POS0462 HYDROXYCHLOROQUINE REDUCES THE TITERS OF ANTI-DOMAIN 1 ANTIBODIES OVER TIME IN PATIENTS WITH PERSISTENTLY POSITIVE ANTIPHOSPHOLIPID ANTIBODIES: RESULTS FROM THE APS ACTION CLINICAL DATABASE AND REPOSITORY (“REGISTRY”)

Background

Data on fluctuation of antibodies directed against domain 1 (anti-D1) of β2-glycoprotein I (β2GPI) are scarce. Patients with antiphospholipid syndrome (APS) and all three criteria tests for antiphospholipid antibodies (aPL) display higher titers of anti-D1, which correlate with anti-β2GPI levels.

Objectives

This project aims at evaluating predictors of the variation of anti-D1 titers over time in a large international cohort of persistently aPL positive patients.

Methods

AntiPhospholipid Syndrome Alliance For Clinical Trials and InternatiOnal Networking (APS ACTION) Registry was created to study the course of persistently aPL-positive patients with or without autoimmune disorders over at least 10 years. Inclusion criteria are positive aPL by Updated Sapporo Criteria tested within one year prior to enrolment. Patients are followed every 12±3 months with clinical data and blood collection. Patients with available blood samples from at least three time points were included in this analysis. Anti-β2GPI and anti-D1 IgG were tested by chemiluminescence (BioFlash, Werfen) at APS ACTION core laboratories. Positive results were defined as >20 CU, according to the manufacturer. Clinical data were retrieved from APS ACTION online database. Anti-D1 titers within the same subject were compared by Friedman’s test. A mixed linear model was built to identify predictors of the fluctuation of anti-D1 antibody titers over time.

Results

In this longitudinal study, 230 patients with anti-D1 tested at 4 time points were included (Table 1). Patients with thrombotic APS had anti-D1 titers significantly higher than those without thrombosis (p=0.022). Among 135 patients with at least one anti-D1 positive result, anti-D1 titers varied significantly over time (Friedman statistics: 508.5, p<0.0001; anti-D1 geometric mean at baseline 189.0; T1 132.3 [-15%]; T2 113.8 [-17%]; T3 109.2 [-6% versus T2, -38% versus T1]). Anti-D1 titers were significantly higher at baseline compared to T3 (p=0.029). In the 4 years of follow-up, 18 new thrombotic events occurred. Patients with double/triple aPL positivity displayed 12.5 fold increase [95%CI 7.4-20.0] in baseline anti-D1 titers. After adjustment for age, gender and number of positive aPL tests, the fluctuation of anti-D1 titers was associated with treatment with hydroxychloroquine (HCQ) at each time-point. In particular, treatment with HCQ, but not those with conventional immunosuppressors, was associated with a 1.3-fold decrease in anti-D1 titers [95%CI 1.1-1.5]. In the same multivariable model, incident vascular events were associated with a 1.5 fold increase of anti-D1 titers. A concomitant diagnosis of systemic lupus erythematosus did not affect the fluctuation of anti-D1 titers.

Table 1.

Demographic and Clinical Characteristics of 230 APS ACTION Registry Patients with anti-D1 tested ≥3 time points during the follow-up

Anti-D1 pos samplesAnti-D1 neg samplesp-valueOverall sample(n=135)(n=95)(n=230)Age [years] mean (SD)42.3 (11.8)48.8 (13.0)0.000145.0 (12.7)%Female (n)71.9 (97)65.3 (62)0.35869.1 (159)Associated systemic autoimmune disease39.3 (53)44.2 (42)0.53941.3 (95)aPL without APS19.3 (26)34.7 (33)0.01025.7 (59)Thrombotic APS54.1 (73)53.7 (51)53.9 (124)Obstetric APS11.9 (16)5.3 (5)9.1 (21)Thrombotic/+obstetric APS14.8 (20)6.3 (6)11.3 (26)aCL IgG89.5 (119/133)25.5 (24/94)<0.000163.0 (143/227)aCL, IgM36.1 (48/133)27.7 (26/94)0.23432.6 (74/227)Anti-2GPI, IgG93.2 (124/133)39.4 (37/94)<0.000170.9 (161/227)Anti-2GPI, IgM34.6 (46/133)21.3 (20/94)0.04329.1 (66/227)LA82.8 (82/99)59.5 (44/74)0.00172.8 (126/173)

Conclusion

Treatment with HCQ and vascular events during follow-up were identified as significant predictors of the fluctuation of anti-D1 antibody titers over time.

Disclosure of Interests

None declared.

Treatment in thrombotic antiphospholipid syndrome: a review

Antiphospholipid syndrome an autoimmune disease characterized by thrombosis and/or pregnancy morbidity alongside the presence of antiphospholipid antibodies (aPL). This review evaluates primary and secondary thromboprophylaxis in patients with aPL and thrombotic events. In primary thromboprophylaxis a risk-stratified approach is needed based on aPL, comorbidity with other autoimmune conditions and cardiovascular vascular risk factors. In primary thromboprophylaxis, the efficacy of low-dose aspirin is debatable and requires better-designed controlled studies. So far warfarin has not been shown to improve venous and/or arterial thrombosis incidence in aPL carriers and instead increased safety concerns. The benefit of hydroxychloroquine is inconclusive despite promising data, requiring large, controlled trials. For secondary thromboprophylaxis warfarin seems to be the best option with potential in renal transplant recipients and better efficacy at high intensity, although maintenance of target international normalized ratio needs careful monitoring. Aspirin has not shown to be beneficial, and data on rivaroxaban are limited and contradictory. Despite all data being informative, there are limitations that need to be addressed with robust clinical trials.

Plasma Tumor Necrosis Factor α Levels and the –238* A Promoter Polymorphism in Patients with Antiphospholipid Syndrome

Objectives. To explore the possible involvement of the proinflammatory and prothrombotic cytokine TNFα in APS by determining the plasma levels in patients and to test for association of TNFA promoter polymorphisms and HLA class II genotypes with both plasma TNF and disease. Patients and Method. We studied 83 Caucasoid patients with APS and two groups of healthy controls. TNFα levels were determined in plasma from 35 patients’ and 21 controls using a highly sensitive sandwich ELISA. The full patient group was genotyped together with 95 ethnically matched healthy controls. -308 and -238 TNFA promoter polymorphisms were assessed by ARMS-PCR. HLA-DQB1, DQA1 and DRB1 genotypes were determined by PCR using sequence specific primers. Results. TNFα levels were significantly higher in patients with APS than healthy controls (median 2.95 pg/ml [range 0.51-10.75] vs. 0.95 pg/ml [0.51-1.6], respectively; p = 0.0001). Frequencies of TNFA-308*2 genotype did not differ between patients and controls. In contrast, TNFA-238*A positive genotype was more frequent in APS patients with arterial thrombosis and pregnancy loss than in controls (OR 3.7 [95% CI 1.37-10.1], p = 0.007 and OR 3.95 [95% CI 1.3-11.7], p = 0.01; respectively). DQB1*0303-DRB1*0701 haplotype was associated with TNFA-238*A in the control group (OR 96.0 [95% CI 9.6-959], p 0.0001) as well as in APS patient’s group (OR 54.2 [95% CI 9.6-306.5], p 0.0001). Conclusions. Raised plasma TNFα levels were found in patients with APS. As a prothrombotic and proinflammatory cytokine, TNFα may be involved in the development of clinical features of APS. The lack of correlation between the TNFA-238 polymorphism and plasma levels associated with disease suggests that the TNFα genetic marker may only indirectly relate to protein levels by virtue of allelic association with a functional marker which may reside in the HLA class II region.

Autoantibodies to domain 1 of beta 2 glycoprotein I determined using a novel chemiluminescence immunoassay demonstrate association with thrombosis in patients with antiphospholipid syndrome

INTRODUCTION

Antibodies to the domain 1 of beta 2 glycoprotein I (β2GPI-D1) have been suggested as a risk marker for thrombosis in patients with the antiphospholipid syndrome (APS). This cross-sectional study aimed to analyze the clinical utility of a novel chemiluminescence assay for the detection of anti-β2GPI-D1 antibodies.

PATIENTS AND METHODS

Sera collected from patients with primary or secondary APS (n = 106; 72 with and 34 without history of thrombosis) and controls (n = 272) were tested for anti-β2GPI-D1 IgG by chemiluminescence assay (QUANTA Flash) and by two anti-β2GPI IgG assays (QUANTA Lite and QUANTA Flash β2GPI IgG).

RESULTS

Anti-β2GPI-D1 IgG titers were significantly higher in patients with thrombosis (P = 0.0032) than those without. At the cut-off of 20 units, which yielded a 99.5% specificity, 24 of 72 (34.9%) patients with thrombosis and four of 34 (11.8%) without thrombosis were anti-β2GPI-D1 IgG positive (odds ratio, OR = 4.0). By further optimizing the cut-off specifically for correlation with thrombosis, 20.8% of the patients with thrombosis and 2.9% of the patients without thrombosis were positive (OR = 8.7). The ORs were significantly lower for antibodies to the full-length β2GPI by either the chemiluminescence assay or ELISA. Using the anti-β2GPI chemiluminescence assay, the OR was 2.3 (recommended cut-off of 20 CU) or 4.1 (optimal cut-off 164.6 CU). Using the anti-β2GPI ELISA, the OR was 2.7 (recommended cut-off of 20 units) or 3.7 (optimal cut-off 7.6 units).

CONCLUSION

These data indicate that anti-β2GPI-D1 IgG are present more frequently and in higher titers in APS patients with thrombotic complications than in those without.The novel β2GPI-D1 chemiluminescence assay appears to be superior to full-length β2GPI assays for the risk assessment of thrombotic events in APS patients.

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.

Evaluation of phosphatidylserine-dependent antiprothrombin antibody testing for the diagnosis of antiphospholipid syndrome: results of an international multicentre study

Objective A task force of scientists at the International Congress on Antiphospholipid Antibodies recognized that phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) might contribute to a better identification of antiphospholipid syndrome (APS). Accordingly, initial and replication retrospective, cross-sectional multicentre studies were conducted to ascertain the value of aPS/PT for APS diagnosis. Methods In the initial study (eight centres, seven countries), clinical/laboratory data were retrospectively collected. Serum/plasma samples were tested for IgG aPS/PT at Inova Diagnostics (Inova) using two ELISA kits. A replication study (five centres, five countries) was carried out afterwards. Results In the initial study ( n = 247), a moderate agreement between the IgG aPS/PT Inova and MBL ELISA kits was observed ( k = 0.598). IgG aPS/PT were more prevalent in APS patients (51%) than in those without (9%), OR 10.8, 95% CI (4.0-29.3), p < 0.0001. Sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratio of IgG aPS/PT for APS diagnosis were 51%, 91%, 5.9 and 0.5, respectively. In the replication study ( n = 214), a moderate/substantial agreement between the IgG aPS/PT results obtained with both ELISA kits was observed ( k = 0.630). IgG aPS/PT were more prevalent in APS patients (47%) than in those without (12%), OR 6.4, 95% CI (2.6-16), p < 0.0001. Sensitivity, specificity, LR + and LR- for APS diagnosis were 47%, 88%, 3.9 and 0.6, respectively. Conclusions IgG aPS/PT detection is an easily performed laboratory parameter that might contribute to a better and more complete identification of patients with APS.

Central nervous system lupus: a clinical approach to therapy

Management of central nervous system (CNS) involvement still remains one of the most challenging problems in systemic lupus erythematosus (SLE). The best available evidence for the treatment of CNS lupus is largely based on retrospectiveseries, case reports and expert opinion. Current therapy is empirical and tailored to the individual patient. Symptomatic, immunosuppressiveand anticoagulant therapies are the main strategies for the management of CNS lupus. The choice depends on the most probable underlying pathogenic mechanism and the severity of the presenting neuropsychiatric symptoms. Thrombotic and nonthrombotic CNS disease needs to be differentiated and requires different management strategies. However, this is often challenging since many, if not most CNS manifestations, may be due to a combination of different pathogenic mechanisms and multiple CNS events may occur in the individual patient. Patients with mild manifestations may need symptomatic treatment only, whereas more severe acute nonthrombotic CNS manifestations may require pulse intravenouscyclophosphamide.Plasmapheresismay also be added in patients with more severe illness refractory to conventionaltreatment. Recently, the use of intrathecalmethotrexateand dexamethasone has been reported in a small series of patients, with a good outcome in patients with severe CNS manifestations.Anticoagulationis warranted in patients with thrombotic disease, particularlyin those with the antiphospholipid syndrome (APS). This article reviews the clinical approach to therapy in patients with CNS lupus.

Antibodies to phosphatidylserine/prothrombin complex and the antiphospholipid syndrome

Antibodies to prothrombin can be detected by ELISA using prothrombin coated onto irradiated plates (aPT) or the phosphatidylserine/prothrombin complex as antigen (aPS/PT) and they have been both related with the clinical manifestation of APS. Current evidence supports the concept that they belong to distinct populations of autoantibodies. Nevertheless, they can both be detected simultaneously in one patient.

This mini-review will focus on data available on aPS/PT antibodies and their clinical utility in the diagnosis of APS.

Thrombotic risk assessment in APS: the Global APS Score (GAPSS)

Recently, we developed a risk score for antiphospholipid syndrome (APS) (Global APS Score or GAPSS). This score derived from the combination of independent risk factors for thrombosis and pregnancy loss, taking into account the antiphospholipid antibodies (aPL) profile (criteria and non-criteria aPL), the conventional cardiovascular risk factors, and the autoimmune antibodies profile. We demonstrate that risk profile in APS can be successfully assessed, suggesting that GAPSS can be a potential quantitative marker of APS-related clinical manifestations.

Morbidity and mortality in the antiphospholipid syndrome during a 10-year period: a multicentre prospective study of 1000 patients

Objectives

To assess the prevalence of the main causes of morbi-mortality in the antiphospholipid syndrome (APS) during a 10-year-follow-up period and to compare the frequency of early manifestations with those that appeared later.

Methods

In 1999, we started an observational study of 1000 APS patients from 13 European countries. All had medical histories documented when entered into the study and were followed prospectively during the ensuing 10 years.

Results

53.1% of the patients had primary APS, 36.2% had APS associated with systemic lupus erythematosus and 10.7% APS associated with other diseases. Thrombotic events appeared in 166 (16.6%) patients during the first 5-year period and in 115 (14.4%) during the second 5-year period. The most common events were strokes, transient ischaemic attacks, deep vein thromboses and pulmonary embolism. 127 (15.5%) women became pregnant (188 pregnancies) and 72.9% of pregnancies succeeded in having one or more live births. The most common obstetric complication was early pregnancy loss (16.5% of the pregnancies). Intrauterine growth restriction (26.3% of the total live births) and prematurity (48.2%) were the most frequent fetal morbidities. 93 (9.3%) patients died and the most frequent causes of death were severe thrombosis (36.5%) and infections (26.9%). Nine (0.9%) cases of catastrophic APS occurred and 5 (55.6%) of them died. The survival probability at 10 years was 90.7%.

Conclusions

Patients with APS still develop significant morbidity and mortality despite current treatment. It is imperative to increase the efforts in determining optimal prognostic markers and therapeutic measures to prevent these complications.

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

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-β(2) glycoprotein 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-β(2)GPI + 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-β(2)GPI + 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-β(2)GPI, respectively).

CONCLUSIONS

Combining LA, anti-β(2)GPI and aPS/PT improves the diagnostic power and helps in stratifying the risk for each patient, according to their aPL profile.

Antibodies to prothrombin

Research on antiphospholipid antibodies (aPL) and the thrombotic manifestations associated with these antibodies has grown since the description of anticardiolipin antibodies (aCL) by Harris and colleagues in the early 1980s. Antiprothrombin (aPT) antibodies are commonly detected by ELISA, using irradiated plates (aPT) or prothrombin in complex with phosphatidylserine (aPS/PT). Although aPT and/or aPS/PT are associated with antiphospholipid syndrome (APS) -related clinical features and these antibodies correlate with each other, aPT and aPS/PT belong to different populations of autoantibodies even though they can both be present in the same patient. Early studies suggested that these antibodies might be the antigenic target of lupus anticoagulant (LA) and their correlation and clinical significance is being investigated.

'Non-criteria' aPL tests: report of a task force and preconference workshop at the 13th International Congress on Antiphospholipid Antibodies, Galveston, TX, USA, April 2010

Abstract: Current classification criteria for definite APS recommend the use of one or more of three positive standardized laboratory assays, including anticardiolipin antibodies (aCL), lupus anticoagulant (LA), and antibodies directed to β(2)glycoprotein I (anti-β(2)GPI) to detect antiphospholipid antibodies (aPL) in the presence of at least one of the two major clinical manifestations (i.e., thrombosis or pregnancy morbidity) of the syndrome. Several other autoantibodies shown to be directed to phospholipids and/or their complexes with phospholipids and/or to proteins of the coagulation cascade, as well as a mechanistic test for resistance to annexin A5 anticoagulant activity, have been proposed to be relevant to APS. A task force of worldwide scientists in the field discussed and analyzed critical questions related to 'non-criteria' aPL tests in an evidence-based manner during the 13th International Congress on Antiphospholipid Antibodies (APLA 2010, 13-16 April 2010, Galveston, Texas, USA). This report summarizes the findings, conclusions, and recommendations of this task force.

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.

Morbidity and mortality in the antiphospholipid syndrome during a 5-year period: a multicentre prospective study of 1000 patients

Objectives:

To identify the main causes of morbidity and mortality in patients with antiphospholipid syndrome (APS) during a 5-year period and to determine clinical and immunological parameters with prognostic significance.

Methods:

The clinical and immunological features of a cohort of 1000 patients with APS from 13 European countries who had been followed up from 1999 to 2004 were analysed.

Results:

200 (20%) patients developed APS-related manifestations during the 5-year study period. Recurrent thrombotic events appeared in 166 (16.6%) patients and the most common were strokes (2.4% of the total cohort), transient ischaemic attacks (2.3%), deep vein thromboses (2.1%) and pulmonary embolism (2.1%). When the thrombotic events occurred, 90 patients were receiving oral anticoagulants and 49 were using aspirin. 31/420 (7.4%) patients receiving oral anticoagulants presented with haemorrhage. 3/121 (2.5%) women with only obstetric APS manifestations at the start of the study developed a new thrombotic event. A total of 77 women (9.4% of the female patients) had one or more pregnancies and 63 (81.8% of pregnant patients) had one or more live births. The most common fetal complications were early pregnancy loss (17.1% of pregnancies) and premature birth (35% of live births). 53 (5.3% of the total cohort) patients died. The most common causes of death were bacterial infection (21% of deaths), myocardial infarction (19%) and stroke (13%). No clinical or immunological predictor of thrombotic events, pregnancy morbidity or mortality was detected.

Conclusion:

Patients with APS still develop significant morbidity and mortality despite current treatment (oral anticoagulants or antiaggregants, or both).

Antiphospholipid antibody tests: spreading the net

OBJECTIVE

To examine the hypothesis that testing for new antiphospholipid antibody specificities may help to identify the antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE) with thrombosis who are repeatedly negative for anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA).

METHODS

Three groups of patients with SLE were studied: (a) SLE/APS (n = 56): 51 female, mean (SD) age 46 (11) years, fulfilling 1999 Sapporo criteria for the APS; (b) SLE/thrombosis (n = 56): 53 female, age 42.6 (12) years, all with a history of thrombosis and persistently negative for aCL and/or LA; (c) SLE only (n = 56): 53 female, age 40 (11) years, without a history of thrombotic events. aCL and LA were retested in all samples. All patients were tested for anti-beta(2)-glycoprotein I (anti-beta(2)GPI) and antiprothrombin antibodies (aPT) by coating prothrombin on irradiated plates or using phosphatidylserine-prothrombin complex as the antigen (aPS-PT).

RESULTS

Anti-beta(2)GPI were only present in patients from the SLE/APS group, all of whom were also positive for aCL. aPT and aPS-PT were also more commonly found in SLE/APS than in SLE/thrombosis or SLE only groups (54% v 5%, p<0.0001 or v 16%, p<0.0001 for aPT and 63% v 2%, p<0.0001 or v 11%, p<0.0001 for aPS-PT, respectively). No differences were found between SLE/thrombosis and SLE only groups (p = 1.5 for beta(2)GPI, p = 0.1 for aPT, and p = 0.1 for aPS-PT).

CONCLUSION

Testing for aPT in patients with SLE with thrombosis, but persistently negative for aCL and LA, may be helpful in some selected cases. Anti-beta(2)GPI are not present in patients who are negative for aCL.

Antiferritin antibodies discovered by phage display expression cloning are associated with radiographic damage in rheumatoid arthritis

OBJECTIVE

Several autoantibodies have been described in individuals with rheumatoid arthritis (RA), leading to interest in the use of such antibodies as diagnostic or prognostic markers in RA as well as in their relevance to disease pathology. The objective of this study was to use a phage display expression cloning system to identify novel autoantibody targets in RA.

METHODS

We used immunoscreening of a phage-displayed complementary DNA (cDNA) library to isolate a cDNA clone encoding the ferritin heavy chain polypeptide. Antiferritin antibody levels in patients with early and established RA, healthy controls, and disease controls were measured by enzyme-linked immunosorbent assay. Antibody-positive and antibody-negative individuals were compared with respect to disease severity as measured by the modified Larsen score, demographic variables, rheumatoid factor status, and carriage of HLA-DRB1 shared epitope alleles.

RESULTS

Antiferritin antibodies were present in 60 (16%) of 366 patients with established RA, 23 (19%) of 118 patients with early RA, 2 (2.7%) of 73 healthy blood donors, 2 (2.1%) of 94 individuals with osteoarthritis, and 2 (2.1%) of 97 patients with systemic lupus erythematosus (P < 0.01, RA patients versus healthy and disease controls). Antiferritin antibodies were more common in men than in women (28.4% versus 12.2%; P < 0.001), and antiferritin levels were associated with the severity of joint damage (P = 0.01).

CONCLUSION

Antiferritin antibodies are observed in a subset of patients with RA, are present early in the disease course, and are associated with the severity of radiographic damage. Further studies are required to explore their potential as diagnostic and prognostic markers in RA.

Association of HLA-DM polymorphism with the production of antiphospholipid antibodies

OBJECTIVE

To investigate whether variation in the HLA-DM gene is important in producing a group of pathogenic autoantibodies-antiphospholipid antibodies (aPL)-on the basis that HLA class II restricted antigen presentation is involved in the production of aPL.

METHODS

HLA-DMA and DMB polymorphisms were genotyped by polymerase chain reaction combined with restriction enzyme digestion in 51 white patients with primary antiphospholipid syndrome (APS), 82 with systemic lupus erythematosus (SLE) (42 with APS and 40 without APS), and 109 healthy white controls. The association with the aPL profile was examined.

RESULTS

The distribution of DMA alleles in APS patients and in patients with APS associated with SLE was significantly different from that in controls by 4x2 chi(2) test with 3 degrees of freedom (p = 0.035 and 0.011, respectively), but it was not different between SLE patients without APS and controls. The allelic distribution of DMA was also different between patients with IgG class anticardiolipin antibody or those with lupus anticoagulant (LA) and controls (p = 0.012 and 0.007, respectively) and between patients with and without LA among SLE patients (p = 0.035). All these differences included the increase in DMA*0102 in the former groups.

CONCLUSIONS

The results suggest that HLA-DMA*0102 or its linked gene(s) form one of the genetic risks for the production of aPL.

Anti-C1q antibodies in nephritis: correlation between titres and renal disease activity and positive predictive value in systemic lupus erythematosus

OBJECTIVE

To investigate antibodies to complement 1q (anti-C1q) and investigate the correlation between anti-C1q titres and renal disease in systemic lupus erythematosus (SLE).

METHODS

151 SLE patients were studied. In patients with biopsy proven lupus nephritis (n = 77), activity of renal disease was categorised according to the BILAG renal score. Sera were tested for anti-C1q by enzyme immunoassay. Serum samples were randomly selected from 83 SLE patients who had no history of renal disease, and the positive and negative predictive value of the antibodies was studied.

RESULTS

Patients with active lupus nephritis (BILAG A or B) had a higher prevalence of anti-C1q than those with no renal disease (74% v 32%; relative risk (RR) = 2.3 (95% confidence interval, 1.6 to 3.3)) (p<0.0001). There was no significant difference in anti-C1q prevalence between SLE without nephritis and SLE with non-active nephritis (BILAG C or D) (32% v 53%, p = 0.06) or between active and non-active nephritis (74% v 53%, p = 0.06). Patients with nephritis had higher anti-C1q levels than those without nephritis (36.0 U/ml (range 4.9 to 401.0) v 7.3 U/ml (4.9 to 401.0)) (p<0.001). Anti-C1q were found in 33 of 83 patients (39%) without history of renal disease. Nine of the 33 patients with anti-C1q developed lupus nephritis. The median renal disease-free interval was nine months. One patient with positive anti-C1q was diagnosed as having hypocomplementaemic urticarial vasculitis syndrome during follow up.

CONCLUSIONS

Anti-C1q in SLE are associated with renal involvement. Monitoring anti-C1q and their titres in SLE patients could be important for predicting renal flares.

Prevalence and clinical correlations of antibodies against six beta2-glycoprotein-I-related peptides in the antiphospholipid syndrome

Two-hundred ninety five patients with the antiphospholipid syndrome (APS) were studied for the presence of antibodies against six anti-beta2GPI-related peptides Abs. The prevalence of a wide spectrum of clinical and laboratory parameters of APS was evaluated in all patients, and correlated with the presence of each anti-beta2GPI peptide antibody. The rates of the various antipeptides Abs ranged from 18.0 to 63.7%. Altogether, 87.1% of the patients had antibody reactivity against at least one of the six beta2GPI-related peptides. A high degree of simultaneous reactivity against several beta2GPI-peptides was found. Positive and negative correlations were found between several antipeptides Abs and the rates of thrombosis and fetal loss. Our results point to a heterogeneous activity of antiphospholipid Abs in APS patients, directed, often concurrently, against various epitopes of the beta2GPI molecule. Evaluation of APS patients for the presence of specific antipeptides Abs may be of a value in predicting the risk for future thrombotic and obstetrical complication, as well as for specific therapeutic purposes.

Value of IgA anticardiolipin and anti-beta2-glycoprotein I antibody testing in patients with pregnancy morbidity

OBJECTIVE

To study the prevalence of IgA antiphospholipid antibodies, particularly anticardiolipin antibodies (aCL) and anti-beta(2)-glycoprotein I (abeta(2)GPI), in a cohort of patients with pregnancy morbidity.

PATIENTS AND METHODS

Serum samples from four groups of patients were studied by an in house enzyme linked immunosorbent assay (ELISA). Group I: 28 patients with primary antiphospholipid syndrome (PAPS) (median age 32.5 years, range 25-34). Twelve patients had a history of thrombosis. All were positive for IgG/M aCL or lupus anticoagulant (LA), or both. Group II: 28 patients with unexplained pregnancy morbidity (median age 35 years, range 23-48). Seven had history of thrombosis. Nine patients were positive for IgG/M aCL. None from this group fulfilled Sapporo criteria for APS. Group III: 28 patients with systemic lupus erythematosus (SLE) (median age 34 years, range 25-52). Eleven had a history of thrombosis. Twenty one patients had IgG/M aCL and/or LA, but only 19 fulfilled Sapporo criteria for APS.

RESULTS

IgA aCL were found in 12, 6, and 14 patients from the groups with PAPS, unexplained pregnancy morbidity, and SLE, respectively. Most patients had these antibodies together with IgG/IgM aCL. Three patients from the group with unexplained pregnancy morbidity and two with SLE had IgA aCL alone. IgA abeta(2)GPI was present in one patient from each group. All IgA abeta(2)GPI were present together with IgG and/or IgM abeta(2)GPI.

CONCLUSIONS

The prevalence of IgA aCL is high in patients with pregnancy morbidity, although IgA aCL are usually present together with IgG and/or IgM aCL. IgA abeta(2)GPI are not useful in identifying additional women with APS and pregnancy morbidity.

Central nervous system involvement in the antiphospholipid (Hughes) syndrome

The antiphospholipid (Hughes) syndrome (APS) is characterized by arterial and/or venous thrombosis and pregnancy morbidity in the presence of anticardiolipin antibodies and/or lupus anticoagulant. APS can occur either as a primary disorder or secondary to a connective tissue disease, most frequently systemic lupus erythematosus. Central nervous system (CNS) involvement is one of the most prominent clinical manifestations of APS, and includes arterial and venous thrombotic events, psychiatric features and a variety of other non-thrombotic neurological syndromes. In this review we focus on the common and some of the less common CNS manifestations that have been reported in association with antiphospholipid antibodies.

The value of IgA antiphospholipid testing for diagnosis of antiphospholipid (Hughes) syndrome in systemic lupus erythematosus

OBJECTIVE

It is recognized that the presence of IgG and IgM anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC) is associated with thrombosis in patients with antiphospholipid syndrome (APS). Some reports have shown that testing for IgA anticardiolipin and anti-beta2-glycoprotein antibodies (anti-beta2-GPI) provides extra diagnostic help in patients with APS, while other authors could not support this data. We designed this cross sectional study to determine the prevalence of IgA aCL, anti-beta2-GPI, and antiprothrombin antibodies and to study their clinical significance in a large cohort of patients with systemic lupus erythematosus (SLE).

METHODS

This study comprised 134 SLE patients (126 women; median age 37.5 yrs, range 16-72). The median duration of the disease was 9 years, range 0.1-38. Of these, 55 (41%) had a history of thrombotic events: 22 (40%) presented an arterial event, 22 (40%) a venous event, and 11 (20%) both arterial and venous events. Of 49 women who had been pregnant, 18 (37%) gave a history of recurrent pregnancy loss. Thrombocytopenia was present in 14/127 patients (11%). Forty patients (30%) were diagnosed as APS secondary to SLE, 23 (17%) had IgG/M aCL and/or LAC without clinical features of APS, and 71 (53%) were SLE patients who were repeatedly negative for IgG/M aCL or LAC. IgG, IgM, IgA aCL and anti-beta2-GPI were detected by ELISA. Antibodies directed to prothrombin were detected by 2 ELISA using prothrombin coated on irradiated plates (aPT) and phosphatidylserine/prothrombin complex (aPS/PT) as antigen.

RESULTS

IgA aCL were found in 18/134 (13%) patients. Of these, 3 (17%) had IgA aCL as well as IgG/M aCL, and 2 (11%) had IgG/M aCL and anti-beta2-GPI. Of the 18 patients positive for IgA aCL, 8 were also positive for LAC. Of these, one (5%) patient had IgA aCL as well as other isotype of aCL, and 7 (39%) patients had both aCL and anti-beta2-GPI. None of these patients had binding of IgA aPT or aPS/PT. Of the entire group of 18 patients, 5 (28%) had IgA aCL as the sole aPL. Four of 5 of these patients were diagnosed as SLE but had no antiphospholipid (aPL) related clinical manifestations. We found no association between the presence of IgA aCL and clinical manifestations of APS. IgA anti-beta2-GPI were found in 8/134 (6%) patients. Of these, one (12.5%) had IgA anti-beta2-GPI as well as IgG/M anti-beta2-GPI and aCL. Of the 8 patients positive for IgA anti-beta2-GPI, 6 (75%) were also positive for LAC. Of these, one (12.5%) patient presented with IgA anti-beta2-GPI along with other isotypes of aCL, and 4 (50%) patients with aCL and other isotype of anti-beta2-GPI. One patient (12.5%) had IgA anti-beta2-GPI along with LAC only, and one patient (12.5%) who was diagnosed as SLE had no aPL related clinical manifestation but had IgA anti-beta2-GPI as the sole aPL.

CONCLUSION

IgA aCL and anti-beta2-GPI are found in SLE, usually along with IgG and/or IgM isotypes. Testing for IgA aCL and anti-beta2-GPI is not a helpful screening test and does not contribute to the recognition of APS in SLE. IgA aPT and aPS/PT are not present in patients with SLE, therefore there is no need to test for these antibodies.

Genetics of antiphospholipid syndrome

The mechanisms of thrombosis in antiphospholipid syndrome (APS) are highly heterogeneous and multifactorial, and some genetic factors may be involved in its pathophysiology. The genetic variants of representative antigen, beta 2-glycoprotein I (beta 2GPI), have been known, and valine/leucine247 polymorphism is a genetic risk for having anti beta 2GPI antibodies and APS. Congenital beta 2GPI deficiency did not correlate with thrombophilia, thus its responsible gene (beta 2GPI-Sapporo) was not a risk for thrombosis. Many other thrombosis-related genetic factors have been investigated in APS, but no additional risk for thrombosis has been indicated in patients with antiphospholipid antibodies.

Plasma tumor necrosis factor alpha levels and the -238*A promoter polymorphism in patients with antiphospholipid syndrome

OBJECTIVES

To explore the possible involvement of the proinflammatory and prothrombotic cytokine TNFalpha in APS by determining the plasma levels in patients and to test for association of TNFA promoter polymorphisms and HLA class II genotypes with both plasma TNFalpha and disease.

PATIENTS AND METHOD

We studied 83 Caucasoid patients with APS and two groups of healthy controls. TNFalpha levels were determined in plasma from 35 patients' and 21 controls using a highly sensitive sandwich ELISA. The full patient group was genotyped together with 95 ethnically matched healthy controls. -308 and -238 TNFA promoter polymorphisms were assessed by ARMS-PCR. HLA-DQB1, DQA1 and DRB1 genotypes were determined by PCR using sequence specific primers.

RESULTS

TNFalpha levels were significantly higher in patients with APS than healthy controls (median 2.95 pg/ml [range 0.51-10.75] vs. 0.95 pg/ml [0.51-1.6], respectively; p = 0.0001). Frequencies of TNFA-308*2 genotype did not differ between patients and controls. In contrast, TNFA-238*A positive genotype was more frequent in APS patients with arterial thrombosis and pregnancy loss than in controls (OR 3.7 [95% CI 1.37-10.1], p = 0.007 and OR 3.95 [95% CI 1.3-11.7], p = 0.01; respectively). DQB1*0303-DRB1*0701 haplotype was associated with TNFA-238*A in the control group (OR 96.0 [95% CI 9.6-959], p <0.0001) as well as in APS patient's group (OR 54.2 [95% CI 9.6-306.5], p <0.0001).

CONCLUSIONS

Raised plasma TNFalpha levels were found in patients with APS. As a prothrombotic and proinflammatory cytokine, TNFalpha may be involved in the development of clinical features of APS. The lack of correlation between the TNFA-238 polymorphism and plasma levels associated with disease suggests that the TNF genetic marker may only indirectly relate to protein levels by virtue of allelic association with a functional marker which may reside in the HLA class II region.

Association of autoantibodies against the phosphatidylserine-prothrombin complex with manifestations of the antiphospholipid syndrome and with the presence of lupus anticoagulant

OBJECTIVE

To clarify the association of autoantibodies against prothrombin with the clinical manifestations of the antiphospholipid syndrome (APS) and with the presence of lupus anticoagulant (LAC).

METHODS

We examined 265 patients who visited our autoimmune disease clinic. IgG and IgM antiprothrombin antibodies were tested by enzyme-linked immunosorbent assay (ELISA) as either antiphosphatidylserine-prothrombin complex (aPS/PT) antibodies or as antibodies against prothrombin coated on irradiated ELISA plates (as antigen) (aPT). IgG, IgM, and IgA anticardiolipin (aCL) antibodies and their beta2-glycoprotein I (beta2GPI) dependency were also evaluated by ELISA. LAC was tested by 3 different methods.

RESULTS

The presence of aPS/PT, but not of aPT, significantly correlated with the clinical manifestations of APS (odds ratio [OR] 4.39, 95% confidence interval [95% CI] 2.06-9.38), and aPS/PT antibodies were as specific as beta2GPI-dependent aCL for APS (93.1% for both). IgG aPS/PT strongly correlated with the presence of LAC as detected using the dilute Russell viper venom time test (OR 38.2, 95% CI 13.4-109.1).

CONCLUSION

Antiprothrombin antibodies are heterogeneous and their clinical relevance depends on the method of detection applied. Positive results on the aPS/PT test can serve as a marker of thrombotic events in patients with autoimmune diseases.

Natural immune response involving anti-endothelial cell antibodies in normal and lupus pregnancy

OBJECTIVE

To determine whether immunoglobulins with affinity for the vascular endothelium displayed any distinguishing behavior during normal and systemic lupus erythematosus (SLE) pregnancy. We also attempted to verify whether isotype expression of anti-endothelial cell antibodies (AECA) would have any predictive value for pregnancy outcome.

METHODS

Sera from 38 pregnant patients with SLE, 68 normal pregnant women, and 84 nonpregnant healthy controls were studied. IgM- and IgG-AECA were determined by cellular enzyme-linked immunosorbent assay using fixed cultured human umbilical vein endothelial cells.

RESULTS

A significantly higher level of IgM-AECA was found during normal pregnancy compared with that in healthy nonpregnant controls (mean +/- SD 39 +/- 12% versus 21 +/- 12%; P < 0.0001). Most pregnant patients with SLE did not have increased titers of IgM-AECA, but instead had levels similar to those found in healthy nonpregnant controls (23 +/- 12%; P not significant). The lowest levels of IgM-AECA in lupus pregnancy were associated with preeclampsia (odds ratio 16, P < 0.005). Conversely, IgG-AECA levels were significantly higher in the serum of normal pregnant women and pregnant SLE patients than in the serum of healthy nonpregnant controls (24 +/- 7% and 24 +/- 14% versus 9 +/- 7%; P < 0.0001).

CONCLUSION

Our results indicate that an active immune response occurs during pregnancy. This response involves increased activity of AECA, suggesting a role of autoantibodies as a possible contributing factor toward fetal tolerance. Our observations further indicate that impaired immune regulation, such as diminished levels of serum IgM-AECA detected in SLE patients, might contribute to the impaired reproductive function commonly found in SLE.

Antiphospholipid antibodies in leprotic patients: a correlation with disease manifestations

OBJECTIVES

Previous studies showed that antiphospholipid antibodies (aPL) are frequent in the sera of leprosy patients and are most probably directed against body tissue cardiolipins. Some groups have demonstrated differences between the binding specificity of "autoimmune-aPL" and "non-autoimmune-aPL". It is widely accepted that a plasma protein, beta 2-Glycoprotein I (beta 2-GPI), is required for the binding of autoimmune anticardiolipin antibodies (aCL) to cardiolipin. However, some reports suggested heterogeneity of leprosy aCL with respect to their beta 2-Glycoprotein I (beta 2GPI) dependency, although no thromboembolic complications have been reported. This study was designed to assess the specificity of aPL by investigating the prevalence of aCL, anti-phosphatidylserine (aPS), anti-phosphatidylinositol (aPI), anti-beta 2GPI and antiprothrombin (aPT) antibodies, and evaluate their clinical significance in a group of patients with lepromatous leprosy.

PATIENTS AND METHODS

35 lepromatous leprosy patients were selected randomly from an Egyptian leprosarium as a study group. 35 normal household contact controls were selected matching the study group for both sex and age. aCL, aPS, aPI, aPT, anti-beta 2GPI and beta 2-dependent aCL antibodies were investigated by ELISA in all patients and controls.

RESULTS

aCL antibodies were more frequent in leprosy patients than in controls [13/35 (37%) vs. 3/35 (9%), respectively, p = 0.02] and significantly correlated with Raynaud's phenomenon, skin nodules, chronic skin ulcers and urticarial skin rash. No association was found with hypopigmentation, hyperpigmentation and saddle nose. None of the patients presented aPS nor aPI. Only 1 subject from the control group presented aPI along with aCL. aPT were present in 2/35 (5.7%) and anti-beta 2GPI in 1/35 (2.9%) leprotic patients. None of the individuals from the control group presented aPT nor anti-beta 2GPI.

CONCLUSIONS

An association was found between the presence of aCL and certain dermatological manifestations of leprosy, such as Raynaud's phenomenon, skin nodules, chronic skin ulcers and urticarial skin rash. As in other infectious diseases, there was a lack of beta 2GPI-dependency and an absence of thrombotic complications.

Association of antiphosphatidylserine/prothrombin autoantibodies with HLA class II genes

OBJECTIVE

To investigate the associations between HLA class II genes and antiphosphatidylserine/prothrombin antibodies (aPS/PT) in a group of British caucasoid patients with antiphospholipid antibodies (aPL).

METHODS

This study included 82 patients with aPL. IgG aPS/PT were detected in sera using enzyme-linked immunosorbent assays. HLA-DQB1, DQA1, and DRB1 genotypes were determined by polymerase chain reaction using sequence-specific primers. All results were compared with 177 matched healthy control subjects.

RESULTS

IgG aPS/PT were present in 41 of 82 patients (50%). The frequencies of DQB1*0301/4, DQB1*0604/5/6/7/9, and DRB1*1302 alleles were increased in patients with aPS/PT compared with controls. To minimize the interference of the association between anti-beta2-glycoprotein I (anti-beta2GPI) and HLA, patients with anti-beta2GPI were excluded from further analyses, and only HLA-DQB1*0301/4 remained significant compared with controls (odds ratio [OR] 2.75, 95% confidence interval [95% CI] 1.2-6.5, P < 0.03). In the haplotype analysis, HLA-DQB1*0301/4;DQA1* 0301/2;DRB1*04 was significantly increased in patients with IgG aPS/PT compared with controls (OR 4.75, 95% CI 1.72-13.10, P = 0.0063).

CONCLUSION

The HLA-DQB1*0301/4;DQA1*0301/ 2;DRB1*04 haplotype and its components may influence the production of aPS/PT in the antiphospholipid syndrome, which partly explains the correlation between the lupus anticoagulant and DQB1*03.

Extensive cutaneous necrosis associated with anticardiolipin antibodies

Extensive cutaneous necrosis (ECN) associated with antiphospholipid antibodies is a rare presentation. We describe 2 patients with ECN and high titers of anticardiolipin antibodies. The mechanism by which these antibodies act has not been established and there is still controversy regarding treatment of these patients without established guidelines. In the few documented cases the use of pulse steroid therapy, anticoagulants, fibrinolytic agents, plasmapheresis, or a combination of them has shown some benefit. Early recognition and treatment of the antiphospholipid syndrome may limit the extent of thrombotic complications that can result in tissue necrosis.

Multiple antiphospholipid tests do not increase the diagnostic yield in antiphospholipid syndrome

The family of antiphospholipid antibodies (aPL) includes a heterogeneous population of autoantibodies whose specificity is directed against not only phospholipids, but their complex with plasma proteins. Anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) tests are widely performed to screen the aPL family which is associated with thrombotic complications in patients with systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS). The clinical significance of other aPL tests, including antibodies against phosphatidylserine (aPS), phosphatidylinositol (aPI), phosphatidic acid (aPA), phosphatidylcholine (aPC) and phosphatidylethanolamine (aPE), has not been established. The purpose of this study was to evaluate whether multiple aPL tests have enhanced diagnostic value for APS. We tested IgG/M/A aPS, aPI, aPA, aPC and aPE by ELISA using 10% bovine serum as blocking and sample diluent in 26 SLE patients with clinical manifestations of APS, but negative for both aCL and LA (Group 1). The results were compared with 32 SLE patients without any features of APS (Group 2) and 24 SLE patients with APS (aCL and/or LA positive) (Group 3). In Group 1, 1/26 (4%) was positive for IgA aPE, less frequent than in other groups, and none of the patients had any other aPL. In Group 2, 1/32 (3%) was positive for aPS, two (6%) for aPI, one (3%) for aPA and four (12.5%) for aPE. None was positive for aPC. In the third group, 13/24 (54%) were positive for aPS, 11 (46%) for aPI, 15 (63%) for aPA, four (17%) for aPC and seven (29%) for aPE. Since aPE was found in some patients, we extended the study, including 207 SLE patients, and tested aPE. IgG/M/A aPE was found in six (3%), 10(5%) and 21 (10%), respectively, but no association was found between aPE and any clinical features of APS. This study suggests that screening by multiple aPL tests does not increase the diagnostic yield in APS.

Antibodies to beta2-glycoprotein I: a potential marker for clinical features of antiphospholipid antibody syndrome in patients with systemic lupus erythematosus

OBJECTIVE

To clarify risk factors for the development of clinical features of antiphospholipid syndrome (APS) in patients with anticardiolipin antibodies (aCL) in systemic lupus erythematosus (SLE).

METHODS

We studied 65 SLE patients, all with positive IgG and/or IgM aCL. Patients were divided into 2 groups; I: 29 SLE patients with features of APS (SLE/APS) and II: 36 aCL positive SLE patients without any feature of APS (SLE/aCL). Serum samples were collected from our serum bank. Anti-beta2-glycoprotein I (anti-beta2-GPI) were tested by ELISA using irradiated plates in the absence of cardiolipin. Anti-dsDNA antibodies were tested by standard Farr assay.

RESULTS

There were no major differences between SLE clinical manifestations in both groups. However, the frequency of IgG anti-beta2-GPI was markedly increased in SLE/APS (18/29, 62%) than in SLE/aCL (4/36, 11%) (chi-squared 18.6, p=0.0001). The levels of anti-dsDNA antibodies in the same samples were slightly lower in SLE/APS.

CONCLUSION

Our data suggest that increased levels of IgG anti-beta2-GPI may be a specific feature of SLE/APS patients rather than reflecting a polyclonal B cell activation.

Autoantibodies to human prothrombin and clinical manifestations in 207 patients with systemic lupus erythematosus

OBJECTIVE

Prothrombin (factor II) is one of the phospholipid binding proteins with a procoagulant property. Some publications have shown the presence of autoantibodies against prothrombin (aPT) in patients with antiphospholipid antibodies (aPL). We assessed the clinical significance of aPT in thrombotic events in patients with systemic lupus erythematosus (SLE).

METHODS

IgG and IgM aPT were tested by ELISA in 207 patients with SLE.

RESULTS

Fifty-eight patients (28%) had positive aPT (> mean + 3 SD of 100 controls). Twenty-eight (14%) had IgG alone, 21 (10%) IgM alone, and 9 (4%) had both IgG and IgM. Patients with aPT had a history of thrombosis more frequently than those without aPT [31/58 (53%) vs 47/149 (32%), chi-squared=7.6, p=0.006]. No correlation was found between the presence of aPT and clinical features of SLE.

CONCLUSION

aPT are frequently found in patients with SLE, and are a potential marker for thrombosis.