CNS dysfunction in the antiphospholipid syndrome

Advances in the Pathophysiology of Thrombosis in Antiphospholipid Syndrome: Molecular Mechanisms and Signaling through Lipid Rafts

The pathological features of antiphospholipid syndrome (APS) are related to the activity of circulating antiphospholipid antibodies (aPLs) associated with vascular thrombosis and obstetric complications. Indeed, aPLs are not only disease markers, but also play a determining pathogenetic role in APS and exert their effects through the activation of cells and coagulation factors and inflammatory mediators for the materialization of the thromboinflammatory pathogenetic mechanism. Cellular activation in APS necessarily involves the interaction of aPLs with target receptors on the cell membrane, capable of triggering the signal transduction pathway(s). This interaction occurs at specific microdomains of the cell plasma membrane called lipid rafts. In this review, we focus on the key role of lipid rafts as signaling platforms in the pathogenesis of APS, and propose this pathogenetic step as a strategic target of new therapies in order to improve classical anti-thrombotic approaches with "new" immunomodulatory drugs.

Neuropsychiatric Manifestations of Antiphospholipid Syndrome—A Narrative Review

Antiphospholipid syndrome (APS) is a common autoimmune pro-thrombotic condition characterised by thrombosis and pregnancy morbidity. There are a broad range of neuropsychiatric manifestations associated with APS, from focal symptoms to more global dysfunction. Patients commonly present with transient ischaemic attacks and ischaemic strokes, with identifiable lesions on brain imaging. However, the underlying pathogenesis remains uncertain in other manifestations, such as cognitive dysfunction, seizures, headache and chorea. The aim is to provide a comprehensive review of the various neuropsychiatric manifestations associated with APS. A detailed literature search was applied to PubMed, including citations from 1983 to December 2021.

Audiological disturbances in patients with primary antiphospholipid syndrome

Background

Antiphospholipid syndrome (APS) is an autoimmune disease of hypercoagulability state in the presence of antibodies against phospholipids. Many neurological deficits related to APS have been described. Sensory neural hearing loss has been described only anecdotally, mostly in case reports. This study investigated a possible association between hearing disorders and APS.

Methods

Seventeen patients (aged 20–80 years) diagnosed with primary APS were evaluated for evidence of hearing disorders. All had otoscopy, full audiometry test, brainstem evoked response audiometry and otoacoustic emissions testing, and completed a questionnaire. Hearing levels were compared to the standard hearing levels of the general population by age group.

Results

Of the 17 APS patients, 10 (age groups 20–29 and 50–59) had significantly reduced hearing levels in all or part of the tested frequencies compared to standard levels. Three patients (age group 60–69) had better hearing levels at low frequencies compared to standard hearing levels.

Conclusion

These findings support the existence of hearing disorders in primary APS.

Pediatric Motor Inflammatory Neuropathy: The Role of Antiphospholipid Antibodies

We report the clinical case of a nine-year-old girl who presented with progressive motor neuropathy, revealed via the detection of a higher delay in F-wave recording using digitalized nerve conduction/electromyography. Since the lupus anticoagulant (LAC) positivity, detected using diluted Russell viper venom time (dRVVT), switched to persistent serological anticardiolipin immunoglobulin G (IgG) positivity, a possible non-thrombotic antiphospholipid antibody (aPL)-related clinical manifestation was suspected, and intravenous immunoglobulin treatment (IVIG) was started. The IVIG treatment was well tolerated and the complete resolution of motor impairment was obtained after the third IVIG infusion. Our findings suggest that it could be useful to check for antiphospholipid antibodies in children with a rapid onset of progressive neurological signs in order to provide the beneficial use of IVIG in the treatment of pediatric aPL neurological conditions.

mTOR-Related Cell-Clearing Systems in Epileptic Seizures, an Update

Recent evidence suggests that autophagy impairment is implicated in the epileptogenic mechanisms downstream of mTOR hyperactivation. This holds true for a variety of genetic and acquired epileptic syndromes besides malformations of cortical development which are classically known as mTORopathies. Autophagy suppression is sufficient to induce epilepsy in experimental models, while rescuing autophagy prevents epileptogenesis, improves behavioral alterations, and provides neuroprotection in seizure-induced neuronal damage. The implication of autophagy in epileptogenesis and maturation phenomena related to seizure activity is supported by evidence indicating that autophagy is involved in the molecular mechanisms which are implicated in epilepsy. In general, mTOR-dependent autophagy regulates the proliferation and migration of inter-/neuronal cortical progenitors, synapse development, vesicular release, synaptic plasticity, and importantly, synaptic clustering of GABA_A receptors and subsequent excitatory/inhibitory balance in the brain. Similar to autophagy, the ubiquitin–proteasome system is regulated downstream of mTOR, and it is implicated in epileptogenesis. Thus, mTOR-dependent cell-clearing systems are now taking center stage in the field of epilepsy. In the present review, we discuss such evidence in a variety of seizure-related disorders and models. This is expected to provide a deeper insight into the molecular mechanisms underlying seizure activity.

Cytokine secretion and the risk of depression development in patients with connective tissue diseases

Research in the past two decades has revolutionized our understanding of depressive illnesses. Proinflammatory cytokines have become a point of interest in the interconnecting areas of neuropsychiatric and autoimmune diseases. The cytokine hypothesis of depression suggests that pro-inflammatory cytokines play a primary role in the mediation of the pathophysiological characteristics of major depression, in which an inflammatory process may be induced by external and internal stressors, such as psychological and inflammatory diseases, respectively. The higher prevalence of depression, particularly in patients with chronic autoimmune connective tissue disorders (CTD), suggests that depression may present a dysfunctional adaptation of cytokine-induced sickness, which could manifest in times of an exacerbated activation of the innate immune system. Inflammation is thought to contribute to the development of clinical depression through its ability to induce sickness behaviors corresponding to the neurovegetative features of depression, through the dysregulation of the hypothalamic-pituitary-adrenal axis, alterations in neurotransmitter synthesis and reuptake, and through its involvement in the neuroprogression pathways. This review explores the complex interrelationships in which inflammatory responses alter neuroendocrine and neuropsychological regulation contributing to depressive symptoms in CTD. The prevalence and characteristics of depression, and its correlation to the levels of inflammatory cytokines and disease activity among different CTD will be reviewed.

Insights into the diagnosis and pathogenesis of the antiphospholipid syndrome

The Antiphospholipid syndrome (APS), formerly known as Anticardiolipin or Hughes syndrome, is a systemic autoimmune disorder characterized by obstetrical complications and thrombotic events affecting almost every organ-system in patients persistently testing positive for antiphospholipid antibodies (aPL). The contribution of the extra-criteria aPL to the pathogenesis of APS have exceeded the expectations of a simple, direct pathologic 'hit' leading to thrombogenesis or obstetrical complications, and more pathologic pathways are being linked directly or indirectly to aPL. The value of extra-criteria aPL is on the rise, and these antibodies are nowadays evaluated as markers for risk assessment in the diagnostic approach to APS. A diagnosis of APS should be considered in pediatric patients with suggestive clinical and laboratory picture. Management of APS remains mostly based on anticoagulation, while other drugs are being tested for efficacy and side effects. Low-dose aspirin may have a role in the management of thrombotic and obstetric APS. Due to the high variability in disease severity and complication recurrence outcomes, new tools are being developed and validated to assess the damage index and quality of life of APS patients.

SLE presenting as demyelinative autoimmune visual loss

A healthy 38-year-old woman developed sudden unilateral vision loss due to retrobulbar optic neuritis in the wake of varicella-zoster virus infection. She had no further central nervous system (CNS) lesions. Antinuclear antibodies (ANA) and anti-aquaporin 4 antibodies were found, consistent with neuromyelitis optica (NMO). Later, serial MRIs showed dynamic short-segment and long-segment myelitis lesions, ANA titre increased and additional autoantibodies were found including anti-dsDNA, anti-chromatin/nucleosome and antiphospholipid antibodies. In that setting, NMO can be regarded a rare presenting manifestation of systemic lupus erythematosus (SLE). The relevant literature is reviewed and the implications of NMO spectrum disorder demyelinating syndromes as the first manifestation of SLE (with or without antiphospholipid syndrome) (APS) or their later development (in a patient diagnosed with SLE) as part of the spectrum of neuropsychiatric SLE are analysed in view of recent research developments in the field.

Antiphospholipid Syndrome With a Distinctive Constellation of Neurological Manifestations: Blue Toes, Red Valves, White Retinal Spots

Antiphospholipid syndrome (APS) encompasses a hypercoagulable state with a markedly increased risk for cerebrovascular complications. In addition to the classic stroke features of APS, however, there are numerous recently described "non-criteria" neurological conditions such as headaches, seizures, and cognitive impairment. We present a case of APS with uncommon neurological manifestations.

The antiphospholipid syndrome: from pathophysiology to treatment

Antiphospholipid antibody syndrome (APS) is an autoimmune acquired thrombophilia characterized by recurrent thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). APS can be primary, if it occurs in the absence of any underlying disease, or secondary, if it is associated with another autoimmune disorder, most commonly systemic lupus erythematosus. The exact pathogenetic mechanism of APS is unknown, but different, not mutually exclusive, models have been proposed to explain how anti-PL autoantibodies might lead to thrombosis and pregnancy morbidity. Diagnosis of APS requires that a patient has both a clinical manifestation (arterial or venous thrombosis and/or pregnancy morbidity) and persistently positive aPL, but the clinical spectrum of the disease encompasses additional manifestations which may affect every organ and cannot be explained exclusively by a prothrombotic state. Treatment for aPL-positive patients is based on the patient's clinical status, presence of an underlying autoimmune disease, and history of thrombotic events. In case of aPL positivity without previous thrombotic events, the treatment is mainly focused on reduction of additional vascular risk factors, while treatment of patients with definite APS is based on long-term anticoagulation. Pregnancy complications are usually managed with low-dose aspirin in association with low molecular weight heparin. Refractory forms of APS could benefit from adding hydroxychloroquine and/or intravenous immunoglobulin to anticoagulation therapy. Promising novel treatments include anti-B cell monoclonal antibodies, new-generation anticoagulants, and complement cascade inhibitors. The objective of this review paper is to summarize the recent literature on APS from pathogenesis to current therapeutic options.

Obstetric antiphospholipid syndrome: a recent classification for an old defined disorder

Obstetric antiphospholipid syndrome (APS) is now being recognized as a distinct entity from vascular APS. Pregnancy morbidity includes >3 consecutive and spontaneous early miscarriages before 10weeks of gestation; at least one unexplained fetal death after the 10th week of gestation of a morphologically normal fetus; a premature birth before the 34th week of gestation of a normal neonate due to eclampsia or severe pre-eclampsia or placental insufficiency. It is not well understood how antiphospholipid antibodies (aPLs), beyond their diagnostic and prognostic role, contribute to pregnancy manifestations. Indeed aPL-mediated thrombotic events cannot explain the obstetric manifestations and additional pathogenic mechanisms, such as a placental aPL mediated complement activation and a direct effect of aPLs on placental development, have been reported. Still debated is the possible association between aPLs and infertility and the effect of maternal autoantibodies on non-vascular manifestations in the babies. Combination of low dose aspirin and unfractionated or low molecular weight heparin is the effective treatment in most of the cases. However, pregnancy complications, in spite of this therapy, can occur in up to 20% of the patients. Novel alternative therapies able to abrogate the aPL pathogenic action either by interfering with aPL binding at the placental level or by inhibiting the aPL-mediated detrimental effect are under active investigation.

Rheumatic fever associated with antiphospholipid syndrome: systematic review

Objective. To evaluate the clinical associations between rheumatic fever and antiphospholipid syndrome and the impact of coexistence of these two diseases in an individual. Methods. Systematic review in electronics databases, regarding the period from 1983 to 2012. The keywords: “Rheumatic Fever,” “Antiphospholipid Syndrome,” and “Antiphospholipid Antibody Syndrome” are used. Results. were identified 11 cases described in the literature about the association of rheumatic fever and antiphospholipid syndrome. Clinical presentation of rheumatic fever was characterized by the predominance of carditis (11/11) and chorea (7/11). Regarding the manifestations of APS, the stroke was observed in 7/11 (63.6%), with one of them having probable embolic origin. Conclusion. The present study brings the information that the association between APS and RF is quite rare, however, is of great clinical importance. Doctors who deal with the RF should include in their differential diagnosis the APS, especially in the presence of stroke in patients with RF and whose echocardiogram does not show intracavitary thrombi.

Early neuropsychiatric involvement in antiphospholipid syndrome

OBJECTIVE

Neuropsychiatric symptoms may be the main manifestations and very early symptoms of developing autoimmune diseases. Early detection and treatment could reverse psychotic symptoms and restore cognitive function.

CASE REPORT

A 24-year-old woman presented with acute psychotic symptoms. Routine physical examinations revealed only mild fever. Due to positive antiphospholipid antibodies, low protein S with elevated d-dimer and brain hypoperfusion, early-phase antiphospholipid syndrome (APS) was suspected. Early immunomodulation treatment led to complete remission of the psychotic symptoms, preservation of cognitive function and prevention of APS progression.

CONCLUSION

Since early detection and treatment can reverse the progression of autoimmune diseases with central nervous system involvement, these should be highlighted when managing high-risk patients.

The efficacy of brain F-fluorodeoxyglucose positron emission tomography in neuropsychiatric lupus patients with normal brain magnetic resonance imaging findings

Brain involvement in systemic lupus erythematosus (SLE) is a significant source of morbidity and mortality. Therefore, the early detection and treatment of brain involvement in SLE is of utmost importance; however, a confirmative diagnostic tool for neuropsychiatric SLE is yet to be developed. In this study, we investigated the efficacy of 18F-FDG-PET for detection of brain involvement in patients with SLE with normal magnetic resonance imaging (MRI) findings. Twenty patients with SLE, who presented with neuropsychiatric symptoms despite normal brain MRI findings and who underwent brain 18F-FDG-PET, were enrolled. The most common neuropsychiatric manifestation was headache (45%), followed by seizure (20%) and mood disorder (20%). 18F-FDG-PET revealed significant glucose metabolic abnormalities in 15 of 20 patients (75%). The temporal (55%) and the occipital (55%) lobes were the most susceptible brain regions, followed by the frontal lobe (50%). However, neuropsychiatric symptoms were not geographically correlated to 18F-FDG-PET findings. Two patients with abnormal 18F-FDG-PET findings underwent follow-up brain 18F-FDG-PET after remission, which showed complete resolution of abnormal glucose metabolism. Our data suggest that 18F-FDG-PET may be an additional diagnostic modality complementary to MRI, when MRI is unable to provide evidence of brain involvement in patients with SLE.

Neurological impairment in experimental antiphospholipid syndrome is associated with increased ligand binding to hippocampal and cortical serotonergic 5-HT1A receptors

The antiphospholipid syndrome (APS) is an autoimmune disease where the presence of high titers of circulating autoantibodies causes thrombosis with consecutive infarcts. In experimental APS (eAPS), a mouse model of APS, behavioral abnormalities develop in the absence of vessel occlusion or infarcts. Using brain hemispheres of control and eAPS mice with documented neurological and cognitive deficits, we checked for lymphocytic infiltration, activation of glia and macrophages, as well as alterations of ligand binding densities of various neurotransmitter receptors to unravel the molecular basis of this abnormal behavior. Lymphocytic infiltrates were immunohistochemically characterized using antibodies against CD3, CD4, CD8 and forkhead box P3 (Foxp3), respectively. GFAP, Iba1 and CD68-immunohistochemistry was performed, to check for activation of astrocytes, microglia and macrophages. Ligand binding densities of NMDA, AMPA, GABAA and 5-HT1A receptors were analyzed by in vitro receptor autoradiography. No significant inflammatory reaction occurred in eAPS mice. There was neither activation of astrocytes or microglia nor accumulation of macrophages. Binding values of excitatory and inhibitory neurotransmitter receptors were largely unchanged. However, ligand binding densities of the modulatory serotonergic 5-HT1A receptors in the hippocampus and in the primary somatosensory cortex of eAPS mice were significantly upregulated which is suggested to induce the behavioral abnormalities observed.

Autoantibodies as biomarkers for the prediction of neuropsychiatric events in systemic lupus erythematosus

OBJECTIVE

Neuropsychiatric events occur unpredictably in systemic lupus erythematosus (SLE) and most biomarker associations remain to be prospectively validated. This study examined a disease inception cohort of 1047 SLE patients to determine which autoantibodies at enrolment predicted subsequent neuropsychiatric events.

METHODS

Patients with a recent SLE diagnosis were assessed prospectively for up to 10 years for neuropsychiatric events using the American College of Rheumatology case definitions. Decision rules of graded stringency determined whether neuropsychiatric events were attributable to SLE. Associations between the first neuropsychiatric event and baseline autoantibodies (lupus anticoagulant (LA), anticardiolipin, anti-β(2) glycoprotein-I, anti-ribosomal P and anti-NR2 glutamate receptor) were tested by Cox proportional hazards regression.

RESULTS

Disease duration at enrolment was 5.4 ± 4.2 months, follow-up was 3.6 ± 2.6 years. Patients were 89.1% female with mean (±SD) age 35.2 ± 13.7 years. 495/1047 (47.3%) developed one or more neuropsychiatric event (total 917 events). Neuropsychiatric events attributed to SLE were 15.4% (model A) and 28.2% (model B). At enrolment 21.9% of patients had LA, 13.4% anticardiolipin, 15.1% anti-β(2) glycoprotein-I, 9.2% anti-ribosomal P and 13.7% anti-NR2 antibodies. LA at baseline was associated with subsequent intracranial thrombosis (total n=22) attributed to SLE (model B) (HR 2.54, 95% CI 1.08 to 5.94). Anti-ribosomal P antibody was associated with subsequent psychosis (total n=14) attributed to SLE (model B) (HR 3.92, 95% CI 1.23 to 12.5, p=0.02). Other autoantibodies did not predict neuropsychiatric events.

CONCLUSION

In a prospective study of 1047 recently diagnosed SLE patients, LA and anti-ribosomal P antibodies are associated with an increased future risk of intracranial thrombosis and lupus psychosis, respectively.

Primary antiphospholipid antibody syndrome presenting with encephalopathy, psychosis and seizures

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by recurrent thrombotic events, miscarriages and thrombocytopenia with persistently positive antiphospholipid antibodies. 1 , 2 APS may be isolated (primary APS) or associated to a connective tissue disease, most often systemic lupus erythematosus (SLE). 1 , 2 APS usually affects young patients before the fifth decade 3 with stroke being the commonest neurological manifestation. 4 Various other neurological manifestations are being recognized in patients with APS including migraine, epilepsy, multi-infarct dementia and chorea. 2 The pathological process underlying the neurological manifestations remains obscure. 1 , 2 Herein we report a case of primary APSpresenting with a group of unusual neurological manifestations in a 68-year-old woman.

Central Nervous System Manifestations in Rheumatic Diseases

Patients with multi-system rheumatic conditions may have a disease affecting the central nervous system (CNS). Central nervous system manifestations vary according to the location of the lesion and range from focal findings (e.g., stroke-like presentations), although serious neurological complications in rheumatic disease appear to be rare. The most prominent features of neurological involvement in rheumatic diseases include cerebral ischaemia and psychiatric symptoms. Little information is available on the prevalence of neurological disease in patients with a rheumatological diagnosis. Involvement of the CNS may be a striking early or presenting feature with a wide variety of manifestations. There is more clarity about the CNS syndromes attributable to systemic lupus erythematosus and new insights into the central mechanisms involved in the manifestations of Sjögren's syndrome and rheumatoid arthritis. Severe CNS involvement is associated with poor prognosis, and high mortality rate. We review the spectrum of neurological diseases in patients with a rheumatological diagnosis.

Neurological manifestations of antiphospholipid syndrome

BACKGROUND

Neurologic disorders are among the most common and important clinical manifestations associated with the antiphospholipid syndrome (APS). It is characterized by diverse neurological manifestations. These include stroke, transient ischaemic attack, Sneddon's syndrome, convulsions/epilepsy, dementia, cognitive deficits, headaches/migraine, chorea, multiple sclerosis-like, transverse myelitis, ocular symptoms and Guillain-Barré syndrome.

MATERIAL AND METHODS

We review the latest data about neurologic disorders and APS.

RESULTS

In patients under 45 years of age, 20% of strokes are potentially associated with APS. Our study group recently reported a correlation between primary APS and peripheral neuropathy. Only one study investigated the occurrence of peripheral neuropathy in patients diagnosed with PAPS through electrophysiological study and showed alterations in 35% of patients. The mechanism of nervous system involvement in APS is considered to be primarily thrombotic. However, other mechanisms have been described, such as antiphospholipid antibodies that bind to the neural tissue, deregulating their functions and having an immediate pathogenic effect.

CONCLUSIONS

This review summarizes the latest data regarding the clinical aspects, radiological and therapeutic of major neurologic manifestations associated with antiphospholipid antibodies.

Neurocognitive deficits and neuroimaging abnormalities are prevalent in children with lupus: clinical and research experiences at a US pediatric institution

Neurocognitive impairments and neuroimaging abnormalities are frequently observed in adults with systemic lupus erythematosus. There is a paucity of similar data in childhood-onset disease. We hypothesized that neurocognitive and neuroimaging abnormalities would be prevalent in children undergoing neuropsychological evaluations. We reviewed patient neurocognitive evaluations performed at a large United States pediatric institution during the period 2001 to 2008. Records were retrieved from 24 children referred to neuropsychology due to clinical indications. Data from 15 children enrolled in a prospective structure-function association study were also analyzed. Subjects were predominantly African-American and Hispanic adolescent girls of average intelligence. aPL positivity and aspirin use was prevalent. Neurocognitive impairment was designated in 70.8% of retrospective, and 46.7% of prospective cohort patients. Deficits were seen at times of wellness, without previous neuropsychiatric lupus, and early in disease courses. Scores >1.5 standard deviations below published age-matched norms were common in tests of executive functioning, visual memory and visual-spatial planning. Features of depression were seen in 33.3% of the children in the retrospective cohort (clinical referrals). Cerebral and cerebellar volume loss was observed in a majority of blinded prospective cohort research magnetic resonance images (73.3% and 67.7% respectively). White matter hyperintensities were observed in retrospective and prospective cohort magnetic resonance images (36.6% and 46.7% respectively). Larger prospective studies that elucidate structure-function associations in children with systemic lupus erythematosus are planned.

An investigation in the possible effect of chronic headache on neuropsychological function in aCL-negative patients with SLE

Controversy exists as to whether patients with migraine may suffer cortical damage. We investigate the possible association between impaired cognitive function and chronic headache in lupus patients. Sixty one patients with systemic lupus erythematosus but without the antiphospholipid (Hughes) syndrome were questioned about headaches and formally assessed for cognitive function. They were also subjected to magnetic resonance imaging (MRI). Twenty one patients denied any significant headaches, 19 reported migrainous headaches and 11 experienced an aura. Eleven patients experienced headaches with features of migraine but did not fulfill the criteria, and seven patients had tension headaches. All patients had stable lupus; there was no difference in the incidence of hypertension, age or previous episodes of neuropsychiatric lupus. Patients with migrainous headaches without aura had marginally shorter duration of disease. There was no difference between the groups with respect to eight different cognitive tests or the ventriculo brain index on MRI. We failed to detect cognitive impairment in lupus patients with chronic headaches including migrainous headaches.

Antibodies to glutamate receptor subtype 3 (GluR3) are found in some patients suffering from epilepsy as the main disease, but not in patients whose epilepsy accompanies antiphospholipid syndrome or Sneddon's syndrome

Autoantibodies (Ab's) to the "B" peptide (amino acids 372-395) of glutamate/AMPA receptor subtype 3 (GluR3) are found in serum and cerebrospinal fluid of some patients with different types of epilepsy. Since such anti-GluR3B Ab's can activate and/or kill neurons in vitro and in vivo, they may contribute to epilepsy. To investigate whether anti-GluR3B Ab's may also be relevant to epilepsy when it accompanies some autoimmune-diseases, we tested for these Ab's in patients suffering from epilepsy that accompanies anti-phospholipid syndrome (APS) or Sneddon's syndrome (SNS), both being autoimmune-diseases with frequent neurological complications. We tested 77 pediatric patients whose epilepsy is their main disease; 31 adult patients whose epilepsy accompanies APS (primary or SLE-associated) or SNS; 45 epilepsy-free APS and SNS patients; and 90 healthy controls. Compared to the controls, significantly elevated anti-GluR3B Ab's were found in 22/77 (29%) patients whose epilepsy is their main disease, but in none of the patients whose seizures accompany APS or SNS. Yet, all the APS and SNS patients harbored the characteristic anti-phospholipid Ab's (aPL), directed against cardiolipin and beta2-glycoprotein I, and had lupus anti-coagulant. Thus, anti-GluR3B Ab's are not crossreactive with aPL, and not produced as a non-specific consequence of seizures on the one hand, or autoimmune-diseases on the other. Taken together with new findings accumulated recently in our lab, we suggest that anti-GluR3B Ab's are produced primarily in the periphery due to specific/non-specific "irritation" of the immune system, and that once they reach the brain via a leaky blood-brain barrier they may cause neuronal/glial damage and facilitate the outburst of epilepsy and additional neurological abnormalities. In contrast, the presence of anti-GluR3B Ab's does not seem to increase the probability of developing APS, SNS or the seizures that often accompany these autoimmune-diseases. These findings may have important diagnostic and therapeutic implications.

Mania: psychiatric manifestations of the antiphospholipid syndrome

BACKGROUND

Antiphospholipid syndrome (APS) is a prothrombotic condition characterized by recurrent vascular thrombosis and/or pregnancy morbidity in the presence of circulating antiphospholipid antibodies. Central nervous system (CNS) involvement is a prominent feature of APS, and many neurological manifestations have been described in published reports. There are limited data on psychiatric syndromes occurring in association with APS, and there have been no previous reports of mania associated with APS.

METHOD

The authors present the case of a 31-year-old man who experienced an acute manic episode in association with APS. They review the literature on psychiatric manifestations of APS, discuss potential mechanisms of CNS pathogenesis, and consider diagnostic and treatment implications of the co-occurrence of APS and psychiatric symptoms.

Concurrent hemichorea and migrainous aura--a perfusion study on the basal ganglia using xenon-computed tomography

A variety of etiologies underlie the neurophysiological imbalance resulting in chorea. We report a 57-year-old woman with a long-history of migraine who suddenly experienced concurrent scintillating scotoma and rapid involuntary movement of her neck and right extremities. Diffusion-weighted magnetic resonance imaging (MRI) failed to detect any fresh ischemic and/or hemorrhagic lesions. Xenon-computed tomography (CT) disclosed gross reduction in the cerebral blood flow (CBF) of the left occipital area. With precise mapping to the brain atlas, extreme hyperperfusion in the motor thalamus was found on the left side. Asymmetrical CBF reduction of the left subthalamic nucleus was also noted. Her symptoms gradually improved and completely disappeared within 15 days. Repeated xenon-CT 1 month post-onset demonstrated normalized CBF in the affected areas. Our study suggests that vascular event underlies the migrainous aura in this case and secondarily provokes a loss of inhibitory control of the motor thalamus resulting in the manifestation of hemichorea.

Neuropsychiatric lupus and infectious triggers

Infections can act as environmental triggers inducing or promoting systemic lupus erythematosus (SLE) in genetically predisposed individuals. The aim of the present study was to compare the titres of antibodies (Abs) to infectious agents with neuropsychiatric (NPSLE) clinical manifestations. The sera of 260 individuals (120 patients with SLE and 140 geographic controls) were evaluated for the titres of Epstein bar virus (EBV), cytomegalovirus (CMV), toxoplasma, rubella and syphilis Abs using the BioPlex 2200 Multiplexed Immunoassay method (BioRad) and by the ELISA method for Helicobacter pylori and Hepatitis B core Ag. All BioPlex 2200 kits used were in developmental stages. Data analysis was performed using SPSS 9.0 statistical analysis software (SPSS Inc., Chicago, IL, USA, 1999). Correlation analysis indicated that rubella IgM Ab titres were marginally, positively associated with psychosis ( P = 0.09). No other associations were detected between the 17 infectious Abs and five NP manifestations. When the positivity cut-off for anti-rubella IgM Abs was set at three standard deviations above normal, three positive subjects were identified: one patient with psychosis and one with depression, for a total NPSLE prevalence of 33.3%. On the contrary, the prevalence of NPSLE in the remaining subjects was 6.5%. Marginally significant correlations between elevated titres of rubella IgM Ab with psychosis and depression were found. Although this nearly 5-fold increase is not statistically significant, it appears that in a larger sample size, significance would be reached. This is the first study reported that examined the correlation of NPSLE manifestations with anti-infectious Abs.

Autoantibodies and neuropsychiatric events at the time of systemic lupus erythematosus diagnosis: results from an international inception cohort study

OBJECTIVE

To examine, in an inception cohort of systemic lupus erythematosus (SLE) patients, the association between neuropsychiatric (NP) events and anti-ribosomal P (anti-P), antiphospholipid (lupus anticoagulant [LAC], anticardiolipin), anti-beta2-glycoprotein I, and anti-NR2 glutamate receptor antibodies.

METHODS

NP events were identified using the American College of Rheumatology case definitions and clustered into central/peripheral and diffuse/focal events. Attribution of NP events to SLE was determined using decision rules of differing stringency. Autoantibodies were measured without knowledge of NP events or their attribution.

RESULTS

Four hundred twelve patients were studied (87.4% female; mean +/- SD age 34.9 +/- 13.5 years, mean +/- SD disease duration 5.0 +/- 4.2 months). There were 214 NP events in 133 patients (32.3%). The proportion of NP events attributed to SLE varied from 15% to 36%. There was no association between autoantibodies and NP events overall. However, the frequency of anti-P antibodies in patients with central NP events attributed to SLE was 4 of 20 (20%), versus 3 of 107 (2.8%) in patients with other NP events and 24 of 279 (8.6%) in those with no NP events (P = 0.04). Among patients with diffuse NP events, 3 of 11 had anti-P antibodies (27%), compared with 4 of 111 patients with other NP events (3.6%) and 24 of 279 of those with no NP events (8.6%) (P = 0.02). Specific clinical-serologic associations were found between anti-P and psychosis attributed to SLE (P = 0.02) and between LAC and cerebrovascular disease attributed to SLE (P = 0.038). There was no significant association between other autoantibodies and NP events.

CONCLUSION

Clinically distinct NP events attributed to SLE and occurring around the time of diagnosis were found to be associated with anti-P antibodies and LAC. This suggests that there are different autoimmune pathogenetic mechanisms, although low sensitivity limits the clinical application of testing for these antibodies.

Antiphospholipid antibodies in blood and cerebrospinal fluids of patients with psychosis

Antiphospholipid antibodies (aPL) have been reported in the cerebrospinal fluids (CSF) of neurology patients but no CSF studies with psychiatric patients exist. We tested serum from 100 hospitalized psychotic patients having hallucinations and/or delusions for aPL. Patients with positive serum aPL findings were asked to submit CSF for aPL testing. Five CSF samples had aPL specificities not found in the patient's serum suggesting the possibility of intrathecal synthesis. Specificity and isotype discordance between CSF and blood aPL in these psychiatric patients implicates a central nervous system independent autoimmune process that may have an underlying association with the pathophysiology of their diseases.

Neurological manifestations of the antiphospholipid syndrome: risk assessments and evidence-based medicine

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterised by autoantibody production and vascular thrombosis or pregnancy morbidity. Autoantibodies generated against phospholipid and phospholipid-binding proteins often impair phospholipid-dependent clotting assays (lupus anticoagulants). These autoantibodies activate endothelial cells, platelets and biochemical cascades and can exist in autoimmune disorders such as lupus. Consistently positive antibodies may worsen the severity of thrombo-occlusive disease. The most common neurological manifestations of APS include stroke and transient ischaemic attacks due to arterial thromboses. Antiphospholipid antibodies may cause additional neurological impairments through both vascular and immune mechanisms. Antiaggregant or anticoagulant therapies are indicated for APS-related ischaemic strokes. Treatment regimens for asymptomatic antibody-positive patients and those with refractory disease remain controversial. There is scant literature on neurological APS manifestations in paediatric patients. Assessment of traditional cardiovascular and inherited thrombophilia risk factors is essential in patients with APS. Modifiable risk factors and valvular heart disease may worsen thrombotic and cerebrovascular outcomes. Alternative therapies such as statins, anti-malarials, angiotensin-converting enzyme inhibitors and thrombin inhibitors warrant further research.

Antibodies against oxidized phospholipids in laboratory tests exploring lupus anti-coagulant activity

Lupus anti-coagulants (LA) are a variety of anti-phospholipid antibodies characterized by their capacity to interfere with phospholipid-dependent coagulation assays. LA are increasingly recognized as important predictors of thrombosis. However, the antigen specificity of LA is still poorly characterized. Growing evidence indicates that oxidized phospholipids are among the targets of anti-phospholipid antibodies. This prompted us to investigate the role of IgG directed against different oxidized phospholipids in 164 subjects without clotting factor defects that were tested for the presence of LA using a LA-sensitive activate partial thromboplastin time (aPTT-FSL) and a screening/confirmation assay based on diluted Russell's viper venom test (dRVVT-PL). The response to aPTT-FSL was significantly (P < 0.0005) associated with high titres of IgG against oxidized phosphatidylserine, phosphatidylethanolamine and phosphatidylinositol, whereas positivity to dRVVT-PL was associated with the elevation of IgG against oxidized phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine (P < 0.0005) and phosphatidylinositol (P < 0.01). No difference in reactivity against oxidized cardiolipin was evident between the different groups. Positivity to the dRVVT-PL test was also associated significantly (P < 0.005) with the elevation of anti-cardiolipin and anti-beta(2)-glycoprotein-1 IgG. However, stepwise logistic regression demonstrated that IgG recognizing oxidized phosphatidylethanolamine and oxidized phosphatidylcholine were the only independent predictors of the response to dRVVT-PL assay, while IgG recognizing oxidized phosphatidylethanolamine and oxidized phosphatidylinositol were independent predictors of the response to aPTT-FSL test. In conclusion, autoantibodies against defined oxidized phospholipids are independent predictors of LA detection by aPTT-FSL or dRVVT-PL assays and might contribute to the variability often observed in the responses to the functional tests detecting LA.

Autoantibodies Involved in Neuropsychiatric SLE and Antiphospholipid Syndrome

OBJECTIVE

We sought (1) to identify and (2) to define the association of all reported antibodies (Abs) with neuropsychiatric lupus (NPSLE), (3) to search for possible mechanisms that are involved in NPSLE, and (4) to determine whether we can recognize a panel of Abs associated with specific neuropsychiatric (NP) manifestations.

METHODS

A MEDLINE search (1975 to 2005) was performed utilizing the following terms: neuropsychiatric lupus, antiphospholipid syndrome, or central nervous system systemic lupus erythematosus matched with the term antibodies.

RESULTS

Twenty Abs (11 brain-specific and 9 systemic) were described in NPSLE patients. These include Abs that target brain-specific antigens (neuronal, ganglioside, synaptosomes, glia, methyl-d-aspartate receptors, lymphocytotoxic) and systemic antigens (nuclear, cytoplasmic, phospholipid, endothelial cells). Cognitive impairment, psychosis, and depression were associated with many Abs. Elevated titers of anticardiolipin Abs (aCL) were reported most often and found in patients with cognitive impairment, psychosis, depression, seizures, chorea, and migraine. No specificity was encountered among brain-specific or systemic Abs for any single NP manifestation. No studies evaluated a specific NP manifestation with the full panel of 20 Abs. A panel of brain-specific and systemic Abs may be helpful in establishing the diagnosis of NPSLE. Postulated mechanisms in experimental models included vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.

CONCLUSIONS

NPSLE is associated with brain-specific and systemic Abs. Cognitive impairment, psychosis, and depression were associated with many Abs, including aCL Abs. Possible mechanisms include vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.

Psychiatric manifestations in systemic lupus erythematosus

Psychiatric abnormalities are common in systemic lupus erythematosus (SLE) with a prevalence of 17% to 75%, reflecting different methods of patient selection and assessment, the different professional orientation of clinicians, and lack of an accepted consensus for diagnosing active neuropsychiatric lupus (NPSLE). The psychiatric syndromes included in the ACR Neuropsychiatric Lupus Nomenclature Committee criteria are cognitive dysfunction, acute confusional state (delirium), anxiety disorder, mood disorder, and psychosis. In SLE patients, identification of psychiatric phenomena and the generation of a differential diagnosis are crucial. Possible mechanisms include vascular injury and pathogenic antibodies. Treatment strategies are based on small case studies. The purpose of this review is to discuss clinical manifestations, pathogenesis and the present therapeutic options in psychiatric lupus.

Neuropsychiatric manifestations of systemic lupus erythematosus

Central nervous system (CNS) involvement in systemic lupus erythematosus (SLE) can produce a broad range of disease-specific neuropsychiatric manifestations that must be differentiated from infections, metabolic complications, and drug-induced toxicity. Despite the development of classification criteria by the American College of Rheumatology, the prevalence of neuropsychiatric systemic lupus erythematosus (NPSLE) varies widely across studies. Some of the neuropsychiatric manifestations are extremely rare, indicating a need for multicenter studies. Mechanisms that can lead to neuropsychiatric manifestations include intracranial vascular lesions (vasculitis and thrombosis); production of autoantibodies to neuronal antigens, ribosomes, and phospholipids; and inflammation related to local cytokine production. As a rule, no reference standard is available for establishing the diagnosis of NPSLE. Several investigations can be used to assist in the clinical diagnosis and to evaluate severity. Treatment remains largely empirical, given the absence of controlled studies. Variable combinations of corticosteroids, immunosuppressants, and symptomatic drugs are used according to the presumptive main pathogenic mechanism.

Cerebral Manifestations in the Antiphospholipid (Hughes) Syndrome

The importance of cerebral disease in patients with the Hughes syndrome is now becoming more widely recognized. The range of neuropsychiatric manifestations of APS is comprehensive, and includes focal symptoms attributable to lesions in a specific area of the brain as well as diffuse or global dysfunction. Patients with APS frequently present with strokes and TIA, but a wide spectrum of other neurologic features-also including non thrombotic neurologic syndromes-has been described in association with the presence of aPL. The recognition of APS has had a profound impact on the understanding and management of the treatment of CNS manifestations associated with connective tissue diseases, in particular, SLE. Many patients with focal neurologic manifestations and aPL, who a few years ago would have received high-dose corticosteroids or immunosuppression, are often successfully treated with anticoagulation. In our opinion, testing for aPL may have a major diagnostic and therapeutic impact not only in patients with autoimmune diseases and neuropsychiatric manifestations, but also in young individuals who develop cerebral ischemia, in those with atypical multiple sclerosis, transverse myelitis, and atypical seizures. We would also recommend testing for aPL for young individuals found with multiple hyperintensity lesions on brain MRI in the absence of other possible causes,especially when under the age of 40 years. It is our practice to anticoagulate patients with aPL suffering from cerebral ischemia with a target INR of 3.0 to prevent recurrences. Low-dose aspirin alone (with occasional exceptions)does not seem helpful to prevent recurrent thrombosis in these patients. Our recommendation, once the patient has had a proven thrombosis associated with aPL, is long-term (possibly life-long) warfarin therapy. Oral anti coagulation carries a risk of hemorrhage, but in our experience the risk of serious bleeding in patients with APS and previous thrombosis treated with oral anticoagulation to a target INR of 3.5 was similar to that in groups of patients treated with lower target ratios. Although a double-blind crossover trial comparing low molecular weight heparin with placebo in patients with aPL and chronic headaches did not show a significant difference in the beneficial effect of low molecular weight heparin versus placebo, in our experience selected patients with aPL and neuropsychiatric manifestations such as seizures, severe cognitive dys-function, and intractable headaches unresponsive to conventional treatment may respond to anticoagulant treatment. The neurologic ramifications of Hughes syndrome are extensive, and it behoves clinicians in all specialties to be aware of this syndrome because treatment with anticoagulation may profoundly change the outlook for these patients.

Hughes syndrome, the antiphospholipid syndrome: a new chapter in neurology

The importance of cerebral disease in patients with the antiphospholipid (Hughes) syndrome (APS) is now becoming more widely recognized. The range of neuropsychiatric manifestations of APS is comprehensive and includes focal symptoms attributable to lesions in a specific area of the brain as well as diffuse or global dysfunction. Patients with APS frequently present with strokes and transient ischemic attacks, but a wide spectrum of other neurologic features, also including nonthrombotic neurological syndromes, has been described in association with the presence of antiphospholipid antibodies. In this review, we attempt to highlight the large variety of the neurological features of APS.

Overlapping humoral autoimmunity links rheumatic fever and the antiphospholipid syndrome

OBJECTIVE

Rheumatic fever (RF) and the antiphospholipid syndrome (APS) are autoimmune diseases that share similar cardiac and neurological pathologies. We assessed the presence of shared epitopes between M protein, N-acetyl-beta-D-glucosamine (GlcNAc) and beta2 glycoprotein-I (beta2GPI), the pathogenic molecules engaged in these autoimmune conditions.

METHODS

Sera from the APS patients were affinity-purified on beta2GPI and beta2GPI-related peptide columns. Sera from RF patients were affinity-purified on protein G column. The beta2GPI and M protein-related peptides were prepared by conventional solid-phase peptide synthesis. The enzyme-linked immunosorbent assay direct binding and inhibition studies were performed on the RF and APS sera for the presence, and cross-reactivity, of antibodies against beta2GPI, beta2GPI-related peptides, streptococcal M protein, M-derived peptides and GlcNAc.

RESULTS

Antibodies (Abs) to beta2GPI were found in 24.4% of 90 RF patients. Antibodies against various beta2GPI-related peptides were found in 1.1-36.7% of the patients. The immunoglobulin G sera from RF patients possessed significant anti-beta2GPI activity, while sera from APS patients contained a considerable anti-streptococcal M protein as well as anti-GlcNAc activity. Furthermore, affinity-purified anti-beta2GPI and anti-beta2GPI-related peptide Abs from APS patients cross-reacted with streptococcal M protein and M5 peptide, while beta2GPI and beta2GPI-related peptides inhibited anti-streptococcal M protein activity from RF patients. The results were confirmed by immunoblot analyses. The beta2GPI also inhibited anti-GlcNAc activity from APS patients with chorea.

CONCLUSIONS

The results of our study, showing a considerable overlap of humoral immunity in RF and APS, support a hypothesis that common pathogenic mechanisms underlie the development of cardiac valve lesions and Central Nervous System abnormalities in both diseases.

Genetic and immunological factors interact in a mouse model of CNS antiphospholipid syndrome

The antiphospholipid syndrome (APS) includes systemic and central nervous system (CNS) pathology associated with antibodies to a complex of phospholipids and beta(2)-glycoprotein I (beta(2)-GPI). We have recently reported the induction of APS associated with behavioral and cognitive deficits in BALB/c female mice that developed 4-5 months after immunization with beta(2)-GPI. In the present study, we examined the influence of genetic factors on the ability to induce experimental APS with CNS involvement by testing several mouse strains immunized with beta(2)-GPI. Female mice from five strains were immunized once with beta(2)-GPI in complete Freund's adjuvant (CFA) or with CFA alone (controls). Autoantibody levels were examined at 1 and 5 months after immunization. Neurological assessment in a staircase test was performed 4-5 months following the immunization. Induction of APS resulted in elevated levels of antibodies against negatively charged phospholipids and beta(2)-GPI in all five mouse strains. Autoantibody levels were significantly higher in Balb/c, ICR, and C57BL/6 mouse strains compared to AKR and C3H. aPL levels dropped significantly more in the C57BL/6 compared to Balb/c mice over a period of 4 months. Hyperactivity reflected by higher number of stairs climbed in 3 min, was induced by APS in the Balb/c and ICR, mouse strains. Exploratory behavior reflected by more frequent rears, was seen in the APS-Balb/c and AKR mice. Hypoactivity and less exploration were seen in the APS-C57BL/6 and C3H mice. The study supports a link between high levels of aPL and behavioral changes in a mouse APS model. Qualitative differences in behavioral patterns may be due to nervous system as well as immune genetic factors. The minimal effect of APS in C57BL/6 mice may provide a suitable background for the study of transgenes in these mice.

Unveiling the enigma of the CNS as a B-cell fostering environment

This Opinion deals with the apparent paradox between the 'immune privileged' status of the central nervous system (CNS) and its propensity to act as a B-cell fostering environment in a variety of neurological disorders. Evidence will be reviewed that: (i) molecules regulating B-cell homing and survival are produced in the CNS, (ii) in different neuroinflammatory diseases, B cells can undergo a local recapitulation of the differentiation occurring in secondary lymphoid organs and (iii) ectopic lymphoid follicles develop in the meninges of multiple sclerosis (MS) patients.

Management of neuropsychiatric lupus

Nervous system disease in systemic lupus erythematosus (SLE) is manifested by a wide variety of clinical manifestations. Despite the development of a universal classification for neuropsychiatric (NP) lupus in 1999, there continues to be considerable variability in the reported prevalence of NP syndromes between different lupus cohorts. Due to the lack of specificity of individual NP manifestations, non-SLE causes such as complications of therapy and co-morbidities must be considered in advance of attributing the event to one or more primary immunopathogenic mechanisms. These include intracranial microangiopathy, autoantibodies to neuronal and non-neuronal antigens, and the generation of proinflammatory cytokines and mediators. The diagnosis of NP-SLE remains largely one of exclusion and is approached in individual patients by thorough clinical evaluation, supported when necessary by autoantibody profiles, diagnostic imaging, electrophysiologic studies and objective assessment of cognitive performance. Given the diversity in clinical manifestations, the management is tailored to the specific needs of individual patients. In the absence of controlled studies, the use of symptomatic therapies, immunosuppressives, anticoagulants and non-pharmacologic interventions is supported by case series and clinical experience.

Neuropsychiatric Lupus

Nervous system disease in patients who have systemic lupus erythematosus (SLE) spans a wide spectrum of neurologic (N) and psychiatric (P) features that may be attributed to a primary manifestation of SLE, complications of the disease or its therapy, or a coincidental disease process. The etiology of primary NP disease is multifactorial and includes vascular injury of intracranial vessels, autoantibodies to neuronal antigens, ribosomes and phospholipid-associated proteins, and the intracranial generation of cytokines. In the absence of a diagnostic gold standard for most of the NP-SLE syndromes, a range of investigations are employed to support the clinical diagnosis and determine the severity of NP disease. Treatment remains largely empiric in the absence of controlled studies, and current strategies include the use of immunosuppressive therapies, appropriate symptomatic interventions, and the treatment of non-SLE factors.

Prevalence of antiphospholipid antibodies in patients with neurological symptoms

OBJECTIVE AND PURPOSE

Neurological involvement is a common feature of the antiphospholipid syndrome (APS). A variety of thrombotic and non-thrombotic manifestations may accompany the presence of antiphospholipid antibodies (aPL).

PATIENTS AND METHODS

We retrospectively reviewed the prevalence of aPL in a cohort of over 350 unselected patients from a neurological clinic and studied the neurological manifestations of APS.

RESULTS

We found that within this cohort the prevalence of aPL was about 15%. Most of the patients with aPL suffered from strokes and transient ischemic attacks (TIA). One patient died from spinal infarction. Non-thrombotic manifestations also occurred in 40% of these patients, such as multiple sclerosis, chorea, seizures or cerebral malignancies. No significant correlations of the titres or different types of aPL and the type of the neurological symptoms could be found. In comparison to age and sex matched patients of the cohort where the presence of aPL could be excluded, the occurrence of non-thrombotic manifestations was significantly more frequent and varied in the group of patients with aPL. The higher incidence of stroke in the non-APS group could be explained by the significantly higher presence of other laboratory risk factors, mainly hypercholesterinemia.

CONCLUSION

This investigation indicates that aPL may play an important role in the etiology of various neurological syndromes.

Central nervous system manifestations of rheumatologic diseases

PURPOSE OF REVIEW

To summarize the current literature on central nervous system manifestations of vasculitides and connective tissue diseases.

RECENT FINDINGS

There have been advances in understanding the mechanisms behind the initiation and perpetuation of inflammatory processes in vasculitic neuropathy. Clinically relevant data have been obtained on the predictive criteria for a positive biopsy result in giant cell arteritis, the imaging characteristics of primary angiitis of the central nervous system, and Behçet disease, and the clinical and radiologic features of neuro-Behçet disease. There is more clarity about the central nervous system syndromes attributable to systemic lupus erythematosus and new insights into the central mechanisms involved in the manifestations of Sjögren syndrome and rheumatoid arthritis. Novel immunomodulatory agents, such as infliximab, have shown some benefit in rheumatoid vasculitis and Sjögren syndrome.

SUMMARY

A better understanding of the clinical, radiographic, and serologic characteristics of various central nervous system complications of rheumatologic diseases has been gained in the past year. Recent advances in understanding the pathophysiology of peripheral nervous system complications and their treatment may affect the management of the central nervous system complications.

Therapeutic Potential of Toleragens in the Management of Antiphospholipid Syndrome

Autoantibodies to beta2-glycoprotein I (beta2GPI) are believed to be the primary cause of coagulation abnormalities in patients with antiphospholipid syndrome (APS). Clinical features include a range of life-threatening thrombotic events and microangiopathies affecting multiple organ systems. Current standard of care relies on long-term, high-intensity anticoagulation and is associated with a high risk for serious bleeding events. The relation between autoantibodies and the pathophysiology of APS is not clearly understood, but numerous in vitro studies have characterized the effects of antiphospholipid autoantibodies on various components of the coagulation cascade, including tissue factor and the protein C pathway. The fine specificity of autoantibodies to beta2GPI is a subject of considerable debate; however, a body of evidence may offer resolution by integrating concepts of antibody affinity and assay sensitivity with carefully designed molecular studies. An investigational new therapy for APS is based on the approach that pathogenic antibodies may be reduced via depletion of circulating autoantibodies and induction of immune tolerance at the B-cell level. Preliminary results from a phase I/II clinical trial with LJP 1082, a B-cell toleragen, indicate the drug was well tolerated and may warrant further development for reduction of thrombotic events in patients with APS.