Endothelium and the brain in CNS lupus

Recurrent left ischemic stroke in a patient with systemic lupus erythematosus: A case report

Key Clinical Message

Some studies have manifested the relationship between SLE and stroke. Therefore, it is very important to pay close attention to the diagnosis of SLE in recurring stroke. In our case, her recurrent stroke attack might be due to the undiagnosed cause of SLE.

Abstract

An ischemic stroke is a medical emergency condition which occurs when blood supply to part of the brain is blocked. Early action is needed; therefore, time is crucial. SLE is an autoimmune disease with multiple joint pain, fever, rashes, and organ damage. We report an old lady who was recently diagnosed with SLE with multiple stroke attack. Although she was diagnosed with SLE much later there was a suspicious about the possible mechanism for her recurrent ischemic stroke. She was given antiplatelet, antiepileptic, antihypertensive, and hydroxychloroquine medicines for the treatment. The neurological symptoms improved only after we provided physiotherapy.

Brain blood vessel autoantibodies in patients with NMDA and GABAA receptor encephalitis: identification of unconventional Myosin-X as target antigen

Introduction: The antibody repertoire from CSF-derived antibody-secreting cells and memory B-cells in patients with encephalitis contains a considerable number of antibodies that do not target the disease-defining autoantigen such as the GABA or NMDA receptors. This study focuses on the functional relevance of autoantibodies to brain blood vessels in patients with GABA_A and NMDA receptor encephalitis. Methods: We tested 149 human monoclonal IgG antibodies from the cerebrospinal fluid of six patients with different forms of autoimmune encephalitis on murine brain sections for reactivity to blood vessels using immunohistochemistry. Positive candidates were tested for reactivity with purified brain blood vessels, effects on transendothelial electrical resistance (TEER), and expression of tight junction proteins as well as gene regulation using human brain microvascular endothelial hCMEC/D3 cells as in vitro blood-brain barrier model. One blood-vessel reactive antibody was infused intrathecally by pump injection in mice to study in vivo binding and effects on tight junction proteins such as Occludin. Target protein identification was addressed using transfected HEK293 cells. Results: Six antibodies reacted with brain blood vessels, three were from the same patient with GABA_AR encephalitis, and the other three were from different patients with NMDAR encephalitis. One antibody from an NMDAR encephalitis patient, mAb 011-138, also reacted with cerebellar Purkinje cells. In this case, treatment of hCMEC/D3 cells resulted in decreased TEER, reduced Occludin expression, and mRNA levels. Functional relevance in vivo was confirmed as Occludin downregulation was observed in mAb 011-138-infused animals. Unconventional Myosin-X was identified as a novel autoimmune target for this antibody. Discussion: We conclude that autoantibodies to blood vessels occur in autoimmune encephalitis patients and might contribute to a disruption of the blood-brain barrier thereby suggesting a potential pathophysiological relevance of these antibodies.

Neuropsychiatric lupus erythematosus: Focusing on autoantibodies

Patients with systemic lupus erythematosus (SLE) frequently suffer from nervous system complications, termed neuropsychiatric lupus erythematosus (NPLE). NPLE accounts for the poor prognosis of SLE. Correct attribution of NP events to SLE is the primary principle in managing NPLE. The vascular injuries and neuroinflammation are the fundamental neuropathologic changes in NPLE. Specific autoantibody-mediated central nerve system (CNS) damages distinguish NPLE from other CNS disorders. Though the central antibodies in NPLE are generally thought to be raised from the periphery immune system, they may be produced in the meninges and choroid plexus. On this basis, abnormal activation of microglia and disease-associated microglia (DAM) should be the common mechanisms of NPLE and other CNS disturbances. Improved understanding of both characteristic and sharing features of NPLE might yield further options for managing this disease.

Thrombosis and Anticoagulation Therapy in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease in which pathogenic autoantibodies and immune complexes are formed and mediate multiple organ and tissue damage. Thrombosis is one of the most common causes of death in patients with SLE. Anticoagulant therapy blocks the vicious cycle between inflammation and thrombosis, which may greatly improve the long-term prognosis of patients with SLE. However, the etiology and pathogenesis of this disease are very complicated and have not yet been fully clarified. Therefore, in the present review, we will highlight the characteristics and mechanisms of thrombosis and focus on the anticoagulant drugs commonly used in clinical practice, thus, providing a theoretical basis for scientific and reasonable anticoagulant therapy in clinical practice.

Connexin 43 Expression in Cutaneous Biopsies of Lupus Erythematosus

INTRODUCTION

Gap junctions are channels between adjacent cells formed by connexins (Cxs). Cxs also form hemichannels that connect the cell with its extracellular milieu. These channels allow the transport of ions, metabolites, and small molecules; therefore, Cxs, and more specifically, connexin (Cx) 43 has been demonstrated to be in control of several crucial events such as inflammation and cell death.

MATERIAL AND METHODS

We examined the immunostaining of Cx43 in the endothelia of the cutaneous blood vessels of biopsies from 28 patients with several variants of lupus erythematosus.

RESULTS

In 19 cases (67.86%), staining of more than half of the dermal vessels including both vessels of the papillary and of the reticular dermis was identified. Only in 4 cases (14.28%), less than 25% of the vessels in the biopsy showed expression of the marker.

CONCLUSIONS

Our results suggest a role of Cx43 in regulating the endothelial activity in lupus erythematosus, which also opens a door for targeted therapeutic options.

The Clinical Spectrum of Autoimmune-Mediated Neurological Diseases in Paediatric Population

Neurological autoimmune diseases have various origins and pathogeneses. Specific antibodies are associated with paraneoplastic syndromes, other infectious agents, or inherited disorders. We aim to evaluate the relation between the autoantibodies, the chosen symptoms, demographic characteristics, and infection history. We retrospectively analysed 508 children during neurological diagnostics. We investigated serum antineuronal, IgG, IgM anti-ganglioside, and anti-aquaporin-4 in both the serum and cerebrospinal fluid (CSF) anti-cell surface and anti-synaptic protein antibodies in 463, 99, 44, 343, and 119 patients, respectively. The CSF polymerase chain reaction detection of Herpesviridae, enterovirus, B19 parvovirus, adenovirus, and parechovirus involved 261 patients. We included available clinical information and electroencephalographic, radiologic, and microbiological results. The IgM anti-ganglioside antibodies increased the risk of tics and positive symptoms (p = 0.0345, p = 0.0263, respectively), the anti-glutamic acid decarboxylase particle of paresis (p = 0.0074), and anti-neuroendothelium of mutism (p = 0.0361). Anti-neuroendothelium, IgM anti-ganglioside, and CSF anti-N-methyl-D-aspartate antibodies were more often associated with consciousness loss (p = 0.0496, p = 0.0044, p = 0.0463, respectively). Anti-myelin antibodies co-occured with Herpes simplex virus (HSV)-2 IgG (p = 0.0415), anti-CV2 with HSV-1 IgM (p = 0.0394), whereas anti-glial fibrillary acidic protein was linked with past Epstein-Barr virus infection. The anti-ganglioside IgM and anti-myelin particles were bilaterally correlated (p = 0.0472). The clinical pictures may overlap, requiring specialistic diagnostics. We noticed the links between the infection aetiology and the specific autoantibody’s positivity.

Antiphospholipid antibodies and cerebrovascular thrombosis in the pediatric population: Few answers to many questions

Most of the knowledge in pediatric antiphospholipid syndrome (APS) is derived from studies performed on the adult population. As in adults, antiphospholipid antibodies (aPL) can contribute to thrombosis, especially cerebrovascular thrombosis, in neonates and children. Since aPL have the potential to cross the placental barrier, and since the pediatric population is prone to infections, re-testing for their positivity is essential to specify their role in cerebrovascular thrombosis.In this review, we aimed at assessing the prevalence of aPL, criteria or non-criteria, in neonatal and childhood ischemic stroke and sinovenous thrombosis trying to find an association between aPL and cerebrovascular thrombosis in the neonatal and pediatric population. Also, we looked into the effect of aPL and anticoagulants/antiplatelets on the long term neurological outcomes of affected neonates or children. The questions regarding the prevalence of aPL among pediatric patients with cerebrovascular thrombosis, the relationship between the titers of aPL and incidence and recurrence of cerebrovascular events, the predictability of the long term neurological outcomes, and the most optimal anticoagulation plan are still to be answered. However, it is crucial for clinicians to screen neonates and children with cerebrovascular thrombosis for aPL and confirm their presence if positive.

Neuropathological spectrum in systemic lupus erythematosus: A single institute autopsy experience

AIM

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by circulating autoantibodies and immune complexes involving virtually every organ of the body. However, with respect to central nervous system (CNS), the mechanism of injury is still debated as complement mediated or thrombo-ischemic in nature. We studied the spectrum of neuropathological changes in twelve autopsy cases of SLE and evaluated the role of immune-complexes and complement activation in contributing to the thrombo-ischemic injury and correlated these features with clinical profile.

METHODS

Autopsy records of all cases of SLE over a period of 20 years (2000-2019) were reviewed. Clinical history including neuropsychiatric symptoms and detailed histopathological analysis was performed. Direct immunofluorescence for IgM, IgG, IgA, C1q, C3, C4d, Kappa, Lambda and immunohistochemistry for C5b-9 was performed on lesional areas in paraffin embedded brain sections. Control tissue from brain was taken from two patients who died of sudden cardiac event.

RESULTS

Our cohort comprised of 12 cases with age range from 12 to 40 years and all were female patients. Microinfarction and vasculopathy seen in eight cases were the commonest findings. Four cases with microinfarcts had non-bacterial thrombotic endocarditis in heart. Microthrombi adjacent to microinfarcts were seen in 4 cases. Variable deposition of immunoglobulins (predominantly IgG) and complements (C1q, C3, C4d) was evident in cortical arterioles (2 cases) and small capillaries (1 case). Neurological symptoms were seen in four cases, of which, three had associated invasive fungal infection with secondary vasculitis. Active lupus vasculitis was identified in a single case. C5b-9 immunoexpression was not detected in any of the cases.

CONCLUSIONS

Our study adds observational data to the existing literature that the predominant neuropathological features of SLE are related to thrombo-ischemic injury and small vasculopathic changes. Only in a minor subset (25%), it is mediated by immune-complexes and complements. Immune-complex deposition on immunofluorescence in cortical vessels (cerebral lupus vasculopathy) is a novel finding which has not been reported earlier.

In vivo evidence of angiogenesis inhibition by β2-glycoprotein I subfractions in the chorioallantoic membrane of chicken embryos

The vascular network expansion and functioning are important factors affecting normal intra-uterine fetal development. This study addressed the previously reported antiangiogenic potential of beta-2-glycoprotein I (β₂GPI) in vivo in the chick embryo model of angiogenesis. The effects of two naturally occurring β₂GPI forms on the development of the chorioallantoic membrane (CAM) vessels and the chicken embryo were investigated. β₂GPI monomers and dimers were obtained by fractioned purification and characterized using SDS-PAGE, immunoblot, and ELISA. The egg exposure was performed by injection of small volumes of 2.5 µg/mL solutions of the β₂GPI subfractions. Angiogenesis was evaluated through quantitative measurements of vascular architecture parameters in the captured CAM images, using computational analysis of texture contrasts and computer vision techniques. Quantitative information was assigned to the CAM vasculature modifications. In vivo, the β₂GPI dimer completely halted the formation of CAM vessels and led to embryo death after 48 h of exposure. The β₂GPI monomer allowed the embryo to develop up to the 10th day, despite early changes of CAM vessels. The impaired normal vessel growth proceeded as a self-limited effect. The β₂GPI monomer-exposed eggs showed reduced vascularization on the 6th day of incubation, but embryos were viable on the 10th day of incubation, with ingurgitated CAM vessels implying sequelae of the angiogenesis inhibition. Both subfractions impaired CAM vasculature development. The β₂GPI dimer proved to be largely more harmful than the β₂GPI monomer. β₂GPI modification by cleavage or dimerization may play a role in angiogenesis control in vivo.

The immunologic etiology of psychiatric manifestations in systemic lupus erythematosus: A narrative review on the role of the blood brain barrier, antibodies, cytokines and chemokines

INTRODUCTION

The aim of this narrative review is to provide an overview of the literature on the possible immunologic pathophysiology of psychiatric manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

A systematic search on PubMed was conducted. English studies with full text availability that investigated the correlation between blood-brain barrier (BBB) dysfunction, intrathecal synthesis of antibodies, antibodies, cytokines, chemokines, metalloproteinases, complement and psychiatric NPSLE manifestations in adults were included.

RESULTS

Both transient BBB-dysfunction with consequent access of antibodies to the cerebrospinal fluid (CSF) and intrathecal synthesis of antibodies could occur in psychiatric NPSLE. Anti-phospholipid antibodies, anti-NMDA antibodies and anti-ribosomal protein p antibodies seem to mediate concentration dependent neuronal dysfunction. Interferon-α may induce microglial engulfment of neurons, direct neuronal damage and production of cytokines and chemokines in psychiatric NPSLE. Several cytokines, chemokines and matrix metalloproteinase-9 may contribute to the pathophysiology of psychiatric NPSLE by attracting and activating Th1-cells and B-cells.

DISCUSSION

This potential pathophysiology may help understand NPSLE and may have implications for the diagnostic management and therapy of psychiatric NPSLE. However, the presented pathophysiological model is based on correlations between potential immunologic etiologies and psychiatric NPSLE that remain questionable. More research on this topic is necessary to further elucidate the pathophysiology of NPSLE.

Identification of novel biomarkers in ischemic stroke: a genome-wide integrated analysis

BACKGROUND

Ischemic Stroke (IS) is the most common neurological emergency disease and has become the second most frequent cause of death after coronary artery disease in 2015. Owing to its high fatality rate and narrow therapeutic time window, early identification and prevention of potential stroke is becoming increasingly important.

METHODS

We used meta-analysis and bioinformatics mining to explore disease-related pathways and regulatory networks after combining messengerRNA (mRNA) and miRNA expression analyses. The purpose of our study was to screen for candidate target genes and microRNA(miRNA) for early diagnosis of potential stroke.

RESULTS

Five datasets were collected from the Gene Expression Omnibus (GEO) database by systematical retrieval, which contained three mRNA datasets (102 peripheral blood samples in total) and two miRNA dataset (59 peripheral blood samples). Approximately 221 different expression(DE) mRNAs (155 upregulated and 66 downregulated mRNAs) and 185 DE miRNAs were obtained using the metaDE package and GEO2R tools. Further functional enrichments of DE-mRNA, DE-miRNA and protein-protein interaction (PPI) were performed and visualized using Cytoscape.

CONCLUSION

Our study identified six core mRNAs and two regulated miRNAs in the pathogenesis of stroke, and we elaborated the intrinsic role of systemic lupus erythematosus (SLE) and atypical infections in stroke, which may aid in the development of precision medicine for treating ischemic stroke. However, the role of these novel biomarkers and the underlying molecular mechanisms in IS require further fundamental experiments and further clinical evidence.

The MRL Model: A Valuable Tool in Studies of Autoimmunity-Brain Interactions

The link between systemic autoimmunity, brain pathology, and aberrant behavior is still a largely unexplored field of biomedical science. Accumulating evidence points to causal relationships between immune factors, neurodegeneration, and neuropsychiatric manifestations. By documenting autoimmunity-associated neuronal degeneration and cytotoxicity of the cerebrospinal fluid from disease-affected subjects, the murine MRL model had shown high validity in revealing principal pathogenic circuits. In addition, unlike any other autoimmune strain, MRL mice produce antibodies commonly found in patients suffering from lupus and other autoimmune disorders. This review highlights importance of the MRL model as a useful preparation in understanding the links between immune system and brain function.

Stroke in systemic lupus erythematosus and antiphospholipid syndrome: risk factors, clinical manifestations, neuroimaging, and treatment

Neurologic disorders are among the most common and important clinical manifestations associated with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS), mainly those that affect the central nervous system (CNS). Risk of cerebrovascular events in both conditions is increased, and stroke represents one of the most severe complications, with an incidence rate between 3% and 20%, especially in the first five years of diagnosis. This article updates the data regarding the risk factors, clinical manifestations, neuroimaging, and treatment of stroke in SLE and APS.

Pregnancy, lupus and antiphospholipid syndrome (Hughes syndrome)

Autoimmune diseases (AD) occur frequently in women during their childbearing years and may influence pregnancy outcome and neonatal health. Patients with systemic lupus erythematosus (SLE) can experience a disease flare-up during pregnancy with potential negative effects on the product of conceptus, especially if the disease is active. Recurrent pregnancy loss is now considered as a treatable clinical condition associated with the presence of circulating antiphospholipid antibodies (aPL). The neonatal lupus syndromes (NLS), caused by the transplacental passage of maternal IgG anti-Ro/SS-A and anti-La/SS-B antibodies to the fetus, carry significant morbidity and mortality in case of cardiac manifestations. Immunosuppressive agents are often administered during pregnancy in order to control maternal disease and to ensure a better pregnancy outcome. Nowadays, owing to our increasing knowledge of the disease pathophysiological mechanisms and the development of combined medical-obstetric clinics, pregnancy outcome in patients with AD has notably improved.

Neuropsychological development of children born to patients with systemic lupus erythematosus

To verify the neuropsychological development in the offspring of patients with systemic lupus erythematosus (SLE), 47 children (23 male and 24 female) from affected women were studied. The tests applied were related to the children’s ages: Griffiths scale up to four years, WPPSI and metaphonological tests (MP, evaluating the phonological consciousness) from four to six years of age, WISC-R test and Rey test (evaluating the visual-space abilities) from six years onwards; finally, specific tests for the diagnosis of learning disabilities (LD) between the ages of seven and 13. Intelligence levels were always normal (mean IQ score 106.32; median 104; SD 9.05). Three out of eight examined children failed MP, therefore may develop LD and will need further evaluation later. Fourteen children were specifically studied for LD and three reported scores lower than normal, but only two (who were brothers) were defined dyslexic. Antiphospholipid antibodies (aPL) were positive in the mothers of the three children with impaired LD tests. Other maternal autoantibodies or drugs administered during pregnancy did not seem to be related to LD. In conclusion, maternal SLE does not impair intelligence levels, but may increase the occurrence of LD particularly in male children (2/8 males examined, 25%). Both maternal aPL and genetic background may have pathogenetic implications.

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.

Acquired neurocutaneous disorders

A variety of neurologic diseases have cutaneous manifestations. These may precede, coincide with, or follow the neurologic findings. An array of autoimmune, genetic, and environmental factors play a role in expression and severity of the neurologic burden in these conditions. This chapter emphasizes congenital and genetic disorders, but we also discuss the pathophysiology and manifestation of various acquired neurocutaneous disorders with an emphasis Behcet's disease, dermatomyositis, Sjögren's syndrome, systemic lupus erythematosus, scleroderma, Parry-Romberg syndrome and Degos disease.

Chance, genetics, and the heterogeneity of disease and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a remarkably complex and heterogeneous systemic autoimmune disease. Disease complexity within individuals and heterogeneity among individuals, even genetically identical individuals, is driven by stochastic execution of a complex inherited program. Genome-wide association studies (GWAS) have progressively improved understanding of which genes are most critical to the potential for SLE and provided illuminating insight about the immune mechanisms that are engaged in SLE. What initiates expression of the genetic program to cause SLE within an individual and how that program is initiated remains poorly understood. If we extrapolate from all of the different experimental mouse models for SLE, we can begin to appreciate why SLE is so heterogeneous and consequently why prediction of disease outcome is so difficult. In this review, we critically evaluate extrinsic versus intrinsic cellular functions in the clearance and elimination of cellular debris and how dysfunction in that system may promote autoimmunity to nuclear antigens. We also examine several mouse models genetically prone to SLE either because of natural inheritance or inheritance of induced mutations to illustrate how different immune mechanisms may initiate autoimmunity and affect disease pathogenesis. Finally, we describe the heterogeneity of disease manifestations in SLE and discuss the mechanisms of disease pathogenesis with emphasis on glomerulonephritis. Particular attention is given to discussion of how anti-DNA autoantibody initiates experimental lupus nephritis (LN) in mice.

Effect of autoimmune diseases on cognitive function

The location of both autoimmune processes and other causes of brain inflammation is important in determining the impact of inflammation on brain function. This chapter focuses on autoimmune and infectious diseases leading to inflammatory brain disease resulting in cognitive defects with a special focus on systemic lupus erythematosus (SLE). Collectively called neuropsychiatric SLE (NPSLE), NPSLE occurs in 20-95% of pediatric patients with SLE (pSLE). The incidence of cognitive dysfunction is difficult to ascertain in pediatric patients as few studies have been performed. Using formal neurocognitive testing of unselected pediatric SLE patients, the rate of cognitive abnormalities was approximately 50% and impairment was associated with longer disease duration in one study. A second small study showed global depression on performance and academic scores while a larger study using a neuropsychiatric inventory showed a 55% rate of dysfunction. These diverging findings may result from the lack of a standardized cognitive assessment battery. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) group of pediatric rheumatologists proposed a 2 hour 40 minutes battery for assessment of cognitive testing of SLE patients from age 9 to 18 years. Further assessments using this battery should provide a better neurocognitive profile of pSLE.

Cranial Nerve Palsies: Sarcoidosis to Systemic Lupus Erythematosus

Cranial palsies are a very rare feature of SLE. Similarly, peripheral sensory-motor axonal neuropathy is very uncommon in SLE. The combination of the two as the presenting symptoms of SLE is a diagnostic challenge particularly in an elderly male patient with a known diagnosis of sarcoidosis. This case serves to highlight the diagnostic considerations in such a patient. The lack of response to standard therapy and the presence of subtle clues like anemia, proteinuria, and mild serositis should prompt the physician to look for alternate diagnoses. The potential association of SLE and sarcoidosis is also discussed. SLE can be present in elderly male patients with cranial and peripheral neuropathy.

The MRL model: an invaluable tool in studies of autoimmunity-brain interactions

The link between systemic autoimmunity, brain pathology, and aberrant behavior is still largely unexplored field of biomedical science. Accumulating evidence points to causal relationships between immune factors, neurodegeneration, and neuropsychiatric manifestations. By documenting autoimmunity-associated neuronal degeneration and cytotoxicity of the cerebrospinal fluid from disease-affected subjects, the murine MRL model had shown high validity in revealing principal pathogenic circuits. In addition, unlike any other autoimmune strain, MRL mice produce antibodies commonly found in patients suffering from lupus and other autoimmune disorders. This review highlights importance of the MRL model as an indispensible preparation in understanding the links between immune system and brain function.

In vivo distribution of β2 glycoprotein I under various pathophysiologic conditions

In vitro studies have documented β2 glycoprotein I (β2GPI) binding to endothelial cells (ECs) and trophoblast using antiphospholipid antibodies. The in vivo binding of β2GPI to these cells and the conditions that favor their interaction have not been investigated. We analyzed the in vivo distribution of cyanine 5.5-labeled β2GPI in mice and evaluated the effect of pregnancy and circulating antibodies on its tissue localization. The signal was detected in the liver by whole body scan and ex vivo analysis. The β2GPI failed to bind to the vascular endothelium and reacted only with the ECs of uterine vessels. In pregnant mice the protein was localized on ECs and trophoblast at the embryo implantation sites. Immunized mice showed a similar β2GPI biodistribution to naive mice but the immunized pregnant animals exhibited a significant increase in fetal loss associated with C3 and C9 deposition at the implantation sites. Treatment of mice with LPS after β2GPI-Cy5.5 injection promoted protein localization on gut and brain ECs associated with IgG, C1q, and C9 deposition in immunized mice. These findings indicate that β2GPI binding to EC requires priming with pro-inflammatory factors which is not needed for uterine and placental localization probably dependent on hormonal changes.

Autoantibodies against the fibrinolytic receptor, annexin A2, in cerebral venous thrombosis

BACKGROUND AND PURPOSE

Cerebral venous thrombosis (CVT) may be a manifestation of underlying autoimmune disease. Antibodies against annexin A2 (anti-A2Ab) coincide with antiphospholipid syndrome, in which antiphospholipid antibodies (aPLA) are associated with thrombosis in any vascular bed. Annexin A2, a profibrinolytic receptor and binding site for β2-glycoprotein-I, the main target for aPLA, is highly expressed on cerebral endothelium. Here we evaluate the prevalence of anti-A2Ab in CVT.

METHODS

Forty individuals with objectively documented CVT (33 women and 7 men) and 145 healthy controls were prospectively studied for hereditary and acquired prothrombotic risk factors, classical aPLA, and anti-A2Ab.

RESULTS

One or more prothrombotic risk factors were found in 85% of CVT subjects, (pregnancy/puerperium in 57.5%, classical aPLA in 22.5%, and hereditary procoagulant risk factors in 17.5%). Anti-A2Ab (titer >3 SD) were significantly more prevalent in patients with CVT (12.5%) than in healthy individuals (2.1%, P<0.01, OR, 5.9).

CONCLUSIONS

Anti-A2Ab are significantly associated with CVT and may define a subset of individuals with immune-mediated cerebral thrombosis.

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.

Losing your nerves? Maybe it's the antibodies

We propose that the normal immunocompetent B cell repertoire is replete with B cells making antibodies that recognize brain antigens. Although B cells that are reactive with self antigen are normally silenced during B cell maturation, the blood-brain barrier (BBB) prevents many brain antigens from participating in this process. This enables the generation of a B cell repertoire that is sufficiently diverse to cope with numerous environmental challenges. It requires, however, that the integrity of the BBBs is uninterrupted throughout life to protect the brain from antibodies that crossreact with microorganisms and brain antigens. Under conditions of BBB compromise, and during fetal development, we think that these antibodies can alter brain function in otherwise healthy individuals.

Colour Doppler ultrasound of the ocular circulation in patients with systemic lupus erythematosus identifies altered microcirculatory haemodynamics

We assessed whether quantitative analysis of Doppler flow velocity waveforms is able to identify subclinical microvascular abnormalities in SLE and whether eigenvector analysis can detect changes not detectable using the resistive index (RI). Fifty-four SLE patients with no conventional cardiovascular risk factors, major organ involvement or retinopathy were compared to 32 controls. Flow velocity waveforms were obtained from the ophthalmic artery (OA), central retinal artery (CRA) and common carotid artery (CA). The waveforms were analysed using eigenvector decomposition and compared between groups at each arterial site. The RI was also determined. The RI was comparable between groups. In the OA and CRA, there were significant differences in the lower frequency sinusoidal components ( P < 0.05 for each component). No differences were apparent in the CA between groups. Eigenvector analysis of Doppler flow waveforms, recorded in proximity of the terminal vascular bed, identified altered ocular microvascular haemodynamics in SLE. Altered waveform structure could not be identified by changes in RI, the traditional measure of downstream vascular resistance. This analytical approach to waveform analysis is more sensitive in detecting preclinical microvascular abnormalities in SLE. It may hold potential as a useful tool for assessing disease activity, response to treatment, and predicting future vascular complications.

Annexin A2 is involved in antiphospholipid antibody-mediated pathogenic effects in vitro and in vivo

Antiphospholipid (aPL) antibodies recognize receptor-bound beta(2) glycoprotein I (beta(2)GPI) on target cells, and induce an intracellular signaling and a procoagulant/proinflammatory phenotype that leads to thrombosis. Evidence indicates that annexin A2 (A2), a receptor for tissue plasminogen activator and plasminogen, binds beta(2)GPI on target cells. However, whether A2 mediates pathogenic effects of aPL antibodies in vivo is unknown. In this work, we studied the effects of human aPL antibodies in A2-deficient (A2(-/-)) mice. A2(-/-) and A2(+/+) mice were injected with immunoglobulin G (IgG) isolated from either a patient with antiphospholipid syndrome (IgG-APS), a healthy control subject (IgG-normal human serum), a monoclonal anti-beta(2)GPI antibody (4C5), an anti-A2 monoclonal antibody, or monoclonal antibody of irrelevant specificity as control. We found that, after IgG-APS or 4C5 injections and vascular injury, mean thrombus size was significantly smaller and tissue factor activity was significantly less in A2(-/-) mice compared with A2(+/+) mice. The expression of vascular cell adhesion molecule-1 induced by IgG-APS or 4C5 in explanted A2(-/-) aorta was also significantly reduced compared with A2(+/+) mice. Interestingly, anti-A2 monoclonal antibody significantly decreased aPL-induced expression of intercellular cell adhesion molecule-1, E-selectin, and tissue factor activity on cultured endothelial cells. Together, these data indicate for the first time that A2 mediates the pathogenic effects of aPL antibodies in vivo and in vitro APS.

Pathogenesis of neuropsychiatric systemic lupus erythematosus and potential biomarkers

Systemic lupus erythematosus is a chronic, multisystemic, autoimmune disease that may involve the central, peripheral, and autonomic nervous systems and can present with a wide variety of neurological and psychiatric manifestations. In this article, we review the recent literature pertaining to the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE). We searched the PUBMED database with no chronological constraints using the following terms: "neuropsychiatric systemic lupus erythematosus" cross-referenced with the terms "pathogenesis" and "biomarkers" for full-text articles in English. The etiology of NPSLE is as yet unknown, though numerous autoantibodies and cytokines have been suggested as possible mediators. Of the numerous autoantibodies and biomarkers examined, anti-phospholipid, anti-ribosomal P, anti-neuronal, anti-glial fibrillary acidic protein (GFAP), anti-endothelial cell, anti-N-methyl-D: -aspartate (NMDA), microtubule-associated protein 2 (MAP-2), and matrix metalloproteinase-9 (MMP-9) appear to be elevated in patients with NPSLE. Cytokines that may be involved in the pathology of NPSLE include interleukin (IL)-2, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and interferons (IFN)-alpha and -gamma. With continued advances in immunological research, new insights into the pathophysiologic mechanisms of NPSLE may lead to the development of biomarkers and new treatment strategies.

Toll-like receptors: another player in the pathogenesis of the anti-phospholipid syndrome

The anti-phospholipid syndrome (APS) is a systemic autoimmune disease characterized by an adaptive immune response against self phospholipid (PL)--binding proteins. Although APS is considered as an autoantibody-mediated disease, there is now evidence that anti-phospholipid antibodies (aPL) are necessary but not sufficient to trigger some of the clinical manifestations of the syndrome. For example, mediators of the innate immunity are recognized to be additional second hits able to induce the thrombotic events in the presence of aPL. Finally, environmental agents - in particular infectious ones - were reported to act as triggers for the production of autoantibodies cross-reacting with PL-binding proteins as well as inflammatory stimuli that potentiate the aPL thrombogenic effect. Altogether, these findings suggest a role for the innate immunity in APS pathogenesis. Toll-like receptors (TLR) are receptors that induce prompt inflammatory responses and mediate functional activation in immune effector cells. There is evidence that aPL, and in particular anti-beta(2) glycoprotein I (beta(2)GPI) antibodies, may activate endothelial cells and monocytes through TLR-4-dependent signalling. Whether or not TLR may behave as surface receptors for beta(2)GPI is still matter of research. Drugs or molecules able to interfere with TLR involvement may represent new therapeutic approaches for APS.

Von Willebrand factor, red cell fragmentation, and disease activity in systemic lupus erythematosus

This study sought to determine whether the plasma levels of Von Willebrand factor (vWf) and the degree of red blood cell (RBC) fragmentation on peripheral smear correlate with disease activity in systemic lupus erythematosus (SLE). Forty consecutive patients who fulfilled the criteria for SLE were studied prospectively for 1 year. Patients were categorized according to the SLE Disease Activity Index (SLEDAI) as either active (>2) or inactive disease and followed up monthly (active) or quarterly (inactive). At each visit, patients were examined fully and had complete blood count, tests on antibodies to double-stranded DNA, C3, and C4 levels, and urinalysis. Citrated plasma was analyzed for vWf antigen by standard enzyme-linked immunosorbent assay. A Wright's stained blood smear was obtained and schistocytes were quantitated on blood smear. The number of schistocytes per 500 RBCs was determined and a schistocyte index (SI) was calculated. At baseline, vWf correlated with SLEDAI (r = 0.64, p < 0.01), SI correlated with SLEDAI (r = 0.62, p < 0.01), and vWf and SI correlated with each other (r = 0.41, p = 0.01). There was an inverse correlation between baseline C3 levels and vWf (r = 0.49, p = 0.0013) and C3 levels and SI (r = 0.40, p = 0.01). Over time, there was also a correlation of SLEDAI with vWf (r = 0.53, p = 0.002) and SI (r = 0.57;p = 0.002). The relation of vWf with SI approached but did not reach statistical significance (r = 0.37, p = 0.06). We found that the plasma levels of vWf and the degree of RBC fragmentation correlate with lupus disease activity over time. Therefore, inflammation in SLE may be associated with endothelial injury.

Quantifying subclinical central nervous lesions in primary antiphospholipid syndrome: the role of magnetization transfer imaging

PURPOSE

To define the role of magnetization transfer imaging (MTI) in detecting subclinical central nervous system (CNS) lesions in primary antiphospholipid syndrome (PAPS).

MATERIALS AND METHODS

Ten non-CNS PAPS patients were compared to 10 CNS PAPS patients and 10 age- and sex-matched controls. All PAPS patients met Sapporo criteria. All subjects underwent conventional MRI and complementary MTI analysis to compose histograms. CNS viability was determined according to the magnetization transfer ratio (MTR) by mean pixel intensity (MPI) and the mean peak height (MPH). Volumetric cerebral measurements were assessed by brain parenchyma factor (BPF) and total/cerebral volume.

RESULTS

MTR histograms analysis revealed that MPI was significantly different among groups (P < 0.0001). Non-CNS PAPS had a higher MPI than CNS PAPS (30.5 +/- 1.01 vs. 25.1 +/- 3.17 percent unit (pu); P < 0.05) although lower than controls (30.5 +/- 1.01 vs. 31.20 +/- 0.50 pu; P < 0.05). MPH in non-CNS PAPS (5.57 +/- 0.20% (1/pu)) was similar to controls (5.63 +/- 0.20% (1/pu), P > 0.05) and higher than CNS PAPS (4.71 +/- 0.30% (1/pu), P < 0.05). A higher peak location (PL) was also observed in the CNS PAPS group in comparison with the other groups (P < 0.0001). In addition, a lower BPF was found in non-CNS PAPS compared to controls (0.80 +/- 0.03 vs. 0.84 +/- 0.02 units; P < 0.05) but similar to CNS PAPS (0.80 +/- 0.03 vs. 0.79 +/- 0.05 units; P > 0.05).

CONCLUSION

Our findings suggest that non-CNS PAPS patients have subclinical cerebral damage. The long-termclinical relevance of MTI analysis in these patients needs to be defined by prospective studies.

Proteomic analysis of autoantibodies in neuropsychiatric systemic lupus erythematosus patient with white matter hyperintensities on brain MRI

The pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) may be related to autoantibody-mediated neural dysfunction, vasculopathy and coagulopathy. We encountered an NPSLE patient whose brain showed characteristic diffuse symmetrical hyperintensity lesions in the cerebral white matter, cerebellum and middle cerebellar peduncles on T2-weighted magnetic resonance (MR) images. In this study, we investigated all the antigens that reacted strongly with autoantibodies in this patient's serum by two-dimensional electrophoresis (2DE), followed by western blotting (WB) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) using rat brain proteins as the antigen source. As a result, we identified four antigens as beta-actin, alpha-internexin, 60 kDa heat-shock protein (Hsp60) and glial fibrillary acidic protein (GFAP). There are several reports on the detection of anti-endothelial cell antibodies (AECAs) in an SLE patients. Recently, one of the antigens reacting with AECAs in SLE patient's sera has been identified as human Hsp60. We speculated that the abnormal findings on brain MR images of our patient may be due to impairment of microcirculation associated with vascular endothelial cell injury mediated by the antibody against Hsp60. This proteomic analysis is a useful tool for identifying autoantigens in autoimmune diseases involving autoantibodies.

Posterior reversible encephalopathy syndrome: another manifestation of CNS SLE?

A variety of neuropsychiatric findings may complicate systemic lupus erythematosus (SLE) and pose diagnostic and therapeutic dilemmas. We describe the clinical and radiographic features of posterior reversible encephalopathy syndrome (PRES) and distinguish PRES from other conditions seen in SLE. Patient charts and magnetic resonance imaging (MRI) findings of four patients with SLE on immunosuppressive therapy with acute or subacute neurologic changes initially suggesting cerebritis or stroke were reviewed. The English language literature was reviewed using the Medline databases from 1996-2006 for other reports of PRES with SLE. Literature review yielded 26 other SLE cases reported with PRES. SLE patients with PRES were more commonly on immunosuppressive drugs, had episodes of relative hypertension, and had renal involvement. Characteristic findings are seen on MRI, which differentiate PRES from other CNS complications of SLE. Clinical and radiographic resolution of abnormalities within 1-4 weeks is typically seen. PRES has been increasingly recognized. Reversible changes are found on brain MRI accompanied by sometimes dramatic signs and symptoms. The therapeutic implications for separating PRES from stroke or cerebritis are important. We propose that PRES should be considered in the differential diagnosis in SLE patients with new-onset neurologic signs and symptoms.