The association between sequential changes in serum antineuronal antibodies and neuropsychiatric systemic lupus erythematosus

The immunologic etiology of psychiatric manifestations in systemic lupus erythematosus: A narrative review on the role of the blood brain barrier, antibodies, cytokines and chemokines

INTRODUCTION

The aim of this narrative review is to provide an overview of the literature on the possible immunologic pathophysiology of psychiatric manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

A systematic search on PubMed was conducted. English studies with full text availability that investigated the correlation between blood-brain barrier (BBB) dysfunction, intrathecal synthesis of antibodies, antibodies, cytokines, chemokines, metalloproteinases, complement and psychiatric NPSLE manifestations in adults were included.

RESULTS

Both transient BBB-dysfunction with consequent access of antibodies to the cerebrospinal fluid (CSF) and intrathecal synthesis of antibodies could occur in psychiatric NPSLE. Anti-phospholipid antibodies, anti-NMDA antibodies and anti-ribosomal protein p antibodies seem to mediate concentration dependent neuronal dysfunction. Interferon-α may induce microglial engulfment of neurons, direct neuronal damage and production of cytokines and chemokines in psychiatric NPSLE. Several cytokines, chemokines and matrix metalloproteinase-9 may contribute to the pathophysiology of psychiatric NPSLE by attracting and activating Th1-cells and B-cells.

DISCUSSION

This potential pathophysiology may help understand NPSLE and may have implications for the diagnostic management and therapy of psychiatric NPSLE. However, the presented pathophysiological model is based on correlations between potential immunologic etiologies and psychiatric NPSLE that remain questionable. More research on this topic is necessary to further elucidate the pathophysiology of NPSLE.

Quality-of-life measurements versus disease activity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic disease affecting the physical, social, and psychological well-being of patients. Different instruments have been developed to measure health-related quality of life, some of which are SLE-specific. Contributors to poor quality of life in patients with SLE include fatigue, fibromyalgia, depression, and cognitive dysfunction. Health-related quality of life is not strongly associated with disease activity or organ damage. The Medical Outcomes Survey Short Form 36 is the most common instrument used to measure quality of life in SLE.

Autoantibodies involved in neuropsychiatric manifestations associated with systemic lupus erythematosus

In the course of Systemic Lupus Erythematosus (SLE), a variety of neuropsychiatric disturbances is reported with a prevalence ranging from 17% to 75%. The diagnosis of these syndromes is difficult and requires a careful psychiatric evaluation. Distinct autoantibodies detectable in serum or cerebrospinal fluid of patients with SLE are associated with the presence of neuropsychiatric disorders. These autoantibodies may have a pathogenic relevance in neuropsychiatric SLE or they may be merely an epiphenomenon. This review describes the various autoantibodies reported to be associated with neuropsychiatric manifestations in SLE and discusses their possible role.

Autoantibodies Involved in Neuropsychiatric SLE and Antiphospholipid Syndrome

OBJECTIVE

We sought (1) to identify and (2) to define the association of all reported antibodies (Abs) with neuropsychiatric lupus (NPSLE), (3) to search for possible mechanisms that are involved in NPSLE, and (4) to determine whether we can recognize a panel of Abs associated with specific neuropsychiatric (NP) manifestations.

METHODS

A MEDLINE search (1975 to 2005) was performed utilizing the following terms: neuropsychiatric lupus, antiphospholipid syndrome, or central nervous system systemic lupus erythematosus matched with the term antibodies.

RESULTS

Twenty Abs (11 brain-specific and 9 systemic) were described in NPSLE patients. These include Abs that target brain-specific antigens (neuronal, ganglioside, synaptosomes, glia, methyl-d-aspartate receptors, lymphocytotoxic) and systemic antigens (nuclear, cytoplasmic, phospholipid, endothelial cells). Cognitive impairment, psychosis, and depression were associated with many Abs. Elevated titers of anticardiolipin Abs (aCL) were reported most often and found in patients with cognitive impairment, psychosis, depression, seizures, chorea, and migraine. No specificity was encountered among brain-specific or systemic Abs for any single NP manifestation. No studies evaluated a specific NP manifestation with the full panel of 20 Abs. A panel of brain-specific and systemic Abs may be helpful in establishing the diagnosis of NPSLE. Postulated mechanisms in experimental models included vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.

CONCLUSIONS

NPSLE is associated with brain-specific and systemic Abs. Cognitive impairment, psychosis, and depression were associated with many Abs, including aCL Abs. Possible mechanisms include vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.

Cognitive dysfunction in the patient with antiphospholipid antibodies: considerations for cause and treatment

The evidence supporting a causal relationship between antiphospholipid (aPL) antibodies and cognitive dysfunction is very limited despite a general impression that one exists. Patients with aPL antibodies may complain of cognitive difficulties in their everyday lives, forcing the clinician to examine this issue. As with other non-thrombotic antiphospholipid syndrome (APS) manifestations, cognitive dysfunction in this population should be approached as a diagnosis of exclusion. The complexity in diagnosing and treating various manifestations of rheumatic disease holds true for identifying and addressing cognitive decline in these patients.

Autoantibody explosion in systemic lupus erythematosus: more than 100 different antibodies found in SLE patients

OBJECTIVE

Description of the various autoantibodies that can be detected in patients with systemic lupus erythematosus (SLE).

METHODS

A literature review, using the terms "autoantibody" and "systemic lupus erythematosus", was conducted to search for articles on autoantibodies in SLE, their target antigens, association with disease activity, or other clinical associations.

RESULTS

One hundred sixteen autoantibodies were described in SLE patients. These include autoantibodies that target nuclear antigens, cytoplasmic antigens, cell membrane antigens, phospholipid-associated antigens, blood cells, endothelial cells, and nervous system antigens, plasma proteins, matrix proteins, and miscellaneous antigens. The target of autoantibody, the autoantigen properties, autoantibody frequencies in SLE, as well as clinical associations, and correlation with disease activity are described for all 116 autoantibodies.

CONCLUSIONS

SLE is the autoimmune disease with the largest number of detectable autoantibodies. Their production could be antigen-driven, the result of polyclonal B cell activation, impaired apoptotic pathways, or the outcome of idiotypic network dysregulation.

Cognitive dysfunction and antiphospholipid antibodies in systemic lupus erythematosus

Nervous system involvement in systemic lupus erythematosus (SLE) is typically diagnosed on the basis of clinical psychiatric and/or neurologic syndromes (NPSLE). Neuropsychological tests can be used to assess nervous system integrity even in the absence of major NP syndromes. Their application has uncovered significant cognitive dysfunction, ranging from mild to severe, in a sizeable proportion of SLE patients irrespective of clinical NP status. Cognitive dysfunction has now been accepted as a bona fide manifestation of NPSLE. The heterogeneity of clinical NPSLE manifestations is paralleled by the diversity of cognitive deficits reported in different studies and within different patients. The success of attempts to explain these deficits on the basis of potential pathogenetic mechanisms, such as antibrain antibodies and proinflammatory cytokines, has been uneven. To date, the most robust findings have emerged in relation to antiphospholipid antibodies, which carry with them important therapeutic implications.

Systemic lupus erythematosus presenting with steroid-responsive parkinsonism and post-hemiplegic dystonia

A young male patient who presented with steroid-responsive parkinsonism, hemiplegia, thrombocytopaenia and systemic illness who was subsequently diagnosed to have systemic lupus erythematosus (SLE) is described. He later developed post-hemiplegic dystonia. Thalamic lesions on magnetic resonance imaging (MRI) are demonstrated. Clinical features and neuropathology of central nervous system lupus are discussed. This is the first report of SLE presenting with Parkinsonism, and the first to demonstrate anatomically-relevant MRI lesions in Parkinsonism associated with SLE.Copyright Lippincott-Raven Publishers

Cognition and mood in systemic lupus erythematosus. Evaluation and pathogenesis

Cognitive dysfunction is frequent in SLE, probably related to primary underlying immune/inflammatory mechanisms operating in the brain. Longitudinal studies relating patterns of cognitive impairment to putative pathogenetic factors would provide evidence for this hypothesis. Such studies could also lead to more specific therapeutic interventions to ameliorate or reverse brain compromise in SLE.

Neurobehavioral alterations in autoimmune mice

Inbred MRL, NZB and BXSB strains of mice spontaneously develop a systemic, lupus-like autoimmune disease. The progress of autoimmunity is accompanied with a cascade of behavioral changes, most consistently observed in tasks reflective of emotional reactivity and the two-way avoidance learning task. Given the possibility that behavioral alterations may reflect a detrimental consequence of autoimmune-inflammatory processes and/or an adaptive response to chronic malaise, they are tentatively labeled as autoimmunity-associated behavioral syndrome (AABS). It is hypothesized that neuroactive immune factors (pro-inflammatory cytokines, brain-reactive antibodies) together with endocrine mediators (corticotropin-releasing factor, glucocorticoids) participate in the etiology of AABS. Since AABS develops natively, and has a considerable face and predictive validity, and since the principal pathway to autoimmunity is known, AABS may be a useful model for the study of CNS involvement in human autoimmune diseases and by extension, for testing autoimmune hypotheses of several mental disorders (major depression, schizophrenia, Alzheimer's disease, autism and AIDS-related dementia).

Nervous system lupus: pathogenesis and rationale for therapy

Several different pathogenic mechanisms appear to be involved in CNS lupus. These include: B-cell/autoantibody-mediated nervous system compromise; immune complex deposition and vasculitis; microthrombosis and vasculopathy; aberrant MHC Class II antigen expression with T-cell mediated disease (multiple-sclerosis model); and, cytokine-induced brain inflammation. These processes are not mutually exclusive: there exist in vitro and in vivo models for each of these. A number of autoantibodies, especially those with specificities for shared neuronal/lymphocyte antigens, are associated with certain forms of cognitive dysfunction or overt nervous system manifestations. In MRL/lpr mice, lymphoid infiltrates in the brain parenchyma are related to a neurobehavioural dysfunction which develops very early in the course of autoimmune disease. Recent results, both in animal models and in human studies on the therapeutic effects of corticosteroids, immunosuppressive drugs or anticoagulants on clinical and subclinical manifestations of CNS lupus are highlighted in an attempt to develop a rationale for intervention based upon presumed pathogenesis.

Corticosteroids and neuropsychological functioning in patients with systemic lupus erythematosus

OBJECTIVE

This study was designed to assess the effects of corticosteroids on select aspects of nervous system functioning, specifically, cognition and mood, as well as disease-related symptoms in individual patients with mild systemic lupus erythematosus (SLE) and mild neuropsychiatric (NP) symptoms.

METHODS

Ten women who had not been taking corticosteroids for at least 6 months were selected from a referral-based lupus clinic to participate in an N of 1 double-blind, controlled trial consisting of 3 randomly assigned drug/placebo pairings, with a drug dose of 0.5 mg/kg of prednisone daily.

RESULTS

Analysis of variance on the group data yielded significant positive drug effects for cognition (P = 0.02), mood (P = 0.003), and SLE symptom ratings (P = 0.0002). Drug efficacy was also evaluated by an objective decision rule, which yielded evidence of overall drug benefit in 5 of the 8 patients who completed the trial, and a deleterious drug effect in 1 patient. Posttrial clinical results indicated that for the 8 women who completed the trial, "acceptable" decisions, leading to remission of SLE symptoms or appropriate withholding of steroids, were made on the basis of this rule.

CONCLUSION

Improvement in cognition, mood, and/or SLE symptom ratings can be observed following brief exposure to relatively low doses of corticosteroids in individual women with mild SLE; these persist over repeated drug exposure. The current application of N of 1 methodology represents the first systematic study of steroid efficacy in central nervous system (CNS)-related problems in SLE. The results can now be applied to the design of randomized, controlled trials of the effects of corticosteroids on CNS function in SLE.

Brain reactive autoantibodies and cognitive impairment in systemic lupus erythematosus

Nervous system involvement in SLE encompasses a wide array of clinical manifestations which may reflect multiple etiologic factors including autoantibodies to nervous tissue antigens. The aim of the present study was to examine the association between autoantibodies to a wide range of brain antigens and cognitive abnormalities in an unselected population of 70 SLE patients. Using a battery of standardized neuropsychological tests, cognitive impairment was identified in 15/70 (21%) SLE patients compared with 1/25 (4%) patients with rheumatoid arthritis and 1/23 (4%) healthy subjects (P = 0.04). Integral membrane proteins were isolated from dissociated brain cells by temperature-induced phase separation with Triton X-114. Synaptosomes were isolated by differential centrifugation and membrane enriched fractions were prepared by lectin affinity chromatography. Western blotting identified IgG reactivity to a wide range of proteins (MW 22-52 K) in SLE patients. The proteins identified were distinct from well-characterized intracellular antigens including ribosomal P proteins. There was no significant difference in the prevalence of anti-brain antibodies between SLE patients who were cognitively impaired and those who were not impaired. Furthermore, there was no association between the presence of autoantibodies and subsets of cognitive dysfunction. These results suggest that circulating autoantibodies to brain antigens are not responsible for the abnormalities in cognitive function in SLE patients.

Lymphocyte antigens in neuropsychiatric systemic lupus erythematosus. Relationship of lymphocyte antibody specificities to clinical disease

OBJECTIVE

To examine the relationships among specific lymphocyte antigenic reactivities of lupus sera and central nervous system complications of systemic lupus erythematosus (SLE), lymphocytotoxic antibody (LCA) positivity, and specific cognitive impairment.

METHODS

Sera from 115 patients with SLE were examined for the presence of IgM- and IgG-class autoantibodies binding to surface target antigens on lymphocytes, by immunoblotting and microdroplet lymphocytotoxicity studies. Seventy-three of these patients also underwent detailed neuropsychological testing within the same time period.

RESULTS

Significant associations were found between reactivities to several lymphocyte antigenic moieties and neuropsychiatric SLE (NPSLE) or cognitive impairment. Specifically, immunoblot reactivities to 31-32-kd, 50-52-kd, 54-56-kd, and 97-98-kd targets were associated with clinical NPSLE; there was a significant association between reactivity to the 50-52-kd moiety in particular and cognitive impairment. There were also associations between LCA and immunoblot reactivity. Furthermore, the previously reported association between LCA positivity and specific visuospatial cognitive impairment was confirmed with data obtained from 2 different batteries of neuropsychological tests.

CONCLUSION

In some cases, specific antigenic targets of LCA-containing sera may be implicated in the pathogenesis of NPSLE:

Antibodies to brain integral membrane proteins in systemic lupus erythematosus

Wheat germ lectin affinity chromatography and temperature-induced phase separation with Triton X-114 were evaluated for the isolation of surface neuronal antigens from rat and human brain and from human neuroblastoma cell lines IMR-6 and SK-N-SH. Both techniques yielded surface proteins which were free of contamination by intracellular proteins but temperature-induced phase separation was technically less demanding and less expensive, required a shorter assay time and resulted in a superior quantity and quality of isolated proteins. Rat brain surface proteins were used for characterization of antineuronal antibody reactivity in sera from patients with systemic lupus erythematosus (SLE). Western blotting identified reactivity in 15 of 75 (20%) SLE sera compared to five of 95 (5%) normal controls (P 0.006). In rat brain the molecular weight of the individual proteins identified ranged from 59 kDa to 22 kDa. Six of these were also present in human brain and two were present in neuroblastoma cell lines. Absorption studies indicated that some of the antigenic proteins were either restricted to brain tissue or shared with other non-neuronal tissues. These techniques should facilitate the characterization of antineuronal antibody reactivities and lead to a clearer understanding of their role in the pathogenesis of autoimmune neurologic disease.

Brain synaptosomal antibodies in systemic lupus erythematosus

Nervous system involvement in systemic lupus erythematosus (SLE) has been linked to the production of autoantibodies that may bind to surface antigens on neuronal cells and cause cellular dysfunction. At present, little is known of the target antigens recognized by these antibodies. The aim of the present study was to examine reactivity to rat brain synaptosomes (RBS) in sera from patients with SLE. Sera from 73 unselected SLE patients and controls were studied. Crude RBS were prepared by differential centrifugation and enriched fractions of synaptosomes (SY-E), myelin (MY-E) and mitochondria (MI-E) were obtained by sucrose density centrifugation. Rat liver (RL) was used for control antigens. Wheat-germ lectin affinity chromatography yielded membrane-enriched fractions of RBS, RL and whole rat brain (WRB). Antibody binding was examined by Western blotting. IgM reactivity was detected in 12/73 sera (16%) and was directed to proteins of 62K, 48K 37K molecular weight. IgG reactivity was present in 5/73 sera (7%) to proteins of 52K, 48K, 37K and 29K molecular weight. Except for binding to the 52K and 37K proteins these autoantibodies were not detected in control sera. Reactivity was usually absent, or present in reduced amounts, in WRB and RL. Additional experiments revealed that binding of IgM to 62K was found predominantly in SY-E and MY-E fractions, 48K in SY-E and MI-E fractions and 37K in the SY-E fraction. Binding of IgG to 48K and 29K was detected in the SY-E and MI-E, but reactivity to 52K and 37K was restricted to the SY-E fraction. Thus, sera from SLE patients contain antibodies to synaptosomal antigens that may contribute to the neuropsychiatric manifestations of the disease.

Assessment of cognitive function in patients with systemic lupus erythematosus

The spectrum of central nervous system manifestations of systemic lupus erythematosus (SLE) is very broad and has been found to include subtle subclinical cognitive dysfunction which may be detected only by the lengthy process of detailed neuropsychological evaluation. This study reports the value of estimating premorbid intelligence as a simple yet effective means of screening for subclinical cognitive dysfunction. Twenty one female patients with clinically quiescent SLE underwent neuropsychological examination at entry to the study. In all patients, this examination included measurement of full-scale intelligence quotient (IQ), verbal and performance IQ as well as verbal and visual memories. In addition, premorbid intelligence was estimated using the Schonell graded word reading test. Nine patients (43%) gave a history of neuropsychiatric (NP) disease. No difference was identified between the results of the neuropsychological evaluation in these 9 patients and in either the other SLE patients or in age and sex matched control patients. Sixteen patients were re-evaluated 1 year later. A comparison of measured full-scale IQ with the estimated premorbid intelligence identified a subgroup of 3 patients who demonstrated a significant reduction in intelligence. Unlike the other 13 patients, these 3 patients had multiple (3 or more) other features of cognitive impairment.

Antibodies to protein P in systemic lupus erythematosus

A synthetic peptide was used to develop an enzyme linked immunosorbent assay (ELISA) to detect antibodies to the ribosomal proteins P0, P1, and P2. Significantly increased levels of IgG antibodies to protein P were found in 16% (18/116) of patients with systemic lupus erythematosus but slightly increased levels were detected in 2% (2/98) of patients with rheumatoid arthritis and one normal control subject. No association was observed between the presence of IgG antibodies to protein P and either lupus psychosis or depression. Sequential studies in individual patients failed to show an association between antibody levels and the development of psychosis.

Diagnosis and pathogenesis of CNS lupus

The central nervous system (CNS) is clinically involved in approximately 40% of all systemic lupus erythematosis (SLE) patients. Minor psychiatric symptoms and abnormalities on neuropsychological testing are being detected with increasing frequency. This review summarizes current thinking concerning the diagnosis and pathogenesis of CNS lupus. The main symptoms of CNS lupus can be diffuse (generalized seizures, psychosis) or focal (stroke, peripheral neuropathies). Neuropsychiatric symptoms often occur in the first year of SLE, but are rarely the presenting symptoms of the disease. In studies on the pathology of CNS lupus, vasculopathy, infarcts and haemorrhages are often observed, whereas vasculitis is rare. Endocardial lesions and mural thrombi have also been reported in 33-50% of CNS lupus patients. In diagnostic imaging of the CNS, magnetic resonance imaging (MRI) scans often provide evidence for edema or small infarcts, both in focal and diffuse CNS lupus, whereas computerized tomography (CT) scans only show gross abnormalities. The first reports on position emission tomography (PET) scans in CNS lupus patients show decreased glucose uptake in the brain. The cerebral blood flow decreases during active diffuse and focal CNS lupus. The blood-brain barrier is somewhat more frequently impaired in diffuse CNS lupus. Intrathecal IgG and IgM production is observed in 25-66% of all CNS lupus patient. Various specificities of autoantibodies have been observed in CNS lupus. Of these, anticardiolipin (ACA) antibodies show a well-documented association with focal involvement of the CNS in SLE. These antibodies could cause thrombosis by interfering with the protein C pathway of fibrinolysis. In addition, they are associated with endocardial and valvular heart disease, which is often observed in SLE and which could cause embolism. The relation between ACA and diffuse CNS lupus is not yet clear. Low-avidity anti-DNA antibodies are also found in CNS lupus, possibly because of their cross-reaction with cardiolipin. Antineuronal antibodies and lymphocytotoxic antibodies have been associated with diffuse CNS lupus and abnormalities on neuropsychological testing. However, the population of these antibodies is rather heterogeneous and it has not been possible to assess a common target antigen. Therefore, it is still obscure whether there is also a second immune-mediated mechanism responsible for the development of the diffuse form of CNS lupus.