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

Exploring the Psychiatric Manifestations of Primary Sjögren's Syndrome: A Narrative Review

Background

Primary Sjögren's syndrome (pSS) is recognized for its autoimmune origin. Its hallmark symptoms, dry eyes and mouth, result from glandular inflammation. Prior literature indicates that pSS not only affects the peripheral system but also involves the central nervous system (CNS), giving rise to various neuropsychiatric symptoms. However, there is limited published research on the psychiatric comorbidities in individuals with pSS.

Methods

A comprehensive search was conducted on PubMed and Google Scholar for this narrative review. The search spanned from inception until August 2023. Its aim was to locate studies focusing on the psychiatric manifestations of pSS and the potential underlying mechanisms.

Results

The most commonly reported psychiatric complications among these individuals are depression and cognitive dysfunction. Other psychiatric manifestations that have been reported in pSS individuals include anxiety, sleep disorders, psychosis, catatonia, bipolar disorder, and obsessive-compulsive disorder.

Conclusion

In conclusion, patients with pSS often display multiple psychiatric symptoms. These symptoms can significantly impair functioning and reduce quality of life. Hence, prompt diagnosis and management are crucial.

Lupus autoantibodies initiate neuroinflammation sustained by continuous HMGB1:RAGE signaling and reversed by increased LAIR-1 expression

Cognitive impairment is a frequent manifestation of neuropsychiatric systemic lupus erythematosus, present in up to 80% of patients and leading to a diminished quality of life. In the present study, we used a model of lupus-like cognitive impairment that is initiated when antibodies that crossreact with excitatory neuronal receptors penetrate the hippocampus, causing immediate, self-limited, excitotoxic death of hippocampal neurons, which is then followed by a significant loss of dendritic complexity in surviving neurons. This injury creates a maladaptive equilibrium that is sustained in mice for at least 1 year. We identified a feedforward loop of microglial activation and microglia-dependent synapse elimination dependent on neuronal secretion of high mobility group box 1 protein (HMGB1) which binds the receptor for advanced glycation end products (RAGE) and leads to microglial secretion of C1q, upregulation of interleukin-10 with consequent downregulation of leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1), an inhibitory receptor for C1q. Treatment with a centrally acting angiotensin-converting enzyme inhibitor or with an angiotensin-receptor blocker restored a healthy equilibrium, microglial quiescence and intact spatial memory.

Combining multimodal magnetic resonance brain imaging and machine learning to unravel neurocognitive function in non-neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To study whether multimodal brain MRI comprising permeability and perfusion measures coupled with machine learning can predict neurocognitive function in young patients with SLE without neuropsychiatric manifestations.

METHODS

SLE patients and healthy controls (HCs) (≤40 years of age) underwent multimodal structural brain MRI that comprised voxel-based morphometry (VBM), magnetization transfer ratio (MTR) and dynamic contrast-enhanced (DCE) MRI in this cross-sectional study. Neurocognitive function assessed by Automated Neuropsychological Assessment Metrics was reported as the total throughput score (TTS). Olfactory function was assessed. A machine learning-based model (i.e. glmnet) was constructed to predict TTS.

RESULTS

Thirty SLE patients and 10 HCs were studied. Both groups had comparable VBM, MTR, olfactory bulb volume (OBV), olfactory function and TTS. While after correction for multiple comparisons the uncorrected increase in the blood-brain barrier (BBB) permeability parameters compared with HCs did not remain evident in SLE patients, DCE-MRI perfusion parameters, notably an increase in right amygdala perfusion, was positively correlated with TTS in SLE patients (r = 0.636, false discovery rate P < 0.05). A machine learning-trained multimodal MRI model comprising alterations of VBM, MTR, OBV and DCE-MRI parameters mainly in the limbic system regions predicted TTS in SLE patients (r = 0.644, P < 0.0005).

CONCLUSION

Multimodal brain MRI demonstrated increased right amygdala perfusion that was associated with better neurocognitive performance in young SLE patients without statistically significant BBB leakage and microstructural abnormalities. A machine learning-constructed multimodal model comprising microstructural, perfusion and permeability parameters accurately predicted neurocognitive performance in SLE patients.

Effect of anti-P ribosomal and anti-NR2 antibodies on depression and cognitive processes in SLE: an integrated clinical and functional MRI study

OBJECTIVES

To explore the effects of anti-ribosomal P protein (anti-P) and anti-N-methyl-D-aspartic acid receptor subunit 2 (anti-NR2) autoantibodies on depression and cognitive dysfunction and their relationships with functional brain connectivity in SLE.

METHODS

This cross-sectional study included adult patients who fulfilled the American College of Rheumatology/European Alliance of Associations for Rheumatology 2019 SLE criteria. Anti-P and anti-NR2 were quantified using ELISA. A 1-hour battery of neuropsychological testing interpreted by a neuropsychologist explored depressive symptoms (Center for Epidemiologic Studies Depression Scale, CES-D), cognitive domains and quality of life (SF-12). Resting-state functional connectivity (rs-fc) MRI analysis was performed within 1 month, and region-of-interest to region-of-interest (ROI-to-ROI) analyses with the graph theory were performed.

RESULTS

Thirty-three patients with SLE (9% male) were enrolled, mean age (SD) of 43.5 (14) years and median disease duration of 10.4 years (2.9-25.4). Anti-P was positive in 6 (18.2%) and anti-NR2 in 14 (42.4%) patients. Depressive symptoms were found in 14 (42.4%) patients using the CES-D (range 0-51). After correction for age, disease duration, disease activity and white matter lesion load, the CES-D score was independently associated with anti-P serum level (β=0.32; p=0.049) and prednisone daily dose (β=0.38; p=0.023). Nineteen patients (57.6%) showed at least a cognitive test alteration, but no significant association with autoantibodies was found. The rs-fc MRI analysis revealed an independent association between the anti-P serum levels and many altered brain ROI properties but no anti-NR2 and prednisone effects on the cerebral network.

CONCLUSIONS

Anti-P was associated with brain network perturbation, which may be responsible for depressive symptoms in patients with SLE.

Association between cognitive impairment and olfactory deficits in systemic lupus erythematosus without major neuropsychiatric syndromes

OBJECTIVE

The aim of the study was to investigate the utility of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), evaluate cognitive deficits in systemic lupus erythematosus (SLE) patients and examine the relationship between cognitive and olfactory functions.

METHODS

55 SLE patients and 50 healthy controls were administered by RBANS including five indexes: immediate memory (IMME), visuospatial/constructional (Vis/Con), language (LANG), attention (ATT), and delayed memory (DEME). Olfactory functions were evaluated by computerized testing including three stages of smell: threshold (THR), identification (ID), and memory (ME) of different odors. The disease activity and cumulative damage were assessed by the SLE Disease Activity Index 2000 (SLEDAI-2K) and the Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index (SDI).

RESULTS

SLE patients exhibited significant lower total RBANS scores, IMME, Vis/Con, ATT, and DEME index scores than healthy controls (p < 0.01 for all and p = 0.027 for attention). Reduced RBANS scores were associated with several organ involvement and autoantibodies. SLE patients with higher SLEDAI-2K scores or with accumulated damage (SDI≥1) showed decreased RBANS scores. All the olfactory scores in SLE patients were significantly decreased than controls (p = 0.001). Patients had higher proportion of anosmia (8.57% vs 0%) and hyposmia (28.58% vs 5.72%) than controls (χ2 = 10.533, p = 0.015). Multivariable regression analysis revealed that olfactory functions had a positive effect on RBANS index scores. Olfactory memory and total scores were significantly correlated with the DEME (r = 0.393, p = 0.021) and total scores (r = 0.429, p = 0.011).

CONCLUSION

This study indicates that significantly cognitive and olfactory functions are impaired in SLE patients. The RBANS is a potentially useful instrument for evaluating neuropsychological status in SLE. Physicians are encouraged to perform routine screening in SLE patients to detect subtle cognitive dysfunction.

The conundrum of neuropsychiatric systemic lupus erythematosus: Current and novel approaches to diagnosis

Recognising neuropsychiatric involvement by systemic lupus erythematosus (SLE) is of growing importance, however many barriers to this exist at multiple levels of our currently available diagnostic algorithms that may ultimately delay its diagnosis and subsequent treatment. The heterogeneous and non-specific clinical syndromes, serological and cerebrospinal fluid (CSF) markers and neuroimaging findings that often do not mirror disease activity, highlight important research gaps in the diagnosis of neuropsychiatric SLE (NPSLE). Formal neuropsychological assessments or the more accessible screening metrics may also help improve objective recognition of cognitive or mood disorders. Novel serum and CSF markers, including autoantibodies, cytokines and chemokines have also shown increasing utility as part of diagnosis and monitoring, as well as in distinguishing NPSLE from SLE patients without SLE-related neuropsychiatric manifestations. Novel neuroimaging studies also expand upon our existing strategy by quantifying parameters that indicate microarchitectural integrity or provide an assessment of neuronal function. Some of these novel markers have shown associations with specific neuropsychiatric syndromes, suggesting that future research move away from considering NPSLE as a single entity but rather into its individually recognized neuropsychiatric manifestations. Nevertheless, it is likely that a composite panel of these investigations will be needed to better address the gaps impeding recognition of neuropsychiatric involvement by SLE.

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.

Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels

Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients.

The diverse and complex modes of action of anti-NMDA receptor autoantibodies

NMDA receptors are ligand-gated ion channels that are found throughout the brain and are required for both brain development and many higher order functions. A variety of human patients with diverse clinical phenotypes have been identified that carry autoantibodies directed against NMDA receptor subunits. Here we focus on two general classes of autoantibodies, anti-GluN1 antibodies associated with anti-NMDA receptor encephalitis and anti-GluN2 antibodies associated with systemic lupus erythematosus (SLE). These two general classes of anti-NMDA receptor autoantibodies display a wide range of pathophysiological mechanisms from altering synaptic composition to gating of NMDARs. While we have made progress in understanding how these autoantibodies work at the molecular and cellular level, many unanswered questions remain including their long-term actions on brain function, the significance of clonal variations, and their effects on different NMDA receptor-expressing cell types in local circuits. This information will be needed to define fully the transition from anti-NMDA receptor autoantibodies to a clinical phenotype.

Autoimmune encephalitis: the first observational study from Iran

BACKGROUND

Even within the most populous countries in the Middle East, such as Iran, autoimmune encephalitis cases have been rarely reported.

OBJECTIVE

We aimed to describe the demographic, clinical, and paraclinical characteristics of Iranian patients with autoimmune encephalitis positive for anti-neuronal autoantibodies.

METHODS

This cross-sectional study included all patients diagnosed with autoimmune encephalitis and referred to our hospital, in Isfahan, Iran, from March 2016 to May 2020. Patients' demographic, clinical, laboratory, radiological, and electroencephalographic features were obtained from their medical records.

RESULTS

We identified a total of 39 (21 females, 53.8%) patients with autoimmune encephalitis (mean age = 34.9 ± 12.8 years). The most commonly detected antibody was anti-NMDAR (n = 26, 66.7%), followed by anti-GABA_BR (n = 8, 20.5%), anti-Zic4 (n = 4, 10.3%), and anti-GAD65 (n = 1, 2.6%) antibodies, in descending order of frequency. Two anti-NMDAR-positive patients had a history of systemic lupus erythematosus (SLE), and four had a prior history of herpes simplex encephalitis. Clinical presentations in patients positive for anti-Zic4 antibodies included cognitive decline (n = 4, 100%), seizures (n = 3, 75%), parkinsonism (n = 1, 25%), and stiff-person syndrome (n = 1, 25%).

CONCLUSION

This was the first case series of Iranian patients with autoimmune encephalitis with some interesting observations, including SLE-associated anti-NMDAR encephalitis, as well as an unusual concurrence of anti-Zic4 antibody positivity and cognitive problems, seizures, parkinsonism, and stiff-person syndrome.

Case Report: Anti-N-Methyl-D-Aspartate Receptor Encephalitis in an Elderly Patient With Primary Sjögren's Syndrome

Neurological manifestations of primary Sjögren's syndrome (SS) are diverse involving the peripheral and central nervous system. Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, as the most prevalent autoimmune encephalitis, was rarely reported to be complicated with primary SS. Herein, we present an elderly patient with a 15-year history of primary SS presenting with progressive cognitive dysfunction due to anti-NMDAR encephalitis that was once misdiagnosed as primary degenerative dementia. Early recognition of anti-NMDAR encephalitis and initiation of treatment with steroids and immunosuppressant gained a favorable outcome. Our findings enhance the awareness that autoimmune encephalitis should be taken into account in the patients with primary SS presenting with progressive cognitive impairment.

Cognitive Impairment in SLE: Mechanisms and Therapeutic Approaches

A wide range of patients with systemic lupus erythematosus (SLE) suffer from cognitive dysfunction (CD) which severely impacts their quality of life. However, CD remains underdiagnosed and poorly understood. Here, we discuss current findings in patients and in animal models. Strong evidence suggests that CD pathogenesis involves known mechanisms of tissue injury in SLE. These mechanisms recruit brain resident cells, in particular microglia, into the pathological process. While systemic immune activation is critical to central nervous system injury, the current focus of therapy is the microglial cell and not the systemic immune perturbation. Further studies are critical to examine additional potential therapeutic targets and more specific treatments based on the cause and progress of the disease.

Rheumatologic Disorders and the Nervous System

PURPOSE

This article describes the neurologic manifestations of systemic autoimmune diseases.

RECENT FINDINGS

Systemic autoimmune diseases can be associated with a wide spectrum of neurologic comorbidities involving the central and peripheral nervous systems. Systemic lupus erythematosus (SLE) can be associated with a number of manifestations predominantly affecting the central nervous system (CNS), whereas peripheral neuropathy is less common. Sjögren syndrome can be associated with peripheral neuropathy in 10% of cases and CNS disease in 2% to 5% of cases. The risk of stroke is increased in SLE, rheumatoid arthritis, temporal arteritis, psoriatic arthritis, and ankylosing spondylitis. Systemic vasculitides present most commonly with mononeuritis multiplex but can also affect the CNS. Cognitive dysfunction is a common symptom among patients with systemic autoimmune diseases, most commonly seen in patients with SLE or Sjögren syndrome.

SUMMARY

Neurologic manifestations of systemic autoimmune disease are important to recognize, as they may often be the presenting manifestation leading to diagnosis of the systemic disease or may be associated with increased morbidity, other complications, or mortality. Timely diagnosis and institution of appropriate treatment, often requiring multidisciplinary care, is essential to minimize morbidity and decrease the risk of permanent neurologic deficits.

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.

The management of neuropsychiatric lupus in the 21st century: still so many unmet needs?

Neuropsychiatric (NP) events occur in the majority of patients with SLE and predominantly affect the CNS in addition to the peripheral and autonomic systems. Approximately 30% of all NP events are attributable to SLE (NPSLE) and present most frequently around the time of SLE onset. NPSLE is associated with increased morbidity and mortality and the proposed pathogenesis includes both ischaemic and neuroinflammatory mechanisms. Following diagnosis and causal attribution, the treatment of NPSLE is tailored to the type of NP event, the predominant putative pathogenic pathway and the activity and severity of the clinical event. There is a dearth of controlled clinical trials to guide management, but therapeutic options include symptomatic, antithrombotic and immunosuppressive agents that are supported by observational cohort studies. Our objective was to review what is currently known about NPSLE and to identify deficiencies in diagnostic biomarkers, novel therapies and clinical trials for this manifestation of SLE.

An exploratory investigation of antibodies to NMDA-type glutamate receptor subunits in serum and cerebrospinal fluid among psychiatric patients with anti-thyroid antibodies

Introduction

Hashimoto's thyroiditis, which is characterized by anti-thyroid antibodies such as the anti-thyroglobulin (Tg) antibody and anti-thyroid peroxidase (TPO) antibody, is one of the autoimmune diseases associated with psychiatric illnesses. We previously reported a high prevalence of antibodies to N-terminals of N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) subunits (GluN1-NT and GluN2B-NT2) among psychiatric patients with anti-thyroid antibodies. However, it remains unclear whether the presence of anti-thyroid antibodies influences antibodies to GluN1-NT or GluN2B-NT2 among psychiatric patients. The present study aims to examine antibodies to GluN1-NT and GluN2B-NT2 in psychiatric patients with anti-thyroid antibodies (PPATs) and in those without (non-PPATs).

Material and methods

We recruited psychiatric inpatients aged 20–60 years. Patients were excluded if they had a history of neurological diseases, dementia, developmental disorders, tumors, or autoimmune diseases except autoimmune thyroiditis. The rest of the participants were divided into two groups according to the presence of serum anti-Tg and anti-TPO antibodies. We investigated serum and cerebrospinal fluid (CSF) antibodies to GluN1-NT and GluN2B-NT2 using an enzyme-linked immunosorbent assay (ELISA).

Results

We initially recruited seventy-three psychiatric inpatients. Forty-six patients were excluded because of the exclusion criteria. Eighteen PPATs and nine non-PPATs were ultimately enrolled. We also collected stored sera of eighteen healthy controls (HCs) who were age- and sex-matched with PPATs. The optical densities (ODs) of serum antibodies to GluN1-NT (p = 0.0020) and GluN2B-NT2 (p = 0.039) were significantly higher in PPATs than in HCs. The ODs of CSF antibodies to GluN1-NT (p = 0.030) and GluN2B-NT2 (p = 0.017) as well as the positive ratios of those antibodies were significantly higher in PPATs than in non-PPATs.

Conclusion

Our finding indicates that detecting anti-thyroid antibodies in psychiatric patients would be a clue to consider psychiatric conditions related to antibodies to GluN1-NT/GluN2B-NT2. Further studies focusing on the relationship between PPATs and antibodies to GluN1-NT/GluN2B-NT2 are needed.

Systemic lupus erythematosus: The search for the ideal biomarker

During the last decades, there has been an increased interest in the discovery and validation of biomarkers that reliably reflect specific aspects of lupus. Although many biomarkers have been developed, few of them have been validated and used in clinical practice, but with unsatisfactory performances. Thus, there is still a need to rigorously validate many of these novel promising biomarkers in large-scale longitudinal studies and also identify better biomarkers not only for lupus diagnosis but also for monitoring and predicting upcoming flares and response to treatment. Besides serological biomarkers, urinary and cerebrospinal fluid biomarkers have emerged for assessing both renal and central nervous system involvement in systemic lupus erythematosus, respectively. Also, novel omics techniques help us to understand the molecular basis of the disease and also allow the identification of novel biomarkers which may be potentially useful for guiding new therapeutic targets.

Prevalence, involved domains, and predictor of cognitive dysfunction in systemic lupus erythematosus

BACKGROUND

Cognitive Dysfunction (CD) can occur in Systemic Lupus Erythematosus (SLE) before the occurrence of Neuropsychiatric Lupus Erythematosus (NPSLE). Given the reversibility and fluctuation of SLE-related CD, the research for possible predictors is of great significance for early detection and intervention.

OBJECTIVE

We sought to determine the prevalence, involved domains, and possible predictors of CD in SLE patients.

METHODS

We conducted a retrospective cross-sectional study at Nanfang Hospital from 2018 to 2019. A total of 78 SLE patients were recruited. The Montreal Cognitive Assessment (MoCA) scale was used to screen cognitive function. Demographic, clinical, and laboratory characteristics were collected. The serum anti-methyl-d-aspartate receptor (anti-NMDAR) antibody and S100β were measured by enzyme-linked immunosorbent assay (ELISA). Multivariate logistic regression analysis and ROC curve were used to assess the predictor of SLE-related CD.

RESULTS

Of 78 recruited patients,53 (67.9%) had CD. It mainly involved delayed recall, abstract generalization, verbal repetition, and fluency. The disease activity index (SLEDAI) was not associated with SLE-related CD (p > 0.05). Multivariate logistic regression showed that an increase in each year of education there was a decrease in the likelihood of CD (OR 0.261, CI 0.080-0.857, p = 0.027) whereas with each unit increase in serum anti-NMDAR antibody there was an increased likelihood of SLE-related CD (OR 1.568, CI 1.073-2.292, p = 0.020).

CONCLUSION

The prevalence of SLE-related CD was 67.9% in our study and SLE-related CD was not associated with disease activity. Serum anti-NMDAR antibody can be used as a predictor for SLE-related CD.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

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.

Rheumatoid arthritis with pachymeningitis - a case presentation and review of the literature

Rheumatoid meningitis (RM) is a rare central nervous system (CNS) manifestation of rheumatoid arthritis (RA) with a wide spectrum of symptoms. We present a review of the literature with a rare illustrative case of a 61-year-old man with a history of seropositive rheumatoid arthritis (RA) who presented headaches, stroke-like symptoms and seizures. MRI revealed the leptomeningeal enhancement in the right hemisphere. As cerebromeningeal fluid showed increased level of protein and was positive for Candida mannan, the initial clinical diagnosis was fungal meningitis. Despite the antifungal treatment the patient’s clinical condition did not improve. Detailed laboratory, radiologic and histopathological diagnostics enabled the diagnosis of RM.

In conclusion is worth to highlight that presentation of RM is variable and complex, diagnosing it is a big dilemma which is why it must be considered in the differential in a patient with long-standing seropositive RA.

Lupus autoantibodies act as positive allosteric modulators at GluN2A-containing NMDA receptors and impair spatial memory

Patients with Systemic lupus erythematosus (SLE) experience various peripheral and central nervous system manifestations including spatial memory impairment. A subset of autoantibodies (DNRAbs) cross-react with the GluN2A and GluN2B subunits of the NMDA receptor (NMDAR). We find that these DNRAbs act as positive allosteric modulators on NMDARs with GluN2A-containing NMDARs, even those containing a single GluN2A subunit, exhibiting a much greater sensitivity to DNRAbs than those with exclusively GluN2B. Accordingly, GluN2A-specific antagonists provide greater protection from DNRAb-mediated neuronal cell death than GluN2B antagonists. Using transgenic mice to perturb expression of either GluN2A or GluN2B in vivo, we find that DNRAb-mediated disruption of spatial memory characterized by early neuronal cell death and subsequent microglia-dependent pathologies requires GluN2A-containing NMDARs. Our results indicate that GluN2A-specific antagonists or negative allosteric modulators are strong candidates to treat SLE patients with nervous system dysfunction.

Cognitive Dysfunction in Systemic Lupus Erythematosus: A Case for Initiating Trials

Cognitive dysfunction (CD) is an insidious and underdiagnosed manifestation of systemic lupus erythematosus (SLE) that has a considerable impact on quality of life, which can be devastating. Given the inconsistencies in the modes of assessment and the difficulties in attribution to SLE, the reported prevalence of CD ranges from 5% to 80%. Although clinical studies of SLE-related CD have been hampered by heterogeneous subject populations and a lack of sensitive and standardized cognitive tests or other validated objective biomarkers for CD, there are, nonetheless, strong data from mouse models and from the clinical arena that show CD is related to known disease mechanisms. Several cytokines, inflammatory molecules, and antibodies have been associated with CD. Proposed mechanisms for antibody- and cytokine-mediated neuronal injury include the abrogation of blood-brain barrier integrity with direct access of soluble molecules in the circulation to the brain and ensuing neurotoxicity and microglial activation. No treatments for SLE-mediated CD exist, but potential candidates include agents that inhibit microglial activation, such as angiotensin-converting enzyme inhibitors, or that protect blood-brain barrier integrity, such as C5a receptor blockers. Structural and functional neuroimaging data have shown a range of regional abnormalities in metabolism and white matter microstructural integrity in SLE patients that correlate with CD and could in the future become diagnostic tools and outcome measures in clinical trials aimed at preserving cognitive function in SLE.

Predictors of damage accrual in systemic lupus erythematosus: a longitudinal observational study with focus on neuropsychological factors and anti-neuronal antibodies

OBJECTIVE

Central nervous system disease occurs in over 20% of patients with systemic lupus erythematosus (SLE) resulting in major morbidity and damage. Cognitive dysfunction is common in SLE, but the cause remains uncertain and treatment options are limited. This study explores the influence of clinical, neuropsychological factors and anti-neuronal antibodies on lupus damage accrual.

METHOD

A prospective cohort with 99 SLE patients recruited between 2008 and 2013 and followed up in 2016 was established. Baseline evaluations were depression (MINI-Plus), cognitive function evaluating attention, visuospatial memory and executive functions, and anti-neuronal antibodies. Activity index (SLEDAI-2K) and SLICC/ACR Damage Index (SDI) were assessed at baseline and last follow-up.

RESULTS

At baseline, median (interquartile range) age was 36.0 years (27.0-45.0), disease duration 3.7 years (0.4-12.4), SLEDAI-2K 6.0 (3.0-12.0), and SDI score 1.0 (0-1.0). Major depression was present in 23%, cognitive deficit in 18%, and received immunomodulators in 36%. Anti-dsDNA/N-methyl-D-aspartate receptor antibodies were present in 19%, anti-ribosomal P in 12%, and anti-neuronal surface P antigen (NSPA) in 5%. After a median follow-up of 55 months (interquartile range 39-78), 11% had damage accrual. In a multivariate analysis, baseline SDI, SLEDAI-2K, and immunomodulators use were associated with final damage, whereas SLEDAI-2K and immunomodulator use were also associated with accrual damage. Models including anti-NSPA showed impact on final and accrual damage. Cognitive deficit, depression, and other autoantibodies were not predictors.

CONCLUSIONS

Disease activity and immunomodulator use associate with lupus damage. Of the anti-neuronal antibodies examined, anti-NSPA emerged as a potential poor prognostic factor, probably related to severe SLE onset requiring elevated corticosteroid doses. Key Points • Anti-NSPA may be a worse prognostic factor in SLE. • Other neuropsychological factors do not influence damage.

Fatigue in SLE: diagnostic and pathogenic impact of anti-N-methyl-D-aspartate receptor (NMDAR) autoantibodies

OBJECTIVES

We explored the impact of circulating anti-N-methyl-D-aspartate receptor (NMDAR) antibodies on the severity of fatigue in patients with systemic lupus erythematosus (SLE).

METHODS

Serum samples of 426 patients with SLE were analysed for the presence of antibodies to the NR2 subunit of the NMDAR. In parallel, the severity of fatigue was determined according to the Fatigue Scale for Motor and Cognitive functions questionnaire. In a subgroup of patients with SLE, the hippocampal volume was correlated with the levels of anti-NR2 antibodies. Isolated immunoglobulin G from patients with anti-NR2 antibodies were used for murine immunohistochemical experiments and functional assays on neuronal cell lines. Treatment effects were studied in 86 patients with lupus under belimumab therapy.

RESULTS

We found a close correlation between the titre of anti-NR2 antibodies, the severity of fatigue, the clinical disease activity index (Systemic Lupus Erythematosus Disease Activity Index 2000) and anti-double stranded DNA antibodies-independently of the presence of neuropsychiatric lupus manifestations. Pathogenic effects could be demonstrated by (1) detection of anti-NR2 antibodies in the cerebrospinal fluid, (2) in situ binding of anti-NR2 antibodies to NMDAR of the hippocampus area and (3) distinct functional effects in vitro: downregulating the energy metabolism of neuronal cells without enhanced cytotoxicity. Treatment with belimumab for at least 6 months affected both the severity of fatigue and the levels of anti-NR2 antibodies.

CONCLUSION

The presence of anti-NR2 antibodies in patients with SLE with fatigue is a helpful diagnostic tool and may offer a major approach in the therapeutic management of this important disabling symptom in patients with SLE.

Anti-GAPDH Autoantibody Is Associated with Increased Disease Activity and Intracranial Pressure in Systemic Lupus Erythematosus

Objective

Systemic lupus erythematosus (SLE) is an immune disease characterized by multiorgan involvement. Neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the most devastating complications of SLE, which lacks efficient diagnostic biomarkers. The recent studies on the anti-GAPDH autoantibodies suggested its potential pathogenic roles in NPSLE. However, the clinical relevance of the anti-GAPDH autoantibodies in patients with SLE is still elusive. In this study, we sought to determine the serum levels of the anti-GAPDH autoantibodies in patients with SLE to investigate the clinical significance of the anti-GAPDH autoantibodies in SLE.

Methods

Concentrations of the glyceraldehyde 3-phosphate dehydrogenase autoantibodies (anti-GAPDH autoantibodies) in the serum of 130 SLE patients and 55 healthy individuals were determined by enzyme-linked immunosorbent assay (ELISA). Among the 130 SLE patients, 95 were SLE patients without neuropsychiatric symptoms and 35 had NPSLE. White blood cell (WBC) count, hemoglobin (HB), platelet count (PLT), IgG, IgA, IgM, anti-dsDNA, C3, C4, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), RF, anti-cardiolipin (Acl), ANA, AnuA, anti-SSA, anti-SSB, β2-GPI, urinalysis, and 24 h urine protein were measured by standard laboratory techniques. Systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K) and Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index scores were evaluated accordingly.

Results

The serum levels of the anti-GAPDH autoantibodies were significantly elevated in the SLE patients, especially in the patients with NPSLE (P = 0.0011). Elevated serum anti-GAPDH was correlated with increased SLEDAI-2K (P = 0.017), ESR, IgG, and IgM and associated with increased intracranial pressure and incidence of cerebrovascular lesions, but it was protective for seizure disorder incidence.

Conclusions

Serum anti-GAPDH autoantibody was increased in both groups of SLE patients with or without neuropsychiatric symptoms and associated with disease severity. It could become an indicator of tissue damages in the brain for the future clinical practice.

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.

An unusual manifestation of Sjögren syndrome encephalitis

Sjögren syndrome (SS) is a systemic inflammatory and autoimmune disease characterized by systemic disorders of the exocrine glands, predominantly the salivary and lacrimal glands. Here, we report a 4-year-old boy who presented with the repetition of generalized tonic-clonic seizures for 1-2 min. Initially, he was diagnosed with idiopathic autoimmune encephalitis and was treated with steroids. He was eventually diagnosed with SS based on the examination results, such as inflammatory cell infiltration into the minor salivary glands and positive serum anti-SSA/Ro antibody. Although central nervous system complications are rare in pediatric SS, this condition should be considered in the differential diagnosis when a patient presents with idiopathic autoimmune encephalitis of unknown cause. Furthermore, SS can occur in relatively young children and can present without imaging abnormalities.

Novel autoantibodies in Sjögren's syndrome: A comprehensive review

Sjögren's syndrome is a systemic autoimmune disease characterized by immune- mediated injury of exocrine glands, as well as a diverse array of extraglandular manifestations. B cell over-activation is a key feature of the disease, attested by the wide spectrum of autoantibodies detected in these patients. Up to date, anti- Ro/SSA and anti-La/SSB antibodies are traditional biomarkers for disease classification and diagnosis. On the other hand, the detection of novel autoantibodies in SS has increased in the last years, opening a window of opportunity to denote particular stages of the disease, to establish clinical phenotypes, and to predict long-term complications such as lymphoma. For instance, anti-SP-1, anti-CA6 and anti-PSP antibodies occur in an earlier stage than anti-Ro/La antibodies, and may identify a subset of primary Sjögren's syndrome patients with mild or incomplete disease, whereas anti-cofilin-1, anti- alpha-enolase and anti-RGI2 antibodies are potential biomarkers of MALT lymphoma. Antibody detection is also important to elucidate new aspects of SS pathophysiology, and in the future to permit a phenotype-specific patient approach. Herein we review the literature regarding new autoantibodies in SS and attempt to dissect their usefulness as diagnostic tools, pathogenic role, identification of clinical phenotypes and as predictors of an overlap syndrome.

An evolving redefinition of autoimmune encephalitis

Autoimmune encephalitis encompasses a wide variety of protean pathologic processes associated with the presence of antibodies against neuronal intracellular proteins, synaptic receptors, ion channels and/or neuronal surface proteins. This type of encephalitis can also involve children with complex patterns of seizures and unexpected behavioural changes, which jeopardize their prompt recognition and treatment. Many epidemiological studies have shown that numerous immune-based forms of encephalitis can be encountered, almost surpassing the rate of postinfectious encephalitides. However, the overall exact prevalence of autoimmune encephalopathies remains underestimated, and the definition of diagnostic algorithms results muddled. The spectrum of neuropsychiatric manifestations in the pediatric population with autoimmune encephalitis is less clear than in adults, but the integration of clinical, immunological, electrophysiological and neuroradiological data is essential for a general approach to patients. In this review we report the most relevant data about both immunologic and clinical characteristics of the main autoimmune encephalitides recognized so far, with the aim of assisting clinicians in the differential diagnosis and favouring an early effective treatment. Correlations between phenotype and autoantibodies involved in the neurological damage of autoimmune encephalitis are largely unknown in the first years of life, because of the relatively small number of pediatric patients adequately studied. Future multicenter collaborative studies are needed to improve the diagnostic approach and tailor personalized therapies in the long-term.

Laboratory and Neuroimaging Biomarkers in Neuropsychiatric Systemic Lupus Erythematosus: Where Do We Stand, Where To Go?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multi-systemic involvement. Nervous system involvement in SLE leads to a series of uncommon and heterogeneous neuropsychiatric (NP) manifestations. Current knowledge on the underlying pathogenic processes and their subsequent pathophysiological changes leading to NP-SLE manifestations is incomplete. Several putative laboratory biomarkers have been proposed as contributors to the genesis of SLE-related nervous system damage. Alongside the laboratory biomarkers, several neuroimaging tools have shown to reflect the nature of tissue microstructural damage associated with SLE, and thus were suggested to contribute to the understanding of the pathophysiological changes and subsequently help in clinical decision making. However, the number of useful biomarkers in NP-SLE in clinical practice is disconcertingly modest. In some cases it is not clear whether the biomarker is truly involved in pathogenesis, or the result of non-specific pathophysiological changes in the nervous system (e.g., neuroinflammation) or whether it is the consequence of a concomitant underlying abnormality related to SLE activity. In order to improve the diagnosis of NP-SLE and provide a better targeted care to these patients, there is still a need to develop and validate a range of biomarkers that reliably capture the different aspects of disease heterogeneity. This article critically reviews the current state of knowledge on laboratory and neuroimaging biomarkers in NP-SLE, discusses the factors that need to be addressed to make these biomarkers suitable for clinical application, and suggests potential future research paths to address important unmet needs in the NP-SLE field.

Psycho-rheumatic Integration in Systemic Lupus Erythematosus: An Insight into Antibodies Causing Neuropsychiatric Changes

The main purpose of this paper is to bring together all the antibodies and markers related to neurological and psychiatric manifestations in systemic lupus erythematosus and also the pharmacology that could help treat these symptoms. Existing research data regarding specific antibodies involved in the disease process and drugs that were being studied was collected and analyzed. After reviewing the studies published by various authors, symptoms were shown to be mainly caused by antibodies against N-methyl-D-aspartate receptor (NMDAR) antibodies, anti-endothelial, anti-ribosomal P, antiphospholipid antibodies, cytokines like interferons and chemokines. The monoclonal antibody rituximab has shown to be beneficial in some of the cases. Based on all the articles reviewed, the antibodies and cytokines showed the most effective evidence in causing the different manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE), but studies regarding the drugs being effective against all the symptoms are inconclusive as there are very few studies. Further research to support the drug’s effectiveness in managing the symptoms is needed. More studies are needed regarding early diagnosis of NPSLE using the antibodies as biomarkers as it could help in preventing these manifestations.

Definition of NPSLE: Does the ACR Nomenclature Still Hold?

Systemic lupus erythematosus (SLE) patients have frequently neuropsychiatric manifestations. From the first description of coma in 1875, a variety of manifestations has been described to occur in SLE. However, the lack of standardization reduced the comparability of published studies. In 1999, the American College of Rheumatology published guidelines to define neuropsychiatric nomenclature in SLE. This was the first step toward uniform diagnostic criteria. Several studies have been published since then applying the ACR criteria and frequencies of different manifestations can now be compared between cohorts. Although these criteria are diagnostic, therapeutic approach to different manifestations varies according to nature and severity of the manifestations. Herby, we will review the different definition for NPSLE published, and determine advantages and limitation.

Cognitive dysfunction improves in systemic lupus erythematosus: Results of a 10 years prospective study

OBJECTIVE

Cognitive impairment (CI) has been described in 3-80% of Systemic lupus erythematosus (SLE) patients but only short-term studies evaluated its over-time changes, suggesting that CI is usually a stable finding. We aimed at evaluating the changes of SLE-related CI in a 10-years prospective single center cohort study.

METHODS

We evaluated 43 patients (M/F 5/38; mean age = 45.7±10.1 years; mean disease duration = 230.8±74.3 months) at baseline (T0) and after 10 years (T1). A test battery designed to detect fronto-subcortical dysfunction across five domains (memory, attention, abstract reasoning, executive and visuospatial function) was administered. A global cognitive dysfunction score (GCD) was obtained and associated with clinical and laboratory features.

RESULTS

Prevalence of CI was 20.9% at T0 and 13.9% at T1 (P = NS). This impairment was prevalently mild at T0 (55.5%) and mild or moderate at T1 (36.3% for both degrees). After 10 years, CI improved in 50% of patients, while 10% worsened. Impaired memory (P = 0.02), executive functions (P = 0.02) and abstract reasoning (P = 0.03) were associated with dyslipidemia at T0. Worsening of visuospatial functions was significantly associated with dyslipidemia and Lupus Anticoagulant (P = 0.04 for both parameters). Finally, GCD significantly correlated with chronic damage measured by SLICC/damage index at T0 (r = 0.3; P = 0.04) and T1 (r = 0.3; P = 0.03).

CONCLUSIONS

For the first time, we assessed CI changes over 10-years in SLE. CI improved in the majority of the patients. Furthermore, we observed an improvement of the overall cognitive functions. These results could suggest that an appropriate management of the disease during the follow-up could be able to control SLE-related CI.

The role of ophthalmic imaging in central nervous system degeneration in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disorder that can involve any organ system. Central nervous system involvement can be a severe life threatening complication, ultimately resulting in severe neurodegenerative changes. Magnetic resonance imaging suggests that neurodegeneration, which may have deleterious effects on brain function, may occur early in SLE and experimental models suggest that neuroprotection may be feasible and beneficial. The retina is an extension of the brain. Recent ophthalmic imaging technologies are capable of identifying early changes in retinal and choroidal morphology and circulation that may reflect CNS degeneration. However, their utility in monitoring CNS involvement in SLE has been poorly studied as these have only been performed in small cohorts, in a cross-sectional design, non-quantitatively and without correlation to disease activity. The authors aim to review the current understanding of neurodegeneration associated with SLE, with particular focus on the visual pathway. We describe the neuropathology of the visual system in SLE and the evidence for retinal and choroidal neurodegenerative and microvascular changes using optical coherence tomography technology. We aim to describe the potential role of optical imaging modalities in NPSLE diagnosis and their likely impact on the study of neuronal function.

Autoimmunity in 2016

The number of peer-reviewed articles published during the 2016 solar year and retrieved using the "autoimmunity" key word remained stable while gaining a minimal edge among the immunology articles. Nonetheless, the quality of the publications has been rising significantly and, importantly, acquisitions have become available through scientific journals dedicated to immunology or autoimmunity. Major discoveries have been made in the fields of systemic lupus erythematosus, rheumatoid arthritis, autoimmunity of the central nervous system, vasculitis, and seronegative spondyloarthrithritides. Selected examples include the role of IL17-related genes and long noncoding RNAs in systemic lupus erythematosus or the effects of anti-pentraxin 3 (PTX3) in the treatment of this paradigmatic autoimmune condition. In the case of rheumatoid arthritis, there have been reports of the role of induced regulatory T cells (iTregs) or fibrocytes and T cell interactions with exciting implications. The large number of studies dealing with neuroimmunology pointed to Th17 cells, CD56(bright) NK cells, and low-level TLR2 ligands as involved in multiple sclerosis, along with a high salt intake or the micriobiome-derived Lipid 654. Lastly, we focused on the rare vasculitides to which numerous studies were devoted and suggested that unsuspected cell populations, including monocytes, mucosal-associated invariant T cells, and innate lymphoid cells, may be crucial to ANCA-associated manifestations. This brief and arbitrary discussion of the findings published in 2016 is representative of a promising background for developments that will enormously impact the work of laboratory scientists and physicians at an exponential rate.

The Role of Brain-Reactive Autoantibodies in Brain Pathology and Cognitive Impairment

Antibodies to different brain proteins have been recently found to be associated with an increasing number of different autoimmune diseases. They need to penetrate the blood–brain barrier (BBB) in order to bind antigens within the central nervous system (CNS). They can target either neuronal or non-neuronal antigen and result in damage either by themselves or in synergy with other inflammatory mediators. Antibodies can lead to acute brain pathology, which may be reversible; alternatively, they may trigger irreversible damage that persists even though the antibodies are no longer present. In this review, we will describe two different autoimmune conditions and the role of their antibodies in causing brain pathology. In systemic lupus erythematosus (SLE), patients can have double stranded DNA antibodies that cross react with the neuronal N-methyl-d-aspartate receptor (NMDAR), which have been recently linked to neurocognitive dysfunction. In neuromyelitis optica (NMO), antibodies to astrocytic aquaporin-4 (AQP4) are diagnostic of disease. There is emerging evidence that pathogenic T cells also play an important role for the disease pathogenesis in NMO since they infiltrate in the CNS. In order to enable appropriate and less invasive treatment for antibody-mediated diseases, we need to understand the mechanisms of antibody-mediated pathology, the acute and chronic effects of antibody exposure, if the antibodies are produced intrathecally or systemically, their target antigen, and what triggers their production. Emerging data also show that in utero exposure to some brain-reactive antibodies, such as those found in SLE, can cause neurodevelopmental impairment since they can penetrate the embryonic BBB. If the antibody exposure occurs at a critical time of development, this can result in irreversible damage of the offspring that persists throughout adulthood.