Lupus anticoagulant: an analysis of the clinical and laboratory features of 219 cases

A Brief History of Hemostasis and Thrombosis at the Mayo Clinic

Coagulation is a crucial biological mechanism in human bodies to prevent blood loss. Abnormal coagulation can cause bleeding diathesis or thrombosis, common pathologic conditions in our clinical practice. Many individuals and organizations have dedicated their efforts in the past decades to understanding the biological and pathological mechanisms of coagulation and developing laboratory testing tools and treatment options to help patients with bleeding or thrombotic conditions. Since 1926, the Mayo Clinic coagulation group has made significant contributions to the clinical and laboratory practice, basic and translational research on various hemostatic and thrombotic disorders, and the education and collaboration to share and advance our knowledge in coagulation through a highly integrated team and practice model. We would like to use this review to share our history and inspire medical professionals and trainees to join the efforts to advance our understanding of coagulation pathophysiology and improve our care for patients with coagulation disorders.

Venous Thromboembolism in Pregnancy: Challenges and Solutions

Venous thromboembolism (VTE) is a serious medical condition that can lead to severe morbidity and mortality, making it a significant public health concern. VTE is a multifactorial condition that results from the interaction of genetic, acquired, and environmental factors. Physiological changes during pregnancy increase the risk of VTE as they express Virchow's triad (increased coagulation factors, decreased fibrinolysis, trauma, and venous stasis). Moreover, pregnancy-related risk factors, such as advanced maternal age, obesity, multiple gestations, and cesarean delivery, further increase the risk of VTE. Managing VTE in pregnancy is challenging due to the complexity of balancing the risks and benefits of anticoagulant therapy for both the mother and the fetus. A multidisciplinary approach involving obstetricians, hematologists, and neonatologists, is necessary to ensure optimal outcomes for both the mother and baby. This review aims to discuss the current challenges associated with VTE in pregnancy and identify potential solutions for improving outcomes for pregnant women at risk for VTE.

Evaluating hypercoagulability in new-onset systemic lupus erythematosus patients using thromboelastography

Background

Thromboelastography (TEG) can reflect the coagulation status in vivo, from clot formation to clot lysis. In the present study, we aimed to evaluate the function of TEG in detecting coagulation in patients with SLE and sought to explore the correlation between clinical and laboratory data.

Methods

A total of 41 patients with new‐onset SLE who had not undergone treatment and 56 healthy controls were included. TEG and other laboratory tests were performed, and clinical data were collected.

Results

A significant difference in the TEG reaction time and TEG achievement of clot firmness was observed between the groups. Moreover, these parameters were correlated with the lupus anticoagulant levels, platelet count, 24‐hour urinary total protein quantity, and systemic lupus erythematosus disease activity index.

Conclusion

Our study demonstrated the prospective value of TEG in evaluating hypercoagulability in patients with SLE.

Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation

Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.

Familial antiphospholipid antibodies and acquired circulating anticoagulants

Familial clustering of elevated antiphospholipid antibody levels has been described, but the reports are heterogeneous with regard to the characterization of the antiphospholipid syndrome (APS), coexisting autoimmune diseases and clinical implications. We report a familial occurrence of APS in two patients, in the presence of SLE in the mother and absence of autoimmune diseases in the daughter along with acquired circulating inhibitors in both cases: platelet inhibitor and factor IX inhibitor, respectively.

Clinicohematologic Spectrum in Patientswith Lupus Anticoagulant

A retrospective analysis of clinicohematologic parameters of 25 patients with lupus anticoagulant was carried out. The hematologic tests included dilute Russel viper venom test (dRVVT), kaolin clotting time (KCT), activated partial thromboplastin time, and prothrombin time. The diagnosis of lupus anticoagulants was based on the presence of prolonged KCT/dRVVT, its absence of correction with normal plasma and correction by phospholipids. Specific factor assays and platelet aggregation studies were performed wherever required. Ten patients (40%) had thrombosis, which was venous in 5 (50%) and arterial in 4 (40%). One patient (10%) had both arterial and venous thrombosis and presented with catastrophic antiphospholipid syndrome. Eighteen female patients conceived. Four (22%) of these had recurrent first trimester abortion. Five (20%) patients had bleeding manifestations. One (4%) of these had hypoprothrombinemia and was diagnosed to have hypoprothrombinemia lupus anticoagulant syndrome. However in two of these patients, no cause of bleeding could be identified other than the presence of lupus anticoagulants. It is concluded that patients with lupus anticoagulant have a varied spectrum of hemostatic disorders. Bleeding may sometimes occur in these patients due to associated thrombocytopenia or associated factor inhibitors. Rarely, it may occur due to presence of lupus anticoagulants alone.

Lupus Anticoagulant, Antiphospholipid Antibodies and Migraine

The records of fifteen patients referred for neurological assessment and found to have lupus anticoagulant or elevated anticardiolipin antibodies were reviewed. The mean age for females in the group was 29.4 years and for males was 35. A diagnosis of migraine, either as an acute or chronic problem, was made in 10 (66%) of these patients. Seven of the 15 patients had ischemic stroke and two patients had other thrombotic complications associated with lupus anticoagulant. Three of the nine female patients with migraine had histories of spontaneous abortions. All migraine patients experienced transient or more prolonged neurological deficits with their headaches. An association between lupus anticoagulant and migraine can only be suggested. Data on the incidence of migraine in patients with lupus anticoagulant in the general medical population does not exist. Furthermore the prevalence of lupus anticoagulant in migraine sufferers is unknown. Therefore further studies are required to investigate this possible association.

Lupus anticoagulants and anticardiolipin antibodies in Indian women with spontaneous, recurrent fetal loss

Spontaneous and recurrent pregnancy loss are common complications of pregnancy resulting from varied causes including antiphospholipid syndrome (APS). Treatment of women with APS increases the chance of a subsequent successful pregnancy. The study aimed to find the prevalence of lupus anticoagulants (LA) and anticardiolipin antibodies (ACAs) in women with spontaneous/recurrent fetal loss and compare with women with normal obstetric history. Hundred women with spontaneous/recurrent fetal loss and 50 healthy pregnant controls were tested for LA by complete blood counts, Prothrombin time, Activated partial thromboplastin time (APTT), LA sensitive APTT and dilute Russell viper venom time (dRVVT) (screening and confirmatory) and ACAs (ELISA). LA was detected in 15 % patients using dRVVT confirmatory test and ACA in 5 %, all controls being negative. Twenty one % patients were detected by LA sensitive APTT (sensitivity 92.9 %, specificity 100 %) and 100 % with dRVVT screening test (sensitivity 98.8 %, specificity 100 %). We recommend that screening for antiphospholipid antibodies must be done in women with spontaneous/recurrent foetal loss even in the absence of other clinical manifestations using a combination of tests.

Monitoring anticoagulation in patients with an unreliable prothrombin time/international normalized ratio: factor II versus chromogenic factor X testing

The international normalized ratio (INR) can be unreliable in patients with lupus anticoagulants (LACs) or other conditions affecting baseline testing. Alternative methods to assess anticoagulation on warfarin through measures of vitamin K-dependent factor activity by clot based or chromogenic assays may be necessary. In this patient population, the ideal method is unknown. Thirty-six patients stable on warfarin with LAC or unreliable INR testing had an INR, a prothrombin time-based clotting assay for factor II (FII) activity, and a chromogenic assay for factor X (CFX) activity were performed simultaneously. Eighty-nine sets of measurements were obtained of which 83 sets included all three assays. CFX and FII levels were well correlated (r = 0.92) in all patients and in 26 patients with a documented antiphospholipid antibody (r = 0.93). Parallel testing was seen in 99% of FII assays. Sixty-one percent of CFX and 57% of FII were within the therapeutic range. In 32 CFX and FII pairs wherein assessment of anticoagulation was discordant, 16 CFX agreed with INR and 13 FII agreed with INR (McNemar's, χ = 0.14, P = 0.7). The number of times tests were discrepant was not statistically different between CFX and FII (P = 0.36). CFX and FII activity are well correlated in patients that require alternative monitoring of warfarin. Either test can be used in this population.

Autonomic dysfunction and primary antiphospholipid syndrome: a frequent and frightening correlation?

INTRODUCTION

the correlation between primary antiphospholipid syndrome (APS) and cardiovascular events is well known, but the correlation between APS and sudden death is not clear; it probably correlates with sympathetic alterations of the autonomic system.

AIM

To compare the autonomic nervous system (ANS) in a group of subjects suffering from APS against that of a control group with no cardiovascular risk factors, matched for age, sex, and body mass index.

SUBJECTS AND METHODS

An equal number (n = 31) of subjects with APS, and healthy controls, underwent autonomic evaluation: tilt test, deep breath, Valsalva maneuver, hand grip, lying-to-standing, Stroop, and sweat tests.

RESULTS

Cases in the APS group were positive for the tilt test, relating to changes in respiratory rate intervals, by comparison with controls. Results of other tests were also altered significantly in APS cases, by comparison with controls. (The sweat and Stroop tests were only performed in 14 cases). Autonomic disease did not correlate with age, sex, history of disease, arterial or venous thrombosis, or antibody positivity; only their coagulation parameters correlated with autonomic dysfunction.

CONCLUSION

Autonomic dysfunction in APS seems to correlate with coagulation parameters. APS patients should receive autonomic evaluation, to minimize the risks of fatal arrhythmias and sudden death.

Antiphospholipid antibody syndrome

Antiphospholipid antibodies are directed against phospholipid-protein complexes and include lupus anticoagulant, anticardiolipin antibodies, and anti-beta-2 glycoprotein I antibodies. Antiphospholipid antibody syndrome is a common cause of acquired thrombophilia and is characterized by venous or arterial thromboembolism or pregnancy morbidity and the presence of antiphospholipid antibodies. Antibodies should be demonstrable on at least 2 occasions separated by 12 weeks. Heterogeneity of the autoantibodies and absence of gold standard assays makes interpretation of laboratory results a challenge for both laboratorians and clinicians. This review discusses the key laboratory and clinical aspects of antiphospholipid antibody syndrome. Particular focus is given to lupus anticoagulant detection, in view of recently updated laboratory guidelines.

Elevated anticardiolipin antibodies in schizophrenic patients before and during neuroleptic medication

The objective of this study was to examine the prevalence of IgG and IgM anticardiolipin antibodies (aCL) in schizophrenic patients and to determine the relation of aCL levels with neuroleptic medication and psychotic symptoms. Twenty-three patients with acute episodes of chronic schizophrenia, drug-free for at least 3 months before entering the study, were tested for aCL at admission (T1) and 42 days (T2) after neuroleptic treatment started. Blood samples were taken from 20 healthy volunteers as well. Diagnosis was performed according to DSM-IV. Serum samples were analysed for IgG and IgM autoantibodies against beta2-glycoprotein-1-cardiolipin complex by commercially available ELISA kits (Binding-site, UK). Significantly higher levels of aCL antibodies of both isotypes were found in schizophrenic patients versus controls. In patients IgM-aCL positivity was significantly more frequent than in controls. The elevated IgM-aCL and IgG-aCL values were not associated with neuroleptic treatment and psychotic symptoms, as measured by the Positive and Negative Syndrome Scale and the Pentagonal Structural Model of Schizophrenic Symptoms. The negative correlation of IgM-aCL and IgG-aCL with the positive symptoms scale and the autistic preoccupation scale (Pentagonal Structural Model) may indicate the consumption of these antibodies in the exacerbation of the disease.

The clinical significance of anti-prothrombin antibodies for risk assessment of thromboembolism in patients with lupus anticoagulant

INTRODUCTION

Thromboembolism is a common manifestation of lupus anticoagulant (LA), however only a subgroup of LA-patients is affected by thrombosis. Study objective was to investigate whether anti-prothrombin antibodies can identify LA-patients at increased risk for thrombosis.

MATERIALS AND METHODS

In total 79 patients, 50 with (42 men/8 women) and 29 without thrombosis (21 men/8 women), were investigated for their presence of anti-prothrombin IgG and IgM antibodies using assays from two different manufacturers (Aeskulisa=assay I, CoaChrom=assay II).

RESULTS

The prevalence of elevated levels of anti-prothrombin IgG, IgM as well as IgG and/or IgM antibodies was 66% [assayI] (36% [assayII]), 38% (24%) and 72% (50%) in patients with thrombosis and 55% (24%), 28% (28%) and 66% (41%) in patients without thrombosis, respectively. Neither anti-prothrombin IgG or IgM nor IgG and/or IgM antibodies were found to indicate an increased risk for thrombosis. In the subgroup of patients with arterial or venous thrombosis there was also no association between anti-prothrombin antibodies and thrombosis. The comparison of median levels of IgG and IgM anti-prothrombin antibodies between patients with and without thrombosis yielded a borderline statistically significant difference only for anti-prothrombin IgG antibodies by using assay II (p=0.033), all other comparisons were not statistically significant.

CONCLUSIONS

In conclusion, presence of anti-prothrombin antibodies was not associated with thromboembolism in LA-patients.

Antibodies to lipids and liposomes: immunology and safety

Naturally occurring antibodies to phospholipids and cholesterol are widespread; they occur commonly during the course of acute infections; they are not causally related to the anti-phospholipid syndrome; they have been associated with other clinical entities only as an epiphenomenon; and they have not been implicated as causing any clinical syndrome or disease. There are theoretical and experimental reasons to believe that normal cells and tissues are protected from binding of antibodies to bilayer lipids by steric hindrance due to adjacent larger molecules, such as large or charged adjacent glycolipids or proteins on the cell surface. There are also reasons to believe that certain natural antibodies to lipids can even serve useful normal functions. Antibodies to liposomal lipids induced by liposomes containing lipid A appear to have characteristics that are similar or identical to naturally occurring antibodies to lipids, and it is therefore believed that such antibodies would not cause adverse clinical effects. Numerous Phase I and II human clinical trials of experimental vaccines containing liposomes and lipid A have shown a high level of safety.

Antiphospholipid syndrome in systemic lupus erythematosus: is the whole greater than the sum of its parts?

This article compares the manifestations of systemic lupus erythematosus (SLE) in the presence and absence of antiphospholipid antibodies (aPLs), the hallmark autoantibodies of antiphospholipid syndrome (APS). The combination of SLE and APS appears to be of greater concern than either entity alone. APS complicates SLE by adding a vaso-occlusive factor to the inflammatory component that adversely affects the prognosis of those who have lupus and aPLs. The increase in both morbidity and mortality when both are present has significant therapeutic implications. Anticoagulation may be a safer and more appropriate therapeutic option than instituting a regimen of corticosteroids and immunosuppressive agents with all their attendant adverse effects. It falls upon the physician to clearly define the disease entity and fully evaluate the disease process.

Antiphospholipid syndrome with catastrophic bleeding and recurrent ischemic strokes as initial presentation of systemic lupus erythematosus

Bleeding is a rare manifestation of lupus anticoagulant-antiphospholipid syndrome unless associated with coagulation factor deficiency, thrombocytopenia, or intrinsic vascular defect. The authors report the clinical and laboratory findings in a 16-year-old boy with potent lupus anticoagulant who initially presented with recurrent epistaxis, hematuria, and gastrointestinal bleeding. Lupus anticoagulant potently inhibited assay systems for coagulation factors, but levels of factors II, IX, and XI appeared to be decreased (2-5% of mean normal levels). Within 2 weeks after diagnosis, spontaneous subdural hematomas developed. During hemostatic therapy, including plasmapheresis and infusions of recombinant activated factor VII and activated prothrombin complex concentrate, an ischemic stroke developed. Subsequent multifocal recurrent ischemic strokes developed despite immunosuppression. This case shows that lupus anticoagulant or antiphospholipid antibodies can cause both hemorrhagic and thrombotic complications in the same patient and may, in some patients, have multiple target antigens (eg, coagulation factors II, IX, XI).

Treatment of antiphospholipid syndrome in pregnancy--a systematic review of randomized therapeutic trials

A comprehensive literature search identified 13 randomized or quasi-randomized therapeutic trials of obstetric antiphospholipid syndrome (aPL) syndrome and all but one are appraised. Several overriding problems with trial design were evident: (i) small trial size, (ii) absence of blinding, (iii) lack of no treatment arms and (iv) highly variable entry criteria, treatments and endpoint definitions leading to trial clinical heterogeneity. Low-dose aspirin and heparin is recommended for obstetric antiphospholipid syndrome but the evidentiary basis for this remains weak. There is no evidence to support treatment with intravenous immunoglobulin or prednisone. Ideally, co-operative large fully blinded placebo controlled randomized trials of therapy in patients with obstetric aPL stratified by different levels of risk are still required.

Drug-induced lupus

Autoantibodies and, less commonly, systemic rheumatic symptoms are associated with treatment with numerous medications and other types of ingested compounds. Distinct syndromes can be distinguished, based on clinical and laboratory features, as well as exposure history. Drug-induced lupus has been reported as a side-effect of long-term therapy with over 40 medications. Its clinical and laboratory features are similar to systemic lupus erythematosus, except that patients fully recover after the offending medication is discontinued. This syndrome differs from typical drug hypersensitivity reactions in that drug-specific T-cells or antibodies are not involved in induction of autoimmunity, it usually requires many months to years of drug exposure, is drug dose-dependent and generally does not result in immune sensitization to the drug. Circumstantial evidence strongly suggests that oxidative metabolites of the parent compound trigger autoimmunity. Several mechanisms for induction of autoimmunity will be discussed, including bystander activation of autoreactive lymphocytes due to drug-specific immunity or to non-specific activation of lymphocytes, direct cytotoxicity with release of autoantigens and disruption of central T-cell tolerance. The latter hypothesis will be supported by a mouse model in which a reactive metabolite of procainamide introduced into the thymus results in lupus-like autoantibody induction. These findings, as well as evidence for thymic function in drug-induced lupus patients, support the concept that abnormalities during T-cell selection in the thymus initiate autoimmunity.

Apolipoprotein and anticardiolipin antibodies in patients with renal amyloidosis

BACKGROUND

Thromboembolic events are seen more frequently in patients with chronic renal failure (CRF) and amyloidosis. The anticardiolipin antibody (ACA) that is important for thromboembolic events has never been studied.

METHODS

This study included 43 amyloidosis patients of different aetiologies; 28 with CRF as well as 20 patients who had CRF without amyloidosis. Thirty normal subjects were included as a control group. We determined the serum levels of ACA, apolipoprotein AI (ApoAl), ApoE and lipoprotein (a) (Lp(a)) in these groups.

RESULTS

Anticardiolipin antibody was found to be positive in 30.2% of patients with amyloidosis, this is in contrast to 3.3% in the control group (chi = 8.25, P < 0.005). We also showed that there was a statistically significant difference (chi = 5.03, P < 0.05) between the CRF patients with amyloidosis (31%) and the CRF patients without amyloidosis (5%). The average levels of serum ApoAI were shown to be significantly lower (P < 0.05) in CRF patients with amyloidosis in comparison with the amyloidosis patients who had normal renal functions (93.60 +/- 27.84 vs 119.8 +/- 36.26 mg/dL, P < 0.05). There was also significant a difference in ApoAI levels between CRF patients with and without amyloidosis (P < 0.001). The serum Lp (a) levels were significantly higher in CRF patients with amyloidosis when compared with the controls (41.2 +/- 22.39 vs 19.13 +/- 8.78 mg/dL, P < 0.001). The serum Lp (a) levels were also positively correlated with ACA (r = 0.211; P < 0.05).

CONCLUSION

In conclusion, ACA positivity is more common in all patients with amyloidosis as compared with CRF patients and normal controls. This study is the first to show the presence of high levels of ACA in patients with CRF, which is caused by secondary amyloidosis. Further studies are recommended to investigate the mechanism of this finding.

Clinical importance of positive test results for lupus anticoagulant and anticardiolipin antibodies

OBJECTIVES

To assess the performance of 4 clotting assays for lupus anticoagulant (LA) detection, to determine the prevalence of LA and anticardiolipin antibodies (aCL), and to correlate LA and aCL prevalence with systemic disease and thrombosis.

PATIENTS AND METHODS

We studied 664 consecutive patients at the Mayo Clinic in Rochester, Minn, who were referred for laboratory testing because of a clinical suspicion of LA or thrombophilia between June 25, 1990, and July 1, 1991.

RESULTS

Of 664 patients tested for LA, 584 also were tested for aCL. Of patients tested for both LA and aCL, 137 (235%) had positive results for one or both tests (13 [95%], LA-positive only; 76 [555%], aCL-positive only; and 48 [35.0%], positive for both). The dilute Russell viper venom time (DRVVT) was the most frequently positive LA assay (74% of the 61 patients with positive results for LA). Twenty-two patients (36.1% of the 61) had positive results for all 4 LA assays, whereas 21 (34.4% of the 61) had positive results for only 1 LA assay: activated partial thromboplastin time (3 patients [4.9%]), plasma clot time (5 patients [8.2%]), kaolin clot time (5 patients [8.2%]), or DRVVT (8 patients [13.1%]). Thromboembolism prevalence was not definitely associated with positive test results (LA only, aCL only, or LA plus aCL), nor was it strongly associated with aCL isotype or titer. Furthermore, thromboembolism prevalence was not increased when all LA assays were positive, although a history of deep venous thrombosis or pulmonary embolism was nonsignificantly associated with positive results for all 4 LA tests. The likelihood of having both LA- and aCL-positive test results was higher among patients with systemic lupus erythematosus (26 [19.0%] of 137 patients with positive results for one or both tests), but they had no more thrombotic events or fetal loss than other patients in our study group.

CONCLUSIONS

The DRVVT identified more patients with LA than the other LA tests, but more than 1 LA test was required to identify all patients with LA. Positive results were much more common for aCL than for LA. No single LA test or anticardiolipin isotype correlated with thrombosis or systemic disease in this population.

Detection of procoagulant phospholipid interfering in tests for lupus anticoagulant

Excess platelets shorten most clotting tests for lupus anticoagulant (LA). Often it is not clear if a shortened, normal or slightly prolonged result in a test masks a weak LA in combination with activated platelets, which express procoagulant phospholipid (PPL). Our aim was to investigate a new LA-insensitive factor Xa-activated clotting time (XACT) test for detecting PPL in plasma specimens submitted for LA testing. In most clotting tests for PPL, specimens are mixed with human platelet-free plasma (PFP) to correct for factor defects. Such tests are usually very sensitive to prolongation by LA, which act against PPL-human clotting factor complexes. We found that phospholipid-free plasma from pigs could be used instead of human platelet-free plasma as substrate plasma without reducing sensitivity of XACT to PPL. However, the pig plasma-based system was significantly less affected by most LA. Activated platelets were detectable despite the presence of most LA. Since some LA still had significant prolonging effect on the XACT despite the use of pig plasma we investigated this further. ELISAs for IgG and IgM anti-beta2GP1 and anti-prothrombin antibodies were carried out on 23 specimens. We did not find that LA in plasmas displaying anti-prothrombin antibodies had less prolonging effect on the test based on pig plasma than that using human platelet-free plasma. Similarly, there were no subtyping trends apparent among results from anti-beta2GPI-positive samples. Our results do not support the concept that anti-prothrombin-dependent LA might be more species specific than anti-beta2GPI-dependent LA.

High prevalence of antiphospholipid antibodies in Asian cancer patients with thrombosis

Thrombotic complications are a significant cause of morbidity and mortality in cancer patients. Studies in Caucasian populations have shown that up to one-third of such patients test positive to antiphospholipid antibodies. Our aim was to determine the prevalence and serotypes of antiphospholipid antibodies in an unselected group of Asian cancer patients with thrombosis. All patients with cancer-related thrombosis seen in the Department of Hematology-Oncology and Radiation Oncology were enrolled in this study. The study period was from April 2000 to May 2001. Antiphospholipid antibodies tests were performed, namely lupus anticoagulant screen, anticardiolipin antibodies (IgG and IgM) and anti-beta-2 glycoprotein I antibodies (B2 GPI) IgG, IgM and IgA. Thirty-three patients were recruited. There were 14 males and 19 females, with an age range of 35-78 years of age. Of those enrolled, there were 25 Chinese, five Malays and three Indians. The patients had several cancer types: 11 (36.7%) patients had adenocarcinoma as the histological cell type. Of the 33 patients, 75.8% had stage IV disease. Arterial thrombosis was seen in eight patients (24.2%), and venous thrombosis occurred in 29 patients (87.9%). Antiphospholipid antibodies were positive in 60.6% of the patients, of which anti-B2GPI IgA antibody was the most prevalent antiphospholipid present (46.9%). The presence of anti-beta-2 glycoprotein I IgA antibody was associated with strokes, extensive and recurrent venous thrombosis, and coincident arterial and venous thrombosis. A high prevalence of antiphospholipid antibodies (60.6%) was found in Asian patients with cancer-related thrombosis. The presence of antiphospholipid antibodies, particularly anti B2GPI IgA, may identify a subset of cancer patients who are at high risk of developing thrombotic complications, and further studies are warranted.

Acquired thrombophilias and pregnancy

Acquired thrombophilias are hypercoagulable states secondary to various aetiologies. In particular, during pregnancy the risks are exaggerated due to the underlying physiological changes. The commonest cause of acquired thrombophilia in pregnancy is antiphospholipid syndrome. Antiphospholipid syndrome (APS) is a complex multisystem disorder that has been associated with varied medical and obstetric complications. The pathogenesis of APS has been further elucidated in recent studies. The two most clinically significant antiphospholipid antibodies that are associated with recurrent pregnancy loss and thromboembolism are anticardiolipin antibodies (aCL) and lupus anticoagulant (LA). The laboratory diagnosis is based on the presence of moderate to high positive aCL and/or LA antibodies. It is crucial that APS is not inappropriately diagnosed as this has implications for counselling and management with thromboprophylaxis during pregnancy. Over the last decade there have been significant changes in the laboratory and clinical criteria for the diagnosis of APS. National and international collaborations have made efforts to standardize the laboratory methods. There have been very few randomized placebo-controlled trials of drug therapy and so not all drug treatment strategies have a strong evidence base. With current management strategies, using low-molecular-weight heparin and aspirin, a greater than 70% live birth rate may be achieved in affected pregnancies. A multidisciplinary approach in the management of these women is vital.

Low molecular weight heparin in immunological recurrent abortion--the incredible cure

The most compelling association between pregnancy loss and autoimmune phenomena has been with the presence of antiphospholipid antibodies (APA)--lupus anticoagulant and anticardiolipin antibody. The 'antiphospholipid antibody syndrome' has been described in women with a history of recurrent pregnancy loss or thrombosis with positive APA or lupus anticoagulant on two occasions. Although several treatments have been advocated, heparin and aspirin treatment is emerging as the treatment of choice for the APA syndrome associated with recurrent pregnancy loss. The rationale for prescribing aspirin in cases of recurrent reproductive failure associated with APA seropositivity is that aspirin may counter APA-mediated hypercoagulability in the choriodecidual space, a situation which if left unaddressed would traumatize the trophoblast and compromise feto-maternal exchange. Heparin on the other hand, through preventing APA from interfering with syncytialization of the early cytotrophoblast and by countering APA interference with phospholipid-decidual reactions that are vital to early implantation, might potentially promote both early implantation and subsequent placentation.

Retinal vein occlusion in two patients with primary antiphospholipid syndrome

Primary antiphospholipid syndrome (APS) is a disease producing vascular thrombus with antiphospholipid antibody without association with autoimmune diseases as systemic lupus erythematosus. Retinal vein occlusion is a rare vascular manifestation in primary APS. We describe 2 cases of primary APS presenting with developing blurred vision. Each had central retinal vein occlusion and high titer of IgG anticardiolipin antibody.

Management of pregnancy in antiphospholipid syndrome

Pregnant women with APS are at high risk of maternal and fetal pregnancy complications. Multidisciplinary teams expert in this condition should coordinate management. Even with current management strategies, the risk of maternal thrombosis, fetal loss, or other adverse obstetric outcomes remains. Close monitoring of the various aspects of this condition may reduce maternal morbidity and improve fetal outcome. The pathogenesis of the adverse pregnancy outcome in APS has not yet been fully elucidated, although active research in this field continues. Until this is ascertained, we must accept that many aspects of management are purely empiric, and it is our duty to counsel patients thoroughly so that they understand the risks and benefits of the treatment options they are offered.

The clonal analysis of anticardiolipin antibodies in a single patient with primary antiphospholipid syndrome reveals an extreme antibody heterogeneity

The mechanism underlying the prothrombotic state that characterizes the primary antiphospholipid syndrome proves to be difficult to define mainly because of the variety of the phospholipid and protein targets of antiphospholipid antibodies that have been described. Much of the debate is related to the use of polyclonal antibodies during the different antiphospholipid assays. To better describe the antiphospholipid antibodies, a strategy was designed to analyze the reactivity of each one antibody making up the polyclonal anticardiolipin activity, breaking down this reactivity at the clonal level. This was performed in a single patient with primary antiphospholipid syndrome by combining (1) the antigen-specific selection of single cells sorted by flow cytometry using structurally bilayered labeled anionic phospholipids and (2) the cloning of immunoglobulin (Ig) variable (V) region genes originating from individual IgG anticardiolipin-specific B cells by a single-cell polymerase chain reaction technique. The corresponding V regions were cloned in order to express human recombinant antibodies in insect cells by a baculovirus expression system. The molecular analysis, the fine specificity, and the protein cofactor dependency of the first 5 monoclonal IgG anticardiolipins are reported here. This clonal analysis reveals the extreme heterogeneity of these antibodies, which could account for the difficulties in the previous attempts to define the pathogenic antiphospholipid response. This approach should help to unravel the complex antiphospholipid immune response and the mechanism of the prothrombotic state associated with these antibodies, but it could also shed some light on their possible origins. (Blood. 2001;97:3820-3828)

Acquired thrombophilic syndromes

As the biochemical mechanisms of hypercoagulable states are revealed, the syndromes of venous thromboembolism have been increasingly associated with specific aberrations. Most of these changes involve an increase in procoagulant potential, for example, by activation of the coagulation cascade, or by a defect or decrease in natural inhibitors of clotting. Similar abnormalities of the fibrinolytic pathways may contribute, as can loss of inhibitory mechanisms of endothelial cells, as well as changes in vascular anatomy and rheologic patterns of blood flow. All of these factors can directly influence thrombus formation and/or the physiologic response to the thrombus.(1)

Double valve replacement in a patient with anticardiolipin antibody syndrome

Cardiopulmonary bypass (CPB) was used during the replacement of the aortic and mitral valves in a 43-year-old female patient. The case was complicated by the presence of a rare hypercoagulable condition called anticardiolipin (antiphospholipid) antibody syndrome. The course of bypass was uneventful and the patient was released from the intensive care unit on the first postoperative day. CPB in the presence of anticardiolipin antibodies is an unusual situation that requires diligent hematological monitoring. Since 1989 there have been only 14 reported cases of these antibodies and cardiopulmonary bypass. Eight of these have involved valve replacements.

Retinopathy in systemic lupus erythematosus: pathogenesis and approach to therapy

The starting point in the assessment of SLE-retinopathy is the clinical examination by ophthalmoscopy and retinal fluorescein angiography. It is noted that two major clinical forms of retinopathy may occur in SLE; (1st) the "classic" type characterized by cotton-wool spots with or without intraretinal hemorrhages, and (2nd) the thrombosis of larger retinal blood vessels, such as central or branch arteries/veins. However, a well-defined pathogenetic classification of SLE-retinopathy has still not been proposed as yet. A practical classification based on the pathogenesis could be of aid to commence a more appropriate treatment. The aims of this paper are; (1st) to focus on the most implicate mechanisms of retinal vascular disease in SLE, (2nd) to mention the most common features associated with the different forms of retinopathy, and finally (3rd) to assess the prevalence of retinopathy in SLE. In our opinion, it seems that two major types of retinopathy exist in SLE: firstly, the Hughes' retinopathy due to antiphospholipid-induced retinal vascular thrombosis, for which anticoagulation is the best treatment, and secondly, the "classic" retinopathy in which at least two major causes could be associated; vasculitis and accelerated atherosclerosis. In patients with "classic" retinopathy, the most appropriate treatment still needs to be established. If "classic" retinopathy is due to vasculitis, immunosuppressive drugs should be administered, while if atherosclerosis play an etiologic role, a prophylaxis with antioxidants or the use of low-dose aspirin should be assessed.

Bleeding in a patient with lupus anticoagulant without associated hemostatic abnormalities

Bleeding is very rare in patients with lupus anticoagulants in the absence of associated hemostatic abnormalities. Few cases have been reported with attention given to work-up for other coagulation defects. We report a case of spontaneous hematoma in a patient with lupus anticoagulant, immunoglobulin (Ig)M anticardiolipin antibodies, and no other associated abnormalities.

Anticardiolipin antibody aggravates cerebral vasospasm after subarachnoid hemorrhage in rabbits

BACKGROUND AND PURPOSE

We previously reported that patients with antiphospholipid antibodies (aPLs) frequently demonstrate cerebral infarction due to cerebral vasospasm after subarachnoid hemorrhage (SAH). To examine the participation of aPLs in the pathogenesis of vasospasm after SAH, we studied the relationships of aPLs and SAH in an animal model.

METHODS

SAH was produced in 34 rabbits that received two subarachnoid injections of autologous arterial blood. The animals were divided into four experimental groups: SAH was induced in group A (n=9), intracutaneous injection of cardiolipin (CL) was performed before the induction of SAH in group B (n=5), intravenous injection of CL was performed before SAH in group C (n=12), and cyclosporin A was infused intravenously after the intravenous injection of CL and induction of SAH in group D (n=8). Enzyme-linked immunosorbent assay identifying the titer of IgG CL antibodies, neurological evaluation, cerebral angiography, and histological examination were performed in all four groups.

RESULTS

A significant elevation of anti-CL antibodies, aggravation of neurological deficit, and reduction of caliber of the basilar artery were observed in rabbits that received the intravenous immunization of CL (group C). The administration of cyclosporin A reduced the titer of anti-CL antibody, aggravation of neurological deficit, constriction of basilar artery, and the incidence of cerebral infarction (group D).

CONCLUSIONS

Anti-CL antibodies may therefore be involved in the deterioration of cerebral vasospasm after SAH.