Prevalence and clinical significance of IgG isotype anti-beta 2-glycoprotein I antibodies in antiphospholipid syndrome: a comparative study with anticardiolipin antibodies

Laboratory assessment of antiphospholipid syndrome: Laboratory data

INTRODUCTION

Thorough assessment of the antiphospholipid syndrome (APS) includes retesting of positive antiphospholipid antibody (aPL) tests after at least 12 weeks, and a full antiphospholipid antibody profile. To what extent this work-up is done in clinical practice is unknown.

METHODS

Data on 25 116 in- and out-hospital patients tested for the presence of lupus anticoagulant (LA), the aPL which most strongly correlates with thrombosis, was extracted from the laboratory information system of the only laboratory that performs LA tests in the Capital Region, Denmark. We estimated fraction of repeated tests, tests repeated within the recommended time span, and fraction with a full aPL profile.

RESULTS

Out of 25 116 patients, 843 were positive for LA (3.3%), and 3948 results were inconclusive (16%). Only 51% (95% CI of the proportion: 48%-54%) (n = 431) of positive tests were repeated. The proportion of inconclusive LA test results increased from 13% (12%-15%) in 2009 to 20% (19%-22%) in 2020. Out of the positive tests repeated within the first year, only 60/353 (17%; 13%-21%) were repeated within 12-16 weeks; 177/353 (50%; 45%-55%) were re-tested within the first 12 weeks of first positive test result. The proportion of patients with a full antiphospholipid antibody profile increased from 161/1978 (8%) in 2010 to 1041/1978 (43%) in 2020.

CONCLUSION

We found several issues with the laboratory workup of APS. This indicates a need for increased awareness of comprehensive laboratory assessment of possible APS as well as a closer collaboration between the laboratory and clinicians.

Thrombosis and antiphospholipid antibody syndrome during acute Q fever: A cross-sectional study

Q fever is a neglected and potentially fatal disease. During acute Q fever, antiphospholipid antibodies are very prevalent and have been associated with fever, thrombocytopenia, acquired heart valve disease, and progression to chronic endocarditis. However, thrombosis, the main clinical criterion of the 2006 updated classification of the antiphospholipid syndrome, has not been assessed in this context. To test whether thrombosis is associated with antiphospholipid antibodies and whether the criteria for antiphospholipid syndrome can be met in patients with acute Q fever, we conducted a cross-sectional study at the French National Referral Center for Q fever.Patients included were diagnosed with acute Q fever in our Center between January 2007 and December 2015. Each patient's history and clinical characteristics were recorded with a standardized questionnaire. Predictive factors associated with thrombosis were assessed using a rare events logistic regression model. IgG anticardiolipin antibodies (IgG aCL) assessed by an enzyme-linked immunosorbent assay were tested on the Q fever diagnostic serum. A dose-dependent relationship between IgG aCL levels and thrombosis was tested using a receiver operating characteristic (ROC) analysis.Of the 664 patients identified for inclusion in the study, 313 (47.1%) had positive IgG aCL and 13 (1.9%) were diagnosed with thrombosis. Three patients fulfilled the antiphospholipid syndrome criteria. After multiple adjustments, only positive IgG aCL (relative risk, 14.46 [1.85-113.14], P = .011) were independently associated with thrombosis. ROC analysis identified a dose-dependent relationship between IgG aCL levels and occurrence of thrombosis (area under curve, 0.83, 95%CI [0.73-0.93], P < .001).During acute Q fever, antiphospholipid antibodies are associated with thrombosis, thrombocytopenia, and acquired valvular heart disease. Antiphospholipid antibodies should be systematically assessed in acute Q fever patients. Hydroxychloroquine, which has been previously shown to antagonize IgG aCL pathogenic properties, should be tested in acute Q fever patients with anticardiolipin antibodies to prevent antiphospholipid-associated complications.Key Point: In addition to fever, thrombocytopenia and acquired valvular heart disease, antiphospholipid antibodies are associated with thrombosis during acute Q fever.

Prevalence of β2-Glycoprotein I Antibody in Patients with Liver Cirrhosis: Relationship with β2-Glycoprotein I Plasma Levels and Thrombosis

Recently, a semiquantitative enzyme-linked immunoassay for detecting IgG or IgM class autoantibody to β2-GPI for use as an aid in the diagnosis of certain autoimmune or thrombotic disorders. We evaluated the prevalence of anti-β2-GPI antibody and its relation to plasma β2-GPI levels and occurrence of thrombosis in 69 patients with liver cirrhosis. As expected, plasma β2-GPI levels were lower in the patients with liver cirrhosis and correlated with Child classification. Anti-β2-GPI antibodies were positive in 11 (15.9%) patients. However, there were no differences in β2-GPI levels, platelet counts, and thrombosis between positive and negative groups for anti-β2-GPI antibodies.

Dos and don'ts in diagnosing antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an acquired autoimmune thrombotic tendency that is identified by the presence of abnormal antiphospholipid laboratory tests in patients who have a history of vascular thrombosis and/or pregnancy complications including recurrent spontaneous miscarriages and a group of other complications due to placental insufficiency. Diagnostic testing for APS is often problematic because of many misconceptions regarding these empirically derived assays. This chapter is intended to provide hematology-oncology consultants with practical information about the uses and limitations of assays used to diagnose APS.

Coxiella burnetii as a possible cause of autoimmune liver disease: a case report

INTRODUCTION

Q fever is a zoonotic infection that may cause severe hepatitis. Q-fever hepatitis has not yet been associated with autoimmune hepatitis and/or primary biliary cirrhosis.

CASE PRESENTATION

We describe a 39-year-old man of Sri Lankan origin with chronic Q-fever hepatitis who developed autoantibodies compatible with autoimmune hepatitis/primary biliary cirrhosis overlap syndrome. Ursodeoxycholic acid in addition to antibiotic therapy markedly improved hepatic enzyme levels suggesting that autoimmunity, potentially triggered by the underlying infection, was involved in the pathogenesis of liver damage.

CONCLUSION

We suggest that Coxiella burnetii might trigger autoimmune liver disease. Patients with Q-fever hepatitis who respond poorly to antibiotics should be investigated for serological evidence of autoimmune hepatitis, primary biliary cirrhosis or overlap syndrome, as these patients could benefit from adjunctive therapy with ursodeoxycholic acid. Conversely, C. burnetii serology might be necessary in patients with autoimmune liver disease in order to exclude underlying Coxiella infection.

Does the anti-prothrombin antibodies measurement provide additional information in patients with thrombosis?

The aim of this study is to get new insight into the relevance of IgG anti-prothrombin antibodies in patients with thrombosis and to determine whether human prothrombin alone (aPT) or complexed to phosphatidylserine (aPS/PT) should be preferentially used for measuring these antibodies by enzyme-linked immunosorbent assay (ELISA). To this end, prevalence of anti-prothrombin antibodies, their characteristics in terms of avidity and heterogeneity, and their relationship with anti-beta2 glycoprotein I antibodies (abeta2GPI) were studied in 152 patients with thrombosis. Patients were divided into two groups according to the presence or absence of antiphospholipid antibodies (aPL), called aPL+ or aPL-, respectively. In the aPL- group (n=90), the prevalence of anti-prothrombin antibodies was substantial (10%) but not significantly different from that of control (5%). In the aPL+ group (n=62), lupus anticoagulant (LA) or anticardiolipin antibodies (aCL) positive, 61% were positive for anti-prothrombin antibodies with no statistical difference between aPT and aPS/PT prevalence (42% vs. 55%, respectively). In the whole thrombotic population, 19% were only aPT and 34% only aPS/PT suggesting the presence of different antibodies. Absorption experiments confirmed the heterogeneity of aPT and aPS/PT. No difference in their avidity was demonstrated. From the aPL+ group, 60 were LA positive. Among them, 18% were negative for abeta2GPI and anti-prothrombin antibodies showing that the detection of these antibodies could not substitute for LA determination. In conclusion, our data show that the screening of the different anti-prothrombin antibodies is not warranted in the aPL+ group since these antibodies do not provide additional information compared to aCL, LA and/or abeta2GPI measurement. Nevertheless, the substantial prevalence of anti-prothrombin antibodies in the aPL- group should be further explored in a large prospective study.

Étude de l'association hépatite auto-immune et antiphospholipides

INTRODUCTION

Only few series have reported the association of autoimmune hepatitis with antiphospholipid antibodies. The aim of our study is to investigate the frequency of these antibodies in a series of autoimmune hepatitis and to search for a correlation with clinical, biological or histological characteristics.

MATERIAL AND METHODS

Antiphospholipid were investigated in 24 patients with well defined autoimmune hepatitis. Characteristics were compared between antiphopholipids positive and negative patients. Characteristics of our patients were also compared toward cases collected in a literature review.

RESULTS

The frequency of antiphospholipid antibodies is of 70.8% in our series. Four patients had a well defined antiphospholid syndrome. Seven patients had a systemic lupus erythematosus in the antiphospholipid group whereas none in the antiphospholipid negative group. The frequency of the different antiphopholipid antibodies was: IgG ACL (52.9%), IgM APE (52.9%), ACC (43.7%), IgG Abeta2GP1 (41.2%). We found no correlation between hypergammaglobulinemia and the presence or the isotype of antiphospholipid antibodies. Clinical presentation and outcome as biological and histological parameters were similar in both groups.

CONCLUSION

Our study report a high frequency of antiphospholipids antibodies in autoimmune hepatitis patients. However we found no clinical, biological or histological correlation with the presence of antiphospholipids. Further longitudinal studies on larger cohorts should clarify the association between antiphospholipid antibodies and autoimmune hepatitis and potential therapeutic issues.

Specificity and sensitivity of anti-beta2-glycoprotein I as compared with anticardiolipin antibody and lupus anticoagulant in Thai systemic lupus erythematosus patients with clinical features of antiphospholipid syndrome

Antibodies to beta(2)-glycoprotein I (anti-beta(2)-GPI) have been reported to have stronger association with clinical antiphospholipid syndrome (APS) than anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC). We investigated the sensitivity and specificity of ELISA for anti-beta(2)-GPI in Thai systemic lupus erythematosus (SLE) patients with clinical features of APS and compared the results with IgG/IgM aCL and LAC to find the test with the best association. The hospital records of 151 Thai SLE patients whose sera had been sent for either IgG/IgM anticardiolipin antibodies or lupus anticoagulant testing were reviewed. Sera of patients either without complete clinical records or those with APS-related manifestations other than vascular thrombosis and pregnancy morbidity (according to the international consensus statement on preliminary classification criteria for definite APS) were excluded. For the remaining subjects (112 patients), their sera were tested for anti-beta(2)-GPI antibody, IgG and IgM anticardiolipin, and lupus anticoagulant. The sensitivity and specificity of each method were compared by using the chi-square test. Among the 112 (74.2%) SLE patients in the study, 35 (31.3%) presented with preliminary clinical criteria for APS (i.e., vascular thrombosis and pregnancy morbidity) whereas 77 (68.7%) did not. The sensitivity and specificity of anti-beta(2)-GPI determination were 57.1 and 79.2%, respectively, whereas those of IgG aCL were 25.7 and 94.8%, of IgM aCL were 5.7 and 98.7%, and of LAC were 44.8 and 77.3%, respectively. The accuracy of the four tests showed similar association with clinical APS (accuracy of test = 72.3, 73.2, 69.6, and 68.3%, respectively). Concerning the sensitivity, specificity, and difficulty of the methods, the combination of anti-beta(2)-GPI and IgG aCL tests was the best for the diagnosis of APS in Thai SLE patients.

Fausses couches spontanées précoces répétées : quelle prise en charge proposer en 2006 ?

More than 1% of the couples whishing children suffer from recurrent miscarriage, but investigations and treatment are not consensual. Most patients have several risk factors, and a minimum investigation of known factors has to be undertaken: karyotyping of the couple, hysteroscopy for searching uterine anatomic anomalies, evaluation for thrombophilias (anticardiolipin antibodies, lupus anticoagulant, protein C activity, Proteine S activity, factor V Leiden and factor II mutations, activated protein C resistance), antinuclear antibodies. Systemic diseases (like lupus) and endocrine abnormalities (like thyroid diseases and diabetes mellitus) have to be detected by clinical examination and questioning. No endocrine investigation is recommended, unless irregular menstruations or sterility. Research in recurrent pregnancy loss are conducted in new associated factors, such as skewed-X-chromosome inactivation, maternal HLA types, modifications in specific immune molecules and cells regulation. Therapeutic proposals are preimplantation genetic diagnosis in case of abnormal karyotiping, hysteroscopic surgery for septate uterus, aspirin plus heparin in antiphospholipid-positive patients, and aspirin plus corticosteroids in systemic lupus. Heparin seems to improve obstetrical prognosis for patients with congenital or acquired thrombophilias, but there are only few studies carried out on the subject. This new therapeutic approach should incite the patients with a negative medical appraisal to be referred to specialized consultations in order to include them in eventual clinical tests. Finally, empathic listening and psychological support are necessary in a pathology with multiple etiological factors.

Diagnostic biologique du syndrome des antiphospholipides

PURPOSE

The antiphospholipid syndrome is a bioclinical entity defined by the occurrence of thromboses, and/or obstetrical complications in the persistent presence of antiphospholipid antibodies, i.e. lupus anticoagulant and/or anticardiolipin antibodies. This review focuses on the methods for antiphospholipid antibodies detection and their clinical usefulness.

CURRENT KNOWLEDGE AND KEY POINTS

Lupus anticoagulant is the strongest risk factor for thrombosis in antiphospholipid syndrome. Twenty years after its description, anticardiolipin ELISA, despite a still improvable standardization and its lack of specificity, is still required for sensitive diagnosis of antiphospholipid syndrome.

FUTURE PROSPECTS AND PROJECTS

A better knowledge of the beta-2-glycoprotein-I role in the pathophysiology of antiphospholipid syndrome might lead to the development of new markers of thrombotic risk.

Predictive value of persistent versus transient antiphospholipid antibody subtypes for the risk of thrombotic events in pediatric patients with systemic lupus erythematosus

Study objectives were to determine, in children with systemic lupus erythematosus (SLE), (1) the association of antiphosholipid antibody (APLA) subtypes with thrombotic events (TEs) and (2) the predictive value of persistent versus transient antibodies for TEs. This is a cohort study of 58 SLE children in whom lupus anticoagulants (LAs), anticardiolipin antibodies (ACLAs), anti–β2-glycoprotein-I (anti–β2-GPI), and antiprothrombin (anti-PT) were assessed on at least 2 occasions (more than 3 months apart). Antibodies were classified as persistent (positive on at least 2 occasions) or transient (positive once). Outcomes were symptomatic TEs confirmed by objective radiographic tests identified retrospectively and prospectively. Seven of the 58 patients (12%) had 10 TEs; 5 patients had TEs during prospective follow-up. Persistent LAs showed the strongest association with TEs (P < .001). Persistent ACLAs (P = .003) and anti–β2-GPI (P = .002) were significantly associated with TEs; anti-PT (P = .063) showed a trend. Persistent or transient LAs and anti–β2-GPI showed similar strength of association, while ACLAs and anti-PT were no longer associated with TEs. Positivity for multiple APLA subtypes showed stronger associations with TEs than for individual APLA subtypes because of improved specificity. Lupus anticoagulant is the strongest predictor of the risk of TEs; other APLA subtypes provide no additional diagnostic value. Anticardiolipin antibodies and anti-PT require serial testing because only persistent antibodies are associated with TEs.

Avidity of anti-beta-2-glycoprotein I antibodies

The terms affinity and avidity are often used indiscriminately, despite clearly differing. Since affinity refers to monovalent binding of antibodies to a monovalent epitope, the majority of data on the binding of anti-beta2-glycoprotein I antibodies (anti-beta2-GPI) characterized their avidity rather than affinity. Anti-beta2-GPI were generally believed to be of low avidity, but heterogeneous avidity of patients' IgG anti-beta2-GPI has been demonstrated. High avidity anti-beta2-GPI monoclonals were reported to possess higher pathogenicity than low avidity anti-beta2-GPI. Polyclonal high avidity anti-beta2-GPI were found to be more common in patients with antiphospholipid syndrome (APS) and associated with thrombosis. Some conformational changes of beta2-GPI are required for the binding of polyclonal anti-beta2-GPI to the antigen: neither high density of the antigen nor high avidity of the anti-beta2-GPI alone is sufficient for the recognition. Avidity of anti-beta2-GPI should be considered in any attempt of inter-laboratory standardisation and/or evaluation of anti-beta2-GPI enzyme-linked immunosorbent assay (ELISA).

Antibodies and clinical features of the antiphospholipid syndrome as criteria for systemic lupus erythematosus

The antiphospholipid syndrome (APS) can occur as a primary diagnosis or as a prominent feature of other diseases, predominantly systemic lupus erythematosus (SLE). The 1982 revised criteria for SLE were published prior to many of the studies which have illuminated current understanding of the antiphospholipid syndrome and several current clinical criteria for SLE, when arising from thrombotic damage to different organ systems, could be attributed to APS, leading to some confusion about where the diagnoses of these two disorders should begin and end. Additionally, APS is a significant generalized risk factor for irreversible organ damage and overall mortality in SLE patients and genetic linkages to HLA in APS hold up whether the disorder is primary or linked to SLE. It is increasingly recognized that APS itself is a complex, heterogenous disorder, involving a spectrum of autoantibodies to phospholipid-binding proteins, many of which have known coagulation-regulating functions. Although the combination of more than one antiphospholipid-related antibody might indicate a more severe phenotype, it is not suggested here that additive criteria for the diagnosis of SLE be accumulated with more than one of these pathologically related autoantibodies. Patients with multiple criteria for APS should be considered to have severe APS but it would be recommended to restrict APS-attributed criteria for SLE to a maximal of two: one immunologic and one clinical. Thus people meeting the Sapporo criteria for APS could gain only a maximum of two criteria for SLE, regardless of how many autoantibodies were detected or how severe the clinical syndrome might be. This would allow manifestations of fullblown APS an appropriate impact towards the diagnosis of SLE without leading to a premature diagnosis of SLE for people who might better be considered to have moderate to severe primary APS.

Anti-nuclear antibody, anti-DNA, and aCL in Graves' disease patients treated with propyluracil or methimazole

One hundred and forty patients with Graves' disease [32 new patients, 54 treated with propylthiouracil (PTU) for a mean of 27.2 months and 54 treated with methimazole (MMI) for a mean of 48.6 months] were tested for anti-thyroid microsomal antibody (AMA), anti-thyroglobulin antibody (ATA), thyroid binding inhibitory immunoglobulin (TBII), and the non organ specific autoantibodies [i.e., anti-nuclear antibody (ANA), anti-double stranded DNA antibody (anti-dsDNA Ab), anti-cardiolipin antibody (aCL Ab) and anti-beta2-glycoprotein I antibody (IgG beta2GPI)]. Treatment with MMI or PTU produced a significant difference in IgG aCL Ab production but not in ANA, dsDNA Ab, IgM aCL or IgG beta2GPI. For those treated with MMI but not those treated with PTU, ANA and anti-dsDNA Ab were positively correlated. IgG and IgM aCL Ab were positively correlated overall and for those on MMI but not PTU treatment. No significant difference was found for any of the four non organ specific antibodies in AMA positive or negative patients but there was a significant difference in IgG aCL positivity rates for ATA positive and negative patients. On the other hand, ANA negative patients were significantly more likely to have higher TBII values. These results suggest that the appearance of the non organ specific autoantibodies is probably largely a coincidental effect of polyclonal activation - except, perhaps, for IgG aCL, which may be related to treatment.

Combined search for anti–β2-glycoprotein i and anticardiolipin antibodies in antiphospholipid syndrome: Contribution to diagnosis

In this study we sought to assess (1) the diagnostic value of a combined search for anti-beta(2)-glycoprotein (abeta(2)-GPIs) and anticardiolipin antibodies (aCLs) in primary (APS I) and secondary (APS II) antiphospholipid syndrome and (2) the influence of the beta(2)-GPI preparation in the ELISA's results. abeta(2)-GPI and aCL concentrations were assessed in 70 patients with APS and compared with those in 65 patients with systemic lupus erythematosus (SLE) without clinical features of APS. In APS patients (38 with APS I, 32 with APS II), the diagnosis had to have been made at least 3 years earlier; in subjects with SLE, the diagnosis had to have been made at least 5 years earlier. All serum samples were tested for abeta(2) -GPI with the use of an in-house ELISA with an abeta(2) -GPI preparation from human plasma. Samples negative for abeta(2) -GPI were controlled with 2 additional beta(2)-GPI preparations, 1 from human serum and 1 from bovine serum. In APS, abeta(2)-GPIs were more frequent than in SLE (76% and 15%, respectively; P <.0001), mainly with IgG isotype and with significantly higher levels than those found in SLE. The specificity for APS was 92% for IgG abeta(2)-GPIs and 68% for IgG aCLs. The highest association with APS was found for the combination of the 2 markers (odds ratio 29; 95% confidence interval 10-76; P <.0001). Among the APS patients, 6 were positive for aCL only and remained negative regardless of which beta 2 -GPI preparation was used; 1 patient was aCL-negative and only positive with human beta 2 -GPI. These data emphasize the heterogeneity of the APS immunologic profile and the diagnostic possibilities of both antibodies.

Diagnostic performance of anti-β2 glycoprotein I and anticardiolipin assays for clinical manifestations of the antiphospholipid syndrome

The objective of the present study was to analyse the performance of the tests for detection of anti-beta2 glycoprotein I (beta2 GP I) and anticardiolipin (aCL) antibodies for identification of clinical manifestations of the antiphospholipid syndrome (APS). Patients with systemic lupus erythematosus (SLE) as well as carriers of infectious diseases such as Kala-azar, syphilis and leptospirosis were studied. Particular interest was given to the presence of clinical complications related to APS. Anticardiolipin and anti-beta2 GP I antibodies were searched using an enzyme-linked immunosorbent assay (ELISA) assay. Clinical manifestations of APS were observed in 34 of the 152 patients (22.3%) with SLE and no patient with infectious disease had such manifestations. Antibodies to cardiolipin in moderate or high levels and anti-beta2 GP I were detected in 55 of 152 (36.1%) and 36 of 152 (23.6%) patients with SLE, respectively, and in 2 of 30 (6.6%) and 16 of 30 (53.3%) patients with Kala-azar, in 9 of 39 (23%) and 6 of 34 (17.6%) patients with leptospirosis, and 14 of 74 (18.9%) and 8 of 70 (11.4%) cases of syphilis, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR) of the anti-beta2 GP I test for the identification of the clinical manifestation of APS were, respectively, 29% [95% confidence interval (CI) = 24%-34%], 78% (95% CI = 73-83%), 15% (95% CI = 11-19%), 89% (95% CI = 85-93%) and 1.38. Regarding the aCL assay, the figure was 29% (95% CI = 24-34%), 76% (95% CI = 71-81%), 14% (95% CI = 10-18%), 89% (95% CI = 86-92%) and 1.26. As the validity and performance of the anti-beta2 GP I assay were similar to the aCL in demonstrating the presence of clinical phenomena associated with APS and due to the difficulties in performing as well as the lack of standardisation of the anti-beta2 GP I test, we suggest that the test for aCL should continue to be the first one performed when the presence of APS is suspected.

Antiphospholipid syndrome in pregnancy

PURPOSE OF REVIEW

Antiphospholipid syndrome is widely recognized as a risk factor for numerous obstetric complications including miscarriage, intrauterine growth restriction, preeclampsia, fetal death and preterm labour. The many recent changes in concept regarding this syndrome, the role of the relevant antibodies, mechanism of action, diagnosis and treatment are assessed in this review.

RECENT FINDINGS

In recent years, our understanding of antiphospholipid syndrome has grown. The antigen has become better defined and is now thought to be beta2 glycoprotein 1. The 'classical' antibodies, lupus anticoagulant and anticardiolipin antibody are known to be pathogenic even when passively transferred to animal hosts. It seems, however, that the pathogenic antibodies are those directed towards beta2 glycoprotein 1, and that those which are directed to phospholipids without binding to beta2 glycoprotein 1 may not be pathogenic, but merely epiphenomena. The treatment of this condition has also been changed due to the influence of randomized trials in which heparin or low molecular weight heparin has replaced the use of steroids.

SUMMARY

There are numerous pitfalls in managing this condition. As beta2 glycoprotein 1 antibodies are not usually tested, the condition may be over diagnosed or misdiagnosed. Similarly, the results of treatment are not usually corrected for confounding factors such as fetal chromosomal aberrations. In the absence of other confounding factors low molecular weight heparins are probably the treatment of choice.

Antiphospholipid syndrome

Antiphospholipid syndrome has received considerable attention from the medical community because of its association with a number of serious clinical disorders, including arterial and venous thromboembolism, acute ischemic encephalopathy, recurrent pregnancy loss, thrombocytopenia, and livido reticularis. It can occur within the context of several diseases, mainly autoimmune disorders, and is then called secondary antiphospholipid syndrome. However, it may be also be present without any recognizable disease, or so-called primary antiphospholipid syndrome. There is no defined racial predominance for primary antiphospholipid syndrome, although a higher prevalence of systemic lupus erythematosus (SLE) occurs in African Americans and the Hispanic population. Multiple terms exist for this syndrome, some of which can be confusing. Lupus anticoagulant syndrome, for example, is a misleading term, because patients may not necessarily have SLE, and it is associated with thrombotic rather than hemorrhagic complications. To avoid further confusion, antiphospholipid syndrome is currently the preferred term for this clinical syndrome. Antiphospholipid antibodies are found in 1% to 5% of young healthy control subjects; however, the incidence increases with age and coexistent chronic disease. The syndrome occurs most commonly in young to middle-aged adults; however, it also can occur in children and the elderly. Among patients with SLE, the prevalence of antiphospholipid antibodies is high, ranging from 12% to 30% for anticardiolipin antibodies, and 15% to 34% for lupus anticoagulant antibodies. In general, anticardiolipin antibodies occur approximately five times more often then lupus anticoagulant in patients with antiphospholipid syndrome. This syndrome is the most common cause of acquired thrombophilia, associated with either venous or arterial thrombosis or both. It is characterized by the presence of antiphospholipid antibodies, recurrent arterial and venous thrombosis, and spontaneous abortion. Rarely, patients with antiphospholipid syndrome may have fulminate multiple organ failure, or catastrophic antiphospholipid syndrome. This is caused by widespread microthrombi in multiple vascular beds, and can be devastating. Patients with catastrophic antiphospholipid syndrome may have massive venous thromboembolism, along with respiratory failure, stroke, abnormal liver enzyme concentrations, renal impairment, adrenal insufficiency, and areas of cutaneous infarction. According to the international consensus statement, at least one clinical criterion (vascular thrombosis, pregnancy complications) and one laboratory criterion (lupus anticoagulant, antipcardiolipin antibodies) should be present for a diagnosis of antiphospholipid syndrome. The hallmark result from laboratory tests that defines antiphospholipid syndrome is the presence of antibodies or abnormalities in phospholipid-dependent tests of coagulation, such as dilute Russell viper venom time. There is no consensus for treatment among physicians. Overall, there is general agreement that patients with recurrent thrombotic episodes require life-long anticoagulation therapy and that those with recurrent spontaneous abortion require anticoagulation therapy and low- dose aspirin therapy during most of gestation. Prophylactic anticoagulation therapy is not justified in patients with high titer anticardiolipin antibodies with no history of thrombosis. However, if a history of recurrent deep vein thrombosis or pulmonary embolism is established, long-term anticoagulant therapy with international normalized ratio (INR) of approximately 3 is needed.

Anti-cardiolipin antibodies in sera from patients with periodontitis

Antiphospholipid antibodies are commonly found in patients with systemic lupus erythematosus or the antiphospholipid syndrome, and a subset of such antibodies is associated with prothrombotic events such as stroke and with adverse pregnancy outcomes and fetal loss. We examined sera from 411 patients who were clinically characterized as to their periodontal disease status for serum levels of beta2-glycoprotein I-dependent anti-cardiolipin autoantibodies (anti-CL). The prevalence of patients with chronic periodontitis (CP) and generalized aggressive periodontitis (GAgP) positive for anti-CL (16.2% and 19.3%, respectively) was greater than that in healthy controls (NP) and localized aggressive periodontitis (LAgP) patients (6.8% and 3.2%). Patients with these autoantibodies demonstrated increased pocket depth and attachment loss compared with patients lacking the antibodies. Analysis of the data indicates that patients with generalized periodontitis have elevated levels of autoantibodies reactive with phospholipids. These antibodies could be involved in elevated risk for stroke, atherosclerosis, or pre-term birth in periodontitis patients.

The antiphospholipid syndrome

The antiphospholipid (aPL) antibody syndrome is an autoimmune condition in which vascular thrombosis and/or recurrent pregnancy losses occur in patients with laboratory evidence for antibodies that bind to phospholipids. There have been significant advances in the recognition of the role of phospholipid-binding cofactors, primarily beta2GPI, as the true immunologic targets of the antibodies. Recent evidence suggests that the antibodies disrupt phospholipid-dependent anticoagulant mechanisms and/or that aPL antibodies induce the expression of procoagulant and proadhesive molecules on endothelial cells. Current diagnosis is based on clinical findings and empirically derived tests, such as assays for antibodies that bind to phospholipids or putative cofactors and coagulation assays that detect inhibition of phospholipid-dependent coagulation reactions. Current treatment relies primarily on anticoagulant therapy. Research advances are expected to bring mechanistically based diagnostic tests and improved therapy that target the roots of the disease process.

Thrombophilia: what's a practitioner to do?

Management of thrombophilia is an ever-changing field as new disorders are described and additional clinical experience accrues. This paper addresses three common management issues in the care of patients with thrombophilia. The first two topics are updates for common but perplexing hypercoagulable states and the last topic introduces a new option for optimal management of oral anticoagulant therapy. Dr. Jacob Rand updates and organizes the approach to patients with antiphospholipid syndrome. This syndrome is a common acquired thrombophilic state, but the diagnosis and treatment of patients remains a challenge. Dr. Rand outlines his diagnostic and treatment strategies based on the current understanding of this complicated syndrome. Dr. Barbara Konkle addresses the special concerns of managing women with thrombophilia. Hematologists are often asked to advise on the risks of hormonal therapy or pregnancy in a woman with a personal or family history of thrombosis or with an abnormal laboratory finding. Dr. Konkle reviews the available data on the risks of hormonal therapy and pregnancy in women with and without known underlying thrombophilic risk factors. In Section III, Dr. Gail Macik will discuss a new approach to warfarin management. Several instruments are now available for home prothrombin time (PT) monitoring. Self-testing and self management of warfarin are slowly emerging as reliable alternatives to traditional provider-based care and Dr. Macik reviews the instruments available and the results of studies that support this new management option.

Optimising testing for phospholipid antibodies

AIM

To compare anticardiolipin (ACL) and anti-beta2 glycoprotein 1 (beta2gp1) enzyme linked immunosorbent assays (ELISAs) in the diagnosis of antiphospholipid syndrome (APS) and to incorporate these results into a meta-analysis of published data.

METHOD

Three representative commercial ACL ELISAs and an in house beta2gp1 assay were optimised and then assessed on 124 sera from normal donors, patients with infection, or patients with APS. A Medline search was screened for papers meeting defined criteria to conduct a meta-analysis. The performance of the assays used in this study was included.

RESULTS

A non-quantitative ACL assay performed at least as well as the anti-beta2gp1 assay in the diagnosis of APS. Meta-analysis confirmed that neither assay is perfect, although the anti-beta2gp1 assay had a higher specificity and lower sensitivity than the ACL assay.

CONCLUSIONS

The pooled data suggest that the ACL assay is used to investigate thrombosis without overt underlying pathology and that the improved specificity of the anti-beta2gp1 assay is exploited where infection, connective tissue disease, or atheroma are present.

Prevalence and isotype distribution of antiphospholipid antibodies in Chilean patients with systemic lupus erythematosus (SLE)

Previous studies have demonstrated that ethnicity plays a role in the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta2 glycoprotein I (abeta2-GPI) antibodies in systemic lupus erythematosus (SLE) patients. Few studies have been done in Latin American populations. Serum samples from 129 Chilean SLE patients were tested for IgG, IgM and IgA aCL and abeta2-GPI by ELISA. Clinical data were reviewed with the focus on clinical manifestations of antiphospholipid syndrome (APS). Positivity for at least one isotype of aCL was found in 30% of patients, while only 10% were positive for at least one isotype of abeta2-GPI. IgG was the most prevalent isotype for aCL (16%), and the isotype distribution was similar (4%) for abeta2-GPI. In general, the presence of aCL was significantly associated with the presence of abeta2-GPI, but a number of samples were positive for only one antibody, some of them associated with clinical manifestations of APS. ACL antibodies at medium-high titers were significantly correlated with thrombosis (P = 0.0007) and fetal loss (P = 0.009); however, the sensitivity of abeta2-GPI for detecting thrombosis and fetal loss was lower than aCL (19 and 17% vs 56 and 50%, respectively), and the specificity slightly higher (91 and 90% vs 84 and 82%). In Chilean SLE patients, aCL and abeta2-GPI antibodies are important in the evaluation of patients with APS. However, the utility of abeta2-GPI antibodies was limited by the low prevalence of these antibodies in comparison with other ethnic groups. Further studies are needed to define the basis of the observed differences among ethnic groups.

Cofactor dependence and isotype distribution of anticardiolipin antibodies in viral infections

BACKGROUND

Antibodies to cardiolipin (aCLs) are often detected in patients with autoimmune disorders or infectious diseases.

OBJECTIVE

To investigate the distribution of aCL isotypes and requirement of protein cofactor in viral infections in order to establish the importance, if any, of these antibodies in these infectious diseases.

PATIENTS AND METHODS

The isotype distribution of aCLs in the sera from 160 patients with infection caused by HIV-1 (n=40), hepatitis A virus (n=40), hepatitis B virus (n=40), or hepatitis C virus (n=40) was studied by standardised enzyme linked immunosorbent assay (ELISA) in the presence and absence of protein cofactor (mainly beta2-glycoprotein I). Serum samples from healthy volunteers and patients with syphilis and antiphospholipid syndrome were also included and served as negative and positive control groups respectively.

RESULTS

The prevalence of one or more aCL isotypes in serum of patients with HIV-1, hepatitis A virus, hepatitis B virus, or hepatitis C virus infection was 47%, 92%, 42%, and 17% respectively (principally IgM and/or IgA). Most of these antibodies were mainly cofactor independent.

CONCLUSIONS

The presence of aCLs in viral infections is principally cofactor independent, suggesting that cofactor dependence of the aCLs should be assessed to distinguish subjects most likely to suffer from clinical symptoms observed in the presence of these antibodies.

Thrombophilia: What's a Practitioner to Do?

Management of thrombophilia is an ever-changing field as new disorders are described and additional clinical experience accrues. This paper addresses three common management issues in the care of patients with thrombophilia. The first two topics are updates for common but perplexing hypercoagulable states and the last topic introduces a new option for optimal management of oral anticoagulant therapy. Dr. Jacob Rand updates and organizes the approach to patients with antiphospholipid syndrome. This syndrome is a common acquired thrombophilic state, but the diagnosis and treatment of patients remains a challenge. Dr. Rand outlines his diagnostic and treatment strategies based on the current understanding of this complicated syndrome. Dr. Barbara Konkle addresses the special concerns of managing women with thrombophilia. Hematologists are often asked to advise on the risks of hormonal therapy or pregnancy in a woman with a personal or family history of thrombosis or with an abnormal laboratory finding. Dr. Konkle reviews the available data on the risks of hormonal therapy and pregnancy in women with and without known underlying thrombophilic risk factors. In Section III, Dr. Gail Macik will discuss a new approach to warfarin management. Several instruments are now available for home prothrombin time (PT) monitoring. Self-testing and self management of warfarin are slowly emerging as reliable alternatives to traditional provider-based care and Dr. Macik reviews the instruments available and the results of studies that support this new management option.

Elevated anti-annexin V antibody levels in antiphospholipid syndrome and their involvement in antiphospholipid antibody specificities

To clarify the involvement of annexin V (ANX) in antiphospholipid antibody (APA) specificities, we studied antiANX antibodies (aANX) using 2 kinds of enzyme-linked immunosorbent assay plates (plain and gamma-irradiated) and anti-beta 2-glycoprotein I antibodies (a-beta 2GPI) in 53 patients with antiphospholipid syndrome (APS). The incidence of aANX IgG-positive results in the autoimmune APS group was significantly higher than that of healthy control subjects. However, we could not demonstrate a significantly higher incidence in the infection- or drug-induced group. Nor could we find an increased incidence of IgM isotype. When the 2 plates were compared, the discrepancies of positivity were demonstrated in both isotypes. We speculated that these discrepancies between the plate surfaces were attributed to the altered antigenicity of ANX. Although positivity of a-beta 2GPI was associated significantly with clinical manifestations, no significant associations were demonstrated between the incidence of aANX-positive results and clinical manifestations. We inferred that the involvement of aANX in the pathogenic mechanism of APS is unlikely.

Which are the best biological markers of the antiphospholipid syndrome?

The diagnosis of antiphospholipid syndrome (APS) requires the presence of both clinical and biological features. Due to the heterogeneity of anti-phospholipid antibodies (aPL) the laboratory approach for their detection includes clotting-based tests for lupus anticoagulant (LA) as well as solid-phase assays for anticardiolipin antibodies (aCL). In addition, as it has been shown that autoimmune aPL recognize epitopes on phospholipid (PL)-binding plasma proteins, assays detecting antibodies to beta 2-glycoprotein I (beta 2-GPI) or prothrombin have been developed. The association between venous or arterial thrombosis and recurrent fetal loss with the presence of conventional aPL (LA and/or aCL) has been confirmed by many studies. The LA and IgG aCL at moderate/high titre seem to exhibit the strongest association with clinical manifestations of the APS. Several reports indicate that LA is less sensitive but more specific than aCL for the APS. Assays against PLs other than CL as well as the use of mixtures of PLs have been proposed to improve the detection of APS-related aPL. Concerning antibodies to PL-binding proteins (detected in the absence of PLs), there is evidence that anti-beta 2-GPI are closely associated with thrombosis and other clinical features of the APS. Moreover, these antibodies may be more specific in the recognition of the APS and in some cases may be present in the absence of aPL detected by standard tests. Many issues are still under debate and are discussed in this review, such as the problems of standardization of anti-beta 2-GPI assays, detection of the IgA isotype of aCL and anti-beta 2-GPI, the coagulation profiles of LA in the recognition of the thrombotic risk and the association of particular markers with subsets of patients with APS.

Monocyte tissue factor induction by activation of beta 2-glycoprotein-I-specific T lymphocytes is associated with thrombosis and fetal loss in patients with antiphospholipid antibodies

Antiphospholipid (aPL) syndrome (APS) is characterized by thromboembolic events, thrombocytopenia, or recurrent miscarriage associated with aPL Abs with specificity for beta2-glycoprotein-I (beta2GPI). We recently reported that at least 44% of patients with the APS possess circulating type 1 (Th1) CD4+ T cells that proliferate and secrete IFN-gamma when stimulated with beta2GPI in vitro. In this study, we show that stimulation of PBMCs from 20 APS patients with beta2GPI induced substantial monocyte tissue factor (TF) (80 +/- 11 TF stimulation index (TF-SI)), whereas no induction was observed using PBMCs from 13 patients with aPL Abs without APS (6 +/- 1 TF-SI) or 7 normal and 7 autoimmune controls (5 +/- 1 and 3 +/- 1 TF-SI, respectively) (p < 0.0001). TF induction on monocytes by beta2GPI was dose dependent and required CD4+ T lymphocytes and class II MHC molecules. Because monocyte TF induction by beta2GPI was observed in all patients with APS, but not in any patient with aPL Abs without APS, this response is a potentially useful predictor for APS in patients with aPL Abs, as well as providing mechanistic insight into thrombosis and fetal loss in these patients.

beta2-Glycoprotein 1 as a marker of antiphospholipid syndrome in women with recurrent pregnancy loss

OBJECTIVE

To determine if beta2-glycoprotein 1 (beta2-GP1) antibodies are a better marker of the antiphospholipid antibody syndrome (APS) in women with recurrent pregnancy loss (RPL).

DESIGN

Evaluation and testing of sera from women with RPL.

SETTING

A university-affiliated reproductive endocrinology practice.

PATIENT(S)

90 women with RPL; 45 women met criteria for APS and 45 women met criteria for RPL without antiphospholipid antibodies (APA). Both groups were of similar age and had a similar history of RPL.

INTERVENTION(S)

Patient sera were obtained from women with RPL and were tested for APA and beta2-GP1.

MAIN OUTCOME MEASURE(S)

A standard antiphospholipid antibody assay was employed to detect the presence of immunoglobulin (Ig)G, IgM, and IgA antibodies in serum against cardiolipin, phosphatidyl inositol, phosphatidyl glycerol, phosphatidyl serine, and phosphatidyl ethanolamine. Samples were also assayed with a commercial beta2-GP1 assay for IgG antibodies.

RESULT(S)

Among the 45 women with APS, 10 (22.2%) had positive IgG antibodies for beta2-GP1. Only 1 woman (2.2%) of 45 was positive for beta2-GP1 among the control group of women with RPL but negative APA. There was no correlation noted among the beta2-GP1-positive patients for a specific phospholipid antibody or isotype.

CONCLUSION(S)

These data suggest that IgG beta2-GP1 antibodies are less sensitive than antiphospholipid antibodies for the diagnosis of APS.

Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered beta2-glycoprotein I

OBJECTIVE

To investigate the in vitro ability of antiphospholipid antibodies (aPL) to bind human trophoblast cells and to affect gonadotropin secretion and invasiveness.

METHODS

Antiphospholipid antibody IgG from women with recurrent miscarriages, beta2-glycoprotein I (beta2GPI)-independent IgG aPL human monoclonal antibody (mAb) (519), and IgM anti-beta2GPI human mAb (TMIG2) were investigated for their binding to trophoblasts cultured for various amounts of time, their ability to affect invasiveness of Matrigel-coated filters, and their release of human chorionic gonadotropin (hCG).

RESULTS

Polyclonal IgG aPL, as well as mAb 519 and TMIG2, bound to trophoblasts, the highest binding being found when cells displayed the greatest amount of syncytium formation. TM1G2 binding was found to be betaGPI dependent. Both polyclonal and monoclonal aPL, but not the controls, significantly reduced hCG release and Matrigel invasiveness.

CONCLUSION

These findings suggest that aPL recognition of both anionic PL and adhered beta2GPI on trophoblast cell structures might represent a potential pathogenetic mechanism for defective placentation in women with the antiphospholipid syndrome.

Anti-beta2-glycoprotein I antibodies in patients with acute venous thromboembolism: prevalence and association with recurrent thromboembolism

To establish the prevalence of antibodies against beta2-glycoprotein I (beta2GPI) in unselected patients with venous thromboembolism, as well as the association with antiphospholipid antibodies (aPL) and a history of previous thromboembolism, we investigated the presence of these antibodies in 227 consecutive patients with acute deep vein thrombosis or pulmonary embolism, of whom 63 were carriers of aPL with or without lupus anticoagulant (LA), and seven were carriers of LA alone. The presence of antibodies against beta2GPI was demonstrated in 19 patients [8.4%; 95% confidence interval (CI), 4.5-11.3%]. All of them belonged to the group of 63 patients with aPL (30.2%). A history of a previous thromboembolism was identified in 11 of the 19 patients with anti-beta2GPI antibodies (57.9%) and in 45 of the 208 patients without these antibodies [21.6%; odds ratio (OR)=4.98; 95% CI, 1.89-13.1; p<0.0005]. In the subgroup of patients with aPL and/or LA, the rate of recurrent thromboembolism among patients with anti-beta2GPI antibodies (11 of 19, 57.9%) was significantly higher than that observed in patients without these antibodies (15 of 51, 29.4%; OR=3.3; 95% CI, 1.1-9.83; p=0.28). We conclude that in patients with acute venous thromboembolism the prevalence of antibodies against beta2GPI is unexpectedly high. The presence of these antibodies seems to identify a subgroup of patients with antiphospholipid antibodies who have a peculiarly high risk of thrombotic recurrences. Further prospective studies are indicated to better define the role of anti-beta2GPI antibodies in the development of recurrent thromboembolism.

Do antibodies to beta2-glycoprotein 1 contribute to the better characterization of the antiphospholipid syndrome?

The aim of this study was to determine if the measurement of anti-beta2-glycoprotein I antibodies (abeta2-GPI) in serum levels contributes to the better characterization of the clinical situation of patients with antiphospholipid syndrome (APS). For this purpose abeta2-GPI of both isotypes was measured in 42 patients with APS and 32 SLE patients without APS. Clinical records of all patients were thoroughly reviewed. The presence of abeta2-GPI was correlated with the clinical manifestations of APS and compared with the presence of anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) activity. There was a positive correlation between levels of aCL and abeta2-GPI for both IgG and IgM isotypes (rho of Spearman=0.82 and 0. 64 respectively, P=0.0001). Both antibodies presented significantly higher titres in LA positive patients (P<0.05). The specificity for APS was 91% for IgG abeta2-GPI vs 75% for IgG aCL and 87% for IgM abeta2-GPI vs 81% for IgM aCL. 68% of patients with thrombosis of 100% of patients with thrombocytopenia showed positive tests for all three markers (aCL, LA, abeta2-GPI). Simultaneous presence of circulating LA and high titres of both aCL and abeta2-GPI identify a subset of patients with primary APS (PAPS) who have a more severe clinical course of the disease. Although the specificity of abeta2-GPI IgG is higher than that of aCL IgG, when all three tests are performed abeta2-GPI testing provides only additional information to that of aCL and LA. Therefore, we concluded that the abeta2-GPI test should not be considered as a substitute for conventional LA or aCL assays. However, performance of abeta2-GPI seems to be important in PAPS with high aCL titres, to alert the physician about the risk for the worst course of the illness.

Anti-beta2-glycoprotein I antibodies in women with recurrent spontaneous abortion, unexplained fetal death, and antiphospholipid syndrome

OBJECTIVE

Studies in rheumatologic and hematologic populations suggest that anti-beta(2)-glycoprotein I antibodies are more specific for the clinical manifestations of antiphospholipid syndrome than anticardiolipin antibodies. However, the association between anti-beta(2)-glycoprotein I and pregnancy loss remains uncertain. We sought to determine whether anti-beta(2)-glycoprotein I is associated with the obstetric features of antiphospholipid syndrome.

STUDY DESIGN

Sera from 4 groups of women were studied: (1) 152 healthy fertile control subjects, (2) 141 subjects with unexplained recurrent spontaneous abortions, (3) 58 subjects with unexplained fetal deaths, and (4) 73 subjects with well-characterized antiphospholipid syndrome. Serum anticardiolipin and anti-beta(2)-glycoprotein I levels were determined by enzyme-linked immunoassay.

RESULTS

Patients with antiphospholipid syndrome had significantly higher levels of immunoglobulin G and immunoglobulin M anticardiolipin and anti-beta(2)-glycoprotein I than the other 3 groups (P <.0001). However, women in the recurrent spontaneous abortion, fetal death, and fertile control groups had similar levels of each antibody. Similarly, there were no differences in the proportion of women with positive test results for each autoantibody in these 3 groups. Linear regression analysis showed significant correlation between anticardiolipin immunoglobulin G and beta(2)-glycoprotein I immunoglobulin G (R (2) = 0.544786, P =.0001) and anticardiolipin immunoglobulin M and beta(2)-glycoprotein I immunoglobulin M (R (2) = 0.525048, P =.0001).

CONCLUSION

Both anticardiolipin and anti-beta(2)-glycoprotein I are associated with antiphospholipid syndrome. However, testing for anti-beta(2)-glycoprotein I does not identify additional patients with either recurrent spontaneous abortions or unexplained fetal deaths who initially have negative test responses for anticardiolipin. This is likely because of the strong correlation between the 2 autoantibodies. Our data do not support routine testing for anti-beta(2)-glycoprotein I in addition to testing for antiphospholipid antibodies in women with recurrent pregnancy loss and unexplained fetal death.

Anticardiolipin and anti-beta2glycoprotein-I antibodies in patients with systemic lupus erythematosus: comparison between Colombians and Spaniards

We studied the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta2glycoprotein I (anti-beta2GPI) antibodies in two populations of patients with systemic lupus erythematosus (SLE), 160 Colombians and 160 Spaniards. All sera were tested in our laboratory by enzyme-linked immunosorbent assay (ELISA) for IgG, IgM, and IgA aCL, as well as IgG and IgM anti-beta2GPI. Positive results for at least 1 of the 3 aCL isotypes were found in 40 Colombians (25%) and 55 Spaniards (34%). IgG aCL was the predominant isotype in both populations. Positive results for at least 1 of the anti-beta2GPI isotypes were found in 34 Colombians (21%) and 29 Spaniards (18%). IgG anti-beta2GPI was the dominant isotype in Colombians, while IgM was predominant in Spaniards. Positivity for anti-beta2GPI in aCL-positive patients was present in 77% in the Colombian group and 50% in the Spaniard group. Among Colombians, IgG aCL and anti-beta2GPI correlated with thrombosis, fetal loss, and thrombocytopenia. Among Spaniards, IgG aCL and IgG anti-beta2GPI correlated with thrombosis, fetal loss, and livedo reticularis. For detecting thrombosis and fetal loss, aCL ELISA was more sensitive than anti-beta2GPI in Spaniards, and anti-beta2GPI ELISA was more specific than aCL in both populations.

Correlation between beta 2-glycoprotein antibodies and antiphospholipid antibodies in patients with reproductive failure

PROBLEM

Antiphospholipid antibodies (APAs) are important in the etiology of reproductive failure. Studies have shown that binding proteins are necessary for the detection of APAs. One of these, beta 2-glycoprotein, has been shown to be necessary for detection of anticardiolipin antibodies. It is felt that some APAs may be directed to the binding protein itself, or to a combination of the binding protein and phospholipid.

METHOD OF STUDY

In this study, a comparison of APAs vs. anti beta 2-glycoprotein antibodies was performed on the sera of 123 women younger than 40 years of age with a history of reproductive failure. Antibodies to six phospholipid epitopes, cardiolipin, phosphatidyle-thanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, phosphatidylglycerol, and phosphatidylserine, were measured.

RESULTS

Of the 123 women tested, 33 had one or more positive immunoglobulin (Ig)G antibodies to phospholipids, of which 9 were to cardiolipin. However, only 1 of 123 women had IgG antibodies to beta 2-glycoprotein and she was APA negative. Thirty-eight of 123 women had one or more IgM antibodies to phospholipids, with none directed to cardiolipin IgM. In contrast, only 8 of the 123 women had IgM antibodies to beta 2-glycoprotein. Five of the eight patients had IgM APA; 4 of 5 had IgM antibodies to PE, 1 to PI.

CONCLUSIONS

There is no correlation between beta 2-glycoprotein antibodies and APA status in this population. To date, our most sensitive test for detecting phospholipid autoimmune-mediated in vitro fertilization failure still appears to be the ELISA assay for APA.

Many faces of lupus anticoagulants

Lupus anticoagulants (LA) are immunoglobulins which inhibit one or more of the in-vitro phospholipid (PL) dependent tests of coagulation. Virtually any physician may encounter LA-positive patients. Such patients present with a variety of diagnostic challenges including arterial and venous thromboembolic events, recurrent fetal loss, TIAs, livedo reticularis, etc. LA and anticardiolipin antibodies (ACA) are the most common cause of acquired thrombophilia. Consequently, it is imperative for clinicians and laboratorians to work together in establishing the diagnosis of LA/ACA. The laboratory diagnosis of LA requires careful adherence to the SSC Subcommittee on Lupus Anticoagulants/Phospholipid-dependent Antibodies guidelines. Four sequential steps are required, including: screening tests, mixing studies (to establish the presence of an inhibitor), confirmatory tests based on increased or altered PL concentrations, and ruling out other coagulopathies (for example, factor VIII inhibitor).

Cerebrovascular ischemic events with high positive anticardiolipin antibodies

BACKGROUND AND PURPOSE

The aim of our study was to characterize the patient profile and prognostic value associated with high positive IgG (>100 GPL) anticardiolipin antibodies (aCL).

METHODS

We studied the clinical, laboratory, radiological, and prospective historical features of ischemic cerebrovascular disease in patients with >100 GPL titers. From our neurology department, 27 consecutive patients were prospectively identified and followed up (mean follow-up time, 34 months).

RESULTS

The mean age of our cohort was 41 years. Lupuslike illness occurred in 3; 23 had primary antiphospholipid syndrome, including 3 who met criteria for Sneddon's syndrome; 1 patient had progressive systemic sclerosis. Cerebral infarcts occurred in 74% and were recurrent in 37%. Systemic ischemic events, most commonly deep vein thrombosis, occurred in 37%. Tobacco use was documented in 85%, hyperlipidemia in 74%, hypertension in 44%, and diabetes mellitus in 7% of patients. A prominent headache history was present in 67%. Lupus anticoagulant (LA) was present in 72%, approximately one half had positive antinuclear antibodies and thrombocytopenia, and one quarter had a false-positive VDRL. We compared mean GPL levels in patients testing positive for specific laboratory features of antiphospholipid syndrome with those testing negative for these parameters. Only the LA(+) group had a significantly higher mean GPL than the LA(-) group (P=0.006). Brain imaging showed nonlacunar infarcts in 73% and lacunes in 12%. Of 19 cerebral angiograms, 5 (26%) showed large-vessel occlusive disease and 6 (32%) branch obstruction. Echocardiograms were abnormal in 75%: thickened left-sided valves in 33% and vegetations in 12%. Recurrent cerebrovascular ischemic events were observed in 96%, with transient events (mean rate, 25%/y) occurring 5 times more frequently than strokes (mean rate, 5%/y). Using a standardized disability scale blinded to aCL titer, neurological impairment was severe in 7%, moderate in 30%, and mild or nonexistent in 63%, and unrelated to mean GPL value (P=0.567). Titers fluctuated greatly for individual patients, and most did not consistently test as highly positive. An analysis of fluctuation in symptom severity with concurrent GPL values did not show a statistically significant correlation. Compared with historical controls having a wide range of positive titers, the presence of high IgG aCL titers did not confer a worse prognosis for disability and recurrent ischemic events.

CONCLUSIONS

Our data suggest that cerebrovascular events associated with high positive GPL are frequently multiple and minor (with no disability-titer correlation), present in relatively young patients, and often associated with tobacco abuse, hyperlipidemia, LA, systemic ischemic events, and occult cardiac disease.