Anti-beta2 Glycoprotein Research Articles

Persistency of low levels of anticardiolipin and anti-Beta2 Glycoprotein1 in thrombosis

Background Antiphospholipid antibodies, the hallmark of the antiphospholipid syndrome, are associated with both venous and arterial thrombosis. Despite some reports stating that this association may be present in patients with low titres of anticardiolipin antibodies, a clear association has only been established in the presence of a moderate to high concentrations (above 40 GPL or MPL). Methods In order to study whether low antibody titres could be associated with thrombosis, we reviewed the files of 196 patients, 94 with and 102 without thrombotic events, for a period of 4.4 and 5.1 years respectively. Files from patients with persistent low titres of antiphospholipid antibodies recorded in the unit database were selected, independently of the associated clinical history or diagnosis. Epidemiology, clinical and treatment information were collected and the serum variability of the antibody titres was analysed in relation to the presence of thrombotic events. Results Thrombotic events were classified as venous 81.9% and arterial 18.1%. 23/94 (24.5%) patients with thrombosis had miscarriages. There were no significant differences between serum concentrations of antiphospholipid antibodies in the thrombotic and non-thrombotic groups. However, there was a higher consistency of the antibody concentrations in patients with thrombosis, as seen by the significantly lower variability of IgG aCL and aß2GP1 titres in patients with thrombosis when compared to non-thrombotic controls ( p = 0.0025 and p < 0.0001, respectively). Conclusion Consistency of low titres of antiphospholipid antibody levels may be associated with a higher risk of thrombotic events overall.

Prevalence of antiphospholipid antibodies among women experiencing unexplained infertility and recurrent implantation failure

The prevalences of antiphospholipid antibodies (APAs) among 1,325 women with a history of unexplained infertility and 676 women experiencing recurrent implantation failure were compared with 789 women experiencing recurrent pregnancy loss and 205 fertile control women. Eight percent and 9% of women with a history of unexplained infertility and recurrent implantation failure had more than one positive APA compared with 1.5% of fertile negative control women and 11% of positive control women experiencing recurrent pregnancy loss.

Clinical Significance of Lupus Anticoagulant and Anti-Beta2 Glycoprotein I Antibodies in a Pediatric Cohort.

Abstract 3989Poster Board III-925 IntroductionAntiphospholipid antibodies (APAs) (lupus anticoagulant (LA), anti-beta2 glycoprotein I (anti-B2GPI) and anti-cardiolipin) are seen in a variety of conditions, yet their clinical implication varies. In adults, some APAs cause thrombosis and/or recurrent pregnancy loss. LAs with specificity for anti-B2GPI appear to be more closely associated with thrombosis. In children, APAs are often transient after viral or bacterial illnesses and little is known about their pathologic potential. In this study, we sought to determine the clinical associations of positive LAs with and without anti-B2GPI activity. Patients and Methods: We tested remnant plasma from 115 pediatric patients with positive LA result (according to the International Society on Thrombosis and Haemostasis guidelines) for anti-B2GPI IgG, IgM, and IgA using an indirect EIA supplied by REAADS (Corgenix Inc, Broomfield, CO) and reviewed the patient's medical records to correlate with the results. ResultsThere were 61 females (53%) and 54 males (47%) with the average age of 10.6 years (range: 0.5 to 19.5 years). An underlying medical condition such as malignancy, autoimmune disorder, infection/sepsis, or concurrent thrombosis was observed in 97 patients (84%). Eighteen patients (16%) were healthy children and LA was detected incidentally during workup for a prolonged PTT. The mean age of the group with positive medical history (11.5 years; range: 0.5 to 13 years) was statistically different than that of the healthy children group which was 5.8 years (range: 0.5 to 3.75 years) (P<0.001). Of the 115 patients, 37 (32%) had thrombosis at the time of LA testing; only 6 patients had known inherited hypercoagulability. Thirty-four of the 37 thrombotic episodes (92%) were venous and 3 were arterial (8%). An autoimmune disorder was present in 46 patients (40%) and 10 developed a thrombosis. Forty-one patients (36%) had active infection/sepsis, and 15 had thrombosis. Of 12 patients with malignancies (10%), 4 had thrombosis. The average age of those with thrombosis, 13.3 years (range: 0.5 to 15 years) was higher than that of children without thrombosis, 10.3 years (range: 0.6 to 10.5 years) (P=0.018). Only 12 of 115 patients (10%) were positive for anti-B2GPI and 3 of them had venous thrombosis. Of the anti-B2GPI positive patients, 8 had underlying autoimmune conditions, 2 had no medical history but had current thrombosis, one had a malignancy with thrombosis, and another had an acute infection. Conclusions: In children, APAs occur in a variety of conditions, but may also be found incidentally. Perhaps surprising, LA was associated with thrombosis in 32% of patients. However, only 10% tested positive for anti-B2GPI, with an even smaller percentage having thrombosis (3%). These results suggest that anti-B2GPI is not necessary for the development of thrombosis in children with LA. Disclosures:No relevant conflicts of interest to declare.

The Association Between Anti-beta2 Glycoprotein 1 Antibodies and Adverse Pregnancy Outcomes.

Abstract 4003Poster Board III-939 BACKGROUNDThe Sapporo criteria include anti-β2 glycoprotein1 (anti-B2GP1) antibodies among antiphospholipid antibodies used to diagnose the antiphospholipid syndrome (APS). Although pre-eclampsia, intra-uterine growth restriction (IUGR), late fetal loss and placental abruption, collectively termed “placenta mediated complications”, are recognized as clinical criteria for the APS, strong evidence to support their association with anti-B2GP1 antibodies is lacking. OBJECTIVEThis study aims to assess the association between anti-B2GP1 antibodies and placenta mediated complications. METHODSWe performed a nested case-control study from a prospective cohort of 7000 mother baby pairs whereby women and their fetuses were recruited between 12-20 weeks gestation. Five hundred cases were randomly selected amongst women who experienced one of the following adjudicated adverse pregnancy outcomes: pre-eclampsia (BP ≥140/90 with proteinuria), placental abruption (antepartum bleeding with objective evidence of placental thrombus), late pregnancy loss (≥ 12 weeks gestation) and IUGR (birth weight less than the 10th percentile of normal population). Random selection of 500 controls was performed amongst women who did not experience the above mentioned adverse pregnancy outcomes. Stored blood samples were analyzed for the presence of anti-B2GP1 IgG and IgM antibodies by enzyme-linked immunosorbent assay. Titers ≥ than 20 G or M units were considered positive. This study has an 80% power to detect an odds ratio of 2.25 at the 5% level of significance based on an estimated 4 % prevalence of anti-B2GP1 IgG and/or IgM antibodies in titers ≥ 20 G/M units in our cohort of pregnant women. RESULTSAnti-B2GP1 IgG and/or IgM antibodies in titers ≥ 20 G/M units were present in 24/497 (4.8%) controls and 33/503 (6.6%) cases. The presence of anti-B2GP1 IgG and/or IgM in titers ' 20 G/M units was not significantly associated with a composite outcome of pre-eclampsia, IUGR, late fetal loss and placental abruption (OR 1.38; 95%CI 0.8-2.37 p=0.18). This combination of antibodies and titers only demonstrated a weak association with IUGR (OR 1.86; 95%CI 1.09-3.18 p=0.02). The presence of anti-B2GP1 IgG and/or IgM antibodies in titers ≥ 40 G/M units also failed to show an association with a composite outcome of pre-eclampsia, IUGR, late fetal loss and placental abruption (OR 2.65; 95%CI 0.7-10.04 p=0.15). However, stronger associations were observed with placental abruption (OR 4.87; 95%CI 1.02-23.25 p=0.047) and IUGR (OR 3.53; 95%CI 1.03-12.15 p=0.045). CONCLUSIONThe presence of anti-B2GP1 IgG and/or IgM antibodies in titers 20 ≥ G/M units during pregnancy is only associated with an increased risk of IUGR. Anti-B2GP1 antibodies in titers ' 40 G/M units, as suggested in the Sapporo diagnostic criteria for the APS, are associated with IUGR and placental abruption and possibly other placenta mediated complications. Larger adequately powered studies will be required to provide definitive answers. Disclosures:No relevant conflicts of interest to declare.

Presence of low titre of antiphospholipid antibodies in cancer patients: a prospective study

Antiphospholipid antibodies (aPL) represent a well-defined risk factor for thrombotic events. aPL have been observed in the plasma of cancer patients, but the role and clinical relevance of aPL in this clinical setting is still unclear. This is a prospective cohort study whose aims were to: (1) compare the prevalence of aPL antibodies in cancer patients at diagnosis to matched control subjects; (2) compare thrombosis-free survival and overall survival in aPL positive and aPL negative cancer patients. One hundred and thirty-seven patients were enrolled upon a diagnosis of cancer, and were screened for lupus anticoagulant (LA), anticardiolipin antibodies, and anti-beta2 glycoprotein I antibodies (IgG and IgM). Two years of follow-up were scheduled. Low-titre aPL antibody positivity was found in 33 patients (24%), and in 6 controls (4.3%; P < 0.0001). During follow-up, nine patients developed a symptomatic, objectively confirmed, thromboembolic event. One thrombotic event was observed among the 33 aPL positive patients (3%), and 8 among the 104 aPL negative ones (7.6%) (P = NS). During follow-up, 21 patients died, and among them, 3 (9.1%) were aPL positive and 18 (17.3%) were aPL negative (P = 0.39; C.I. 0.28-0.05). In conclusion, a high prevalence of low-titre aPL was found in cancer patients at diagnosis, but no statistical difference in thrombosis-free survival or in overall survival was observed between aPL positive and aPL negative patients.

Accuracy of the First Fully Automated Method for Anti‐cardiolipin and Anti‐β2 Glycoprotein I Antibody Detection for the Diagnosis of Antiphospholipid Syndrome

In this study we evaluated the diagnostic accuracy for antiphospholipid syndrome (APS) of new fully automated immunoassays for anticardiolipin (aCL) and anti-beta2 glycoprotein I (anti-beta2-GPI) auto-antibody detection (EliA-Phadia), and compared the results with those obtained with Orgentec and Inova ELISA methods. Sixty-two APS patients and 123 controls (20 syphilis, 33 Lyme disease, 30 HCV infection and cryoglobulinemia, 40 healthy subjects) were studied. Using the 99(th) percentile cutoff, the sensitivity and specificity of EliA aCL IgG, aCL IgM, anti-beta2-GPI IgG, and anti-beta2-GPI IgM were 69.4% and 81.9%, 64.5% and 86.7%, 64.5% and 98.8%, and 53.2% and 92.8%, respectively. Using the Sydney criteria cutoff (>40 GPL/MPL units), sensitivity and specificity of EliA aCL IgG and aCL IgM were 45.2% and 98.8%, and 35.5% and 97.5%, respectively. The best diagnostic efficiency was obtained combining the aCL tests (>40 GPL/MPL units) with the anti-beta2-GPI tests (sensitivity 85.7%, specificity 90.4%). The area under the ROC curves for EliA, Orgentec, and Inova methods were 0.870, 0.940, and 0.850 for aCL IgG; 0.820, 0.820, and 0.820 for aCL IgM; 0.910, 0.960, and 0.920 for anti-beta2-GPI IgG; 0.840, 0.840, and 0.820 for anti-beta2-GPI IgM, respectively. Finally, the overall agreement between EliA assays and the other two ELISA methods ranged from moderate (anti-beta2-GPI IgG EliA versus Orgentec: Cohen's k = 0.426) to good (anti-beta2-GPI IgM EliA vs. Inova: k = 0.841). In conclusion, newly developed EliA methods for antiphospholipid antibody detection perform similarly to other ELISA assays and represent a useful tool for APS laboratory diagnosis in daily practice.

Neonatal and Pregnancy Outcome in Primary Antiphospholipid Syndrome: A 10-year Experience in One Medical Center

Antiphospholipid syndrome (APS) in pregnancy is characterized by the presence of maternal autoantibodies in association with recurrent fetal loss and severe obstetric complications such as prematurity, intrauterine growth retardation, or placental insufficiency. This study aimed to assess the perinatal outcomes in neonates born to mothers with APS. The medical records of pregnant women with APS and their offspring were retrospectively collected between January 1997 and July 2007. Maternal and perinatal histories including demographic data, medications, obstetric histories, and neonatal clinical manifestations and laboratory data were analyzed. Eleven women with a diagnosis of primary APS were included. Eight of these patients had experienced frequent spontaneous abortions (72.7%), and four had unexplained fetal deaths (36.3%). None of them had vascular thrombosis. Specific autoimmune antibodies were detected, including anticardiolipin antibody (n=6), anti-beta2 glycoprotein I (n=3), and antiphospholipid antibody (n=7). Among the pregnancies, five had preterm births (45.4%), two had intrauterine growth retardation (18.1%), and one had intrauterine fetal demise (9.1%). Thrombocytopenia was noted in three babies, all of whose mothers had lower platelet counts. One patient with neonatal thrombocytopenia developed intracranial hemorrhage, seen on brain images. This limited study suggests that neonates born to mothers with primary APS are at risk of prematurity, being small for gestational age, and having thrombocytopenia. Further large, prospective studies are required to better define the perinatal outcomes.

Clinical Reasoning: A 62-year-old woman with deafness, unilateral visual loss, and episodes of numbness

In May 2007, a 62-year-old woman presented with two episodes of right-hand numbness. The episodes were accompanied by profound fatigue. Each event lasted 5 minutes, and both occurred within a 2-week period. She also recalled an episode of right-sided numbness 30 years previously. She had a past medical history of hypothyroidism, hypertension, hypercholesterolemia, and multiple miscarriages. About 15 years ago, she began losing hearing in her left and then right ear, and she had been completely deaf for the last 8 years. Prior testing had revealed that the patient had sensorineural hearing loss, but the etiology could not be determined. Family and social history were unremarkable. ### Questions for consideration: 1. What is the differential diagnosis for episodic neurologic abnormalities? 2. What diagnostic testing would you perform? The differential diagnosis of transient sensory dysfunction is broad and includes TIA, complicated migraine, seizure, metabolic derangement, peripheral nerve compression, compressive myelopathy, multiple sclerosis (MS), and conversion disorder.1 Particularly in patients over the age 55, transient neurologic attacks that are focal, nonfocal, or a mixture of both are associated with an increased risk of stroke. Therefore, an evaluation of our patient should include carotid ultrasound, transthoracic echocardiogram, and head CT or MRI of the brain.2 The history of multiple miscarriages raises the suspicion for antiphospholipid syndrome, which may cause a hypercoagulable state. Anticardiolipin antibodies, anti beta-2 glycoprotein antibodies, and lupus anticoagulant assays could be performed to investigate this possibility. An EEG may be considered to identify epileptiform discharges, especially given the patient’s post-event fatigue. A diagnostic evaluation for the cause of her two episodes of numbness was unrevealing. Then, in January 2008, the patient noted blurred vision in her left eye that progressed over 3 days. She denied pain on eye movements, photopsia, metamorphopsia, or other neurologic deficit. Initial eye examination showed a left relative afferent defect …

Case Reports of the Use of Immunoadsorption or Plasma Exchange in High‐risk Pregnancies of Women With Antiphospholipid Syndrome

Conventional treatment of antiphospholipid syndrome (APS) pregnancies with aspirin and/or heparin is sometimes unable to counteract maternal and/or fetal complications. In this article we report the cases of two patients who were unresponsive to conventional treatment for APS during their first pregnancy, and who were treated in the following pregnancy with plasma exchange and immunoadsorption respectively, in addition to conventional therapy. Both patients had a history of thrombotic events, a previous pregnancy loss at the 11th week of gestation and the same antiphospholipid antibody profile (lupus anticoagulant activity and high titers of immunoglobulin G (IgG) anti-beta2 glycoprotein I and IgG anticardiolipin antibodies). Patient 1 was treated from the fourth week of her second pregnancy with weekly plasma exchange. Due to fetal growth restriction and oligohydramnios in the 26th week she delivered, by cesarean section, a healthy female infant weighing 730 g who survived. Patient 2 was treated from the seventh week of her second pregnancy with twice a week protein A immunoadsorption. The pregnancy proceeded normally until the 36th week, when, due to slight intrauterine growth restriction, she delivered a healthy baby girl weighing 2375 g by cesarean section. Anti-beta2 glycoprotein I antibody trends were similar during both types of treatment. On the basis of our findings obtained from only two cases it is impossible to define the best aphaeretic treatment of APS high risk pregnancies. Nevertheless, as a whole these data suggest better disease control using the immunoadsorption technique as compared to plasma exchange, despite their apparently similar anti-beta2 glycoprotein I antibody removal capabilities.

How we diagnose the antiphospholipid syndrome

AbstractThe antiphospholipid syndrome (APS) is an acquired thrombophilia, characterized by the occurrence of venous and arterial events. This article examines the laboratory and key clinical aspects of APS. Particular focus is given to anti–beta 2-glycoprotein I (β2GPI) antibodies in view of their recent inclusion in the APS classification criteria. The clinical utility of using the β2GPI enzyme-linked immunosorbent assay, in conjunction with the established lupus anticoagulant assays and cardiolipin enzyme-linked immunosorbent assay, for diagnosing and risk stratifying patients suspected of having APS is discussed. The relative importance of the various assays in diagnosing obstetric APS (early and late gestation miscarriages) is explored. The implications of recent epidemiologic findings for possibly understanding the underlying pathophysiologic mechanisms of obstetric APS are highlighted. Insights into which patients with obstetric APS may be at most risk of thrombotic complications are presented.

Antiphospholipid antibody profiles in lupus nephritis with glomerular microthrombosis: a prospective study of 124 cases

IntroductionGlomerular microthrombosis (GMT) is a common vascular change in patients with lupus nephritis (LN). The mechanism underlying GMT is largely unknown. Although several studies have reported the association of antiphospholipid antibodies (aPL) with GMT, the relation between GMT and aPL remains controversial. Previous studies have demonstrated that some aPL could bind to several hemostatic and fibrinolytic proteases that share homologous enzymatic domains. Of the protease-reactive aPL, some can inhibit the anticoagulant activity of activated protein C and the fibrinolytic function of plasmin, and hinder the antithrombin inactivation of thrombin. The purpose of this study was to investigate the prevalence of GMT in LN patients and examine the relation between the aPL profiles (including some protease-reactive aPL) and GMT.MethodsRenal biopsy specimens were examined for the presence of glomerular microthrombi. Plasma samples from 25 LN patients with GMT (LN-GMT group) and 99 LN patients without GMT (LN-non-GMT group) were tested for lupus anticoagulant and antibodies against cardiolipin, β2 glycoprotein I, plasmin, thrombin, tissue plasminogen activator, and annexin II.ResultsThe prevalence of GMT in LN patients was 20.2%. Compared with the LN-non-GMT group, the LN-GMT group had an elevated systemic lupus erythematosus disease activity index; elevated renal tissue injury activity and chronicity indices; elevated serum creatinine, blood urea nitrogen, and proteinuria levels; a lower serum C3 level and much intense glomerular C3, C1q staining; and a higher frequency of hypertension (P < 0.05 for all). Additionally, the detection rate of lupus anticoagulant, immunoglobulin G (IgG) anti-β2 glycoprotein I and anti-thrombin antibodies were higher in the LN-GMT group than in the LN-non-GMT group (P < 0.05 for all). No statistical differences were found in the detection rates of IgG anti-cardiolipin, plasmin, tissue plasminogen activator, or annexin II antibodies (P > 0.05 for all). No detectable difference in IgM autoantibodies to the above antigens was observed between the two groups.ConclusionsGMT occurs in approximately 20.2% of LN patients. Patients with GMT have severer renal tissue injuries and poorer renal functions than patients without GMT. The lupus anticoagulant and antibodies against β2 glycoprotein I and thrombin may play a role in GMT.

Clinically asymptomatic antiphospholipid antibodies – diagnostic and therapeutic problems

The presence of asymptomatic antiphospholipid antibodies (aAPA) creates many difficult diagnostic and clinical problems - they might be a cause either of incorrect hemorrhagic diathesis recognition or an unnecessary anticoagulant therapy. Patients with aAPA should be counseled individually regarding potential thrombotic and/or obstetric complications. An increased risk of these complications is particularly high when lupus anticoagulant (LAC) and IgG anti-beta2 glycoprotein antibodies coexist. The approaches to the diagnosis and management of treatment of patients with aAPA are also discussed.

Spectrum of Antiphospholipid Antibodies and Associated Thrombotic and Obstetric Events among Patients with Antiphospholipid Syndrome

Introduction: Antiphospholipid antibody syndrome (APS) is characterized by arterial or venous thrombosis, and/or adverse obstetric outcomes in the presence of persistent antiphospholipid antibodies (APab). Between 2–10% of all patients with APS are reported to present solely with anti beta-2 glycoprotein 1 antibodies (b2GP1 abs) (ref 1). In 2006 the Sapporo criteria were revised to include b2GP1 abs to the panel of diagnostic tests. While presence of a lupus anticoagulant (LA) has been found to correlate well with occurrence of thromboses, the prognostic and predictive roles of b2GP1 abs and anticardiolipin antibodies (ACLA) need better definition. Previous studies suggest both the severity of the initial event and the risk for recurrent events is greater among patients demonstrating presence of more than one APab on laboratory testing (ref 2 and 3), but this aspect needs further confirmation.Objectives:To identify the spectrum of clinical thrombotic and obstetric manifestations associated with the different APab profiles;To determine the prevalence and clinical significance of the b2GP1 ab positive and ACLA/LA negative phenotype; andTo evaluate the significance of IgM b2GP1 ab and IgM ACLA.Methods: Medical records of patients tested for all three antiphospholipid antibodies at the University of Minnesota Medical Center from Dec 2000 to Dec 2005 were reviewed. Patients that met the modified criteria for APS were included. IgG and IgM ACLA were measured using the Diamedix kit (VAX diagnostics) and IgG and IgM b2GP1 abs using the Inovalite kit (NOVA diagnostics). LA was determined using standard protocol.Results: Over the 5 year period, all three laboratory assays were obtained in 560 individuals, but only 76 (13.5%) patients who met both the clinical and laboratory criteria for APS were included in this study. Seven of the 76 patients (9.2%) had isolated, persistently positive b2GP1 abs. LA alone was present in 21 patients (27.6%). Twenty nine patients (38%) had all three APabs, and had a higher incidence of thrombosis at multiple sites at the time of diagnosis as well as increased rate of recurrent events, in comparison to those with two or less than two APab. Isolated ACLA was present in only 2 patients (2.6%). Interestingly, both IgM (47%) and IgG (50%) b2GP1 abs were associated with thrombosis, whereas only IgG ACLA was found to be associated with thrombosis.Conclusion: The presence of b2GP1 abs as the sole laboratory anomaly is uncommon, but is noted in patients with APS, thus warranting it's testing at the time of clinical suspicion. Amongst the different antibody types LA seems to be the strongest predictor for thrombotic events and ACLA seems to have a weaker link, consistent with the results of previous studies (ref 4). The presence of all three AP antibodies does increase the risk for recurrent and multiple thromboses.

Autoantibody Production during Chronic Graft-Versus-Host Disease Does Not Associate with Long-Term Persistence of Host B Cells in Humans

Background. Chronic graft-versus-host disease (cGvHD) is a common complication of allogeneic hemopoietic cell transplantation (allo-HCT). The pathogenesis of cGvHD is poorly understood. In cGvHD, the homeostasis of B lymphocytes is perturbed, as demonstrated by the production of autoantibodies. B-cell depletion with monoclonal antibodies (mAb) interferes with autoantibody production and ameliorates signs and symptoms of cGvHD. In mouse models, cGvHD and autoantibodies associate with the long-term persistence of host B cells after allo-HCT (Sylvain Perruche et al., Transplantation 2006). It has been postulated that host B cells may present alloantigens to donor T cells and, in turn, receive help for autoantibody production. This could be crucial to the pathogenesis of cGvHD. Aim. To investigate whether the long-term persistence of host B lymphocytes is associated with cGvHD and autoantibodies in humans.Patients and methods. We recruited 13 consecutive patients with active cGvHD (4 mild, 5 moderate, 4 severe according to NIH classification) with a median time of onset of 6 months (range 3–36) from HLA-identical sibling (9 patients) and HLA-matched unrelated (4) allo-HCT. As controls, we chose 10 patients that underwent HLAidentical sibling (2), HLA-matched unrelated (5) or haploidentical (3) allo-HCT and never experienced cGvHD. In the two groups, we studied:circulating autoantibodies, including anti-nuclear (ANA), anti-DNA, anti-extractable nuclear antigen, anti-beta2 glycoprotein, anti-neutrophil cytoplasm, anti-thyroid, anti-mytocondria antibodies, rheumatoid factor,absolute numbers of T (CD3+, CD4+, CD8+), conventional B (CD19+), B1 (CD5+/CD19+) and NK cells (CD16+/CD56+) in the graft and in the peripheral blood,microchimerism by short-tandem repeats (STR) on B, T and myeloid cells purified by immunomagnetic cell sorting (sensitivity 0,01%).Results. Patients with cGvHD had high-titer circulating ANA (>1:160) more frequently than controls (54% versus 10%, P<0,05). All other autoantibodies were negative. Peripheral T-cell counts were lower in patients with cGvHD than in controls (for CD8+ cells P<0,05). This was not due to a difference in the absolute numbers of T lymphocytes within the graft between the two groups. Peripheral counts of conventional B and B1 cells in patients with cGvHD were similar to controls. Autoantibodies and cGvHD were not associated with the persistence of host B lymphocytes, since the analysis of STR on purified B cells revealed that they were all of donor origin. T and myeloid cells were also of donor origin. Of interest, in univariate analysis, in vivo B-cell depletion with mAb for the prophylaxis against Epstein-Barr virus-related lymphoproliferative disease showed a trend towards a lower risk of cGvHD (P=0,06).Conclusions. This study indicates that autoantibody production during cGvHD does not associate with long-term persistence of host B cells in humans. Moreover, it suggests that the early depletion of donor B lymphocytes in vivo may be effective for GvHD prophylaxis

P48 Anti-beta 2-glycoprotein as compared with anticardiolipin antibody and lupus anticoagulant in diagnosis of antiphospholipid antibody syndrome

P48 Anti-beta 2-glycoprotein as compared with anticardiolipin antibody and lupus anticoagulant in diagnosis of antiphospholipid antibody syndrome

Anticorps antiphospholipide, syndrome des anticorps antiphospholipides et infections virales

Since the association between antiphospholipid antibodies and syphilis was first described, many other viral, bacterial and parasitic infections have been shown to induce antiphospholipid antibodies, notably anticardiolipin antibodies. These aPL are usually associated neither with anti-beta2 glycoprotein I antibodies (anti-beta2-GPI) nor with thrombotic events, even if cases of arterial and deep venous thrombosis have been reported in such circumstances. A literature review shows that anticardiolipin antibodies occur frequently in viral infections, particularly in HIV (49.8%), HBV (24%) and HCV (20%). The prevalence of anti-beta2 glycoprotein I antibodies (anti-beta2GPI) is lower (HCV: 1.7%, HIV: 5.6%, HBV: 3.3%) and there is no demonstrated association with a risk of thrombotic events or hematological manifestations defining antiphospholipid syndrome (APS). Regarding other viral infections, including viral hepatitis A, herpes virus (CMV, EBV, VZV), parvovirus B19 and HTLV-1 infections, only a few studies are available but data confirm the high prevalence of antiphospholipid antibodies at the acute phase. Finally, antiphospholipid antibodies, mainly anticardiolipin, are frequently associated with viral infections. Their presence may probably reflect an intense or chronic antigenic stimulation of the immune system. However, their evolution under antiviral therapy and correlation with the quality of the virological control and/or the immune restoration remain to be determined.

Thrombophilic dimension of recurrent fetal loss in Indian patients

We studied the prevalence of acquired and genetic thrombophilia in 198 women with recurrent fetal loss who were having three or more than three abortions. Seventy-nine women had only early pregnancy losses, that is, first trimester abortions, 30 women had only late pregnancy losses, that is, second and third trimester abortions whereas 89 had both early and late pregnancy losses. The control group included 100 age-matched fertile parous women who did not have any obstetric complications and had at least one normal healthy child. Several genetic and acquired thrombophilia markers were studied. The strongest association was observed with anticardiolipin (odds ratio 22.6, confidence interval 5.7-89, P = 0) followed by lupus anticoagulant, anti-beta2 glycoprotein-1, antiannexin. Association of antiphospholipid antibody syndromes was detected with the time of pregnancy loss in anticardiolipin, lupus anticoagulants, which was significantly associated with early pregnancy loss as compared with second and third trimester loss. In case of beta2 glycoprotein-1, antiannexin it was less significantly associated with early pregnancy loss as compared with second and third trimester loss. The risk of fetal loss with protein S deficiency was the highest risk observed for any heritable thrombophilia, followed by protein C, factor V Leiden, endothelial protein C receptor, antithrombin III deficiency and beta448 fibrinogen polymorphism. Modest risks were also observed with 5,10-methylenetetrahydrofolate reductase, plasminogen activator inhibitor 4G/4G polymorphisms and beta448 fibrinogen polymorphism. A combination of two or more than two genetic risk factors were observed in 55 (27.7%), whereas the genetic and acquired risk factors were observed in 107 (54%) of the cases. Thrombophilia is an important contributing factor for both early and late pregnancy losses; approximately two-thirds of our cases of unexplained fetal losses could be explained by acquired or heritable thrombophilia or both, which is in line with other western studies.

Technical Aspects in Laboratory Testing for Antiphospholipid Antibodies: Is Standardization an Impossible Dream?

Anticardiolipin (aCL) and anti-beta2 glycoprotein I (anti-beta2GPI) assays are widely performed because they are part of the laboratory criteria for the antiphospholipid syndrome (APS). Despite several standardization workshops and the availability of a worldwide accepted calibrator material for aCL, a high variability in numerical assay results and in sample classification is still observed in comparative studies and external quality control surveys. For anti-beta2GPI assays, comparison of numerical values is impeded by the absence of a common calibrator material, and external quality surveys similarly show a large overlap in sample classification. Numerous variables impact assay results, among them the source and integrity of beta2GPI, the secondary calibration process, and the assessment and derivation of cutoff values. For both assays, the vast majority of laboratories use commercial kits whose number has risen considerably in the past years. However, many problems persist, and there is a need to improve the comparability in assay results. The use of monoclonal antibodies as reference calibrators has to be especially considered, with their suitability evaluated by future collaborative studies and external quality controls surveys. Manufacturers should provide more precise information on results obtained when testing control groups for establishing reference ranges and cutoff values. From the customers' perspective, it is important that each laboratory, even if using commercial kits, assesses its local cutoff value whenever possible. In the field of autoimmunity, assay standardization is a difficult but nevertheless important task. Much more effort is needed to reduce the high interlaboratory variability in assay results even if absolute standardization cannot be feasibly achieved.

Are the Current Attempts at Standardization of Antiphospholipid Antibodies Still Useful? Emerging Technologies Signal a Shift in Direction

The pathogenic role of antiphospholipid antibodies (aPL) has been widely established over past years in several experimental models and clinical studies. Accordingly, the detection of aPL by immunoassays (anticardiolipin antibodies; anti-beta2 glycoprotein I antibodies) has become a routine practice in the clinical workup of patients with systemic autoimmune diseases. aPL are mostly assayed using commercial ELISA kits, whose performance has not been found to be sufficiently concordant among the different manufacturers. In the past years, collaborative groups have spent considerable effort to reach some form of standardization but this process is still ongoing. Such lack of standardization has recently become even more crucial, as manufacturers have had to face an increasing demand for fully automated tests for aPL, like those test systems that have been developed for other autoantibodies (e.g., antinuclear antibodies, anti-ENA antibodies). We therefore report our recent experience with two newly developed automated methods for anticardiolipin antibodies testing. In particular, we discuss the results obtained using routine samples, as we believe that these better reflect the "real-life" situation in which those automated methods will operate. We also mention other emerging technologies in the field of aPL detection.

Clinical Utility of Laboratory Tests Used to Identify Antiphospholipid Antibodies and to Diagnose the Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is defined by thrombotic and/or obstetric events together with the presence of antiphospholipid antibodies in plasma of patients. The original laboratory criteria of APS included lupus anticoagulants (LA) and/or IgG/IgM anticardiolipin antibodies (aCL). They were recently updated with the addition of IgG/IgM anti-beta2 glycoprotein I antibodies (anti-beta2GPI), a better definition of "medium to high antibody titer," and the extension to 12 weeks of the "persistence in time." The revised criteria represent an improvement; however, the potential overdiagnosis of APS remains possible, thus putting patients at risk of overtreatment. To reduce this possibility, proposals have been made to implement strict guidelines for the performance of the LA assay, to exclude aCL measurements in their current application from the criteria, and to limit the measurement of anti-beta2GPI to the G isotype. This should also help in simplifying the laboratory workup of patients being investigated for APS.