Review: Nervous System Disease in Systemic Lupus Erythematosus: Current Status and Future Directions

TWEAKing the Hippocampus: The Effects of TWEAK on the Genomic Fabric of the Hippocampus in a Neuropsychiatric Lupus Mouse Model

Neuropsychiatric manifestations of systemic lupus erythematosus (SLE), specifically cognitive dysfunction and mood disorders, are widely prevalent in SLE patients, and yet poorly understood. TNF-like weak inducer of apoptosis (TWEAK) has previously been implicated in the pathogenesis of neuropsychiatric lupus (NPSLE), and we have recently shown its effects on the transcriptome of the cortex of the lupus-prone mice model MRL/lpr. As the hippocampus is thought to be an important focus of NPSLE processes, we explored the TWEAK-induced transcriptional changes that occur in the hippocampus, and isolated several genes (Dnajc28, Syne2, transthyretin) and pathways (PI3K-AKT, as well as chemokine-signaling and neurotransmission pathways) that are most differentially affected by TWEAK activation. While the functional roles of these genes and pathways within NPSLE need to be further investigated, an interesting link between neuroinflammation and neurodegeneration appears to emerge, which may prove to be a promising novel direction in NPSLE research.

White matter hyperintensities associate with cognitive slowing in patients with systemic lupus erythematosus and neuropsychiatric symptoms

Objective

To compare cognitive function between patients with different phenotypes of neuropsychiatric systemic lupus erythematosus (NPSLE) and assess its association with brain and white matter hyperintensity (WMH) volumes.

Methods

Patients attending the Leiden University Medical Centre NPSLE clinic between 2007 and 2015 without large brain infarcts were included (n=151; 42±13 years, 91% women). In a multidisciplinary consensus meeting, neuropsychiatric symptoms were attributed to systemic lupus erythematosus (SLE) (NPSLE, inflammatory (n=24) or ischaemic (n=12)) or to minor/non-NPSLE (n=115). Multiple regression analyses were performed to compare cognitive function between NPSLE phenotypes and to assess associations between brain and WMH volumes and cognitive function cross-sectionally.

Results

Global cognitive function was impaired in 5%, learning and memory (LM) in 46%, executive function and complex attention (EFCA) in 39% and psychomotor speed (PS) in 46% of all patients. Patients with inflammatory NPSLE showed the most cognitive impairment in all domains (p≤0.05).

Higher WMH volume associated with lower PS in the total group (B: −0.14 (95% CI −0.32 to −0.02)); especially in inflammatory NPSLE (B: −0.36 (95% CI −0.60 to −0.12). In the total group, lower total brain volume and grey matter volume associated with lower cognitive functioning in all domains (all: 0.00/0.01 (0.00;0.01)) and lower white matter volume associated with lower LM, EFCA and PS (all: 0.00/0.01 (0.00;0.01)).

Conclusion

We demonstrated that an association between brain and WMH volumes and cognitive function is present in patients with SLE, but differs between (NP)SLE phenotypes. WMHs associated with PS especially in inflammatory NPSLE, which suggests a different, potentially more severe underlying pathophysiological mechanism of cognitive impairment in this phenotype.

Neuro-psychiatric manifestations in patients with systemic lupus erythematosus: A systematic review and results from the Swiss lupus cohort study

Objectives

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease associated with neuro-psychiatric (NP) manifestations. Frequency and patterns of neuro-psychiatric systemic lupus erythematosus (NPSLE) vary substantially between patients. We conducted a systematic review (SR) of the literature and examined prevalence and characteristics of NPSLE in the Swiss SLE cohort study (SSCS).

Methods

The SR search was performed between January 1999 and January 2020. We included prospective/cross-sectional studies focusing on NPSLE. We secured study characteristics, cohort compositions and frequencies of NP manifestations, assessed heterogeneity across reports and investigated sources of variation using meta-regression models. Regarding the SSCS, we reviewed all patients included and classified NP manifestations.

Results

The SR searches identified 530 studies. We included 22 studies in our meta-analysis, the mean frequency of NPSLE ranged from 10.6% to 96.4%. The frequency of NPSLE in the SSCS was 28.1%. Severe events including cerebrovascular insults, seizures and psychosis appeared in 7.1%, 5.3% and 6.5% respectively. There was a linear relationship between duration of SLE and cumulative incidence of NPSLE.

Conclusions

The spectrum of NPSLE is very broad. The diagnostic work-up and rates of reported manifestations varied substantially across studies. We call for concerted efforts and consensus regarding definitions of NPSLE that will facilitate accurate diagnosis and attribution to SLE, particularly with a view to timely intervention and patient outcomes.

Cognitive Dysfunction in Systemic Lupus Erythematosus: Immunopathology, Clinical Manifestations, Neuroimaging and Management

Cognitive dysfunction (CD) is a common yet often clinically subtle manifestation that considerably impacts the health-related quality of life in patients with systemic lupus erythaematosus (SLE). Given the inconsistencies in CD assessment and challenges in its attribution to SLE, the reported prevalence of CD differs widely, ranging from 3 to 88%. The clinical presentation of CD in SLE is non-specific and may manifest concurrently with overt neuropsychiatric illness such as psychosis or mood disorders or as isolated impairment of attention, working memory, executive dysfunction or processing speed. Despite the lack of standardized and sensitive neuropsychological tests and validated diagnostic biomarkers of CD in SLE, significant progress has been made in identifying pathogenic neural pathways and neuroimaging. Furthermore, several autoantibodies, cytokines, pro-inflammatory mediators and metabolic factors have been implicated in the pathogenesis of CD in SLE. Abrogation of the integrity of the blood-brain barrier (BBB) and ensuing autoantibody-mediated neurotoxicity, complement and microglial activation remains the widely accepted mechanism of SLE-related CD. Although several functional neuroimaging modalities have consistently demonstrated abnormalities that correlate with CD in SLE patients, a consensus remains to be reached as to their clinical utility in diagnosing CD. Given the multifactorial aetiology of CD, a multi-domain interventional approach that addresses the risk factors and disease mechanisms of CD in a concurrent fashion is the favourable therapeutic direction. While cognitive rehabilitation and exercise training remain important, specific pharmacological agents that target microglial activation and maintain the BBB integrity are potential candidates for the treatment of SLE-related CD.

Neuropsychiatric Events in Systemic Lupus Erythematosus

OBJECTIVES

To determine predictors for change in neuropsychiatric (NP) event status in a large, prospective, international, inception cohort of SLE patients METHODS: Upon enrollment and annually thereafter, NP events attributed to SLE and non-SLE causes and physician determined resolution were documented. Factors potentially associated with onset and resolution of NP events were determined by time-to-event analysis using a multistate modelling structure.

RESULTS

NP events occurred in 955/1,827 (52.3%) patients and 592/1910 (31.0%) unique events were attributed to SLE. For SLE NP events multivariate analysis revealed positive associations with male sex, concurrent non-SLE NP events excluding headache, active SLE and corticosteroids. There was a negative association with Asian race/ethnicity, post-secondary education, and immunosuppressive or anti-malarial drugs. For non-SLE NP events, excluding headache, there was a positive association with concurrent SLE NP events and negative associations with African and Asian race/ethnicity. NP events attributed to SLE had a higher resolution rate than non-SLE NP events, with the exception of headache that had comparable resolution rates. For SLE NP events, multivariate analysis revealed resolution was more common with Asian race/ethnicity and for central/focal NP events. For non-SLE NP events resolution was more common with African race/ethnicity and less common with older age at SLE diagnosis.

CONCLUSIONS

In a large and long-term study of the occurrence and resolution of NP events in SLE we identified subgroups with better and worse prognosis. The course of NP events differs greatly depending on their nature and attribution.

Hippocampal microglia CD40 mediates NPSLE cognitive dysfunction in mice

Neuropsychiatric systemic lupus erythematosus (NPSLE) is the most serious and complicated clinical manifestation of lupus erythematosus. Cognitive dysfunction is the most common symptom of NPSLE. A variety of potential mechanisms or mediators related to the pathogenesis of NPSLE cognitive dysfunction have been proposed. However, the involvement of microglia CD40 has not been reported yet. This study aimed to investigate whether hippocampal microglia CD40 of MRL/MpJ-Fas^lpr (MRL/lpr) mice was involved in NPSLE cognitive dysfunction. This study found, using quantitative polymerase chain reaction, western blotting and immunohistochemistry, that hippocampal CD40 was aberrantly overexpressed in the MRL/lpr lupus mice. It also determined using flow cytometry and immunofluorescence that the aberrantly overexpressed CD40 was mainly derived from hippocampal microglia. The adeno-associated virus was used to inhibit microglia CD40 expression, and the brain damage and cognitive dysfunction of MRL/lpr mice improved. Also, imiquimod (IMQ)-induced lupus mice had the same NPSLE cognitive dysfunction, brain damage, and overexpressed hippocampal microglia CD40 as MRL/lpr mice. Therefore, IMQ-induced lupus mouse was proposed as one of the mouse models for studying NPSLE cognitive dysfunction for the first time in this study. The findings indicated that hippocampal microglia CD40 was involved in the development of NPSLE cognitive dysfunction, thus providing a novel research direction for the study of the pathogenesis of NPSLE.

Different phenotypes of neuropsychiatric systemic lupus erythematosus are related to a distinct pattern of structural changes on brain MRI

Objectives

The underlying structural brain correlates of neuropsychiatric involvement in systemic lupus erythematosus (NPSLE) remain unclear, thus hindering correct diagnosis.

We compared brain tissue volumes between a clinically well-defined cohort of patients with NPSLE and SLE patients with neuropsychiatric syndromes not attributed to SLE (non-NPSLE). Within the NPSLE patients, we also examined differences between patients with two distinct disease phenotypes: ischemic and inflammatory.

Methods

In this prospective (May 2007 to April 2015) cohort study, we included 38 NPSLE patients (26 inflammatory and 12 ischemic) and 117 non-NPSLE patients. All patients underwent a 3-T brain MRI scan that was used to automatically determine white matter, grey matter, white matter hyperintensities (WMH) and total brain volumes. Group differences in brain tissue volumes were studied with linear regression analyses corrected for age, gender, and total intracranial volume and expressed as B values and 95% confidence intervals.

Results

NPSLE patients showed higher WMH volume compared to non-NPSLE patients (p = 0.004). NPSLE inflammatory patients showed lower total brain (p = 0.014) and white matter volumes (p = 0.020), and higher WMH volume (p = 0.002) compared to non-NPSLE patients. Additionally, NPSLE inflammatory patients showed lower white matter (p = 0.020) and total brain volumes (p = 0.038) compared to NPSLE ischemic patients.

Conclusion

We showed that different phenotypes of NPSLE were related to distinct patterns of underlying structural brain MRI changes. Especially the inflammatory phenotype of NPSLE was associated with the most pronounced brain volume changes, which might facilitate the diagnostic process in SLE patients with neuropsychiatric symptoms.

Key Points

• Neuropsychiatric systemic lupus erythematosus (NPSLE) patients showed a higher WMH volume compared to SLE patients with neuropsychiatric syndromes not attributed to SLE (non-NPSLE).

• NPSLE patients with inflammatory phenotype showed a lower total brain and white matter volume, and a higher volume of white matter hyperintensities, compared to non-NPSLE patients.

• NPSLE patients with inflammatory phenotype showed lower white matter and total brain volumes compared to NPSLE patients with ischemic phenotype.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07970-2.

Exercise alleviates symptoms of CNS lupus

Systemic lupus erythematosus (lupus) is a global health problem where 20-80% patients display cognitive problems and central nervous system (CNS) dysfunction. Early diagnosis and treatment of lupus remains a clinical challenge. Exercise improves experimental lupus nephritis. However, the effects of exercise in CNS lupus remains unknown. This study investigates the effects of controlled exercise (CE) that consisted of treadmill walking (5 m/min for 10 min everyday) on experimental CNS lupus using the well-established mouse model, MRL/lpr mice. The MRL/lpr mice were subjected to CE from 8 weeks (preclinical) to 16 weeks (disease). Multiplex gene expression analysis revealed significant upregulation of genes involved in neurite growth, proliferation and synaptic plasticity, and a decrease in inflammatory genes including complement proteins, NFkB, chemokines and cytokines in exercised mice compared to the unmanipulated, age-matched controls. The loss of blood-brain barrier integrity, astrogliosis and edema seen in MRL/lpr mice were reduced with exercise. Exercised mice performed better in behavioral assessments such as open field, nesting, and tail suspension test. For the first time our results show that a supervised, well-regulated and controlled exercise regimen alleviates CNS lupus and could potentially serve as an intervention strategy to improve the quality of life. Exercise could also serve as an adjunct therapy for lupus and other neuroinflammatory diseases, thereby reducing the need for the current therapies with toxic side effects. The validity of the findings and a safe exercise regimen needs to be established by additional studies in patients.

Fatigue in patients with systemic lupus erythematosus and neuropsychiatric symptoms is associated with anxiety and depression rather than inflammatory disease activity

INTRODUCTION

We aimed to investigate risk factors for fatigue in patients with systemic lupus erythematosus (SLE) and neuropsychiatric symptoms in order to identify potential interventional strategies.

METHODS

Patients visiting the neuropsychiatric SLE (NPSLE) clinic of the Leiden University Medical Center between 2007-2019 were included. In a multidisciplinary consensus meeting, SLE patients were classified as having neuropsychiatric symptoms of inflammatory origin (inflammatory phenotype) or other origin (non-inflammatory phenotype). Fatigue was assessed with the SF-36 vitality domain (VT) since 2007 and the multidimensional fatigue inventory (MFI) and visual analogue scale (VAS) since 2011. Patients with a score on the SF-36 VT ≥1 standard deviation (SD) away from the mean of age-related controls of the general population were classified as fatigued; patients ≥2 SD away were classified as extremely fatigued. Disease activity was measured using the SLE disease activity index-2000. The influence of the presence of an inflammatory phenotype, disease activity and symptoms of depression and anxiety as measured by the hospital anxiety and depression scale (HADS) was analyzed using multiple regression analyses corrected for age, sex and education.

RESULTS

348 out of 371 eligible patients filled in questionnaires and were included in this study . The majority was female (87%) and the mean age was 43 ± 14 years. 72 patients (21%) had neuropsychiatric symptoms of an inflammatory origin. Fatigue was present in 78% of all patients and extreme fatigue was present in 50% of patients with an inflammatory phenotype vs 46% in the non-inflammatory phenotype. Fatigue was similar in patients with an inflammatory phenotype compared to patients with a non-inflammatory phenotype on the SF-36 VT (β: 0.8 (95% CI -4.8; 6.1) and there was less fatigue in patients with an inflammatory phenotype on the MFI and VAS (β: -3.7 (95% CI: -6.9; -0.5) and β: -1.0 (95% CI -1.6; -0.3)). There was no association between disease activity and fatigue, but symptoms of anxiety and depression (HADS) associated strongly with all fatigue measurements.

CONCLUSION

This study suggests that intervention strategies to target fatigue in (NP)SLE patients may need to focus on symptoms of anxiety and depression rather than immunosuppressive treatment.

CNS involvement in systemic vasculitides

Both the CNS and the PNS can be involved in almost all of the vasculitides - including the primary systemic vasculitic disorders, such as microscopic polyangiitis and polyarteritis nodosa, and in non-vasculitic systemic disorders, such as systemic lupus erythematosis and sarcoidosis. The latter diseases also include infections and toxininduced disorders - particularly drugs of abuse such as cocaine and amphetamines. Here we will summarise the spectrum of these disorders as they affect the CNS, concentrating in particular on their distinguishing clinical and investigational features.

The effects of disease activity on neuronal and behavioural cognitive processes in systemic lupus erythematosus

OBJECTIVES

Factors common across many chronic diseases, such as fatigue and depression affect cognitive dysfunction (CD) but the effect of systemic lupus erythematosus (SLE) disease activity on CD remains unclear. We aimed to explore the effects of disease activity in SLE on cognitive function whilst taking into consideration other potential mediators.

METHODS

Two groups of SLE patients were recruited; stable/low disease activity (SLE-S, n = 36) and active disease (SLE-F, n = 26). The SLE-F group were studied during a flare; with a second visit when disease activity had reduced. In addition to demographic, clinical and psychiatric data, CD was measured using a computerised battery of tests (CANTAB®). fMRI was used to examine neuronal responses to working memory and emotional processing tasks.

RESULTS

No differences between the groups/visits were found using the CANTAB® battery. The fMRI results showed that the SLE-F group had a less attenuated response in the medial prefrontal cortex (a default mode network-DMN region) compared with the SLE-S group during the working memory task (p = 0.012). Exploratory correlations within the SLE-F group showed associations between neuronal responses and depression, cognitive fatigue, disease activity measures and IL-6.

CONCLUSION

Functional brain processes but not cognitive behavioural measures were affected by disease activity. Flaring SLE patients were less able to suppress DMN regions during a working memory task. This could reflect emotional interference during cognitive tasks and may cause cognitive fatigue. A number of factors are associated with brain function in flaring patients, which has potential implications for holistic treatments.

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.

A novel therapeutic approach using the Zipper method to treat chorea in a pediatric-onset systemic lupus erythematosus patient

Pediatric-onset systemic lupus erythematosus is among the prototypic systemic autoimmune diseases seen in children. Although the neuropsychiatric involvement rate varies during the course of the disease, it is an important cause of morbidity and mortality. The clinical picture of neuropsychiatric SLE (NPSLE) is highly variable, and neurological features can precede systemic findings, leading to some diagnostic difficulties. NPSLE requires early and aggressive immunosuppressive therapy. Some patients can be resistant to immunosuppressive therapy. Chorea is a rare manifestation that occurs in 1.2%-2% of SLE patients and can result from an immunologically mediated mechanism, antiphospholipid autoantibodies or ischemia. Herein we present the first case of pediatric-onset SLE diagnosed with central nervous system involvement and treated with Zipper method. The Zipper method is a new immunomodulation treatment. The clinical findings of the patient, which were resistant to corticosteroids and cyclophosphamide, resolved by this novel treatment.

Role of Serum IL-6 in Neuropsychiatric Systemic lupus Erythematosus

Objective

The present study was designed in order to elucidate the roles of serum interleukin 6 (IL‐6) in the pathogenesis in neuropsychiatric systemic lupus erythematosus (NPSLE).

Methods

Paired serum and cerebrospinal fluid (CSF) samples were obtained from 101 patients with SLE when they presented active neuropsychiatric manifestations (69 patients with diffuse psychiatric/neuropsychological syndromes [diffuse NPSLE] and 32 patients with neurologic syndromes or peripheral nervous system involvement [focal NPSLE]) and from 22 control patients without SLE with noninflammatory neurological diseases. The levels of albumin and IL‐6 in CSF and sera were measured by enzyme‐linked immunosorbent assay.

Results

Serum IL‐6 and CSF IL‐6 were elevated in NPSLE compared with non‐SLE controls. Among NPSLE, serum IL‐6 and CSF IL‐6 were significantly elevated in acute confusional state (ACS) compared with non‐ACS diffuse NPSLE (anxiety disorder, cognitive dysfunction, mood disorder, and psychosis) or focal NPSLE. Q albumin (CSF/serum albumin quotient) was also significantly higher in ACS than in the other two groups of NPSLE. Of note, serum IL‐6 (r = 0.2801, p = 0.0207), but not CSF IL‐6 (r = 0.1602, p = 0.1918), was significantly correlated with Q albumin in patients with diffuse NPSLE, including ACS and non‐ACS.

Conclusion

These results indicate that serum IL‐6 as well as CSF IL‐6 is involved in the pathogenesis of NPSLE. Moreover, it is suggested that serum IL‐6 might play a most important role in blood‐brain barrier breakdown in NPSLE.

Management of inflammatory neurologic and psychiatric manifestations of systemic lupus erythematosus: A systematic review

BACKGROUND

The neurological and psychiatric manifestations of systemic lupus erythematosus (NPSLE) are a heterogeneous group of conditions with variable clinical presentation and significant morbidity and mortality.

OBJECTIVES

Our aim was to comprehensively assess and present the evidence for treatments used in the management of inflammatory NPSLE.

METHODS

Medline, Embase, CINHAL and Cochrane CENTRAL were searched from 1990 to end of March 2019 using key words that related to NPSLE and treatment. Included studies comprised clinical trials, observational studies or case series with ≥5 patients and sufficient data related to treatment and outcome in NPSLE patients.

RESULTS

There were 7222 studies identified in the search, of which 90 were included in the review. There was a notable paucity of clinical trials, with only two randomised controlled trials and one pilot study. Treatment categories included corticosteroids (14 studies), cyclophosphamide (18 studies), synthetic DMARDs (7 studies), biologic therapies (14 studies), therapeutic plasma exchange (6 studies), intravenous immunoglobulin (2 studies), autologous stem cell transplant (3 studies), other therapies (8 studies), combination therapies (6 studies), studies with grouped outcome data (5 studies) and observational studies with therapy-specific associations (7 studies). Corticosteroids are accepted as first line treatment in NPSLE and there is low-moderate evidence supporting their benefit. Moderate evidence, based on consistent data in numerous studies and some trial data, supports the use of cyclophosphamide in the treatment of NPSLE. Limited data support some synthetic DMARDs such as mycophenolate, azathioprine and intrathecal methotrexate. In refractory disease, low-moderate evidence supports rituximab therapy and limited evidence supports benefit following autologous stem cell transplant. Regarding adjuvant treatments, limited evidence favours addition of plasma exchange, intravenous immunoglobulin and hydroxychloroquine. There exists very limited data for other therapies.

CONCLUSION

There are multiple therapeutic options for the management of inflammatory NPSLE including systemic, biologic and interventional therapies; however, currently there is a paucity of high-quality trial data to guide firm recommendations. In order to better understand the optimal treatment of NPSLE and its different subtypes, further well-designed clinical trials 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.

Serological comparison of systemic lupus erythematosus with neuropsychiatric lupus using synthetic nucleic acid antigens

Neuropsychiatric systemic lupus erythematosus is an autoimmune disorder characterized by an irregular exchange between the central nervous system and the immune system, leading to the outbreak of neurological conditions with possible disabling effects. Although neuropsychiatric systemic lupus erythematosus is the most common expression of lupus condition, it is still poorly understood. In this study, we focus on the development of an advantageous method based on the application of synthetic nucleic acids and protein-based antigen arrays in order to characterize autoreactive antibodies in neuropsychiatric systemic lupus erythematosus. We confirmed the benefits of using synthetic oligonucleotides such as assay reproducibility, elevated affinity and specificity to autoreactive antibodies. We also demonstrated presence of autoantibodies towards three particular synthetic double stranded antigens and verify similarity of antinuclear antibody patterns in ordinary lupus and neuropsychiatric systemic lupus erythematosus.

Blood-brain barrier leakage in systemic lupus erythematosus is associated with gray matter loss and cognitive impairment

OBJECTIVES

To examine the association between blood-brain barrier (BBB) integrity, brain volume and cognitive dysfunction in adult patients with systemic lupus erythematosus (SLE).

METHODS

A total of 65 ambulatory patients with SLE and 9 healthy controls underwent dynamic contrast-enhanced MRI scanning, for quantitative assessment of BBB permeability. Volumetric data were extracted using the VolBrain pipeline. Global cognitive function was evaluated using a screening battery consisting of tasks falling into five broad cognitive domains, and was compared between patients with normal versus extensive BBB leakage.

RESULTS

Patients with SLE had significantly higher levels of BBB leakage compared with controls (p=0.04). Extensive BBB leakage (affecting over >9% of brain volume) was identified only in patients with SLE (16/65; 24.6%), who also had smaller right and left cerebral grey matter volumes compared with controls (p=0.04). Extensive BBB leakage was associated with lower global cognitive scores (p=0.02), and with the presence of impairment on one or more cognitive tasks (p=0.01).

CONCLUSION

Our findings provide evidence for a link between extensive BBB leakage and changes in both brain structure and cognitive function in patients with SLE. Future studies should investigate the mechanisms underlying BBB-mediated cognitive impairment, validate the diagnostic utility of BBB imaging, and determine the potential of targeting the BBB as a therapeutic strategy in patients with SLE.

Advances in the diagnosis, pathogenesis and treatment of neuropsychiatric systemic lupus erythematosus

PURPOSE OF REVIEW

Diagnosing and treating neuropsychiatric systemic lupus erythematosus (NPSLE) remains challenging as the pathogenesis is still being debated. In this review, we discuss studies evaluating recent advances in diagnostic methods, pathogenic mediators and potential treatments.

RECENT FINDINGS

Screening tools used for neurodegenerative diseases were found to be both sensitive and moderately specific for cognitive dysfunction in NPSLE. Neuroimaging can be used to distinguish systemic lupus erythematosus (SLE) patients from healthy controls, but further refinement is needed to differentiate between lupus patients with and without neuropsychiatric manifestations. Elevated levels of specific molecules in the cerebrospinal fluid and/or serum, as well as the presence of certain autoantibodies, have been identified as potential biomarkers in attempts to facilitate a more accurate and objective diagnosis. Among such autoantibodies, anti-NR2 and anti-ribosomal P autoantibodies also have a pathogenic role, although newer studies demonstrate that blood-brain barrier damage may not always be required as previously believed. These and other observations, together with new evidence for disease attenuation after microglial modulation, suggest direct involvement of the central nervous system in NPSLE pathogenesis.

SUMMARY

Neuropsychiatric involvement of SLE includes a variety of symptoms that impact quality of life and patient prognosis. There have been recent advances in improving the diagnosis of NPSLE as well as in dissecting the underlying pathogenesis. The attenuation of neuropsychiatric disease in mouse models demonstrates the potential for targeted therapies, which are based on a clearer understanding of the pathogenesis of NPSLE. Further assessment of these treatments is required in NPSLE patients, as well as the potential use of neuroimaging to distinguish between SLE patients with or without neuropsychiatric manifestations.

Low C4 as a risk factor for severe neuropsychiatric flare in patients with systemic lupus erythematosus

OBJECTIVE

This study aimed to explore the risk factors for 'severe' neuropsychiatric (NP) flare in patients with systemic lupus erythematosus (SLE).

METHODS

This retrospective study comprised newly diagnosed 184 adult SLE patients who visited Hokkaido University Hospital between 2006 and 2017. In this study, severe NP flare was defined as the occurrence of at least one newly developed British Isles Lupus Assessment Group A score in the neurological domain. Overall severe NP flare-free survival was estimated by Kaplan-Meier analysis. Clinical and demographic profiles at SLE diagnosis were assessed as potential risk items in the adjusted multivariate Cox regression model.

RESULTS

The median follow-up period was 7.9 years (interquartile range (IQR) 4.6-12.3) years. A total of 28 (15.2%) patients had one or more severe NP flares during the observation period. The median time from patient enrolment date to severe NP flare occurrence was 3.1 years (IQR 0.9-6.3 year). The 2- and 10-year severe NP flare-free survival rates were 92.7% and 86.0%, respectively. Among the manifestations of severe NP flare, psychosis was the most frequent (19.1%). In the multivariate model, low serum levels of C4 (hazard ratio (HR) = 3.67, p = 0.013) and severe NP manifestations at SLE diagnosis (HR = 7.11, p < 0.001) emerged as independent risk factors for developing severe NP flare.

CONCLUSION

The first severe NP flare presented early in the course of SLE. Low C4 level and severe NP manifestations at SLE diagnosis could predict the development of severe NP flare.

Comparative proteomics analysis of plasma protein in patients with neuropsychiatric systemic lupus erythematosus

Background

The aim of this study was to evaluate serum biomarkers of systemic lupus erythematous (SLE) patients, with and without neuropsychiatric (NP) manifestation by high-resolution proteomic analysis.

Methods

SLE patients with NP (NPSLE, n=9), SLE patients without NP (non-NPSLE, n=9) and healthy controls (HC, n=9) were prospectively enrolled in this study, and their plasma samples were collected and pooled into 3 NPSLE, 3 non-NPSLE and 3 HC samples for discovery profile. The TMT-LC-MS/MS-based proteomics approach was used to identify the differential proteome among the three matched groups, and the data were analyzed by bioinformatics tools, including Gene Ontology (GO) categories, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, to explore canonical pathways and networks involved in the pathogenesis of NPSLE. To validation of differentially expressed proteomics results, four proteins were measured by ELISA.

Results

There were altogether 223 differentially expressed proteins in NPSLE groups compared with healthy controls (HC), of which 96 proteins increased while 127 proteins decreased. Compared with non-NPSLE, there were only 49 differentially expressed proteins in NPSLE groups, of which 37 proteins increased while 12 proteins decreased. The significantly changed pathway that those proteins are involved in was complement and coagulation cascades in NPSLE group compared with health controls. However, we didn't find significantly changed pathway between NPSLE group and non-NPSLE group. Five proteins were found significantly changed in all group-comparisons with consistent tendencies using Venn analysis, including Vitamin D binding protein (VDBP), C-reactive protein (CRP), KRT16, IGHV4-4 and CTRP3. Four proteins including CTRP3, VDBP, PAPPA and TRYP2 were selected to estimate the validity of the proteomics approach by ELISA. The expression levels of CTRP3 and TRYP2 were significantly changed in NPSLE patients compared with either HC or non-NPSLE patients.

Conclusions

Our research has successfully established serum protein profiles of NPSLE and non-NPSLE patients through TMT technology and screened out five proteins significantly changed in group-comparisons with consistent tendencies. The pathway of complement and coagulation cascades may participate in pathogenesis of NPSLE and non-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.

Galectin-9 as a biomarker for disease activity in systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by elevated interferon (IFN) signature genes. Galectin-9 (Gal-9) is a β-galactoside-binding lectin that is reportedly useful as a biomarker for IFN gene signatures. In a cross-sectional study of Japanese patients with recent-onset SLE, we aimed to determine whether raised serum Gal-9 levels were associated with the disease activity or organ damage seen in SLE patients.

Methods

The current study included 58 Japanese patients with SLE and 31 age-matched healthy individuals. Disease activity and organ damage were assessed using SLE Disease Activity 2000 (SLEDAI-2K) and Systemic Lupus International Collaborating Clinics (SLICC) damage index. Serum and cerebrospinal fluid (CSF) Gal-9 concentrations were quantified using ELISA. Correlation analyses between Gal-9 and clinical parameters including disease activity were performed.

Results

Serum levels of Gal-9 were significantly increased in patients with SLE compared with the control group (16.6 ng/ml, [interquartile range (IQR); 3.6–59.7] versus 4.74 ng/ml, [IQR; 3.0–9.5], p<0.0001). Gal-9 was significantly correlated with disease activity measures in the SLEDAI-2K. Serum Gal-9 levels were significantly greater in patients with SLE-related organ involvement (23.1 ng/ml, [IQR; 5.1–59.7] versus 12.5ng/ml, [IQR; 3.6–39.0], p = 0.013). Whereas there was no difference in serum levels of CXCL10 or M2BPGi between patients with and without SLE-related organ involvement. Serum levels of Gal-9 were significantly higher in SLE patients with active renal involvement determined by BILAG renal score (A-B) compared to those without active renal involvement (C-E). Whereas there was no significant difference in serum levels of Gal-9 between SLE patients with or without active other organ involvements (neurological or hematological) determined by BILAG score. SLE patients with detectable circulating IFN-α had raised serum Gal-9 levels. Levels of Gal-9 were significantly higher in the CSF from patients with recent-onset neuropsychiatric SLE (NPSLE) than in those from non-SLE controls (3.5 ng/ml, [IQR; 1.0–27.2] versus 1.2 ng/ml, [IQR; 0.9–2.1], p = 0.009).

Conclusions

Gal-9 could be a serologic marker of disease activity and organ involvement in SLE patients. Future studies evaluating the role of Gal-9 in the SLE phenotype may provide insights into SLE pathogenesis.

Neuropsychiatric events in systemic lupus erythematosus: a longitudinal analysis of outcomes in an international inception cohort using a multistate model approach

OBJECTIVES

Using a reversible multistate model, we prospectively examined neuropsychiatric (NP) events for attribution, outcome and association with health-related quality of life (HRQoL), in an international, inception cohort of systemic lupus erythematosus (SLE) patients.

METHODS

Annual assessments for 19 NP events attributed to SLE and non-SLE causes, physician determination of outcome and patient HRQoL (short-form (SF)-36 scores) were measured. Time-to-event analysis and multistate modelling examined the onset, recurrence and transition between NP states.

RESULTS

NP events occurred in 955/1827 (52.3%) patients and 592/1910 (31.0%) unique events were attributed to SLE. In the first 2 years of follow-up the relative risk (95% CI) for SLE NP events was 6.16 (4.96, 7.66) and non-SLE events was 4.66 (4.01, 5.43) compared with thereafter. Patients without SLE NP events at initial assessment had a 74% probability of being event free at 10 years. For non-SLE NP events the estimate was 48%. The majority of NP events resolved over 10 years but mortality was higher in patients with NP events attributed to SLE (16%) versus patients with no NPSLE events (6%) while the rate was comparable in patients with non-SLE NP events (7%) compared with patients with no non-SLE events (6%). Patients with NP events had lower SF-36 summary scores compared with those without NP events and resolved NP states (p<0.001).

CONCLUSIONS

NP events occur most frequently around the diagnosis of SLE. Although the majority of events resolve they are associated with reduced HRQoL and excess mortality. Multistate modelling is well suited for the assessment of NP events in SLE.

Broad Learning Enhanced 1H-MRS for Early Diagnosis of Neuropsychiatric Systemic Lupus Erythematosus

In this paper, we explore the potential of using the multivoxel proton magnetic resonance spectroscopy (¹H-MRS) to diagnose neuropsychiatric systemic lupus erythematosus (NPSLE) with the assistance of a support vector machine broad learning system (BL-SVM). We retrospectively analysed 23 confirmed patients and 16 healthy controls, who underwent a 3.0 T magnetic resonance imaging (MRI) sequence with multivoxel ¹H-MRS in our hospitals. One hundred and seventeen metabolic features were extracted from the multivoxel ¹H-MRS image. Thirty-three metabolic features selected by the Mann-Whitney U test were considered to have a statistically significant difference (p < 0.05). However, the best accuracy achieved by conventional statistical methods using these 33 metabolic features was only 77%. We turned to develop a support vector machine broad learning system (BL-SVM) to quantitatively analyse the metabolic features from ¹H-MRS. Although not all the individual features manifested statistics significantly, the BL-SVM could still learn to distinguish the NPSLE from the healthy controls. The area under the receiver operating characteristic curve (AUC), the sensitivity, and the specificity of our BL-SVM in predicting NPSLE were 95%, 95.8%, and 93%, respectively, by 3-fold cross-validation. We consequently conclude that the proposed system effectively and efficiently working on limited and noisy samples may brighten a noinvasive in vivo instrument for early diagnosis of NPSLE.

Structural and functional brain connectomes in patients with systemic lupus erythematosus

BACKGROUND AND PURPOSE

Systemic lupus erythematosus (SLE) is an immune-mediated disease that may affect the nervous system. We explored the topographical organization of structural and functional brain connectivity in patients with SLE and its correlation with neuropsychiatric (NP) involvement and autoantibody profiles.

METHODS

Graph theoretical analysis was applied to diffusion tensor magnetic resonance imaging (MRI) and resting-state functional MRI data from 32 patients with SLE and 32 age- and sex-matched healthy controls. Structural and functional connectivity matrices between 116 cortical/subcortical brain regions were estimated using a bivariate correlation analysis, and global and nodal network metrics were calculated.

RESULTS

Structural, but not functional, global network properties (strength, transitivity, global efficiency and path length) were abnormal in patients with SLE versus controls (P < 0.0001), especially in patients with anti-double-stranded DNA (ADNA) autoantibodies (P = 0.03). No difference was found according to NP involvement or anti-phospholipid autoantibody status. Patients with SLE and controls shared identical structural hubs and the majority of functional hubs. In patients with SLE, all structural hubs showed reduced strength and clustering coefficient compared with controls (P from 0.001 to <0.0001), especially in patients with ADNA autoantibodies. Only a few differences in functional hub properties were found between patients with SLE and controls. Structural and functional hub measures did not differ according to NP involvement or anti-phospholipid autoantibody status. Significant correlations were found between clinical, MRI and network measures (r from -0.56 to 0.60, P from 0.0003 to 0.05).

CONCLUSIONS

Abnormalities of global and nodal structural connectivity occur in patients with SLE, especially with ADNA autoantibodies, with a diffuse disruption of structural integrity. Functional network integrity may contribute to preserve clinical functions.

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.

From Systemic Inflammation to Neuroinflammation: The Case of Neurolupus

It took decades to arrive at the general consensus dismissing the notion that the immune system is independent of the central nervous system. In the case of uncontrolled systemic inflammation, the relationship between the two systems is thrown off balance and results in cognitive and emotional impairment. It is specifically true for autoimmune pathologies where the central nervous system is affected as a result of systemic inflammation. Along with boosting circulating cytokine levels, systemic inflammation can lead to aberrant brain-resident immune cell activation, leakage of the blood⁻brain barrier, and the production of circulating antibodies that cross-react with brain antigens. One of the most disabling autoimmune pathologies known to have an effect on the central nervous system secondary to the systemic disease is systemic lupus erythematosus. Its neuropsychiatric expression has been extensively studied in lupus-like disease murine models that develop an autoimmunity-associated behavioral syndrome. These models are very useful for studying how the peripheral immune system and systemic inflammation can influence brain functions. In this review, we summarize the experimental data reported on murine models developing autoimmune diseases and systemic inflammation, and we explore the underlying mechanisms explaining how systemic inflammation can result in behavioral deficits, with a special focus on in vivo neuroimaging techniques.