Antibodies against N-methyl-D-aspartate receptors in patients with systemic lupus erythematosus without major neuropsychiatric syndromes

[Formula: see text] Cognitive dysfunction in pediatric systemic lupus erythematosus: current knowledge and future directions

Cognitive dysfunction (CD) is a neurologic complication of pediatric systemic lupus erythematosus (SLE) that remains poorly understood and understudied, despite the potential negative effects of CD on long-term socioeconomic status and quality of life. Data regarding the prevalence and risk factors for CD in pediatric SLE as well as the optimal screening, treatment, and long-term outcomes for CD are lacking. In this review, we present current knowledge on CD in pediatric SLE with a focus on the application to clinical practice. We discuss the challenges in diagnosis, clinical screening methods, potential impacts, and interventions for this complication. Finally, we discuss the remaining gaps in our knowledge of CD in pediatric SLE, and avenues for future research efforts.

Mouse models, antibodies, and neuroimaging: Current knowledge and future perspectives in neuropsychiatric systemic lupus erythematosus (NPSLE)

As a chronic autoimmune disease systemic lupus erythematosus (SLE) can also affect the central and the peripheral nervous system causing symptoms which are summed up as neuropsychiatric systemic lupus erythematosus (NPSLE). These symptoms are heterogenous including cognitive impairment, seizures, and fatigue, leading to morbidity or even mortality. At present, little is known about the pathophysiological processes involved in NPSLE. This review focuses on the current knowledge of the pathogenesis of NPSLE gained from the investigation of animal models, autoantibodies, and neuroimaging techniques. The antibodies investigated the most are anti-ribosomal P protein antibodies (Anti-rib P) and anti-N-Methyl-D-Aspartic Acid Receptor 2 antibodies (Anti-NR2), which represent a subpopulation of anti-dsDNA autoantibodies. Experimental data demonstrates that Anti-rib P and Anti-NR2 cause different neurological pathologies when applied intravenously (i.v.), intrathecally or intracerebrally in mice. Moreover, the investigation of lupus-prone mice, such as the MRL/MpJ-Faslpr/lpr strain (MRL/lpr) and the New Zealand black/New Zealand white mice (NZB × NZW F1) showed that circulating systemic antibodies cause different neuropsychiatric symptoms compared to intrathecally produced antibodies. Furthermore, neuroimaging techniques including magnetic resonance imaging (MRI) and positron emission tomography (PET) are commonly used tools to investigate structural and functional abnormalities in NPSLE patients. Current research suggests that the pathogenesis of NPSLE is heterogenous, complex and not yet fully understood. However, it demonstrates that further investigation is needed to develop individual therapy in NPSLE.

Cognitive impairment in the immune-mediated inflammatory diseases compared with age-matched controls: Systematic review and meta-regression

OBJECTIVES

To compare the magnitude of cognitive impairment against age-expected levels across the immune mediated inflammatory diseases (IMIDs: systemic lupus erythematosus [SLE], rheumatoid arthritis [RA], axial spondyloarthritis [axSpA], psoriatic arthritis [PsA], psoriasis [PsO]).

METHODS

A pre-defined search strategy was implemented in Medline, Embase and Psychinfo on 29/05/2021. Inclusion criteria were: (i) observational studies of an IMID, (ii) healthy control comparison, (iii) measuring cognitive ability (overall, memory, complex attention/executive function, language/verbal fluency), and (iv) sufficient data for meta-analysis. Standardised mean differences (SMD) in cognitive assessments between IMIDs and controls were pooled using random-effects meta-analysis. IMIDs were compared using meta-regression.

RESULTS

In total, 65 IMID groups were included (SLE: 39, RA: 19, axSpA: 1, PsA: 2 PsO: 4), comprising 3141 people with IMIDs and 9333 controls. People with IMIDs had impairments in overall cognition (SMD: -0.57 [95% CI -0.70, -0.43]), complex attention/executive function (SMD -0.57 [95% CI -0.69, -0.44]), memory (SMD -0.55 [95% CI -0.68, -0.43]) and language/verbal fluency (SMD -0.51 [95% CI -0.68, -0.34]). People with RA and people with SLE had similar magnitudes of cognitive impairment in relation to age-expected levels. People with neuropsychiatric SLE had larger impairment in overall cognition compared with RA.

CONCLUSIONS

People with IMIDs have moderate impairments across a range of cognitive domains. People with RA and SLE have similar magnitudes of impairment against their respective age-expected levels, calling for greater recognition of cognitive impairment in both conditions. To further understand cognition in the IMIDs, more large-scale, longitudinal studies are needed.

The expanding role of synthetic nucleic acids for diagnosis and treatment

PURPOSE OF REVIEW

The presence of autoantibodies is a characteristic and diagnostic index of systemic lupus erythematosus (SLE). Antidouble-stranded DNA (antids-DNA) antibodies are the most frequent autoantibodies found in SLE related to the diagnosis and disease activity of SLE, and are measured by established methods like ELISA as a polyclonal autoantibody. However, there is no reliable data on the relationship between the respective reactivity of these polyclonal antids-DNA antibodies against different epitopes generated from the original antigen and the disease phenotype. Of the complications in SLE, neuropsychiatric SLE (NPSLE) is a troublesome and frequent phenotype of the disease but no specific diagnostic autoantibodies in serum have been found. First in this review, the possibility of antids-DNA antibodies for identifying primary NPSLE in patients with SLE based on the reactivity of different synthetic nucleic acids is described as a diagnostic marker. The purpose of this review is to examine diagnostic and therapeutic opportunities to modulate autoimmune in the central nervous system (CNS) developing the CNS inflammatory disorders.

RECENT FINDINGS

Khatri et al. investigated antids-DNA antibodies in order to develop a reliable method based on the application of synthetic nucleic acids and protein-based antigen arrays to characterize autoreactive antibodies specially for NPSLE. They found autoantibodies in three particular synthetic double stranded antigens and the antinuclear antibody patterns in ordinary lupus and NPSLE. These discoveries are leading to precision medicine in the CNS inflammatory disorders.

SUMMARY

Verifying the similarity of antids-DNA obtained from patients with NPSLE can be useful as a diagnostic marker. mRNA vaccination can locally suppress autoimmunity in the CNS associated with critical steps for the develop of CNS autoinflammation. Synthetic nuclei acids may provide a diagnostic and therapeutic target in patients with autoimmune CNS inflammatory disorders.

Neuronal NR4A1 deficiency drives complement-coordinated synaptic stripping by microglia in a mouse model of lupus

Neuropsychiatric lupus (NPSLE) is a frequent manifestation of systemic lupus erythematosus (SLE) that occurs in 40–90% of SLE patients; however, the underlying mechanisms remain elusive, causing a severe lack of therapeutic targets for this condition. Here, we show that complement-coordinated elimination of synapses participated in NPSLE in MRL/lpr mice, a lupus-prone murine model. We demonstrated that lupus mice developed increased anxiety-like behaviors and persistent phagocytic microglial reactivation before overt peripheral lupus pathology. In the lupus brain, C1q was increased and localized at synaptic terminals, causing the apposition of phagocytic microglia and ensuing synaptic engulfment. We further determined that neuronal Nr4a1 signaling was essential for attracting C1q synaptic deposition and subsequent microglia-mediated synaptic elimination. Minocycline-mediated deactivation of microglia, antibody blockade of C1q, or neuronal restoration of Nr4a1 protected lupus mice from synapse loss and NP manifestations. Our findings revealed an active role of neurons in coordinating microglia-mediated synaptic loss and highlighted neuronal Nr4a1 and C1q as critical components amenable to therapeutic intervention in NPSLE.

Autoimmune Epilepsy - Novel Multidisciplinary Analysis, Discoveries and Insights

Epilepsy affects ~50 million people. In ~30% of patients the etiology is unknown, and ~30% are unresponsive to anti-epileptic drugs. Intractable epilepsy often leads to multiple seizures daily or weekly, lasting for years, and accompanied by cognitive, behavioral, and psychiatric problems. This multidisciplinary scientific (not clinical) 'Perspective' article discusses Autoimmune Epilepsy from immunological, neurological and basic-science angles. The article includes summaries and novel discoveries, ideas, insights and recommendations. We summarize the characteristic features of the respective antigens, and the pathological activity in vitro and in animal models of autoimmune antibodies to: Glutamate/AMPA-GluR3, Glutamate/NMDA-NR1, Glutamate/NMDA-NR2, GAD-65, GABA-R, GLY-R, VGKC, LGI1, CASPR2, and β2 GP1, found in subpopulations of epilepsy patients. Glutamate receptor antibodies: AMPA-GluR3B peptide antibodies, seem so far as the most exclusive and pathogenic autoimmune antibodies in Autoimmune Epilepsy. They kill neural cells by three mechanisms: excitotoxicity, Reactive-Oxygen-Species, and complement-fixation, and induce and/or facilitate brain damage, seizures, and behavioral impairments. In this article we raise and discuss many more topics and new insights related to Autoimmune Epilepsy. 1. Few autoimmune antibodies tilt the balance between excitatory Glutamate and inhibitory GABA, thereby promoting neuropathology and epilepsy; 2. Many autoantigens are synaptic, and have extracellular domains. These features increase the likelihood of autoimmunity against them, and the ease with which autoimmune antibodies can reach and harm these self-proteins. 3. Several autoantigens have 'frenetic character'- undergoing dynamic changes that can increase their antigenicity; 4. The mRNAs of the autoantigens are widely expressed in multiple organs outside the brain. If translated by default to proteins, broad spectrum detrimental autoimmunity is expected; 5. The autoimmunity can precede seizures, cause them, and be detrimental whether primary or epiphenomenon; 6. Some autoimmune antibodies induce, and associate with, cognitive, behavioral and psychiatric impairments; 7. There are evidences for epitope spreading in Autoimmune Epilepsy; 8. T cells have different 'faces' in the brain, and in Autoimmune Epilepsy: Normal T cells are needed for the healthy brain. Normal T cells are damaged by autoimmune antibodies to Glutamate/AMPA GluR3, which they express, and maybe by additional autoantibodies to: Dopamine-R, GABA-R, Ach-R, Serotonin-R, and Adrenergic-R, present in various neurological diseases (summarized herein), since T cells express all these Neurotransmitter receptors. However, autoimmune and/or cytotoxic T cells damage the brain; 9. The HLA molecules are important for normal brain function. The HLA haplotype can confer susceptibility or protection from Autoimmune Epilepsy; 10. There are several therapeutic strategies for Autoimmune Epilepsy.

Formal neurocognitive function and anti-N-methyl-D-aspartate receptor antibodies in paediatric lupus

Objective

SLE is a chronic multisystem autoimmune inflammatory disease impacting a number of organs, including the central nervous system (CNS). The pathophysiology of CNS lupus is multifactorial, making diagnosis problematic. Neurocognitive (NC) testing and specific biomarkers to identify the development of neuropsychiatric (NP) symptoms in lupus are needed. Paediatric patients with SLE have high incidence of NP disease. While serum anti-N-methyl-D-aspartate receptor (NMDAR) antibodies have shown promise as a biomarker of NP in adults with SLE, much less is known with regard to paediatric patients with SLE.

Methods

We performed a cross-sectional study in paediatric patients with SLE. Serum NMDAR antibodies were measured and compared with levels in patients with juvenile idiopathic arthritis (JIA). Formal NC testing was performed in accordance with the Childhood Arthritis & Rheumatology Research Alliance neuropsychological core test battery. NC functioning was compared in the two groups and with NMDAR antibody levels.

Results

Serum NMDAR antibody levels were significantly higher in paediatric patients with SLE compared with patients with JIA. There were no significant correlations between NMDAR antibody levels and any measure of NC functioning. In an exploratory examination of anti-ribosomal P (RibP) antibody and NC functioning in a subset of patients with SLE, RibP antibody-positive patients exhibited worse scores for Verbal Memory Index and Design Fluency Test Switching compared with RibP antibody-negative patients. A globally significant association between disease status and NC functioning was observed. Specifically, patients with SLE had lower scores compared with patients with JIA for full-scale IQ, letter–word recognition, reading fluency and calculation skills after adjusting for multiple comparisons.

Conclusion

These collective results suggest that although serum NMDAR may serve as a biomarker, formal NC testing is superior in identifying paediatric patients with SLE with NP manifestations. RibP also may potentially serve as a biomarker of NP manifestations in paediatric patients with SLE. Additional and longitudinal studies are needed.

What are the latest clinical findings regarding the association of neurotoxic brain antibodies found in the cerebrospinal fluid in patients with autoimmune disorders?

PURPOSE OF REVIEW

Recently, experiments show that the autoantibodies with direct access to neurons following blood brain barrier (BBB) disruption destroy neurons and lead to remodeling in damaged neurons. These are critical steps in autoantibody-mediated central nervous system disorder called neuropsychiatric syndromes in systemic lupus erythematosus (NPSLE). The purpose of this review is to examine therapeutic opportunities to repress neuronal remodeling by microglia after acute neuronal injury by autoantibodies.

RECENT FINDINGS

Recent studies have demonstrated that BBB disruption is a critical step for developing NPSLE, and serum anti-Sm antibodies have been significantly associated with BBB breakdown. In addition, it has been reported that antiglucose regulated protein-78 in patients with SLE also disrupt the BBB. Experiments with anti-N-methyl-D-aspartate antibodies show that HMGB1 and C1q were essential to activate microglia which, in turn, remodel damaged neurons in vivo. Interestingly treatment with angiotensin-converting enzyme inhibitor inactivated microglia and blunted neuronal remodeling as well as positively affected behavioral abnormalities.

SUMMARY

BBB disruption, acute neuronal damage and neuronal remodeling by activated microglia are all critical steps for NPSLE development, and each step will afford novel therapeutic targets.

Developmental process in diffuse psychological/neuropsychiatric manifestations of neuropsychiatric systemic lupus erythematosus

Systemic lupus erythematosus (SLE) involves excessive autoimmune reactions, with pathogenesis characterized by autoantibody production. Although the specific mechanism underlying the development of neuropsychiatric syndromes in SLE (NPSLE) is still unclear, recent studies indicate the involvement of autoimmune pathophysiology. We previously identified the presence of anti-N-methyl-d-aspartate receptor subunit GluN2 antibody (anti-GluN2) as a functional autoantibody which is able to impair neurons and is essential for the diagnosis of diffuse psychiatric/neuropsychological syndromes in NPSLE (dNPSLE). Other autoantibodies like anti-Sm antibodies and anti-glucose-regulated protein 78 antibodies are known to compromise blood brain barrier (BBB) integrity. We demonstrated that high mobility group box-1 protein (HMGB1) decorates synapses on neurons damaged by anti-neuron antibodies, including anti-GluN2, where it behaves as a linker to enhance C1q binding to synapses in a dNPSLE model mouse. This C1q binding via HMGB1 is a critical step for remodeling by activated microglia, which leads to reductions in neuronal complexity and long-term behavioral abnormalities. Suppression of activated microglia can significantly reduce central nervous system (CNS) dysfunction. In this review, we describe the critical steps in the development of dNPSLE in particular, including the phases of BBB breakdown, acute neuronal damage by autoantibodies and neuronal remodeling due to activated microglia.

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.

Neuropsychiatric lupus: new mechanistic insights and future treatment directions

Patients with systemic lupus erythematosus (SLE) frequently show symptoms of central nervous system (CNS) involvement, termed neuropsychiatric SLE (NPSLE). The CNS manifestations of SLE are diverse and have a broad spectrum of severity and prognostic implications. Patients with NPSLE typically present with nonspecific symptoms, such as headache and cognitive impairment, but might also experience devastating features, such as memory loss, seizures and stroke. Some features of NPSLE, in particular those related to coagulopathy, have been characterized and an evidence-based treatment algorithm is available. The cognitive and affective manifestations of NPSLE, however, remain poorly understood. Various immune effectors have been evaluated as contributors to its pathogenesis, including brain-reactive autoantibodies, cytokines and cell-mediated inflammation. Additional brain-intrinsic elements (such as resident microglia, the blood-brain barrier and other neurovascular interfaces) are important facilitators of NPSLE. As yet, however, no unifying model has been found to underlie the pathogenesis of NPSLE, suggesting that this disease has multiple contributors and perhaps several distinct aetiologies. This heterogeneity presents a challenge for clinicians who have traditionally relied on empirical judgement in choosing treatment modalities for patients with NPSLE. Improved understanding of this manifestation of SLE might yield further options for managing this disease.

Antibodies and the brain: anti-N-methyl-D-aspartate receptor antibody and the clinical effects in patients with systemic lupus erythematosus

PURPOSE OF REVIEW

Neuropsychiatric manifestations are one of the fatal complications in patients with systemic lupus erythematosus (SLE). However, the diagnosis and monitoring of that aspect of SLE is still challenging, as there are no reliable biomarkers linked to central nervous system (CNS) damage. This review emphasizes potential candidate autoantibodies that appear to be associated with development of behavioral and psychiatric manifestations in SLE patients.

RECENT FINDINGS

Developments in the pathogenesis in SLE, not surprising for this immune disorder, point to specific, autoantibody toxicity. Namely, the discovery of an antibody which reacts with DNA and with the extracellular domain of N-methyl-D-aspartate (NMDA) receptor subunit GluN2A and 2B (anti-NMDA), an important receptor on neurons that is ubiquitous in the CNS, may lead to new insights into the behavioral and psychiatric manifestations in SLE. These anti-NMDA antibodies induce neuronal apoptosis and degeneration of surviving neurons in murine models. This functional antibody is also detected in SLE patients who have behavioral and psychiatric manifestations. The presence of anti-NMDA in cerebrospinal fluid but not in serum is associated significantly with overwhelming CNS abnormalities, suggesting importance of direct access of autoantibodies to brain dysfunction.

SUMMARY

As anti-NMDA autoantibodies are present in patients who develop psychiatric manifestations in SLE, it is possible that novel therapeutic approaches will depend on altering the activity of these autoantibodies.

Novel anti-suprabasin antibodies may contribute to the pathogenesis of neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is often difficult to diagnose and distinguish from other diseases, because no NPSLE-specific antibodies have been identified. We developed a novel proteomic strategy for identifying and profiling antigens in immune complexes in the cerebrospinal fluid (CSF), and applied this strategy to 26 NPSLE patients. As controls, we also included 25 SLE patients without neuropsychiatric manifestations (SLE), 15 with relapsing remitting multiple sclerosis (MS) and 10 with normal pressure hydrocephalus (NPH). We identified immune complexes of suprabasin (SBSN) in the CSF of the NPSLE group. The titer of anti-SBSN antibodies was significantly higher in the CSF of the NPSLE group compared to those of the SLE, MS and NPH groups. Microarray data showed that the senescence and autophagy pathways were significantly changed in astrocytes exposed to anti-SBSN antibodies. Our findings indicate that SBSN could be a novel autoantibody for the evaluation of suspected NPSLE.

Subcortical gray matter atrophy is associated with cognitive deficit in multiple sclerosis but not in systemic lupus erythematosus patients

Cognitive impairment is a significant clinical problem both in multiple sclerosis (MS) and systemic lupus erythematosus (SLE) patients. In MS cognitive dysfunction has been associated with brain atrophy and total demyelinating lesion volume. In SLE cognitive impairment is much less understood, and its link to structural brain damage remains to be established. The aim of this study was to identify the relationship between subcortical gray matter volume and cognitive impairment in MS and SLE. We recruited 37 MS and 38 SLE patients matched by age, disease duration and educational level. Patients underwent magnetic resonance imaging (MRI) and a battery of psychometric tests. Severity of cognitive impairment was similar in both cohorts despite larger white matter lesion load in MS patients. Psychometric scores were associated with global and subcortical gray matter atrophy measures and lesion load in MS, but not in SLE. In SLE, the lack of a relationship between cognitive impairment and structural damage, defined either as atrophy or white matter lesions, indicates a different causal mechanism of cognitive deficit.

Effects of sustained i.c.v. infusion of lupus CSF and autoantibodies on behavioral phenotype and neuronal calcium signaling

Systemic lupus erythematosus (SLE) is a potentially fatal autoimmune disease that is often accompanied by brain atrophy and diverse neuropsychiatric manifestations of unknown origin. More recently, it was observed that cerebrospinal fluid (CSF) from patients and lupus-prone mice can be neurotoxic and that acute administration of specific brain-reactive autoantibodies (BRAs) can induce deficits in isolated behavioral tasks. Given the chronic and complex nature of CNS SLE, the current study examines broad behavioral performance and neuronal Ca²⁺ signaling in mice receiving a sustained infusion of cerebrospinal fluid (CSF) from CNS SLE patients and putative BRAs (anti-NR2A, anti-ribosomal P, and anti-α-tubulin). A 2-week intracerebroventricular (i.c.v.) infusion of CSF altered home-cage behavior and induced olfactory dysfunction, excessive immobility in the forced swim test, and perseveration in a learning task. Conversely, sustained administration of purified BRAs produced relatively mild, both inhibitory and stimulatory effects on olfaction, spatial learning/memory, and home-cage behavior. In vitro studies revealed that administration of some CSF samples induces a rapid influx of extracellular Ca²⁺ into murine neurons, an effect that could be partially mimicked with the commercial anti-NR2A antibody and blocked with selective N-methyl-D-aspartate (NMDA) receptor antagonists. The current findings confirm that the CSF from CNS SLE patients can be neuroactive and support the hypothesis that intrathecal BRAs induce synergistically diverse effects on all domains of behavior. In addition, anti-NMDA receptor antibodies may alter Ca²⁺ homeostasis of central neurons, thus accounting for excitotoxicity and contributing to the heterogeneity of psychiatric manifestations in CNS SLE and other autoantibody-related brain disorders.

Microglia activation induced by serum of SLE patients

To investigate the potential involvement of microglia in the neuropathology of systemic lupus erythematosus (SLE), we examined whether SLE patient sera could activate BV2 microglia in vitro. Exposure to SLE patient sera resulted in morphological changes in the microglia, an increase in MHC II and CD86 protein expression, and an obvious release of nitric oxide and proinflammatory cytokines. However, the SLE sera did not induce a specific change in the production of immunoregulatory cytokines. Inactivating complements or neutralizing proinflammatory cytokines in the SLE sera did not suppress microglial activation. Our results highlight the potential role of microglia in neuroinflammation in SLE patients.

Clinical utility of circulating anti-N-methyl-d-aspartate receptor subunits NR2A/B antibody for the diagnosis of neuropsychiatric syndromes in systemic lupus erythematosus and Sjögren's syndrome: An updated meta-analysis

BACKGROUND/PURPOSE

Neuropsychiatric (NP) events are found in patients with rheumatic diseases, commonly in systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). The standard nomenclature and case definitions for 19 NPSLE syndromes by the American College of Rheumatology (ACR) Committee on Research cover a wide range of NP events seen in both SLE and SS. Despite advances in the understanding of SLE and SS, NP syndromes continue to pose diagnostic challenges. Correct attribution of NP events is critical in determining the correct treatment and prognosis. Anti-N-methyl-_d-aspartate receptor subunits NR2A/B (anti-NR2A/B) antibodies have been demonstrated in the sera of SLE and SS patients and have been associated with collective or specific NP syndromes, though not consistently. Interpretation of anti-NR2A/B antibody data in the medical literature is rendered difficult by small sample size of patient groups. By combining different studies to generate a pooled effect size, a meta-analysis can increase the power to detect differences in the presence or absence of NP syndromes. Hence, we set out to perform a meta-analysis to assess the association between anti-NR2A/B antibodies and NP syndromes in SLE and SS.

METHODS

A literature search was conducted using PubMed and other databases from inception to June 2016. We abstracted data relating to anti-NR2A/B antibodies from the identified studies. The random effects model was used to calculate overall combined odds ratio (OD) with its corresponding 95% confidence interval (CI) to evaluate the relationship between anti-NR2A/B antibodies and NP syndromes in SLE and SS patients with and without NP events. We also included our own cohort of 57 SLE patients fulfilling the ACR 1997 revised classification criteria and 58 healthy controls (HCs).

RESULTS

In total, 17 studies with data on anti-NR2A/B antibodies in 2212 SLE patients, 66 SS patients, 99 disease controls (DCs) (e.g. antiphospholipid syndrome, myasthenia gravis and autoimmune polyendocrine syndrome I) and 538 HCs were used in this analysis. Overall pooled prevalence of serum/plasma anti-NR2A/B antibodies was higher in SLE patients [24.6% (95% CI 18.5-32.0%)] and SS patients [19.7% (95% CI 11.8-31.0%)] compared to DCs [14.8% (95% CI 2.2-56.9)] and HCs [7.6% (95% CI 4.6-12.4%)] (p=0.001). There was a significantly greater proportion of SLE and SS patients with NP syndromes who demonstrated positivity for serum/plasma anti-NR2A/B antibody [pooled OR=1.607 (95% CI 1.041-2.479), p=0.032] as compared to SLE and SS patients without NP syndromes in 13 studies. Usable data for cerebrospinal fluid anti-NR2A/B antibodies were available in only 4 studies [pooled OR=0.831 (95% CI 0.365-1.888), p=0.658]. Among the 19 NP syndromes, serum/plasma anti-NR2A/B antibodies were not specifically associated with any NP syndrome, including cognitive dysfunction (p=0.259) and mood disorder (p=0.503). Meta-regression identified proportion of anti-double-stranded deoxyribonucleic acid antibody positivity (p=0.009) and SLE Disease Activity Index (p=0.028) as moderators for the heterogeneity of serum/plasma anti-NR2A/B antibodies.

CONCLUSION

Circulating anti-NR2A/B antibody testing has a diagnostic value for NP syndromes in SLE and SS collectively. However, the evidence to date suggests that anti-NR2A/B antibody positivity cannot distinguish specific NP syndromes.

The diagnosis and clinical management of the neuropsychiatric manifestations of lupus

Neuropsychiatric (NP) involvement in Systemic Lupus Erythematosus (SLE), can be a severe and troubling manifestation of the disease that heavily impacts patient's health, quality of life and disease outcome. It is one of the most complex expressions of SLE which can affect central, peripheral and autonomous nervous system. Complex interrelated pathogenetic mechanisms, including genetic factors, vasculopathy, vascular occlusion, neuroendocrine-immune imbalance, tissue and neuronal damage mediated by autoantibodies, inflammatory mediators, blood brain barrier dysfunction and direct neuronal cell death can be all involved. About NPSLE a number of issues are still matter of debate: from classification and burden of NPSLE to attribution and diagnosis. The role of neuroimaging and new methods of investigation still remain pivotal and rapidly evolving as well as is the increasing knowledge in the pathogenesis. Overall, two main pathogenetic pathways have been recognized yielding different clinical phenotypes: a predominant ischemic-vascular one involving large and small blood vessels, mediated by aPL, immune complexes and leuko-agglutination which it is manifested with more frequent focal NP clinical pictures and a predominantly inflammatory-neurotoxic one mediated by complement activation, increased permeability of the BBB, intrathecal migration of autoantibodies, local production of immune complexes and pro-inflammatory cytokines and other inflammatory mediators usually appearing as diffuse NP manifestations. In the attempt to depict a journey throughout NPSLE from diagnosis to a reasoned therapeutic approach, classification, epidemiology, attribution, risk factors, diagnostic challenges, neuroimaging techniques and pathogenesis will be considered in this narrative review based on the most relevant and recent published data.

Anti-NR2 antibodies, blood-brain barrier, and cognitive dysfunction

Cognitive dysfunction (CD) is one of the most common neuropsychiatric manifestations of systemic lupus erythematosus (SLE). In animal models, antibodies to NR2 subunit of N-methyl D-aspartate receptor (anti-NR2) cause memory impairment, but only with blood-brain barrier (BBB) disruption or intrathecal administration. Several studies have failed to find association of aNR2 with CD, but none have assessed BBB integrity. S100B, an astrocyte-specific protein, has been used as biomarker of BBB disruption in traumatic brain injury and some neurodegenerative disorders. Antibodies to this immunologically privileged protein (anti-S100B) might indicate preceding BBB disruption. We hypothesized that aNR2 antibody is pathogenic in SLE patients only with BBB disruption. Demographic, clinical, and laboratory data was collected from patients with SLE. Total throughput score (TTS) of the Automated Neuropsychological Assessment Metrics (ANAM) was used as primary outcome measure. CD was defined as TTS < 1.5 SD below an age-, sex-, and race-matched RA population mean. Serum was analyzed by established ELISA techniques. Fifty-seven patients were evaluated and 12 had CD. Age, ethnicity, and family income were significantly different between the two groups (p < 0.05). In a multiple regression model adjusting for other variables, no significant effects of anti-NR2, S100B, or anti-S100B on TTS were found. Even at high levels of S100B and anti-S100B, no significant influence of anti-NR2 on TTS was found. The anti-NR2 was not associated with CD in SLE even in context of potential BBB disruption. This suggests that, if pathogenic, these antibodies may be produced intrathecally.

Antiglutamate Receptor Antibodies and Cognitive Impairment in Primary Antiphospholipid Syndrome and Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome have an increased risk to develop cognitive impairment. A possible role for antiphospholipid antibodies (aPL) and antiglutamate receptor (anti-NMDA) antibodies in the pathogenesis of neurological manifestations of these two conditions, have been suggested. In particular, the role of anti-NMDA antibodies in the pathogenesis of neuropsychiatric SLE is supported by several experimental studies in animal models and by the finding of a correlation between anti-NMDA positivity in cerebrospinal fluid and neurological manifestations of SLE. However, data from the literature are controversial, as several studies have reported a correlation of these antibodies with mild cognitive impairment in SLE, but more recent studies have not confirmed this finding. The synergism between anti-NMDA and other concomitant autoantibodies, such as aPL, can be hypothesized to play a role in inducing the tissue damage and eventually the functional abnormalities. In line with this hypothesis, we have found a high incidence of at least one impaired cognitive domain in a small cohort of patients with primary APS (PAPS) and SLE. Interestingly, aPL were associated with low scoring for language ability and attention while anti-NMDA titers and mini-mental state examination scoring were inversely correlated. However, when patients were stratified according to the presence/absence of aPL, the correlation was confirmed in aPL positive patients only. Should those findings be confirmed, the etiology of the prevalent defects found in PAPS patients as well as the synergism between aPL and anti-NMDA antibodies would need to be explored.

Antibodies as Mediators of Brain Pathology

The brain is normally sequestered from antibody exposure by the blood brain barrier. However, antibodies can access the brain during fetal development before the barrier achieves full integrity, and in disease states when barrier integrity is compromised. Recent studies suggest that antibodies contribute to brain pathology associated with autoimmune diseases such as systemic lupus erythematosus and neuromyelitis optica, and can lead to transient or permanent behavioral or cognitive abnormalities. We review these findings here and examine the circumstances associated with antibody entry into the brain, the routes of access and the mechanisms that then effect pathology. Understanding these processes and the nature and specificity of neuronal autoantibodies may reveal therapeutic strategies toward alleviating or preventing the neurological pathologies and behavioral abnormalities associated with autoimmune disease.

Impact analysis of autoantibody level and NR2 antibody level in neuropsychiatric SLE treated by methylprednisolone combined with MTX and DXM intrathecal injection

The objective is to explore the clinical curative effects of methylprednisolone combined with MTX and DXM intrathecal injection in treating neuropsychiatric systemic lupus erythematosus (NPSLE) and its effects on autoantibody level and anti-N-methyl-D-aspartate receptor subtype NR2a/2b antibody (anti-NR2 antibody) level. Thirty six admitted NPSLE patients were treated by methylprednisolone combined with MTX and DXM intrathecal injection. Thirty six SLE patients without neuropsychiatric symptoms were selected as non-NPSLE group. Clinical indexes including SLE activity index, erythrocyte sedimentation rate (ESR), cerebrospinal fluid pressure (CSFP), cerebrospinal fluid protein were observed before and after treatment. Autoantibodies including anti-nuclear antibody (ANA), anti-double stranded DNA antibody (anti-dsDNA antibody), anti-extractable nuclear antigen antibody (ENA-Ab) were detected before and after treatment. Enzyme linked immunosorbent assay was used to detect NR2 antibody level before and after treatment in two groups. Upon treatment of methylprednisolone combined with MTX and DXM intrathecal injection, SLE activity index, ESR, CSFP, cerebrospinal fluid protein of 36 NPSLE patients were significantly decreased. Before treatment, positive rates of ANA, anti-dsDNA antibody, and anti-ENA antibody in both NPSLE group and non-NPSLE group had no significant difference. However, positive rate of anti-NR2 antibody in NPSLE group was significantly higher than that of non-NPSLE group. After treatment, positive rates of autoantibodies and anti-NR2 antibody in both NPSLE and non-NPSLE group were significantly decreased. Anti-NR2 antibody can be a screening index of NPSLE, and methylprednisolone combined with MTX and DXM intrathecal injection has significant curative effects and can effectively decrease autoantibody level and anti-NR2 antibody level.

Anti-NR2A/B Antibodies and Other Major Molecular Mechanisms in the Pathogenesis of Cognitive Dysfunction in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects approximately 1–45.3 per 100,000 people worldwide. Although deaths as a result of active and renal diseases have been substantially declining amongst SLE patients, disease involving the central nervous system (CNS), collectively termed neuropsychiatric systemic lupus erythematosus (NPSLE), remains one of the important causes of death in these patients. Cognitive dysfunction is one of the most common manifestations of NPSLE, which comprises deficits in information-processing speed, attention and executive function, in conjunction with preservation of speech. Albeit a prevalent manifestation of NPSLE, the pathogenetic mechanisms of cognitive dysfunction remain unclear. Recent advances in genetic studies, molecular techniques, neuropathology, neuroimaging and cognitive science have gleaned valuable insights into the pathophysiology of lupus-related cognitive dysfunction. In recent years, a role for autoantibodies, molecular and cellular mechanisms in cognitive dysfunction, has been emerging, challenging our previous concept of the brain as an immune privileged site. This review will focus on the potential pathogenic factors involved in NPSLE, including anti-N-methyl-d-aspartate receptor subunit NR2A/B (anti-NR2A/B) antibodies, matrix metalloproteinase-9, neutrophil extracellular traps and pro-inflammatory mediators. Better understanding of these mechanistic processes will enhance identification of new therapeutic modalities to halt the progression of cognitive decline in SLE patients.

Association of hippocampal atrophy with cerebrospinal fluid antibodies against the NR2 subtype of the N-methyl-D-aspartate receptor in patients with systemic lupus erythematosus and patients with primary Sjögren's syndrome

OBJECTIVE

Cognitive dysfunction is common in both systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (SS). Antibodies against the NR2 subtype of the N-methyl-D-aspartate receptor (anti-NR2 antibodies) cause hippocampal atrophy and cognitive impairment in mice and have been associated with memory impairment in both patients with SLE and patients with primary SS. In addition, a reduced volume of hippocampal gray matter has been demonstrated in both SLE and primary SS. This study was undertaken to investigate whether there is a connection between the presence of anti-NR2 antibodies and hippocampal atrophy in human diseases.

METHODS

Fifty patients with SLE and 50 patients with primary SS underwent clinical examination and cerebral magnetic resonance imaging. Anti-NR2 antibodies in cerebrospinal fluid (CSF) were measured, and hippocampal gray matter volumes were compared between patients who were positive for and those who were negative for anti-NR2 antibodies.

RESULTS

Patients with anti-NR2 antibodies in CSF had less hippocampal gray matter than patients without these antibodies. No other differences regarding gray matter volumes in other parts of the brain were identified.

CONCLUSION

The present findings indicate that anti-NR2 antibodies in patients with SLE and primary SS cause neuronal death manifested as reduced hippocampal gray matter, as has been previously demonstrated in mice with autoimmune disease.

Biomarkers for childhood-onset systemic lupus erythematosus

Childhood-onset systemic lupus erythematosus (cSLE) is a systemic autoimmune disease characterized by the presence of autoantibodies. cSLE often affects multiple organs in the body and is known to have a poorer prognosis than adult-onset disease (Azevedo et al. 2014). Current laboratory tests are clearly insufficient for identifying and monitoring the disease. Recent studies have yielded novel biomarkers for cSLE which can be used for monitoring disease activity and response to treatment. The most encouraging biomarkers will be discussed herein and include cell-bound complement activation products, some genomic profiles, and urinary proteins such as neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and others. Previous studies suggested that a combination of the novel biomarkers might help to enhance sensitivity and specificity for early diagnosis, disease monitoring, and prediction of cSLE flares.

Anti-N-methyl-D-aspartate receptor and anti-ribosomal-P autoantibodies contribute to cognitive dysfunction in systemic lupus erythematosus

Objective

Autoantibodies against N-methyl-D-aspartate receptor (anti-NMDAR) and ribosomal-P (anti-P) antigens are potential pathogenic factors in the frequently observed diffuse brain dysfunctions in patients with systemic lupus erythematosus (SLE). Although studies have been conducted in this area, the role of anti-NMDAR antibodies in SLE cognitive dysfunction remains elusive. Moreover, the specific contribution of anti-P antibodies has not been reported yet. The present study attempts to clarify the contribution of anti-NMDAR and anti-P antibodies to cognitive dysfunction in SLE.

Methods

The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to assess a wide range of cognitive function areas in 133 Chilean women with SLE. ANCOVA models included autoantibodies, patient and disease features.

Results

Cognitive deficit was found in 20%. Higher SLEDAI-2K scores were associated with impairment in spatial memory and learning abilities, whereas both anti-NMDAR and anti-P antibodies contributed to deficits in attention and spatial planning abilities, which reflect fronto-parietal cortex dysfunctions.

Conclusions

These results reveal an association of active disease together with specific circulating autoantibodies, such as anti-NMDAR and anti-P, with cognitive dysfunction in SLE patients.

Glutamate receptor antibodies in neurological diseases: anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies, anti-NMDA-NR2A/B antibodies, anti-mGluR1 antibodies or anti-mGluR5 antibodies are present in subpopulations of patients with either: epilepsy, encephalitis, cerebellar ataxia, systemic lupus erythematosus (SLE) and neuropsychiatric SLE, Sjogren's syndrome, schizophrenia, mania or stroke. These autoimmune anti-glutamate receptor antibodies can bind neurons in few brain regions, activate glutamate receptors, decrease glutamate receptor's expression, impair glutamate-induced signaling and function, activate blood brain barrier endothelial cells, kill neurons, damage the brain, induce behavioral/psychiatric/cognitive abnormalities and ataxia in animal models, and can be removed or silenced in some patients by immunotherapy

Glutamate is the major excitatory neurotransmitter of the Central Nervous System (CNS), and it is crucially needed for numerous key neuronal functions. Yet, excess glutamate causes massive neuronal death and brain damage by excitotoxicity--detrimental over activation of glutamate receptors. Glutamate-mediated excitotoxicity is the main pathological process taking place in many types of acute and chronic CNS diseases and injuries. In recent years, it became clear that not only excess glutamate can cause massive brain damage, but that several types of anti-glutamate receptor antibodies, that are present in the serum and CSF of subpopulations of patients with a kaleidoscope of human neurological diseases, can undoubtedly do so too, by inducing several very potent pathological effects in the CNS. Collectively, the family of anti-glutamate receptor autoimmune antibodies seem to be the most widespread, potent, dangerous and interesting anti-brain autoimmune antibodies discovered up to now. This impression stems from taking together the presence of various types of anti-glutamate receptor antibodies in a kaleidoscope of human neurological and autoimmune diseases, their high levels in the CNS due to intrathecal production, their multiple pathological effects in the brain, and the unique and diverse mechanisms of action by which they can affect glutamate receptors, signaling and effects, and subsequently impair neuronal signaling and induce brain damage. The two main families of autoimmune anti-glutamate receptor antibodies that were already found in patients with neurological and/or autoimmune diseases, and that were already shown to be detrimental to the CNS, include the antibodies directed against ionotorpic glutamate receptors: the anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies and anti-NMDA-NR2 antibodies, and the antibodies directed against Metabotropic glutamate receptors: the anti-mGluR1 antibodies and the anti-mGluR5 antibodies. Each type of these anti-glutamate receptor antibodies is discussed separately in this very comprehensive review, with regards to: the human diseases in which these anti-glutamate receptor antibodies were found thus far, their presence and production in the nervous system, their association with various psychiatric/behavioral/cognitive/motor impairments, their possible association with certain infectious organisms, their detrimental effects in vitro as well as in vivo in animal models in mice, rats or rabbits, and their diverse and unique mechanisms of action. The review also covers the very encouraging positive responses to immunotherapy of some patients that have either of the above-mentioned anti-glutamate receptor antibodies, and that suffer from various neurological diseases/problems. All the above are also summarized in the review's five schematic and useful figures, for each type of anti-glutamate receptor antibodies separately. The review ends with a summary of all the main findings, and with recommended guidelines for diagnosis, therapy, drug design and future investigations. In the nut shell, the human studies, the in vitro studies, as well as the in vivo studies in animal models in mice, rats and rabbit revealed the following findings regarding the five different types of anti-glutamate receptor antibodies: (1) Anti-AMPA-GluR3B antibodies are present in ~25-30% of patients with different types of Epilepsy. When these anti-glutamate receptor antibodies (or other types of autoimmune antibodies) are found in Epilepsy patients, and when these autoimmune antibodies are suspected to induce or aggravate the seizures and/or the cognitive/psychiatric/behavioral impairments that sometimes accompany the seizures, the Epilepsy is called 'Autoimmune Epilepsy'. In some patients with 'Autoimmune Epilepsy' the anti-AMPA-GluR3B antibodies associate significantly with psychiatric/cognitive/behavior abnormalities. In vitro and/or in animal models, the anti-AMPA-GluR3B antibodies by themselves induce many pathological effects: they activate glutamate/AMPA receptors, kill neurons by 'Excitotoxicity', and/or by complement activation modulated by complement regulatory proteins, cause multiple brain damage, aggravate chemoconvulsant-induced seizures, and also induce behavioral/motor impairments. Some patients with 'Autoimmune Epilepsy' that have anti-AMPA-GluR3B antibodies respond well (although sometimes transiently) to immunotherapy, and thanks to that have reduced seizures and overall improved neurological functions. (2) Anti-NMDA-NR1 antibodies are present in patients with autoimmune 'Anti-NMDA-receptor Encephalitis'. In humans, in animal models and in vitro the anti-NMDA-NR1 antibodies can be very pathogenic since they can cause a pronounced decrease of surface NMDA receptors expressed in hippocampal neurons, and also decrease the cluster density and synaptic localization of the NMDA receptors. The anti-NMDA-NR1 antibodies induce these effects by crosslinking and internalization of the NMDA receptors. Such changes can impair glutamate signaling via the NMDA receptors and lead to various neuronal/behavior/cognitive/psychiatric abnormalities. Anti-NMDA-NR1 antibodies are frequently present in high levels in the CSF of the patients with 'Anti-NMDA-receptor encephalitis' due to their intrathecal production. Many patients with 'Anti-NMDA receptor Encephalitis' respond well to several modes of immunotherapy. (3) Anti-NMDA-NR2A/B antibodies are present in a substantial number of patients with Systemic Lupus Erythematosus (SLE) with or without neuropsychiatric problems. The exact percentage of SLE patients having anti-NMDA-NR2A/B antibodies varies in different studies from 14 to 35%, and in one study such antibodies were found in 81% of patients with diffuse 'Neuropshychiatric SLE', and in 44% of patients with focal 'Neuropshychiatric SLE'. Anti-NMDA-NR2A/B antibodies are also present in subpopulations of patients with Epilepsy of several types, Encephalitis of several types (e.g., chronic progressive limbic Encephalitis, Paraneoplastic Encephalitis or Herpes Simplex Virus Encephalitis), Schizophrenia, Mania, Stroke, or Sjorgen syndrome. In some patients, the anti-NMDA-NR2A/B antibodies are present in both the serum and the CSF. Some of the anti-NMDA-NR2A/B antibodies cross-react with dsDNA, while others do not. Some of the anti-NMDA-NR2A/B antibodies associate with neuropsychiatric/cognitive/behavior/mood impairments in SLE patients, while others do not. The anti-NMDA-NR2A/B antibodies can undoubtedly be very pathogenic, since they can kill neurons by activating NMDA receptors and inducing 'Excitotoxicity', damage the brain, cause dramatic decrease of membranal NMDA receptors expressed in hippocampal neurons, and also induce behavioral cognitive impairments in animal models. Yet, the concentration of the anti-NMDA-NR2A/B antibodies seems to determine if they have positive or negative effects on the activity of glutamate receptors and on the survival of neurons. Thus, at low concentration, the anti-NMDA-NR2A/B antibodies were found to be positive modulators of receptor function and increase the size of NMDA receptor-mediated excitatory postsynaptic potentials, whereas at high concentration they are pathogenic as they promote 'Excitotoxcity' through enhanced mitochondrial permeability transition. (4) Anti-mGluR1 antibodies were found thus far in very few patients with Paraneoplastic Cerebellar Ataxia, and in these patients they are produced intrathecally and therefore present in much higher levels in the CSF than in the serum. The anti-mGluR1 antibodies can be very pathogenic in the brain since they can reduce the basal neuronal activity, block the induction of long-term depression of Purkinje cells, and altogether cause cerebellar motor coordination deficits by a combination of rapid effects on both the acute and the plastic responses of Purkinje cells, and by chronic degenerative effects. Strikingly, within 30 min after injection of anti-mGluR1 antibodies into the brain of mice, the mice became ataxic. Anti-mGluR1 antibodies derived from patients with Ataxia also caused disturbance of eye movements in animal models. Immunotherapy can be very effective for some Cerebellar Ataxia patients that have anti-mGluR1 antibodies. (5) Anti-mGluR5 antibodies were found thus far in the serum and CSF of very few patients with Hodgkin lymphoma and Limbic Encephalopathy (Ophelia syndrome). The sera of these patients that contained anti-GluR5 antibodies reacted with the neuropil of the hippocampus and cell surface of live rat hippocampal neurons, and immunoprecipitation from cultured neurons and mass spectrometry demonstrated that the antigen was indeed mGluR5. Taken together, all these evidences show that anti-glutamate receptor antibodies are much more frequent among various neurological diseases than ever realized before, and that they are very detrimental to the nervous system. As such, they call for diagnosis, therapeutic removal or silencing and future studies. What we have learned by now about the broad family of anti-glutamate receptor antibodies is so exciting, novel, unique and important, that it makes all future efforts worthy and essential.

Libman-Sacks endocarditis and embolic cerebrovascular disease

OBJECTIVES

The aim of this study was to determine whether Libman-Sacks endocarditis is a pathogenic factor for cerebrovascular disease (CVD) in systemic lupus erythematosus (SLE).

BACKGROUND

A cardioembolic pathogenesis of SLE CVD manifested as: 1) neuropsychiatric systemic lupus erythematosus (NPSLE), including stroke and transient ischemic attacks (TIA); 2) neurocognitive dysfunction; and 3) magnetic resonance imaging of focal brain lesions has not been established.

METHODS

A 6-year study of 30 patients with acute NPSLE (27 women, 38 ± 12 years of age), 46 age- and sex-matched SLE controls without NPSLE (42 women, 36 ± 12 years of age), and 26 age- and sex-matched healthy controls (22 women, 34 ± 11 years of age) who underwent clinical and laboratory evaluations, transesophageal echocardiography, carotid duplex ultrasound, transcranial Doppler ultrasound, neurocognitive testing, and brain magnetic resonance imaging/magnetic resonance angiography. Patients with NPSLE were re-evaluated after 4.5 months of therapy. All patients were followed clinically for a median of 52 months.

RESULTS

Libman-Sacks vegetations (87%), cerebromicroembolism (27% with 2.5 times more events per hour), neurocognitive dysfunction (60%), and cerebral infarcts (47%) were more common in NPSLE than in SLE (28%, 20%, 33%, and 0%) and healthy controls (8%, 0%, 4%, and 0%, respectively) (all p ≤ 0.009). Patients with vegetations had 3 times more cerebromicroemboli per hour, lower cerebral blood flow, more strokes/TIA and overall NPSLE events, neurocognitive dysfunction, cerebral infarcts, and brain lesion load than those without (all p ≤ 0.01). Libman-Sacks vegetations were independent risk factors of NPSLE (odds ratio [OR]: 13.4; p < 0.001), neurocognitive dysfunction (OR: 8.0; p = 0.01), brain lesions (OR: 5.6; p = 0.004), and all 3 outcomes combined (OR: 7.5; p < 0.001). Follow-up re-evaluations in 18 of 23 (78%) surviving patients with NPSLE demonstrated improvement of vegetations, microembolism, brain perfusion, neurocognitive dysfunction, and lesion load (all p ≤ 0.04). Finally, patients with vegetations had reduced event-free survival time to stroke/TIA, cognitive disability, or death (p = 0.007).

CONCLUSIONS

The presence of Libman-Sacks endocarditis in patients with SLE was associated with a higher risk for embolic CVD. This suggests that Libman-Sacks endocarditis may be a source of cerebral emboli.

White matter abnormalities and working memory impairment in systemic lupus erythematosus

OBJECTIVE/BACKGROUND

Many patients with systemic lupus erythematosus (SLE) have working memory deficits. Few studies have evaluated working memory performance and neurometabolite profile using magnetic resonance spectroscopy in SLE.

METHODS

We gave the Paced Auditory Serial Addition Test (PASAT), a measure of working memory, to 73 patients with SLE. We calculated total score, dyads, chunking, and cognitive fatigue. Using magnetic resonance spectroscopy, we determined the ratio of choline to creatine (Ch/Cr) in normal-looking right and left frontal lobe white matter.

RESULTS

Twenty-nine percent of patients showed impaired working memory on the PASAT. Total PASAT score inversely correlated with right and left frontal white matter Ch/Cr. Left frontal white matter Ch/Cr correlated with percent chunking and inversely correlated with total and percent dyads. Right frontal white matter Ch/Cr correlated with percent chunking and inversely correlated with total and percent dyads. There was no relationship between cognitive fatigue and either left or right frontal white matter Ch/Cr. Longer disease duration was associated with higher left frontal white matter Ch/Cr. Correlations remained significant when we considered disease duration and left frontal white matter Ch/Cr against total PASAT score and total dyads.

CONCLUSIONS

Patients with SLE were impaired on the PASAT. Lower total PASAT score and fewer dyads correlated with higher left frontal microstructural white matter damage, while cognitive fatigue did not. This pattern suggests that early white matter damage interferes with working memory in SLE and provides further insight into the neurobiological basis of mild cognitive dysfunction related to microstructural white matter injury.

Epilepsy associated with systemic autoimmune disorders

Systemic autoimmune disorders affect multiple organ systems. Brain involvement commonly causes seizures, which may be the presenting symptom. Systemic lupus erythematosus, Sjorgren's syndrome, Wegener's granulomatosis, sarcoidsosis, celiac disease, Crohn's disease, Behcet's, and Hashimoto's encephalopathy are reviewed. Mechanisms underlying CNS pathology in systemic autoimmune disorders-and specifically factors predisposing these patients-are discussed, including vascular disease (e.g., prothrombotic state, anticardiolipin antibody, emboli, vasculitis), antineuronal antibodies, immune complexes, cytokines, metabolic disorders, infection, and therapy. Diagnostic and therapeutic strategies must be individualized for both the disorder and the patient. Systemic autoimmune disorders affect multiple organ systems and frequently involve the central and peripheral nervous systems. Seizures are among the most common neurological manifestation and occasionally can be the presenting symptom. There are many causes of seizures in systemic autoimmune disorders (Table 1), and the first clinical challenge is to determine not only the cause but also the significance of seizures. In some cases, they are clues to metabolic or infectious disorders or medication toxicity; in other cases, seizures herald a life-threatening progression of the underlying illness.

Effects of prolonged treatment with memantine in the MRL model of CNS lupus

OBJECTIVES

Neuropsychiatric manifestations and brain atrophy of unknown etiology are common and severe complications of systemic lupus erythematosus (SLE). An autoantibody that binds to N-methyl-D-aspartate (NMDA) receptor NR2 has been proposed as a key factor in the etiology of central nervous system (CNS) SLE. This hypothesis was supported by evidence suggesting memantine (MEM), an uncompetitive NMDA receptor antagonist, prevents behavioral dysfunction and brain pathology in healthy mice immunized with a peptide similar to an epitope on the NR2 receptor. Given that SLE is a chronic condition, we presently examine the effects of MEM in MRL/lpr mice, which develop behavioral deficits alongside SLE-like disease.

METHODS

A broad behavioral battery and 7-Tesla MRI were used to examine whether prolonged treatment with MEM (~25 mg/kg b.w. in drinking water) prevents CNS involvement in this spontaneous model of SLE.

RESULTS

Although MEM increased novel object exploration in MRL/lpr mice, it did not show other beneficial, substrain-specific effects. Conversely, MEM was detrimental to spontaneous activity in control MRL +/+ mice and had a negative effect on body mass gain. Similarly, MRI revealed comparable increases in the volume of periventricular structures in MEM-treated groups.

CONCLUSIONS

Sustained exposure to MEM affects body growth, brain morphology, and behavior primarily by pharmacological, and not autoimmunity-dependant mechanisms. Substrain-specific improvement in exploratory behavior of MEM-treated MRL/lpr mice may indicate that the NMDA system is merely a constituent of a complex pathogenenic cascade. However, it was evident that chronic administration of MEM is unable to completely prevent the development of a CNS SLE-like syndrome.

Immune function and brain abnormalities in patients with systemic lupus erythematosus without overt neuropsychiatric manifestations

Objective: This study examined the relationship between immune, cognitive and neuroimaging assessments in subjects with systemic lupus erythematosus (SLE) without histories of overt neuropsychiatric (NP) disorders.

Methods: In total, 84 subjects with nonNPSLE and 37 healthy controls completed neuropsychological testing from the American College of Rheumatology SLE battery. Serum autoantibody and cytokine measures, volumetric magnetic resonance imaging, and magnetic resonance spectroscopy data were collected on a subset of subjects.

Results: NonNPSLE subjects had lower scores on measures of visual/complex attention, visuomotor speed and verbal memory compared with controls. No clinically significant differences between nonNPSLE patients and controls were found on serum measures of lupus anticoagulant, anticardiolipin antibodies, beta 2-glycoproteins, or pro-inflammatory cytokines (interleukin (IL)-1, IL-6, interferon alpha (IFN-alpha), and interferon gamma (IFN-gamma)). Higher scores on a global cognitive impairment index and a memory impairment index were correlated with lower IFN-alpha. Few associations between immune functions and neuroimaging parameters were found.

Conclusions: Results indicated that nonNPSLE patients demonstrated cognitive impairment but not immune differences compared with controls. In these subjects, who were relatively young and with mild disease, no relationship between cognitive dysfunction, immune parameters, or previously documented neuroimaging abnormalities were noted. Immune measures acquired from cerebrospinal fluid instead of serum may yield stronger associations.

Memory impairment associated with neurometabolic abnormalities of the hippocampus in patients with non-neuropsychiatric systemic lupus erythematosus

Objective: Memory impairment is common in patients with systemic lupus erythematosus (SLE). This study examined hippocampal volumes and neurometabolic alterations in relation to memory function in SLE patients without a history of neuropsychiatric syndromes (nonNPSLE).

Methods: Subjects included 81 nonNPSLE patients and 34 healthy controls. Volumetric magnetic resonance imaging and magnetic resonance spectroscopy of the right and left hippocampal areas (RH, LH) were performed. Verbal and visual memory tests were administered and a Memory Impairment Index (MII) was derived from standardized tests.

Results: Higher memory impairment (MII) was correlated with lower RH glutamate + glutamine/creatine ( p = 0.009) and lower RH N-acetylaspartic acid/creatine ( p = 0.012) in nonNPSLE patients. A trend for a negative correlation between RH and LH volumes and MII was evident for absolute hippocampal volumes. Lower RH glutamate + glutamine/creatine was also correlated with worse performance in a mean visual memory index ( p = 0.017).

Conclusions: An association between reduced memory and lower N-acetylaspartic acid/creatine in the RH suggests neuronal damage in nonNPSLE patients with very mild and early disease. Alterations in glutamate + glutamine/creatine further indicate early metabolic changes in nonNPSLE are related to memory impairment, a finding that might suggest that memory impairment relates to presynaptic glutamatergic dysfunction in the hippocampus.