Aptamer-Based Screen of Neuropsychiatric Lupus Cerebrospinal Fluid Reveals Potential Biomarkers That Overlap With the Choroid Plexus Transcriptome.

OBJECTIVE: As no gold-standard diagnostic test exists for neuropsychiatric systemic lupus erythematosus (NPSLE), we undertook this study to execute a broad screen of NPSLE cerebrospinal fluid (CSF) using an aptamer-based platform. METHODS: CSF was obtained from NPSLE patients and subjected to proteomic assay using the aptamer-based screen. Potential biomarkers were identified and validated in independent NPSLE cohorts in comparison to other neurologic diseases. RESULTS: Forty proteins out of the 1,129 screened were found to be elevated in NPSLE CSF. Based on enzyme-linked immunosorbent assay validation, CSF levels of angiostatin, α2-macroglobulin, DAN, fibronectin, hepatocellular carcinoma clone 1, IgM, lipocalin 2, macrophage colony-stimulating factor (M-CSF), and serine protease inhibitor G1 were significantly elevated in a predominantly White NPSLE cohort (n = 24), compared to patients with other neurologic diseases (n = 54), with CSF IgM (area under the curve [AUC] 0.95) and M-CSF (AUC 0.91) being the most discriminatory proteins. In a second Hong Kong-based NPSLE cohort, CSF IgM (AUC 0.78) and lipocalin 2 (AUC 0.85) were the most discriminatory proteins. Several CSF proteins exhibited high diagnostic specificity for NPSLE in both cohorts. Elevated CSF complement C3 was associated with an acute confusional state. Eleven molecules elevated in NPSLE CSF exhibited concordant elevation in the choroid plexus, suggesting shared origins. CONCLUSION: Lipocalin 2, M-CSF, IgM, and complement C3 emerge as promising CSF biomarkers of NPSLE with diagnostic potential.

CXCL13 Neutralization Attenuates Neuropsychiatric Manifestations in Lupus-Prone Mice.

Neuropsychiatric lupus (NPSLE), the nervous system presentation of systemic lupus erythematosus (SLE), remains challenging to treat due to its unclear pathogenesis and lack of available targeted therapies. A potential contributor to disease progression is brain tertiary lymphoid structures (TLS); these ectopic lymphoid follicles that can develop tissue-targeted antibodies have recently been described in the MRL/lpr lupus mouse strain, a classic model for studying NPSLE. The brains of MRL/lpr mice show a significant increase of CXCL13, an important chemokine in lymphoid follicle formation and retention that may also play a role in the disease progression of NPSLE. The aim of the present study was to inhibit CXCL13 and examine the effect of this intervention on lymphoid formation and the development of neurobehavioral manifestations in lupus mice. Female MRL/lpr mice were injected with an anti-CXCL13 antibody, an IgG1 isotype-matched antibody, or PBS either three times a week for 12 weeks intraperitoneally (IP) starting at 6-8 weeks of age, or continuously intracerebroventricularly (ICV) with an osmotic pump over a two-week period starting at 15 weeks of age. Cognitive dysfunction and depression-like behavior were assessed at the end of treatment. When treatment was delivered IP, anti-CXCL13 treated mice showed significant improvement in cognitive function when compared to control treated mice. Depression-like behavior was attenuated as well. Furthermore, mice that received anti-CXCL13 by the ICV route showed similar beneficial effects. However, the extent of lymphocyte infiltration into the brain and the general composition of the aggregates were not substantively changed by anti-CXCL13 irrespective of the mode of administration. Nevertheless, analysis of brain gene expression in anti-CXCL13 treated mice showed significant differences in key immunological and neuro-inflammatory pathways that most likely explained the improvement in the behavioral phenotype. Our results indicate that CXCL13 affects the behavioral manifestations in the MRL/lpr strain and is important to the pathogenesis of murine NPSLE, suggesting it as a potential therapeutic target.

COVID-19 Infection Among Healthcare Workers: Serological Findings Supporting Routine Testing.

A growing body of evidence demonstrates that asymptomatic and pre-symptomatic transmission of SARS-CoV-2 is a major contributor to the COVID-19 pandemic. Frontline healthcare workers in COVID-19 hotspots have faced numerous challenges, including shortages of personal protective equipment (PPE) and difficulties acquiring clinical testing. The magnitude of the exposure of healthcare workers and the potential for asymptomatic transmission makes it critical to understand the incidence of infection in this population. To determine the prevalence of asymptomatic SARS-CoV-2 infection amongst healthcare workers, we studied frontline staff working in the Montefiore Health System in New York City. All participants were asymptomatic at the time of testing and were tested by RT-qPCR and for anti-SARS-CoV-2 antibodies. The medical, occupational, and COVID-19 exposure histories of participants were recorded via questionnaires. Of the 98 asymptomatic healthcare workers tested, 19 (19.4%) tested positive by RT-qPCR and/or ELISA. Within this group, four (4.1%) were RT-qPCR positive, and four (4.1%) were PCR and IgG positive. Notably, an additional 11 (11.2%) individuals were IgG positive without a positive PCR. Two PCR positive individuals subsequently developed COVID-19 symptoms, while all others remained asymptomatic at 2-week follow-up. These results indicate that there is considerable asymptomatic infection with SARS-CoV-2 within the healthcare workforce, despite current mitigation policies. Furthermore, presuming that asymptomatic staff are not carrying SARS-CoV-2 is inconsistent with our results, and this could result in amplified transmission within healthcare settings. Consequently, aggressive testing regiments, such as testing frontline healthcare workers on a regular, multi-modal basis, may be required to prevent further spread within the workforce and to patients.

Managing a Specialty Service During the COVID-19 Crisis: Lessons From a New York City Health System.

The COVID-19 pandemic has stretched health care resources to a point of crisis throughout the world. To answer the call for care, health care workers in a diverse range of specialties are being retasked to care for patients with COVID-19. Consequently, specialty services have had to adapt to decreased staff available for coverage coupled with a need to remain available for specialty-specific emergencies, which now require a dynamic definition. In this Invited Commentary, the authors describe their experiences and share lessons learned regarding triage of patients, staff safety, workforce management, and the psychological impact as they have adapted to a new reality in the Department of Neurosurgery at Montefiore Medical Center, a COVID-19 hot spot in New York City.

A Novel Microglia-Specific Transcriptional Signature Correlates With Behavioral Deficits in Neuropsychiatric Lupus.

Neuropsychiatric symptoms of systemic lupus erythematosus (NP-SLE) affect over one-half of SLE patients, yet underlying mechanisms remain largely unknown. We demonstrate that SLE-prone mice (CReCOM) develop NP-SLE, including behavioral deficits prior to systemic autoimmunity, reduced brain volumes, decreased vascular integrity, and brain-infiltrating leukocytes. NP-SLE microglia exhibit numerical expansion, increased synaptic uptake, and a more metabolically active phenotype. Microglia from multiple SLE-prone models express a "NP-SLE signature" unrelated to type I interferon. Rather, the signature is associated with lipid metabolism, scavenger receptor activity and downregulation of inflammatory and chemotaxis processes, suggesting a more regulatory, anti-inflammatory profile. NP-SLE microglia also express genes associated with disease-associated microglia (DAM), a subset of microglia thought to be instrumental in neurodegenerative diseases. Further, expression of "NP-SLE" and "DAM" signatures correlate with the severity of behavioral deficits in young SLE-prone mice prior to overt systemic disease. Our data are the first to demonstrate the predictive value of our newly identified microglia-specific "NP-SLE" and "DAM" signatures as a surrogate for NP-SLE clinical outcomes and suggests that microglia-intrinsic defects precede contributions from systemic SLE for neuropsychiatric manifestations.

Tertiary lymphoid structures in the choroid plexus in neuropsychiatric lupus.

The central nervous system manifestations of systemic lupus erythematosus (SLE) remain poorly understood. Given the well-defined role of autoantibodies in other lupus manifestations, extensive work has gone into the identification of neuropathic autoantibodies. However, attempts to translate these findings to patients with SLE have yielded mixed results. We used the MRL/MpJ-Faslpr/lpr mouse, a well-established, spontaneous model of SLE, to establish the immune effectors responsible for brain disease. Transcriptomic analysis of the MRL/MpJ-Faslpr/lpr choroid plexus revealed an expression signature driving tertiary lymphoid structure formation, including chemokines related to stromal reorganization and lymphocyte compartmentalization. Additionally, transcriptional profiles indicated various stages of lymphocyte activation and germinal center formation. The extensive choroid plexus infiltrate present in MRL/MpJ-Faslpr/lpr mice with overt neurobehavioral deficits included locally proliferating B and T cells, intercellular interactions between lymphocytes and antigen-presenting cells, as well as evidence for in situ somatic hypermutation and class switch recombination. Furthermore, the choroid plexus was a site for trafficking lymphocytes into the brain. Finally, histological evaluation in human lupus patients with neuropsychiatric manifestations revealed increased leukocyte migration through the choroid plexus. These studies identify a potential new pathway underlying neuropsychiatric lupus and support tertiary lymphoid structure formation in the choroid plexus as a novel mechanism of brain-immune interfacing.

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.

Mechanisms of neuropsychiatric lupus: The relative roles of the blood-cerebrospinal fluid barrier versus blood-brain barrier.

The pathogenesis of neuropsychiatric lupus (NPSLE) is believed to include the entry of circulating neuropathic antibodies to the brain via a pathologically permeable blood-brain barrier (BBB). Nevertheless, direct evidence of BBB pathology or mechanisms underlying BBB dysfunction is missing. Here, we examined BBB integrity in an established NPSLE mouse model (MRL/faslpr/lpr). Surprisingly, challenging the barrier with various exogenous tracers demonstrated insignificant changes in BBB permeability. Furthermore, electron microscopy showed no ultrastructure changes supporting hyper-permeability. However, we found that abnormal function of the blood-cerebrospinal fluid barrier (BCSFB) in the choroid plexus underlies brain exposure to neuropathic antibodies. Considerable intrathecal lymphocyte infiltration likely occurs through the BCSFB, accompanied by epithelial hyper-permeability to antibodies. Our results challenge the commonly held view of BBB disruption in NPSLE, supporting a shift in focus to BCSFB dysfunction as a causative factor in the disease.

The blood brain barrier and neuropsychiatric lupus: new perspectives in light of advances in understanding the neuroimmune interface.

Experts have previously postulated a linkage between lupus associated vascular pathology and abnormal brain barriers in the immunopathogenesis of neuropsychiatric lupus. Nevertheless, there are some discrepancies between the experimental evidence, or its interpretation, and the working hypotheses prevalent in this field; specifically, that a primary contributor to neuropsychiatric disease in lupus is permeabilization of the blood brain barrier. In this commonly held view, any contribution of the other known brain barriers, including the blood-cerebrospinal fluid and meningeal barriers, is mostly excluded from the discussion. In this review we will shed light on some of the blood brain barrier hypotheses and try to trace their roots. In addition, we will suggest new research directions to allow for confirmation of alternative interpretations of the experimental evidence linking the pathology of intra-cerebral vasculature to the pathogenesis of neuropsychiatric lupus.

The role of B cells and autoantibodies in neuropsychiatric lupus.

The central nervous system manifestations of SLE (neuropsychiatric lupus, NPSLE) occur frequently, though are often difficult to diagnose and treat. Symptoms of NPSLE can be quite diverse, including chronic cognitive and emotional manifestations, as well as acute presentations, such as stroke and seizures. Although the pathogenesis of NPSLE has yet to be well characterized, B-cell mediated damage is believed to be an important contributor. B-cells and autoantibodies may traverse the blood brain barrier promoting an inflammatory environment consisting of glia activation, neurodegeneration, and consequent averse behavioral outcomes. This review will evaluate the various suggested roles of B-cells and autoantibodies in NPSLE, as well as therapeutic modalities targeting these pathogenic mediators.

Neuropsychiatric systemic lupus erythematosus persists despite attenuation of systemic disease in MRL/lpr mice.

BACKGROUND: Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease marked by both B and T cell hyperactivity which commonly affects the joints, skin, kidneys, and brain. Neuropsychiatric disease affects about 40 % of SLE patients, most frequently manifesting as depression, memory deficits, and general cognitive decline. One important and yet unresolved question is whether neuropsychiatric SLE (NPSLE) is a complication of systemic autoimmunity or whether it is primarily driven by brain-intrinsic factors. METHODS: To dissect the relative contributions of the central nervous system from those of the hematopoietic compartment, we generated bone marrow chimeras between healthy control (MRL/+) and lupus-prone MRL/Tnfrsf6 (lpr/lpr) mice (MRL/+ → MRL/lpr), as well as control chimeras. After bone marrow reconstitution, mice underwent extensive behavioral testing, analysis of brain tissue, and histological assessment. RESULTS: Despite transfer of healthy MRL/+ bone marrow and marked attenuation of systemic disease, we found that MRL/+ → MRL/lpr mice had a behavioral phenotype consisting of depressive-like behavior and visuospatial memory deficits, comparable to MRL/lpr → MRL/lpr control transplanted mice and the behavioral profile previously established in MRL/lpr mice. Moreover, MRL/+ → MRL/lpr chimeric mice displayed increased brain RANTES expression, neurodegeneration, and cellular infiltration in the choroid plexus, as well as blood brain barrier disruption, all in the absence of significant systemic autoimmunity. CONCLUSIONS: Chimeric MRL/+ → MRL/lpr mice displayed no attenuation of the behavioral phenotype found in MRL/lpr mice, despite normalized serum autoantibodies and conserved renal function. Therefore, neuropsychiatric disease in the MRL/lpr lupus-prone strain of mice can occur absent any major contributions from systemic autoimmunity.

Neuropsychiatric Lupus, the Blood Brain Barrier, and the TWEAK/Fn14 Pathway.

Patients with systemic lupus erythematosus (SLE) can experience acute neurological events such as seizures, cerebrovascular accidents, and delirium, psychiatric conditions including depression, anxiety, and psychosis, as well as memory loss and general cognitive decline. Neuropsychiatric SLE (NPSLE) occurs in between 30 and 40% of SLE patients, can constitute the initial patient presentation, and may occur outside the greater context of an SLE flare. Current efforts to elucidate the mechanistic underpinnings of NPSLE are focused on several different and potentially complementary pathways, including thrombosis, brain autoreactive antibodies, and complement deposition. Furthermore, significant effort is dedicated to understanding the contribution of neuroinflammation induced by TNF, IL-1, IL-6, and IFN-γ. More recent studies have pointed to a possible role for the TNF family ligand TWEAK in the pathogenesis of neuropsychiatric disease in human lupus patients, and in a murine model of this disease. The blood brain barrier (BBB) consists of tight junctions between endothelial cells (ECs) and astrocytic projections which regulate paracellular and transcellular flow into the central nervous system (CNS), respectively. Given the privileged environment of the CNS, an important question is whether and how the integrity of the BBB is compromised in NPSLE, and its potential pathogenic role. Evidence of BBB violation in NPSLE includes changes in the albumin quotient (Q alb) between plasma and cerebrospinal fluid, activation of brain ECs, and magnetic resonance imaging. This review summarizes the evidence implicating BBB damage as an important component in NPSLE development, occurring via damage to barrier integrity by environmental triggers such as infection and stress; cerebrovascular ischemia as result of a generally prothrombotic state; and immune mediated EC activation, mediated by antibodies and/or inflammatory cytokines. Additionally, new evidence supporting the role of TWEAK/Fn14 signaling in compromising the integrity of the BBB in lupus will be presented.