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

Impact of belimumab therapy on the quality of life in patients with systemic lupus erythematosus: A cohort study

Systemic lupus erythematosus (SLE) is a chronic and extremely disabling connective-tissue autoimmune disease with a tremendous impact on the quality of life (QoL). Belimumab, a B-lymphocyte-stimulator-specific inhibitor, is the first biologic drug approved as add-on therapy in patients with active, refractory auto-antibody-positive SLE.The impact of belimumab on the QoL of SLE patients was evaluated using a generic questionnaire short-form health survey 36 (SF-36) and the disease-specific questionnaire SLE-specific quality of life (SLEQoL).The Italian version of the SLEQoL and the SF-36 were administered to 46 SLE patients before and after 6 months of belimumab therapy. The control population consisted of 40 age-matched healthy individuals. The questionnaires were completed before and after belimumab treatment and the results were compared using the Wilcoxon signed-rank test. In addition, data from healthy controls and SLE patients were compared using the Mann-Whitney test. Dichotomous variables were compared using Fisher's exact test.For SLE patients, the addition of belimumab to their therapeutic regimen significantly improved their health-related QoL (HRQoL), according to the results of the SF-36 and SLEQoL. The comparison of the data obtained before and after belimumab treatment showed a decrease in all six SLEQoL domains and an increase in all eight SF-36 domains. Moreover, treatment led to a reduction in the median prednisone dose, to 0 mg/day (IQR 0-4.5 mg/day). Before belimumab therapy, SLE patients had a worse HRQoL than the control group, based on both questionnaires, but after belimumab treatment the outcome scores between SLE patients and controls were similar, suggesting that belimumab therapy resulted in a strong improvement in HRQoL. These findings were supported by a decrease in the SELENA-SLEDAI score, a measure of disease activity.In addition to clinical remission and low disease activity, the goals of an innovative therapeutic strategy for SLE should include the attainment of a good HRQoL. Our study demonstrates that the combined use of the SF-36 and SLEQoL questionnaires can provide clinicians with a better understanding of the HRQoL of SLE patients.

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

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

NMDA Receptors in Health and Diseases: New Roles and Signaling Pathways-Anti-N-Methyl-D-Aspartate Receptor (NMDAR) Autoantibodies as Potential Biomarkers of Fatigue in Patients with Rheumatic Diseases

Fatigue is a widespread and complex symptom with motor and cognitive components; it is diagnosed predominantly by questionnaire. We recently published a correlation between anti-N-methyl-D-aspartate receptor (NMDAR) antibodies and fatigue in patients with SLE (systemic lupus erythematosus). In the present study, we examined whether this association also applies to patients with other rheumatic diseases. Serum samples of 88 patients with different rheumatic diseases were analyzed for the presence of anti-NR2 antibodies and Neurofilament light chain (NfL) protein. The severity of fatigue was determined according to the FSMC questionnaire (Fatigue Scale for Motor and Cognitive Functions) and correlated with the circulating antibody titer and NfL level accordingly. Positive titers of anti-NR2 antibodies were detected in patients with both autoimmune and non-autoimmune rheumatic diseases. These patients suffer predominantly from severe fatigue. The circulating NfL level did not correlate with the anti-NR2 titer and the fatigue severity in all patient groups. The association of severe fatigue with circulating anti-NR2 antibodies in patients with rheumatic diseases, independently from the main disease, suggests an individual role of these autoantibodies in fatigue pathophysiology. Thus, the detection of these autoantibodies might be a helpful diagnostic tool in rheumatic patients with fatigue.

Brain mapping inflammatory-arthritis-related fatigue in the pursuit of novel therapeutics

Despite developments in pharmacological treatments, chronic fatigue is an unresolved issue for most people with inflammatory arthritis that severely disrupts their personal and working lives. Fatigue in these patients is not strongly linked with peripheral disease activity but is associated with CNS-derived symptoms such as chronic pain, sleep disturbance, and depression. Therefore, a neurobiological basis should be considered when pursuing novel fatigue-specific therapeutics. In this Review, we focus on clinical imaging biomarkers that map candidate brain regions and are crucial in fatigue pathophysiology. We then evaluate neuromodulation techniques that could affect these candidate brain regions and are potential treatment strategies for fatigue in patients with inflammatory arthritis. We delineate work that is still required for neuroimaging and neuromodulation to eventually become part of a clinical pathway to treat and manage fatigue.

Impact of Belimumab on Patient-Reported Outcomes in Systemic Lupus Erythematosus: Insights from Clinical Trials and Real-World Evidence

Systemic lupus erythematosus (SLE) is a chronic, autoimmune disease, characterised by a relapsing-remitting pattern of inflammatory activity, with each relapse contributing to irreversible end-organ damage with detrimental effects on patients' course, adding up to morbidity burden and shortening life-length. Along with several other demographic, socioeconomic, and life-style factors, high inflammatory activity and accrued organ damage have been coupled with adverse health-related quality of life (HRQoL) within physical, mental, and psychosocial aspects. The management of SLE has improved substantially during the last decades, owing to a technological explosion that has advanced drug development towards more targeted options. Being the first drug to be approved for SLE in more than half a century and the first in history biological agent for SLE, the introduction in 2011 of the monoclonal antibody belimumab that specifically binds to the soluble counterpart of B cell activating factor (BAFF) was a breakthrough in SLE drug development. The efficacy and favourable safety profile of belimumab has been demonstrated across several clinical trials and observational studies. Herein, we reviewed the literature and provide a summary on the effects of belimumab on SLE patients' HRQoL based on 23 studies. Belimumab has been shown to induce clinically important improvements in physical aspects of HRQoL and in fatigue, the latter being a common and major complaint within the SLE population. People with SLE overall benefit more from belimumab within physical compared with mental aspects of HRQoL. However, despite improvements of clinical and immunological features upon therapy with belimumab, HRQoL perception remains unsatisfactory for a substantial percentage of the patients. Finally, our review made apparent an urgent need for optimisation of the use of patient-reported outcome measures, both in research and clinical practice.

Omega-3 fatty acids: Current insights into mechanisms of action in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is one of the autoimmune diseases characterized by the lack of self-tolerance and the formation of immune complexes and nuclear autoantigens resulting in inflammation in multiple organs. Nowadays, the major aim of SLE therapy is the control of disease activity. However, the biological heterogeneity between patients and the absence of safe and specific targeted treatments complicate the lupus management. Therefore, the potential prophylactic effects of natural therapy considering the potential side effects of classical pharmacology, also the role of diet therapy in decreasing co-morbidities and improving quality of life in SLE patients could be a promising approach to SLE disease. Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) are one of the agents that are considered for their preventive and therapeutic properties in disease activity of SLE and the related complications. The intake of omega-3 PUFAs likely has a direct relationship with improvements in inflammatory, cardiovascular, depressive, and neuromotor symptoms of the patients. The current review summarizes clinical and preclinical studies with comprehensive insights into the mechanisms of action of omega-3 fatty acids (omega-3 FAs) in Systemic Lupus Erythematosus to provide an update on the negative and positive aspects of the intake of omega-3 FAs in SLE patients.

Do biological agents improve health-related quality of life in patients with systemic lupus erythematosus? Results from a systematic search of the literature

Despite an unprecedented rise in the number of biological therapies developed for systemic lupus erythematosus (SLE) during the last decades, most randomised clinical trials (RCTs) have failed to reach their primary efficacy endpoint. These endpoints mainly constitute composite outcomes that encompass disease activity indices derived from clinician-reported and laboratory data and do not necessarily reflect the patient perspective, as symptoms that represent major concerns to patients, such as fatigue, are seldom part of the evaluation. To overcome this limitation, patient-reported outcomes (PROs) constitute useful tools for evaluating the effect of an intervention on facets that are particularly relevant for the patients. In the present review, we performed a systematic literature search aiming to examine the effect of biological therapies on SLE patients' health-related quality of life (HRQoL) and fatigue in RCT and real-life settings. We summarised results concerning 14 different biological agents, the majority of which targeting B cells or type I interferons, and discuss strategies that have been used to analyse HRQoL data, putting emphasis on minimal clinically important differences and the potential use of PROs as distinct targets in treat-to-target approaches. Lastly, we discuss differences between generic and disease-specific PRO measures and highlight the need of using a combination thereof aiming to capture the patient perspective in a comprehensive manner.

Structural and Functional Characterization of Gray Matter Alterations in Female Patients With Neuropsychiatric Systemic Lupus

Objective

To investigate morphological and functional alterations within gray matter (GM) in female patients with neuropsychiatric systemic lupus (NPSLE) and to explore their clinical significance.

Methods

54 female patients with SLE (30 NPSLE and 24 non-NPSLE) and 32 matched healthy controls were recruited. All subjects received a quantitative MRI scan (FLAIR, 3DT1, resting-state functional MRI). GM volume (GMV), fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree of centrality (DC) were obtained. Between-group comparison, clinical correlation, and discrimination of NPSLE from non-NPSLE were achieved by voxel-based analysis, cerebellar seed-based functional connectivity analysis, regression analysis, and support vector machine (SVM), respectively.

Results

Patients with NPSLE showed overt subcortical GM atrophy without significantly abnormal brain functions in the same region compared with controls. The dysfunction within the left superior temporal gyri (L-STG) was found precede the GM volumetric loss. The function of the nodes in default mode network (DMN) and salience network (SN) were weakened in NPSLE patients compared to controls. The function of the cerebellar posterior lobes was significantly activated in non-NPSLE patients but attenuated along with GM atrophy and presented higher connectivity with L-STG and DMN in NPSLE patients, while the variation of the functional activities in the sensorimotor network (SMN) was the opposite. These structural and functional alterations were mainly correlated with disease burden and anti-phospholipid antibodies (aPLs) (r ranges from -1.53 to 1.29). The ReHos in the bilateral cerebellar posterior lobes showed high discriminative power in identifying patients with NPSLE with accuracy of 87%.

Conclusion

Patients with NPSLE exhibit both structural and functional alterations in the GM of the brain, which especially involved the deep GM, the cognitive, and sensorimotor regions, reflecting a reorganization to compensate for the disease damage to the brain which was attenuated along with pathologic burden and cerebral vascular risk factors. The GM within the left temporal lobe may be one of the direct targets of lupus-related inflammatory attack. The function of the cerebellar posterior lobes might play an essential role in compensating for cortical functional disturbances and may contribute to identifying patients with suspected NPSLE in clinical practice.

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.

Different cerebral functional segregation in Sjogren's syndrome with or without systemic lupus erythematosus revealed by amplitude of low-frequency fluctuation

BACKGROUND

Sjögren's syndrome (SjS) associated with systemic lupus erythematosus (SjS-SLE) was considered a standalone but often-overlooked entity.

PURPOSE

To assess altered spontaneous brain activity in SjS-SLE and SjS using amplitude of low-frequency fluctuation (ALFF).

MATERIAL AND METHODS

Sixteen patients with SjS-SLE, 17 patients with SjS, and 17 matched controls underwent neuropsychological tests and subsequent resting-state functional magnetic resonance imaging (fMRI) examinations. The ALFF value was calculated based on blood oxygen level dependent (BOLD) fMRI. Statistical parametric mapping was utilized to analyze between-group differences and multiple comparison was corrected with Analysis of Functional NeuroImages 3dClustSim. Then, the ALFFs of brain regions with significant differences among the three groups were correlated to corresponding clinical and neuropsychological variables by Pearson correlation.

RESULTS

ALFF differences in the bilateral precuneus/posterior cingulate cortex (PCC), right parahippocampal gyrus/caudate/insula, and left insula were found among the three groups. Both SjS-SLE and SjS displayed decreased ALFF in the right parahippocampal gyrus, right insula, and left insula than HC. Moreover, SjS-SLE showed wider decreased ALFF in the bilateral precuneus and right caudate, while the SjS group exhibited increased ALFF in the bilateral PCC. Additionally, patients with SjS-SLE exhibited lower ALFF values in the bilateral PCC and precuneus than SjS. Moreover, ALFF values in the right parahippocampal gyrus and PCC were negatively correlated to fatigue score and disease duration, respectively, in SjS-SLE.

CONCLUSION

SjS-SLE and SjS exhibited common and different alteration of cerebral functional segregation revealed by AlFF analysis. This result appeared to indicate that SjS-SLE might be different from SjS with a neuroimaging standpoint.

Current Status of the Evaluation and Management of Lupus Patients and Future Prospects

The vastly diverse nature of systemic lupus erythematosus (SLE) poses great challenges to clinicians and patients, as well as to research and drug development efforts. Precise management of lupus patients would be advanced by the ability to identify specific abnormalities operative in individual patients at the time of encounter with the clinician. Advances in new technologies and bioinformatics have greatly improved the understanding of the pathophysiology of SLE. Recent research has focused on the discovery and classification of sensitive and specific markers that could aid early accurate diagnosis, better monitoring of disease and identification of appropriate therapy choices based on specific dysregulated molecular pathways. Here, we summarize some of the advances and discuss the challenges in moving toward precise patient-centric management modalities in SLE.

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.

N-methyl-D-aspartate Receptor Antibody and White Matter Deficits in Schizophrenia Treatment-Resistance

Insufficient or lack of response to antipsychotic medications in some patients with schizophrenia is a major challenge in psychiatry, but the underlying mechanisms remain unclear. Two seemingly unrelated observations, cerebral white matter and N-methyl-D-aspartate receptor (NMDAR) hypofunction, have been linked to treatment-resistant schizophrenia (TRS). As NMDARs are critical to axonal myelination and signal transduction, we hypothesized that NMDAR antibody (Ab), when present in schizophrenia, may impair NMDAR functions and white matter microstructures, contributing to TRS. In this study, 50 patients with TRS, 45 patients with nontreatment-resistant schizophrenia (NTRS), 53 patients with schizophrenia at treatment initiation schizophrenia (TIS), and 90 healthy controls were enrolled. Serum NMDAR Ab levels and white matter diffusion tensor imaging fractional anisotropy (FA) were assessed. The white matter specificity effects by NMDAR Ab were assessed by comparing with effects on cortical and subcortical gray matter. Serum NMDAR Ab levels of the TRS were significantly higher than those of the NTRS (P = .035). In patients with TRS, higher NMDAR Ab levels were significantly associated with reduced whole-brain average FA (r = -.37; P = .026), with the strongest effect at the genu of corpus callosum (r = -.50; P = .0021, significant after correction for multiple comparisons). Conversely, there was no significant correlation between whole-brain or regional cortical thickness or any subcortical gray matter structural volume and NMDAR Ab levels in TRS. Our finding highlights a potential NMDAR mechanism on white matter microstructure impairment in schizophrenia that may contribute to their treatment resistance to antipsychotic medications.

Twelve-Week Internet-Based Individualized Exercise Program in Adults With Systemic Lupus Erythematosus: Protocol for a Randomized Controlled Trial

Background

Systemic lupus erythematosus is a systemic autoimmune disease, which is associated with high cardiovascular risk, a predisposition to metabolic disorders, muscle wasting, and fatigue. Exercise therapy has become an important part of the long-term treatment of comorbidities in systemic lupus erythematosus. Exercise can lead to various benefits in patients with systemic lupus erythematosus such as increased aerobic capacity and exercise tolerance, resulting in an increased quality of life, decreased depression, and decreased fatigue. At the moment, no evidence-based treatment guidelines that recommend exercise for patients with systemic lupus erythematosus exist. Also, the efficacy of different training programs requires further investigation.

Objective

This study focuses on the feasibility, efficacy, and safety of an internet-based exercise program in patients with systemic lupus erythematosus. Furthermore, we investigate the feasibility and efficiency of anaerobic training compared to aerobic training.

Methods

Overall, patients with systemic lupus erythematosus from the Division of Nephrology, Rheumatology, and Immunology outpatient clinic of the University Medical Center Mainz who are clinically stable status are included and randomized in an aerobic exercise group (n=10), anaerobic exercise group (n=10), or treatment as usual group (n=10). After completing initial clinical testing and physical fitness tests, patients undergo supervised 12-week online exercise programs, receiving weekly individualized training plans adapted to their physical performance. The primary outcome is change in physical fitness (VO2 peak) after 12 weeks compared to baseline. Secondary outcomes are disease activity measured via laboratory results (complement, autoantibodies) and questionnaires, as well as changes in muscle mass (anaerobic exercise group), results of the Chair-Stand test, and measurements of circulating cell-free DNA and extracellular vesicles.

Results

The study was registered in May 2019. Enrollment began in May 2019. Of 40 patients who were initially screened, 30 patients fulfilled the inclusion criteria and were included in the study; 1 participant withdrew prior to the start of the exercise program. Among the 25 patients who completed the study, no serious adverse events have been reported; 3 participants withdrew during the program (due to frequent colds, n=1; Crohn relapse, n=1; physical strain, n=1), and 1 participant has not yet completed the program. Data analysis is ongoing, and results are expected to be submitted for publication in January 2021.

Conclusions

We expect the online exercise intervention to be a feasible and efficient tool to provide regular individualized exercise for patients with systemic lupus erythematosus.

Trial Registration

ClinicalTrials.gov NCT03942718; http://clinicaltrials.gov/ct2/show/NCT03942718.

International Registered Report Identifier (IRRID)

DERR1-10.2196/18291

Systemic Lupus Erythematosus (SLE) Therapy: The Old and the New

Despite recent improvements in the treatment of systemic lupus erythematosus (SLE), disease activity, comorbidities and drug toxicity significantly contribute to the risk of progressive irreversible damage accrual and increased mortality in patients with this chronic disease. Moreover, even lupus patients in remission often report residual symptoms, such as fatigue, which have a considerable impact on their health-related quality of life. In recent decades, SLE treatment has moved from the use of hydroxychloroquine, systemic glucocorticosteroids and conventional immunosuppressive drugs to biologic agents, of which belimumab is the first and only biologic agent approved for the treatment for SLE to date. Novel therapies targeting interferons, cytokines and their receptors, intracellular signals, plasma cells, T lymphocytes and co-stimulatory molecules are being evaluated. In the context of a holistic approach, growing evidence is emerging of the importance of correct lifestyle habits in the management of lupus manifestations and comorbidities. The aim of this paper is to provide an overview of current pharmacological and non-pharmacological treatment options and emerging therapies in SLE.