Antibody-specific behavioral effects: Intracerebroventricular injection of antiphospholipid antibodies induces hyperactive behavior while anti-ribosomal-P antibodies induces depression and smell deficits in mice

Antiphospholipid Antibodies in Mental Disorders

Thrombotic events striking the central nervous system are clinical criteria for the antiphospholipid syndrome (APS). Besides these, neuropsychiatric non-APS criteria manifestations are increasingly described in patients with persistently positive antiphospholipid antibodies (aPL). Among these are psychiatric manifestations. Animal models mainly describe hyperactive behavior and anxiety associated with hippocampal abnormalities. Cases of associations with psychosis, mood disorders, bipolarity, anxiety, obsessive-compulsive behavior, and depression have been reported but are still rare. Systematic human clinical association studies are concordant with a risk of psychosis, depression (simple to major), and anxiety disorders, but these are limited and of inconstant methodological quality. Brain imaging in patients, also insufficiently investigated, shows early signs of hypoperfusion and of subtle diffuse white matter changes compatible with an alteration of the axonal structure and changes in the myelin sheath. Direct interactions of aPL with the brain cells, both on cell lines and on animal and human brain biopsies, targeting both glial cells, astrocytes, and neurons, can be demonstrated. These clusters of arguments make the association between psychiatric diseases and aPL increasingly plausible. However, a considerable amount of clinical research must still be performed in accordance with the highest standards of methodological quality. The therapeutic management of this association, in terms of both prevention and cure, currently remains unresolved.

Advanced neuroimaging in systemic lupus erythematosus: identifying biomarkers for cognitive dysfunction

BACKGROUND

Cognitive dysfunction (CD) is a common manifestation of central nervous system involvement in patients with systemic lupus erythematosus (SLE). Patients with SLE may develop CD insidiously at an early stage of the disease, and the lack of a standardized diagnostic test poses a major challenge in prompt diagnosis and management of these patients. This review summaries the current application of various magnetic resonance imaging (MRI) techniques for patients with SLE complicated with CD, aiming to identify potential quantitative neuroimaging biomarkers for patients with SLE and CD.

METHODS

We systematically searched several databases between January 2003 to December 2024. We screened retrospective and prospective studies based on search criteria keywords (including structural or functional MRI, cognitive function, lupus, and systemic lupus erythematosus) to identify peer-reviewed articles that reported advanced structural and functional MRI metrics and evaluated CD in human patients with SLE.

RESULTS

123 studies (19 Bold-MRI studies, 9 DTI studies, 2 ASL studies, 4 MTI studies, 5 machine learning, and 84 other studies) were identified. Neuroimaging findings show that patients with CD have abnormal manifestations in the limbic system, hippocampus, corpus callosum, and frontal cortex, and these manifestations are closely related to cognitive functions. The most commonly affected cognitive domains are memory, attention, and executive ability. Multimodal MRI, integrating structural, functional, and perfusion parameters, combined with machine learning, can effectively predict cognitive function.

CONCLUSION

Advanced MRI analysis can identify the abnormalities in the whole brain and local brain regions associated with CD in patients with SLE. The integration of machine learning and multimodal MRI offers new perspectives for early identification and mechanistic studies of CD in SLE patients. More studies are needed to identify potential neuroimaging biomarkers to facilitate early diagnosis, timely treatment, and accurate prognosis for SLE patients with CD.

Neurological Manifestations of Systemic Lupus Erythematosus: A Comprehensive Review

Neurological involvement in systemic lupus erythematosus (SLE) poses significant challenges, impacting patient morbidity, mortality, and quality of life. This narrative review provides an update on the pathogenesis, clinical presentation, diagnosis, and management of neurological SLE. The multifaceted pathophysiology involves immune-mediated and vascular mechanisms such as autoantibodies, neuroinflammation, complement dysregulation, and genetic factors. Neuropsychiatric SLE (NPSLE) manifests in a variety of ways, including cognitive dysfunction, mood disorders, psychosis, cerebrovascular disease, demyelinating syndromes, and neuropathies. Diagnosing neurological SLE is complicated by nonspecific and fluctuating symptoms, requiring comprehensive neurological examination, neuroimaging, autoantibody profiling, and cerebrospinal fluid analysis. Current management strategies include corticosteroids, immunosuppressive agents, and emerging biologics targeting specific immune pathways. Managing neuropsychiatric symptoms, seizures, and neuropathic pain remains a complex aspect of treatment. This review highlights the importance of early recognition and tailored management approaches to improve patient outcomes in neurological SLE.

TO SHOw how we have been ENgaged in the APS FiELD (What we learned on APS collaborating with Professor Yehuda Shoenfeld)

The present review reports the history of our scientific collaboration with Professor Shoenfeld's group. The collaboration started at the end of the 80s and was mainly focused on studies on the pathogenetic mechanisms of the anti-phospholipid syndrome (APS). Following the initial collaborative studies on antibodies against endothelium in systemic autoimmune vasculitis, we were able to use a similar strategy in APS. This line of research has resulted in the characterization of beta 2 glycoprotein I (β2GPI)-dependent anti-phospholipid antibodies (aPL) as mechanisms capable of mediating an endothelial perturbation crucial for the pathogenesis of APS. Thanks to these studies, the collaboration has led to the characterization of the membrane receptors for β2GPI and the cellular signaling resulting from antibody binding. This mechanism has also been shown to mediate the aPL effect on other cell types involved in APS pathogenesis. Finally, the exchange of information made it possible to replicate and extend the setting of animal models of the syndrome, which proved to be valuable tools for understanding the pathogenesis of the syndrome. It has been a long story recently refueled by common studies on the similarity of pro-inflammatory and pro-coagulant endotheliopathy in APS and in COVID-19.

The Cotard Delusion in a Patient With Neuropsychiatric Systemic Lupus Erythematosus: The Challenges of Autoimmune Psychosis

The clinical features of neuropsychiatric systemic lupus erythematosus (NPSLE) are heterogeneous. Furthermore, therapeutic decision-making for NPSLE depends on the recognition of clinical syndromes that have not been sufficiently studied. This report describes the case of a 36-year-old woman with NPSLE who exhibited severe cognitive dysfunction and affective psychosis with persistent nihilistic delusions such as those described in the Cotard delusion. The patient insisted for several months that she was already dead. CSF analysis showed elevated levels of anti-ribosomal P antibodies and a positive determination of oligoclonal bands. Additionally, 18F -FDG PET/CT imaging revealed severe bilateral frontal hypermetabolism suggestive of brain inflammation and occipital hypometabolism. Results from the Systematic Lupus Erythematosus Disease Activity Index 2000 and the Systemic Lupus Erythematosus Disease Activity Score were consistent with an active state of the immunological disease. We then determined by an algorithm that this neuropsychiatric event could be attributed to the activity of the underlying immunological disease. Despite immunosuppressive and symptomatic treatment, only a partial improvement in cognition was achieved. The psychopathological features of the Cotard delusion remained unchanged 4 months after onset. However, we observed rapid remission of affective psychosis and significant improvement in cognition following electroconvulsive therapy. Subsequent follow-up examinations showed a sustained remission. This case describes a protracted form of the Cotard delusion, the diagnostic challenges that arise in the context of SLE, and treatment dilemmas that necessitate collaboration between neurology, psychiatry, and rheumatology.

Diagnosis and Management of Pediatric Neuropsychiatric Systemic Lupus Erythematosus: An Update

Neuropsychiatric systemic lupus erythematosus (NPSLE) is a potentially serious and life-threatening complication of SLE. The presentation and severity of neuropsychiatric involvement in SLE may show considerable variability. The disease can affect the neural tissue directly or may be associated with vascular involvement, mainly associated with anti-phospholipid (aPL) antibodies. A direct causal link with SLE may sometimes be challenging since there are many confounding factors and the symptoms may be non-specific. Despite its remarkable sensitivity in detecting hemorrhagic and ischemic stroke, transverse myelitis and ischemic infarction, magnetic resonance imaging (MRI) lacks the spatial resolution required to identify microvascular involvement. When standard MRI fails to detect a suspicious lesion, it is advisable to use advanced imaging modalities such as positron emission tomography (PET), single photon emission computed tomography (SPECT) or quantitative MRI, if available. Even with these advanced modalities, the specificity of neuroimaging in NPSLE remains inadequate (60-82% for MRI). Neuropsychiatric syndromes, such as cerebrovascular events, seizures and cognitive impairments appear to be associated with serum aPL antibodies. Some studies have shown that anti-ribosomal P antibodies have a low sensitivity for NPSLE and a limited contribution to the differentiation of different clinical entities. Treatment has two main goals: symptomatic relief and treatment of the disease itself. Commonly used immunosuppressants for NPSLE include cyclophosphamide (CYC), azathioprine (AZA), and mycophenolate mofetil (MMF). According to EULAR's current recommendation, strong immunosuppressants such as CYC and rituximab (RTX) should be preferred. Biologics have also been used in NPSLE. Fingolimod, eculizumab, and JAK inhibitors are potential drugs in the pipeline. Developing targeted therapies will be possible by a better understanding of the pathological mechanisms.

The bidirectional relationship of depression and disturbances in B cell homeostasis: Double trouble

Major depressive disorder (MDD) is a recurrent, persistent, and debilitating neuropsychiatric syndrome with an increasing morbidity and mortality, representing the leading cause of disability worldwide. The dysregulation of immune systems (including innate and adaptive immune systems) has been identified as one of the key contributing factors in the progression of MDD. As the main force of the humoral immunity, B cells have an essential role in the defense against infections, antitumor immunity and autoimmune diseases. Several recent studies have suggested an intriguing connection between disturbances in B cell homeostasis and the pathogenesis of MDD, however, the B-cell-dependent mechanism of MDD remains largely unexplored compared to other immune cells. In this review, we provide an overview of how B cell abnormality regulates the progression of MMD and the potential consequence of the disruption of B cell homeostasis in patients with MDD. Abnormalities of B-cell homeostasis not only promote susceptibility to MDD, but also lead to an increased risk of developing infection, malignancy and autoimmune diseases in patients with MDD. A better understanding of the contribution of B cells underlying MDD would provide opportunities for identification of more targeted treatment approaches and might provide an overall therapeutic benefit to improve the long-term outcomes of patients with MDD.

Neuropsychiatric Systemic Lupus Erythematosus: Molecules Involved in Its Imunopathogenesis, Clinical Features, and Treatment

Systemic lupus erythematosus (SLE) is an idiopathic chronic autoimmune disease that can affect any organ in the body, including the neurological system. Multiple factors, such as environmental (infections), genetic (many HLA alleles including DR2 and DR3, and genes including C4), and immunological influences on self-antigens, such as nuclear antigens, lead to the formation of multiple autoantibodies that cause deleterious damage to bodily tissues and organs. The production of autoantibodies, such as anti-dsDNA, anti-SS(A), anti-SS(B), anti-Smith, and anti-neuronal DNA are characteristic features of this disease. This autoimmune disease results from a failure of the mechanisms responsible for maintaining self-tolerance in T cells, B cells, or both. Immune complexes, circulating antibodies, cytokines, and autoreactive T lymphocytes are responsible for tissue injury in this autoimmune disease. The diagnosis of SLE is a rheumatological challenge despite the availability of clinical criteria. NPSLE was previously referred to as lupus cerebritis or lupus sclerosis. However, these terms are no longer recommended because there is no definitive pathological cause for the neuropsychiatric manifestations of SLE. Currently, the treatment options are primarily based on symptomatic presentations. These include the use of antipsychotics, antidepressants, and anxiolytic medications for the treatment of psychiatric and mood disorders. Antiepileptic drugs to treat seizures, and immunosuppressants (e.g., corticosteroids, azathioprine, and mycophenolate mofetil), are directed against inflammatory responses along with non-pharmacological interventions.

Functional IgG Autoantibodies against Autonomic Nervous System Receptors in Symptomatic Women with Silicone Breast Implants

The association between the clinical picture of symptomatic women with silicone breast implants (SBI) and dysregulated immunity was in dispute for decades. In the current study, we describe for the first time the functional activity of purified IgG antibodies derived from symptomatic women with SBIs (suffering from subjective/autonomic-related symptoms), both in vitro and in vivo. We found that IgGs, derived from symptomatic women with SBIs, dysregulate inflammatory cytokines (TNFα, IL-6) in activated human peripheral blood mononuclear cells, compared to healthy-women-derived IgGs. Importantly, behavioral studies conducted following intracerebroventricular injection of IgGs derived from symptomatic women with SBIs (who have dysregulated circulating level of IgG autoantibodies directed against autonomic nervous system receptors) into mice brains demonstrated a specific and transient significant increment (about 60%) in the time spent at the center of the open field arena compared with mice injected with IgG from healthy women (without SBIs). This effect was accompanied with a strong trend of reduction of the locomotor activity of the SBI-IgG treated mice, indicating an overall apathic-like behavior. Our study is the first to show the potential pathogenic activity of IgG autoantibodies in symptomatic women with SBIs, emphasizing the importance of these antibodies in SBI-related illness.

Cognitive dysfunction in SLE: An understudied clinical manifestation

Neuropsychiatric lupus (NPSLE) is a debilitating manifestation of SLE which occurs in a majority of SLE patients and has a variety of clinical manifestations. In the central nervous system, NPSLE may result from ischemia or penetration of inflammatory mediators and neurotoxic antibodies through the blood brain barrier (BBB). Here we focus on cognitive dysfunction (CD) as an NPSLE manifestation; it is common, underdiagnosed, and without specific therapy. For a very long time, clinicians ignored cognitive dysfunction and researchers who might be interested in the question struggled to find an approach to understanding mechanisms for this manifestation. Recent years, however, propelled by a more patient-centric approach to disease, have seen remarkable progress in our understanding of CD pathogenesis. This has been enabled through the use of novel imaging modalities and numerous mouse models. Overall, these studies point to a pivotal role of an impaired BBB and microglial activation in leading to neuronal injury. These insights suggest potential therapeutic modalities and make possible clinical trials for cognitive impairment.

Neuropsychiatric lupus erythematosus: Focusing on autoantibodies

Patients with systemic lupus erythematosus (SLE) frequently suffer from nervous system complications, termed neuropsychiatric lupus erythematosus (NPLE). NPLE accounts for the poor prognosis of SLE. Correct attribution of NP events to SLE is the primary principle in managing NPLE. The vascular injuries and neuroinflammation are the fundamental neuropathologic changes in NPLE. Specific autoantibody-mediated central nerve system (CNS) damages distinguish NPLE from other CNS disorders. Though the central antibodies in NPLE are generally thought to be raised from the periphery immune system, they may be produced in the meninges and choroid plexus. On this basis, abnormal activation of microglia and disease-associated microglia (DAM) should be the common mechanisms of NPLE and other CNS disturbances. Improved understanding of both characteristic and sharing features of NPLE might yield further options for managing this disease.

Progress in the Pathogenesis and Treatment of Neuropsychiatric Systemic Lupus Erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) has a broad spectrum of subtypes with diverse severities and prognoses. Ischemic and inflammatory mechanisms, including autoantibodies and cytokine-mediated pathological processes, are key components of the pathogenesis of NPSLE. Additional brain-intrinsic elements (such as the brain barrier and resident microglia) are also important facilitators of NPSLE. An improving understanding of NPSLE may provide further options for managing this disease. The attenuation of neuropsychiatric disease in mouse models demonstrates the potential for novel targeted therapies. Conventional therapeutic algorithms include symptomatic, anti-thrombotic, and immunosuppressive agents that are only supported by observational cohort studies, therefore performing controlled clinical trials to guide further management is essential and urgent. In this review, we aimed to present the latest pathogenetic mechanisms of NPSLE and discuss the progress in its management.

Insights into the role of neutrophils in neuropsychiatric systemic lupus erythematosus: Current understanding and future directions

Central nervous system (CNS) involvement of systemic lupus erythematosus (SLE), termed neuropsychiatric SLE (NPSLE), is a major and debilitating manifestation of the disease. While patients with SLE mostly complain of common neuropsychological symptoms such headache and mild mood disorders that may not even be technically attributed to SLE, many SLE patients present with life-threatening NPSLE syndromes such as cerebrovascular disease, seizures and psychosis that are equally challenging in terms of early diagnosis and therapy. While we are just beginning to unravel some mysteries behind the immunologic basis of NPSLE, advancements in the mechanistic understanding of the complex pathogenic processes of NPSLE have been emerging through recent murine and human studies. The pathogenic pathways implicated in NPSLE are multifarious and various immune effectors such as cell-mediated inflammation, autoantibodies and cytokines including type I interferons have been found to act in concert with the disruption of the blood-brain barrier (BBB) and other neurovascular interfaces. Beyond antimicrobial functions, neutrophils are emerging as decision-shapers during innate and adaptive immune responses. Activated neutrophils have been recognized to be involved in ischemic and infective processes in the CNS by releasing neutrophil extracellular traps (NETs), matrix metalloproteinase-9 and proinflammatory cytokines. In the context of NPSLE, these mechanisms contribute to BBB disruption, neuroinflammation and externalization of modified proteins on NETs that serve as autoantigens. Neutrophils that sediment within the peripheral blood mononuclear cell fraction after density centrifugation of blood are generally defined as low-density neutrophils (LDNs) or low-density granulocytes. LDNs are a proinflammatory subset of neutrophils that are increased with SLE disease activity and are primed to undergo NETosis and release cytokines such as interferon-α and tumor necrosis factor. This review discusses the immunopathogenesis of NPSLE with a focus on neutrophils as a core mediator of the disease and potential target for translational research in NPSLE.

Autoantibodies in systemic lupus erythematosus: From immunopathology to therapeutic target

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ inflammatory damage and wide spectrum of autoantibodies. The autoantibodies, especially anti-dsDNA and anti-Sm autoantibodies are highly specific to SLE, and participate in the immune complex formation and inflammatory damage on multiple end-organs such as kidney, skin, and central nervous system (CNS). However, the underlying mechanisms of autoantibody-induced tissue damage and systemic inflammation are still not fully understood. Single cell analysis of autoreactive B cells and monoclonal antibody screening from patients with active SLE has improved our understanding on the origin of autoreactive B cells and the antigen targets of the pathogenic autoantibodies. B cell depletion therapies have been widely studied in the clinics, but the development of more specific therapies against the pathogenic B cell subset and autoantibodies with improved efficacy and safety still remain a big challenge. A more comprehensive autoantibody profiling combined with functional characterization of autoantibodies in diseases development will shed new insights on the etiology and pathogenesis of SLE and guide a specific treatment to individual SLE patients.

Neurological and Neuropsychiatric Manifestations of Antiphospholipid-Antibody Syndrome (APS)

Antiphospholipid antibody syndrome (APS) is an autoimmune disorder mediated by the presence of a group of autoantibodies, specifically the anticardiolipin antibody (aCL), the beta-2 glycoprotein I (β2GPI), and the lupus anticoagulant (LA). Patients diagnosed with antiphospholipid antibody syndrome (APS) present with many symptoms, the most common being the consequence of thrombotic events that can be catastrophic and lead to mild to severe residual disabilities over a significant amount of time and can impair the quality of life. These events are often present in the younger population. Many times, these thrombotic events are heralded by a spectrum of psychiatric symptoms, which when worked up in the right direction may hint toward an oncoming thrombotic event and may potentially prevent those events by prompting primary prophylaxis treatment by the treating physician. In this review, we aim to comprehensively put forth the many neurological and neuropsychiatric manifestations of APS, their pathology, and management.

Progress in the mechanism of neuronal surface P antigen modulating hippocampal function and implications for autoimmune brain disease

PURPOSE OF REVIEW

The aim of this study was to present a new regulation system in the hippocampus constituted by the neuronal surface P antigen (NSPA) and the tyrosine phosphatase PTPMEG/PTPN4, which provides mechanistic and therapeutic possibilities for cognitive dysfunction driven by antiribosomal P protein autoantibodies in patients with systemic lupus erythematosus (SLE).

RECENT FINDINGS

Mice models lacking the function of NSPA as an E3 ubiquitin ligase show impaired glutamatergic synaptic plasticity, decreased levels of NMDAR at the postsynaptic density in hippocampus and memory deficits. The levels of PTPMEG/PTPN4 are increased due to lower ubiquitination and proteasomal degradation, resulting in dephosphorylation of tyrosines that control endocytosis in GluN2 NMDAR subunits. Adult hippocampal neurogenesis (AHN) that normally contributes to memory processes is also defective in the absence of NSPA.

SUMMARY

NSPA function is crucial in memory processes controlling the stability of NMDAR at PSD through the ubiquitination of PTPMEG/PTPN4 and also through AHN. As anti-P autoantibodies reproduce the impairments of glutamatergic transmission, plasticity and memory performance seen in the absence of NSPA, it might be expected to perturb the NSPA/PTPMEG/PTPN4 pathway leading to hypofunction of NMDAR. This neuropathogenic mechanism contrasts with that of anti-NMDAR antibodies also involved in lupus cognitive dysfunction. Testing this hypothesis might open new therapeutic possibilities for cognitive dysfunction in SLE patients bearing anti-P autoantibodies.

Neuropsychiatric Systemic Lupus Erythematosus: a remaining challenge

Systemic Lupus Erythematosus (SLE) is an autoimmune disease, which affects a wide range of organs with variable clinical features. Involvement of the nervous system is a challenging and multifaceted manifestation of the disease, presenting with a broad range of symptoms. Neuropsychiatric lupus (NPSLE) encompasses seven syndromes of the peripheral and 12 of the central nervous system, associated with a high disease burden. Despite advances in the management of SLE, NP manifestations still pose a challenge to clinicians. First, diagnosis and attribution to SLE is difficult due to the lack of specific biomarkers or imaging modalities. Second, therapeutic options are limited, and evidence is mainly based on case reports and expert consensus, as clinical trials are sparse. Moreover, no validated outcome measure on disease activity exists. Current recommendations for treatment include supportive as well as immunosuppressive medication, depending on the type and severity of manifestations. As NPSLE manifestations are increasingly recognized, a broader spectrum of therapeutic options can be expected.

Cognitive Impairment in Anti-Phospholipid Syndrome and Anti-Phospholipid Antibody Carriers

Cognitive impairment is frequently reported among anti-phospholipid syndrome (APS) patients as well as anti-phospholipid antibody (aPL) carriers, but it is less studied than other manifestations of this condition. Moreover, the exact prevalence of cognitive impairment in these patients has not been accurately determined, mainly due to inconsistency in the tools used to identify impairment, small sample sizes, and variability in the anti-phospholipid antibodies measured and positivity cutoffs. The notion of a direct pathogenic effect is supported by the observation that the higher the number of aPLs present and the higher the load of the specific antibody, the greater the risk of cognitive impairment. There is some evidence to suggest that besides the thrombotic process, inflammation-related pathways play a role in the pathogenesis of cognitive impairment in APS. The cornerstone treatments of APS are anti-coagulant and anti-thrombotic medications. These treatments have shown some favorable effects in reversing cognitive impairment, but solid evidence for the efficacy and safety of these treatments in the context of cognitive impairment is still lacking. In this article, we review the current knowledge regarding the epidemiology, pathophysiology, clinical associations, and treatment of cognitive impairment associated with APS and aPL positivity.

The SARS-CoV-2 as an instrumental trigger of autoimmunity

Autoimmunity may be generated by a variety of factors by creating a hyper-stimulated state of the immune system. It had been established long ago that viruses are a substantial component of environmental factors that contribute to the production of autoimmune antibodies, as well as autoimmune diseases. Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human immunodeficiency virus (HIV) are viruses that withhold these autoimmune abilities. In a similar manner, SARS-CoV-2 may be counted to similar manifestations, as numerous records demonstrating the likelihood of COVID-19 patients to develop multiple types of autoantibodies and autoimmune diseases. In this review, we focused on the association between COVID-19 and the immune system concerning the tendency of patients to develop over 15 separate types of autoantibodies and above 10 distinct autoimmune diseases. An additional autoimmunity manifestation may be one of the common initial symptoms in COVID-19 patients, anosmia, the complete loss of the ability to sense smell, and other olfactory alterations. We summarize current knowledge on principal mechanisms that may contribute to the development of autoimmunity in the disease: the ability of SARS-CoV-2 to hyper-stimulate the immune system, induce excessive neutrophil extracellular traps formation with neutrophil-associated cytokine responses and the molecular resemblance between self-components of the host and the virus. Additionally, we will examine COVID-19 potential risk on the new-onsets of autoimmune diseases, such as antiphospholipid syndrome, Guillain-Barré syndrome, Kawasaki disease and numerous others. It is of great importance to recognize those autoimmune manifestations of COVID-19 in order to properly cope with their outcomes in the ongoing pandemic and the long-term post-pandemic period. Lastly, an effective vaccine against SARS-CoV-2 may be the best solution in dealing with the ongoing pandemic. We will discuss the new messenger RNA vaccination strategy with an emphasis on autoimmunity implications.

Mood Disorder in Systemic Lupus Erythematosus Induced by Antiribosomal P Protein Antibodies Associated with Decreased Serum and Brain Tryptophan

Antiribosomal P protein (anti-P) autoantibodies commonly develop in patients with systemic lupus erythematosus. We have previously established hybridoma clones producing anti-P mAbs. In this study, we explored the pathogenesis of behavioral disorders induced by anti-P Abs using these mAbs. New Zealand Black × New Zealand White F1, New Zealand White, C57BL/6, and BALB/c mice were treated with 1 mg of anti-P Abs once every 2 wk. The behavioral disorder was evaluated by the tail suspension test, forced swim test, and open field test. Following administration of anti-P Abs, New Zealand Black × New Zealand White F1 and C57BL/6 mice developed depressive behavior and showed increased anxiety with elevated serum TNF-α and IL-6 levels. Anti-P Abs were not deposited in the affected brain tissue; instead, this mood disorder was associated with lower serum and brain tryptophan concentrations. Tryptophan supplementation recovered serum tryptophan levels and prevented the behavioral disorder. TNF-α and IL-6 were essential for the decreased serum tryptophan and disease development, which were ameliorated by treatment with anti-TNF-α neutralizing Abs or dexamethasone. Peritoneal macrophages from C57BL/6 mice produced TNF-α, IL-6, and IDO-1 via interaction with anti-P Abs through activating FcγRs, which were required for disease development. IVIg, which has an immunosuppressive effect partly through the regulation of FcγR expression, also prevented the decrease in serum tryptophan and disease development. Furthermore, serum tryptophan concentrations were decreased in the sera of systemic lupus erythematosus patients with anti-P Abs, and lower tryptophan levels correlated with disease activity. Our study revealed some of the molecular mechanisms of mood disorder induced by anti-P Abs.

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.

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.

Update on the pathogenesis of central nervous system lupus

PROPOSE OF REVIEW

Neuropsychiatric systemic lupus erythematosus (NPSLE) is an emerging frontier in lupus care encompassing a wide spectrum of clinical manifestations. Its pathogenesis remains poorly understood because of the complexity of pathophysiologic mechanisms involved and limited access to tissue. We highlight recent advances in the pathophysiology of neuropsychiatric lupus.

RECENT FINDINGS

Disruption of blood-brain barrier (BBB) facilitating entrance of neurotoxic antibodies into the central nervous system (CNS), neuroinflammation and cerebral ischemia are the key mechanisms. Disruption of the BBB may occur not only at the traditional BBB, but also at the blood-cerebrospinal fluid barrier. Certain autoantibodies, such as anti-N-methyl-D-aspartate receptors, antiribosomal P and antiphospholipid antibodies may cause injury in subsets of patients with diffuse neuropsychiatric disease. Activation of microglia via autoantibodies, interferon-a or other immune reactants, may amplify the inflammatory response and promote neuronal damage. New inflammatory pathways, such as TWEAK/Fn14, Bruton's tyrosine kinase, Nogo-a and ACE may represent additional potential targets of therapy. Novel neuroimaging techniques suggest alterations in brain perfusion and metabolism, increased concentration of neurometabolites, indicative of glial activation, vasculopathy and neuronal impairment.

SUMMARY

NPSLE encompasses a diverse phenotype with distinct pathogenic mechanisms, which could be targeted by novel therapies or repositioning of existing drugs.

[Mental disorders and cognitive impairment in patients with antiphospholipid syndrome]

Mental disorders (mainly anxiety and depressive disorders) and cognitive impairment are often found in patients with antiphospholipid syndrome (APS), but their prevalence, structure, and mechanisms of occurrence are not well researched. The review provides literature data on the frequency, spectrum and possible causes of mental disorders and cognitive impairment in patients with APS, the pathogenetic mechanisms of these disorders (in particular, the important role of antiphospholipid antibodies, stress factors, chronic inflammation), the relationship between APS, mental disorders and as well as cognitive impairment is examined. Special attention is paid to the influence of mental disorders and cognitive impairment on patients adherence to treatment, their quality of life, as well as the particularities of psychopharmacotherapy of mental disorders in patients with APS. The aim of the review is to actualize the interdisciplinary problem of mental disorders and cognitive impairment in patients with APS and the need to introduce a partnership model of care.

Autoantibodies associated with neuropsychiatric systemic lupus erythematosus: the quest for symptom-specific biomarkers

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organs, including the central nervous system. Neuropsychiatric SLE (NPSLE) is a severe and potentially fatal condition. Several factors including autoantibodies have been implicated in the pathogenesis of NPSLE. However, definitive biomarkers of NPSLE are yet to be identified owing to the complexity of this disease. This is a major barrier to accurate and timely diagnosis of NPSLE. Studies have identified several autoantibodies associated with NPSLE;some of these autoantibodies are well investigated and regarded as symptom-specific. In this review, we discuss recent advances in our understanding of the manifestations and pathogenesis of NPSLE. In addition, we describe representative symptom-specific autoantibodies that are considered to be closely associated with the pathogenesis of NPSLE.

Immunological biomarkers in neuropsychiatric systemic lupus erythematosus: a comparative cross-sectional study from a tertiary care center in South India

INTRODUCTION

The prevalence of various immunological biomarkers in neuropsychiatric systemic lupus erythematosus (NPSLE) differs among various patients with varied neuropsychiatric manifestations and different populations. We studied the prevalence of these biomarkers; especially the neuron specific autoantibodies in patients with systemic lupus erythematosus (SLE) and compared them among patients with and without neuropsychiatric involvement.

METHODOLOGY

This is a comparative cross-sectional study conducted in a tertiary care hospital in South India. The prevalence of immunological biomarkers including complement levels, systemic and brain specific autoantibodies (anti-myelin antibody, anti-myelin oligodendrocyte glycoprotein and anti-myelin-associated glycoprotein antibody) were assessed and compared among those with and without NPSLE and with different NPSLE manifestations.

RESULTS

A total of 522 SLE patients were enrolled in the study. The mean age of the study participants was 28.5 ± 8.8 years and 93.5% were women. Neuropsychiatric manifestations were seen in 167 (32%) patients. Seizure was the most common neuropsychiatric manifestation seen in 41.3%, followed by psychosis (18.6%), mood disorder (16.8%), stroke (10.8%), mononeuropathy (10.2%), headache (9.6%), acute confusional state (6.6%) and aseptic meningitis (5.4%). Patients with NPSLE had a higher SLE disease activity index score. Most of the autoantibodies, that is anticardiolipin antibody (aCL), anti-β2 glycoprotein 1 antibody (β2GP1), lupus anticoagulant (LA), anti-nucleosome, anti-ribosomal P, anti-Ro52, anti-Ro60 and anti-La, were seen in higher proportion in the NPSLE group, although the difference failed to reach statistical significance. On subgroup analysis, psychosis was significantly higher in patients with anti-ribosomal P positivity than without (11.8% versus 4.1%, p.0.007; odds ratio (OR) 3.1, confidence interval (CI) 1.4-6.8), while stroke had a higher proportion among those with positive b2GP1 IgG (6.3% versus 1.8%, p.0.03; OR 3.6, CI 1.2-11.0). A higher proportion of demyelination was seen among the LA positive than the negative (10.3% versus 0.2%, p.0.03; OR 5.39, CI 1.15-24.17) and anti-myelin oligodendrocyte glycoprotein in mood disorder (14.3% versus 3.4%, p = 0.03; OR 4.66, CI 1.13-19.13).

CONCLUSION

No single biomarker correlated with NPSLE. Among different NPSLE manifestations, the prevalence of IgG β2GP1 in stroke, LA in demyelination, anti-ribosomal P in psychosis and anti-myelin oligodendrocyte glycoprotein in mood disorder were higher. Further studies on the pathogenic mechanisms underlying NPSLE and its different manifestations may help us to identify better biomarkers.

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.

A review and meta-analysis of anti-ribosomal P autoantibodies in systemic lupus erythematosus

The discovery of autoantibodies to ribosomal proteins (anti-RibP) dates back more than fifty years when antibodies to ribosomes were identified in systemic lupus erythematosus (SLE) sera. Over the years, anti-RibP autoantibodies have been the subject of extensive study and became known as a highly specific biomarker for the diagnosis of SLE and were associated with neuropsychiatric SLE (NPSLE), lupus nephritis (LN) and hepatitis (LH). As demonstrated by studies on cultured human cells and of murine models, there is evidence to suggest that anti-RibP may have a pathogenic role in LN and NPSLE. Despite a wealth of evidence, in comparison to other SLE autoantibodies such as anti-Sm and anti-dsDNA, anti-RibP has not been included in classification criteria for SLE. A significant challenge is the variability of assays used to detect anti-RibP, including the antigens and diagnostic platforms employed. This may account for the marked variation in frequencies (10-47%) in SLE and its association with clinical and demographic features reported in SLE cohorts. We performed a systematic literature review and meta-analysis to help clarify its prevalence, various clinical and serological associations in SLE based on the different RibP antigens and assay platforms used.

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.

Management of Psychosis in Neuropsychiatric Lupus

Manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE) are heterogeneous. Acute psychosis is an uncommon but well-recognized manifestation of NPSLE. With no specific biomarkers to date, the diagnosis of NPSLE relies on clinical acumen for circumstantial evidence and exclusion of important differential diagnoses. The attribution of psychosis to NPSLE is facilitated by the application attribution models. In particular, the American College of Rheumatology nomenclature, Systemic Lupus International Collaborating Clinics attribution models and Italian algorithm for the attribution of psychosis to NPSLE are revisited. The mainstay of treatment for psychosis attributable to NPSLE is immunosuppression and symptomatic control. In refractory cases, immunomodulatory and emerging biological agents may be considered. This article reviews the diagnostic dilemma, pathogenic mechanisms and treatment of psychosis in SLE patients.

Cross-reactivity between annexin A2 and Beta-2-glycoprotein I in animal models of antiphospholipid syndrome

Antiphospholipid syndrome (APS) affects coagulation and the brain by autoimmune mechanisms. The major antigen in APS is beta-2-glycoprotein I (β2-GPI) is known to complex with annexin A2 (ANXA2), and antibodies to ANXA2 have been described in APS. We measured these antibodies in mice with experimental APS (eAPS) induced by immunization with β2-GPI. Sera of these mice reacted significantly with recombinant ANXA2 by enzyme-linked immunosorbent assay (ELISA) and the eAPS mice had significantly high levels of immunoglobulin G (IgG) in the brain by immunoblot assays compared to adjuvant immunized controls. Immunoprecipitation performed by mixing eAPS brain tissue with protein-G beads resulted in identification of two autoantigens unique to the eAPS group, one of which was ANXA2. In order to study more directly and methodically the specific role of anti-ANXA2 antibodies in APS, we immunized mice with β2-GPI which contained no ANXA2 or with ANXA2 and measured antibodies to these proteins. Levels of antibodies to ANXA2 measured by ELISA were 0.72 ± 0.007 arbitrary units (a.u), 0.24 ± 0.03 and 0.02 ± 0.01 a.u for sera from ANXA2, β2-GPI and control mice, respectively (p < 0.0001 and p = 0.037 for the comparison of the ANXA2 and β2-GPI groups to the controls). Purified IgG from β2-GPI sera did not show cross-binding with ANXA2. Antibodies to β2-GPI and phospholipids were found in the β2-GPI immunized group only. The present study suggests an immune response to the β2-GPI-ANXA2 complex in eAPS and provides a novel ANXA2 immunization model which will serve to study the role of ANXA2 antibodies in of APS.

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

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

Ribosomal P antibody: 30 years on the road

The identity of the protein antigens targeted by anti-cytoplasmic antibodies in lupus was discovered 30 years ago. These antigens are three acidic ribosomal phosphoproteins, P0, P1, and P2. Precise identification of the shared epitope on these three proteins enabled sensitive and specific immunoassays to be developed. Anti-P antibodies are highly specific for systemic lupus erythematosus (SLE) and occur in 15%–35% of patients, depending on ethnicity as well as the age of onset. Increased frequencies of detection of anti-P have been reported in childhood SLE as well as in neuropsychiatric, renal, and hepatic disease. While longitudinal studies by the Systemic Lupus International Collaborating Clinics (SLICC) consortium supported the association of anti-P with neuropsychiatric lupus, the predictive value of antibody determination remains controversial. This is likely explained by the heterogeneity of neuropsychiatric lupus as well as by the different methodologies used for assay. A number of experimental studies have suggested a direct pathogenic role for anti-P antibodies in brain disease. Findings include cross reactivity between anti-P and a neuronal surface antigen, which was detected in areas of the brain involved in memory, cognition, and emotion. Direct injection of anti-P antibodies into the brains of rodents was also associated with abnormal electrical activity and behavioral disturbances. Taken together, research over the last 30 years has established anti-P antibodies as a useful diagnostic marker of SLE and at least a subset of patients with neuropsychiatric disease. Further research is required to fine tune the association of anti-P with clinical manifestations and establish beyond high probability a pathophysiologic role for the antibodies.

Long-term neurodevelopmental outcome of children born to prospectively followed pregnancies of women with systemic lupus erythematosus and/or antiphospholipid syndrome

Background

Systemic lupus erythematosus (SLE) and antiphospholipid antibody syndrome (APS) are autoimmune diseases that affect women of childbearing age. Maternal IgG antiphospholipid antibodies (aPL) can cross the placenta during pregnancy and theoretically reach the fetal brain. Some studies showed an increased number of learning disabilities in these children.

Objectives

To evaluate the long-term neurodevelopmental outcome of 40 children (median age 7.4 years) born to mothers with SLE and/or APS carrying positive IgG aPL during the third trimester of pregnancy.

Methods

Children were checked for neurological physical exam and intellectual/cognitive functioning by the Wechsler scale for corrected age. We submitted to the mothers the Child Behavior CheckList (CBCL) and a homemade set of questions created by pediatric neurologists.

Results

In all children neurological physical exam and intelligence levels were found to be normal. A cognitive impairment or a discrepant cognitive profile was found in 3 (7%) and 11 (28%) children, respectively. Learning disabilities were diagnosed in 3 children (19% of school-age children), all born to mothers with triple aPL positivity. A history of epilepsy was shown in four children (10%). Conclusions: Children born to women with SLE and/or APS may need a long-term follow-up focusing on milestones of neurodevelopment in order to detect and correct any alteration as early as possible.

Depressive and Anxiety Disorders in Systemic Lupus Erythematosus Patients without Major Neuropsychiatric Manifestations

Depressive and anxiety disorders are frequently observed in patients with Systemic Lupus Erythematosus (SLE). However, the underlying mechanisms are still unknown. We conducted this survey to understand the prevalence of depression and anxiety in SLE patients without major neuropsychiatric manifestations (non-NPSLE) and to explore the relationship between emotional disorders, symptoms, autoantibodies, disease activity, and treatments in SLE. 176 SLE patients were included, and SLE disease activity index (SLEDAI), Hamilton Depression Rating Scale (HAMD), and Hamilton Anxiety Rating Scale (HAMA) were recorded to evaluate their disease activity and emotional status. We found that depressive and anxiety disorders were common among SLE patients: 121 (68.8%) patients were in depression status while 14 (8.0%) patients could be diagnosed with depression. Accordingly, 101 (57.4%) were in anxiety status and 21 (11.9%) could be diagnosed with anxiety. Depression was associated with disease activity, and anxiety was associated with anti-P0 antibody, while both of them were associated with proteinuria. HAMA and HAMD scores were in strong positive correlation and they were independent risk factors of each other. We concluded that the high prevalence of depression and anxiety and the association between depression and SLE disease activity might reveal the covert damage of central nervous system in SLE. The role of anti-P0 antibody in SLE patients with emotional disorders warrants more researches.

Cognitive disorders and antiphospholipid antibodies

Cognitive disorders have frequently been described in the field of antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Nevertheless, the relationship between those disorders and antiphospholipid antibodies (aPL) remains unclear and seems to involve various mechanisms. Overlap with systemic lupus erythematosus, the small sample size of studies, and discrepancies in antiphospholipid antibodies and cognitive impairment determinations complicate analyses of the literature data. In this paper, we summarize current knowledge on epidemiologic, clinical data, imaging findings and treatment of cognitive dysfunction associated with aPL. We separately analyzed data on aPL-positive carriers without history of clinical feature of APS, APS patients without overlaps autoimmune disease, and SLE-associated aPL patients.

The diagnosis and clinical management of the neuropsychiatric manifestations of lupus

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

Anti-ribosomal-phosphoprotein autoantibodies penetrate to neuronal cells via neuronal growth associated protein, affecting neuronal cells in vitro

OBJECTIVE

Anti-ribosomal-phosphoprotein antibodies (anti-Ribos.P Abs) are detected in 10-45% of NPSLE patients. Intracerebroventricular administration of anti-ribosomal-P Abs induces depression-like behaviour in mice. We aimed to discern the mechanism by which anti-Ribos.P Abs induce behavioural changes in mice.

METHODS

Anti-Ribos.P Abs were exposed to human and rat neuronal cell cultures, as well as to human umbilical vein endothelial cell cultures for a control. The cellular localization of anti-Ribo.P Abs was found by an immunofluorescent technique using a confocal microscope. Identification of the target molecules was undertaken using a cDNA library. Immunohistochemistry and an inhibition assay were carried out to confirm the identity of the target molecules. Neuronal cell proliferation was measured by bromodeoxyuridine, and Akt and Erk expression by immunoblot.

RESULTS

Human anti-Ribos.P Abs penetrated into human neuronal cells and rat hippocampal cell cultures in vitro, but not to endothelial cells as examined. Screening a high-content human cDNA-library with anti-Ribos.P Abs identified neuronal growth-associated protein (GAP43) as a target for anti-Ribos.P Abs. Ex vivo anti-Ribos.P Abs bind to mouse brain sections of hippocampus, dentate and amygdala. Anti-Ribos.P Abs brain-binding was prevented by GAP43 protein. Interestingly, GAP43 inhibited in a dose-dependent manner the anti-Ribos.P Abs binding to recombinant-ribosomal-P0, indicating mimicry between the ribosomal-P0 protein and GAP43. Furthermore, anti-Ribos.P Abs reduced neuronal cell proliferation activity in vitro (P < 0.001), whereas GAP43 decreased this inhibitory activity by a factor of 7.6. The last was related to Akt and Erk dephosphorylation.

CONCLUSION

Anti-Ribos.P Abs penetrate neuronal cells in vitro by targeting GAP43. Anti -Ribos.P Abs inhibit neuronal-cell proliferation via inhibition of Akt and Erk. Our data contribute to deciphering the mechanism for anti-Ribos.P Abs' pathogenic activity in NPSLE.

Lupus anti-ribosomal P autoantibody proteomes express convergent biclonal signatures

Lupus-specific anti-ribosomal P (anti-Rib-P) autoantibodies have been implicated in the pathogenesis of neurological complications in systemic lupus erythematosus (SLE). The aim of the present study was to determine variable (V)-region signatures of secreted autoantibody proteomes specific for the Rib-P heterocomplex and investigate the molecular basis of the reported cross-reactivity with Sm autoantigen. Anti-Rib-P immunoglobulins (IgGs) were purified from six anti-Rib-P-positive sera by elution from enzyme-linked immunosorbent assay (ELISA) plates coated with either native Rib-P proteins or an 11-amino acid peptide (11-C peptide) representing the conserved COOH-terminal P epitope. Rib-P- and 11-C peptide-specific IgGs were analysed for heavy (H) and light (L) chain clonality and V-region expression using an electrophoretic and de-novo and database-driven mass spectrometric sequencing workflow. Purified anti-Rib-P and anti-SmD IgGs were tested for cross-reactivity on ELISA and their proteome data sets analysed for shared clonotypes. Anti-Rib-P autoantibody proteomes were IgG1 kappa-restricted and comprised two public clonotypes defined by unique H/L chain pairings. The major clonotypic population was specific for the common COOH-terminal epitope, while the second shared the same pairing signature as a recently reported anti-SmD clonotype, accounting for two-way immunoassay cross-reactivity between these lupus autoantibodies. Sequence convergence of anti-Rib-P proteomes suggests common molecular pathways of autoantibody production and identifies stereotyped clonal populations that are thought to play a pathogenic role in neuropsychiatric lupus. Shared clonotypic structures for anti-Rib-P and anti-Sm responses suggest a common B cell clonal origin for subsets of these lupus-specific autoantibodies.

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

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

Secreted autoantibody repertoires in Sjögren's syndrome and systemic lupus erythematosus: A proteomic approach

The structures of epitopes bound by autoantibodies against RNA-protein complexes have been well-defined over several decades, but little is known of the clonality, immunoglobulin (Ig) variable (V) gene usage and mutational status of the autoantibodies themselves at the level of the secreted (serum) proteome. A novel proteomic workflow is presented based on affinity purification of specific Igs from serum, high-resolution two-dimensional gel electrophoresis, and de novo and database-driven sequencing of V-region proteins by mass spectrometry. Analysis of anti-Ro52/Ro60/La proteomes in primary Sjögren's syndrome (SS) and anti-Sm and anti-ribosomal P proteomes in systemic lupus erythematosus (SLE) has revealed that these antibody responses are dominated by restricted sets of public (shared) clonotypes, consistent with common pathways of production across unrelated individuals. The discovery of shared sets of specific V-region peptides can be exploited for diagnostic biomarkers in targeted mass spectrometry platforms and for tracking and removal of pathogenic clones.

Depression in Autoimmune Diseases

Up to 50% of patients with autoimmune diseases show an impairment of health-related quality of life and exhibit depression-like symptoms. The immune system not only leads to inflammation in affected organs, but also mediates behavior abnormalities including fatigue and depression-like symptoms. This review focuses on the different pathways involved in the communication of the immune system with the neuronal network and the body's timing system. The latter is built up by a hierarchically organized expression of clock genes. As discussed here, the activation of the immune system interferes with high amplitude expression of clock genes, an effect which may play a pivotal role in depression-like behavior in autoimmune diseases.

Olfactory impairment in patients with the fibromyalgia syndrome and systemic sclerosis

Patients with autoimmune diseases often present with olfactory impairment. The aim of the study was to assess the olfactory functions of female patients with fibromyalgia (FM) compared with patients with systemic sclerosis (SSc) and with healthy female controls. Olfactory functions were assessed in 24 patients with FM, 20 patients with SSc and 21 age-matched healthy controls. The sense of smell was evaluated using the Sniffin' Sticks test including the three stages of smell: threshold, discrimination, and identification (TDI) of the different odors. The severity of fibromyalgia was assessed using the fibromyalgia impact questionnaire (FIQ). The short form 36 (SF-36) questionnaire was also completed in order to seek a relationship between the patients perception of quality of life and the different aspects of the smell sense. Depression was evaluated in both FM and SSc patients utilizing the Beck depression inventory-II (BDI-II) questionnaire. Patients with FM had significantly lower TDI smell scores compared with both SSc patients and healthy controls (p < 0.005, One-Way ANOVA). Hyposmia (defined as TDI scores below 30) were observed in 14 of 24 (42 %) patients with FM compared to 3 of 20 (15 %) patients with SSc and 1 of the healthy controls (4.3 %) (p < 0.02). FM patients had significantly lower thresholds of smell compared to both healthy controls and patients with SSc (p < 0.001), whereas for patients with SSc only the ability to discriminate between odors was impaired (p < 0.006). We could not detect any statistical correlation between smell abilities and clinical manifestation of SSc or the FIQ and SF-36 scores among FM patients. However the correlation between depression, defined by the BDI-II score, and the sense of smell differed between patients with FM and patients with SSc. As only among SSc patients a lower sense of smell correlated with a higher BDI-II score (p = 0.02). Our findings suggest that there is a decrease in the sense of smell both in FM and SSc patients compared with healthy controls. However these impairments differ between patients group and might represent different mechanisms that affect the sense of smell.

The importance of cytokines and autoantibodies in depression

The relationship between depression and immunity has been widely discussed. Cytokines, such as TNF-α, play an important role in immune system; these cytokines interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. Antibodies have also been implicated in the pathophysiology of depression. The association between decreased serotonin levels and excessive glutamatergic activity forms the first biochemical basis for cytokine-induced depression. Cytokines and antibodies (anti-ribosomal-P and anti-N-methyl-D-aspartate receptor antibodies) are deeply related to pathogenesis of neurodevelopmental disorders, especially depression. Tumor necrosis factor alpha (TNF-α) may underlie the mechanism of depression by an activation of the hypothalamo-pituitary-adrenocortical (HPA) axis, an activation of neuronal serotonin transporters and the stimulation of the indoleamine 2,3-dioxygenase which leads to tryptophan depletion. In the last 20 years since the initial reports of neural-immune interactions in depression, studies have shown a clear association between activation of the immune system mediated by proinflammatory cytokines. Genes encoding cytokines are highly polymorphic and single nucleotide polymorphisms, associated with increased or reduced cytokine production, have been described. To date, there are only few studies that investigated the relationship between depression and proinflammatory cytokines in patients with autoimmune diseases. Although an associative link between neuroinflammation and mood disorders is widely accepted, further studies are necessary to establish the cause-effect relationship. In this paper, we review the role of cytokines, focusing on TNF-α and antibodies in the depression and hypothesize how TNF-α may underlie and mediate the inflammatory process depression in patients with autoimmune disease.