serological markers in the development of thrombosis. METHODS In this 5-year prospective, randomized, open, controlled trial, 166 patients with aPL were randomly assigned using a minimization protocol to receive treatment with LDA (n = 82) or LDA + W [international normalized ratio (INR) = 1.5] (n = 84). Sixty-six patients who declined randomization were followed up in an observational arm. Clinical and laboratory characteristics and medication side effects were recorded. RESULTS There were no differences in the number of thromboses between patients treated with LDA (4/82) or LDA + W (4/84) [hazard ratio (HR) 1.07, 95% CI 0.27, 4.3]. The incidence of thrombosis in the randomized patients was 8/166 (1.8 events/100 person-years) (HR 1.07, 95% CI 0.27, 4.3) and in the observational arm was 7/66 (4.9 events/100 person-years) (HR 2.43, 95% CI 0.87, 6.79). Sixty-five of 66 patients included in the observational arm received LDA. None of the examined clinical or serological factors appeared to predict thrombosis. Medication side effects included mild gastrointestinal symptoms in the LDA group (n = 2) and bleeding in the LDA + W group (n = 11; 1 nasal and 10 menorrhagia). The risk difference for bleeding was 13% (CI 6, 20). CONCLUSION No differences in the number of thromboses were observed between patients treated with LDA vs those treated with LDA + W. More episodes of bleeding were detected in the LDA + W group. The LDA + W regime was significantly less safe and not as acceptable as LDA alone. TRIAL REGISTRATION ISRCTN81818945; http://isrctn.org/.

Prevalence of antibodies to prothrombin in solid phase (aPT) and to phosphatidylserine-prothrombin complex (aPS/PT) in patients with and without lupus anticoagulant

Antibodies to prothrombin in solid phase (aPT) and those to phosphatidiyserine-prothrombin complex (aPS/PT) have been suggested to strongly correlate with the presence of lupus anticoagulant (LA). As their clinical diagnostic value and true relationship with the LA remains elusive, we designed this study to evaluate the prevalence and significance of aPT and aPS/PT in a large cohort of patients with and without LA. Samples from 257 patients were included. aPT and aPS/PT were tested by ELISA. LA was tested as per the current criteria from the ISTH Subcommittee on LA-Phospholipid-dependent antibodies. aPS/PT and aPT were found in 51% and 32% of LA-positive (LA+ve) patients and in 22% and 28% of LA-negative (LA-ve) patients, respectively. Thrombosis, particularly venous thrombosis was associated with IgG aPT in the LA+ve group (p=0.0006) and in the LA-ve group (p=0.017). Antibodies to phosphatidylserine-prothrombin, either IgG and IgM were associated with thrombosis in general (p=0.0003) in particularly with venous thrombosis in the LA+ve group (p<0.0001 for IgG and p=0.025 for IgM; respectively) and the LA-ve group (p=0.028, 0.02 and 0.001, respectively). Further multivariate logistic regression analysis showed that LA and of IgG and/or IgM aPS/PT were independent risk factors for thrombosis and pregnancy loss. In conclusion, aPS/PT, but not aPT, are more frequently found in patients with LA. Their association with thrombosis seems to be independent of the presence of LA.

The global anti-phospholipid syndrome score in primary APS

OBJECTIVE The aim of this study was to evaluate the clinical relevance of the global APS score (GAPSS) in a cohort of primary APS patients. METHODS This study included 62 consecutive patients with primary APS. Data on clinical manifestations, conventional cardiovascular risk factors and aPL profile were collected. The GAPSS was calculated for each patient by adding together the points corresponding to the risk factors, based on a linear transformation derived from the β regression coefficient as follows: 3 for hyperlipidaemia, 1 for arterial hypertension, 5 for aCL IgG/IgM, 4 for anti-β2 glycoprotein I IgG/IgM, 3 for aPS-PT IgG/IgM and 4 for LA. RESULTS Higher GAPSS values were seen in patients who experienced thrombosis alone when compared with those with pregnancy loss alone [11.5 (S.D. 4.6) and 8.7 (S.D. 3.2), P = 0.04]. Patients with both thrombosis and pregnancy loss showed higher GAPSS than those with pregnancy loss alone [12.5 (S.D. 4.6) vs 8.7 (S.D. 3.2), P = 0.02]. Higher GAPSS values were also shown after subgrouping for the site of thrombosis when compared with pregnancy loss alone [12.2 (S.D. 5.2) for arterial thrombosis, 12.0 (S.D. 4.0) for venous vs 8.7 (S.D. 3.2), P = 0.02 and P = 0.04, respectively]. Patients with thrombotic recurrences showed higher GAPSS values when compared with those without recurrence [13.7 (S.D. 3.1) vs 9.4 (S.D. 3.9), P = 0.02]. This was also seen when comparing recurrences vs no recurrences independently of the site of the thrombotic event [13.9 (S.D. 3.6) vs 11.0 (S.D. 4.3), P = 0.01 for arterial and 13.6 (S.D. 2.18) vs 8.91 (S.D. 3.6), P < 0.01 for venous thrombosis]. GAPSS values ≥11 were strongly associated with a higher risk of recurrence [odds ratio (OR) 18.27 (95% CI 3.74, 114.5) for a cut-off of 11, OR 20.64 (95% CI 3.92, 185.92) for a cut-off of 12 and 21.64 (95% CI 3.89, 189.56) for a cut-off of 15]. GAPSS values ≥11 seemed to have the best risk accuracy in terms of sensitivity and specificity. CONCLUSION The GAPSS is demonstrated to be a valid tool for a substantial improvement in risk stratification for thrombosis in primary APS.

Thrombotic Risk Assessment in Systemic Lupus Erythematosus: Validation of the Global Antiphospholipid Syndrome Score in a Prospective Cohort

This study was performed to prospectively and independently validate the Global Antiphospholipid Syndrome Score (GAPSS), a system derived from the combination of independent risk factors for thrombosis, including antiphospholipid antibodies (aPL) and conventional cardiovascular risk factors.

Migraine and antiphospholipid antibodies: no association found in migraine-discordant monozygotic twins

Migraine headache (with and without aura) is common in the general population and is known to be influenced by genetic factors with heritability estimates between 34-57±. Antiphospholipid syndrome (APS) is a hypercoagulable state characterized by clinical features including venous and arterial thromboses, pregnancy loss and migraine, and by association with antiphospholipid antibodies (aPL). Numerous small studies have investigated whether aPL are associated with migraine in the general population—-with contradictory results. In this study, the question was addressed by studying the prevalence of aPL in members of monozygotic (MZ) twin pairs differing in their migraine status. Such twins provide a unique natural experiment, matched as they are for age, sex and genetic factors, and allow the role of environmental factors, such as aPL, to be determined. Despite 95± power to detect a difference of 0.59 IgG units per litre in anticardiolipin antibody IgG titres, no difference in prevalence of aPL could be detected in migraine-discordant MZ twins.

The clinical value of testing for antibodies to phosphatidylethanolamine (aPE) in patients with systemic lupus erythematosus (SLE)

UNLABELLED The value of testing for aPE in venous thrombosis and fetal death is in constant debate. We evaluated if testing for aPE has a diagnostic value in patients with SLE. PATIENTS AND METHODS We included 224 patients. aPE were tested by an in-house ELISA using FCS. RESULTS aPE were found in 41% of the patients. IgG and IgM aPE were more frequently found along with other aPL than in those negative for aPL (p=0.003 and p=0.01). IgG aPE were more frequently found in patients with definite APS than in those without (p=0.003). aPE were more frequent in patients with thrombosis than in those without, particularly the IgG isotype (p=0.03). When subdividing between venous and arterial thrombosis, only an association between IgG aPE with venous thrombosis was retained (p=0.01). Titres of IgG aPE were significantly higher in patients with arterial or those with venous thrombosis, when compared to the patients without thrombosis (p=0.004 and p=0.001). Titres of IgM aPE were higher in patients with arterial thrombosis when compared to those without (p=0.014). No associations were found between the presence of aPE and/or pregnancy morbidity. The presence of aPE did not correlate with that of any other aPL. After multivariate analysis all clinical associations failed to retain significance. CONCLUSIONS aPE are frequently seen in SLE and do not correlate with other routinely tested aPL. Although more prevalent, aPE is not an independent risk factor for thrombosis or pregnancy morbidity in patients with SLE.

Validation of a commercially available kit to detect anti-phosphatidylserine/prothrombin antibodies in a cohort of systemic lupus erythematosus patients

BACKGROUND Antiprothrombin antibodies detection comprises two different ELISAs: prothrombin coated on irradiated plates (aPT) or phosphatidylserine/prothrombin (aPS/PT) as the antigen. While several commercial kits are available for the detection of aPT, aPS/PT are usually detected by in-house assays. Recently, a new commercially available kit was launched and, therefore, we decided to test its efficiency by comparing it to our in-house assay. METHODS aPS/PT were tested by our in-house assay (aPS/PT(ih)) in 75 SLE patients, using Immulon 1 plates coated with phosphatidylserine, purified human prothrombin and 1%BSA-TBS-CaCl as blocking and diluents. Data from this assay were compared to those obtained by the QUANTA Lite aPS/PT screen, IgG and IgM Elisa (INOVA Diagnostics, Inc, San Diego, USA) commercial kits (aPS/PT(c)). RESULTS aPS/PT were found in 41.3% and 46.7% of SLE patients by the aPS/PT(ih) and the aPS/PT(c), respectively. There was a positive correlation between IgG aPS/PT(ih) and aPS/PT(c) assays (R(2)=0. 861 by Spearman test, p=0.0027). Sensitivity and specificity for APS were 62.2% and 97.4% (AUC 0.780) for the aPS/PT(ih) assay and 70.3% and 84.2% (AUC 0.858) for the aPS/PT(C). Shorter running times were also seen when comparing the aPS/PT(ih) vs. aPS/PT(c) (7hours vs. 3hours, respectively). CONCLUSION The aPS/PT(C) is a reproducible and accurate test for the detection of aPS/PT, bringing also the advantage of shorter running times.