Differential roles of the anti-ribosomal P antibody and antineuronal antibody in the pathogenesis of central nervous system involvement in systemic lupus erythematosus

Neuropsychiatric involvement in systemic lupus erythematosus: A review

The neuropsychiatric involvement in systemic lupus erythematosus (NPSLE) is a challenge for clinicians, both at a diagnostic and therapeutic level. Although in 1999 the American College of Rheumatology (ACR) proposed a set of definitions for 19 NPSLE syndromes, with the intention of homogenizing the terminology for research purposes and clinical practice, the prevalence of NPSLE varies widely according to different series and is estimated to be between 37 and 95%. This is due to multiple factors such as the unalike definitions used, the diverse design of the studies, type of population, race, type and severity of symptoms, and follow-up of the different cohorts of patients with SLE. In recent years, some authors have tried excluding minor neuropsychiatric manifestations in order to try to reduce this wide variation in the prevalence of NPSLE since they are very prevalent in the general population; others authors have developed various models for the attribution of neuropsychiatric events to SLE that can assist clinicians in this diagnostic process, and finally, some authors developed and validated in 2014 a new algorithm based on the definitions of the ACR that includes the evaluation of the patient's lupus activity together with imaging techniques and the analysis of cerebrospinal fluid (CSF), with the aim of trying to differentiate the true neuropsychiatric manifestations attributable to SLE. In 2010, the European League Against Rheumatism (EULAR) developed recommendations for the management of NPSLE. We found abundant literature published later where, in addition to the recommendations for the management of the 19 NPSLE syndromes defined by the ACR, additional recommendations are given for other neurological and/or psychiatric syndromes, conditions, and complications that have been associated to SLE in recent years. We review below the diagnostic and therapeutic management of the different entities.

What are the latest clinical findings regarding the association of neurotoxic brain antibodies found in the cerebrospinal fluid in patients with autoimmune disorders?

PURPOSE OF REVIEW

Recently, experiments show that the autoantibodies with direct access to neurons following blood brain barrier (BBB) disruption destroy neurons and lead to remodeling in damaged neurons. These are critical steps in autoantibody-mediated central nervous system disorder called neuropsychiatric syndromes in systemic lupus erythematosus (NPSLE). The purpose of this review is to examine therapeutic opportunities to repress neuronal remodeling by microglia after acute neuronal injury by autoantibodies.

RECENT FINDINGS

Recent studies have demonstrated that BBB disruption is a critical step for developing NPSLE, and serum anti-Sm antibodies have been significantly associated with BBB breakdown. In addition, it has been reported that antiglucose regulated protein-78 in patients with SLE also disrupt the BBB. Experiments with anti-N-methyl-D-aspartate antibodies show that HMGB1 and C1q were essential to activate microglia which, in turn, remodel damaged neurons in vivo. Interestingly treatment with angiotensin-converting enzyme inhibitor inactivated microglia and blunted neuronal remodeling as well as positively affected behavioral abnormalities.

SUMMARY

BBB disruption, acute neuronal damage and neuronal remodeling by activated microglia are all critical steps for NPSLE development, and each step will afford novel therapeutic targets.

Developmental process in diffuse psychological/neuropsychiatric manifestations of neuropsychiatric systemic lupus erythematosus

Systemic lupus erythematosus (SLE) involves excessive autoimmune reactions, with pathogenesis characterized by autoantibody production. Although the specific mechanism underlying the development of neuropsychiatric syndromes in SLE (NPSLE) is still unclear, recent studies indicate the involvement of autoimmune pathophysiology. We previously identified the presence of anti-N-methyl-d-aspartate receptor subunit GluN2 antibody (anti-GluN2) as a functional autoantibody which is able to impair neurons and is essential for the diagnosis of diffuse psychiatric/neuropsychological syndromes in NPSLE (dNPSLE). Other autoantibodies like anti-Sm antibodies and anti-glucose-regulated protein 78 antibodies are known to compromise blood brain barrier (BBB) integrity. We demonstrated that high mobility group box-1 protein (HMGB1) decorates synapses on neurons damaged by anti-neuron antibodies, including anti-GluN2, where it behaves as a linker to enhance C1q binding to synapses in a dNPSLE model mouse. This C1q binding via HMGB1 is a critical step for remodeling by activated microglia, which leads to reductions in neuronal complexity and long-term behavioral abnormalities. Suppression of activated microglia can significantly reduce central nervous system (CNS) dysfunction. In this review, we describe the critical steps in the development of dNPSLE in particular, including the phases of BBB breakdown, acute neuronal damage by autoantibodies and neuronal remodeling due to activated microglia.

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.

Is serum TWEAK a useful biomarker of neuropsychiatric systemic lupus erythematosus?

The aim of this study was to determine the role of the tumor necrosis factor like weak inducer of apoptosis (TWEAK) as a serum biomarker of neuropsychiatric involvement in systemic lupus erythematosus (NPSLE). Levels of TWEAK levels were measured in sera of 92 patients with systemic lupus erythematosus (SLE), including 28 patients with neuropsychiatric lupus, and in 59 healthy controls using ELISA. All SLE patients underwent rheumatological, neurological and psychiatric assessment. We found no significant differences in TWEAK levels, between SLE patients and the healthy controls (p=0.2411). Similarly, no difference was observed between subgroup of NPSLE and healthy controls (p=0.7658). The mean SLE disease activity (SLEDAI) was 13.25. No correlations between TWEAK levels with disease activity (SLEDAI, r=0.2113, p=0.2805) or the most common NPSLE manifestations such as headache (r=0.2079), seizures (r=0.1101), cerebrovascular disease (r= 0.2347), cognitive dysfunction (r=0.1597) and anxiety (r=0.1397) were observed. Our data do not support the use of serum TWEAK as a discriminating biomarker for NPSLE. The role of the TWEAK in NPSLE remains to be investigated.

Neuroprotective effect of microglia against impairments of auditory steady-state response induced by anti-P IgG from SLE patients in naïve mice

OBJECTIVE

Autoantibodies against ribosomal P proteins (anti-P antibodies) are strongly associated with the neuropsychiatric manifestations of systemic lupus erythematosus (NPSLE). The present study was designed to assess whether anti-P antibodies can induce abnormal brain electrical activities in mice and investigate the potential cytopathological mechanism.

METHODS

Affinity-purified human anti-ribosomal P antibodies were injected intravenously into mice after blood-brain barrier (BBB) disruption. The auditory steady-state response (ASSR) was evaluated based on electroencephalography (EEG) signals in response to 40-Hz click-train stimuli, which were recorded from electrodes implanted in the skull of mice. Immunofluorescence staining was used to examine the morphology and density of neurons and glia in the hippocampus and cortex. The presence of apoptosis in the brain tissues was studied using the TUNEL assay. A PLX3397 diet was used to selectively eliminate microglia from the brains of mice.

RESULTS

Circulating anti-P antibodies caused an enhancement of the ASSR and the activation of microglia through the disrupted BBB, while no obvious neural apoptosis was observed. In contrast, when microglia were depleted, anti-P antibodies induced a serious reduction in the ASSR and neural apoptosis.

CONCLUSION

Our study indicates that anti-P antibodies can directly induce the dysfunction of auditory-evoked potentials in the brain and that microglia are involved in the protection of neural activity after the invasion of anti-P antibodies, which could have important implications for NPSLE.

Differential expression of antibodies to NMDA receptor in anti-NMDA receptor encephalitis and in neuropsychiatric systemic lupus erythematosus

Objective

Anti-NMDA receptor encephalitis is the most prevalent autoimmune encephalitis having characteristic clinical features with autoantibodies against tetrameric transmembrane channels composed of combinations of NR1 subunits of NMDA receptors with NR2 subunits, which are detected by cell-based assay (anti-NR1/NR2). On the other hand, antibodies against the linear epitope in NR2 subunit (anti-NR2) have been shown to be expressed in patients with diffuse psychiatric/neuropsychological syndromes of neuropsychiatric SLE (diffuse NPSLE). However, it has not been explored whether anti-NR1/NR2 might be detected in NPSLE, nor has it been clear whether anti-NR2 might have cross-reactivity with anti-NR1/NR2. The current study was therefore performed to explore the prevalence of anti-NR1/NR2 in NPSLE.

Methods

Serum specimens were obtained from 31 patients with NPSLE (22 with diffuse NPSLE and 9 with neurological syndromes or polyneuropathy) and from 18 normal healthy subjects. Anti-NR2 and anti-NR1/NR2 were measured by ELISA and cell-based assay, respectively. The positivity for anti-NR2 was defined by a value exceeding mean+2 SD of normal healthy subjects.

Results

Anti-NR2 was positive in the sera of 19 of 31 patients with NPSLE (in 15 of 22 patients with diffuse NPSLE). By contrast, anti-NR1/NR2 was positive only in 2 of 31 patients with NPSLE (in 2 of 22 patients with diffuse SLE). The positivity for anti-NR1/NR2 was not correlated with anti-NR2 values.

Conclusions

These results demonstrate that the prevalence of anti-NR1/NR2 is extremely low in NPSLE. Moreover, the data also confirm that anti-NR2 antibodies do not have cross-reactivity with anti-NR1/NR2.

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

OBJECTIVES

We explored the impact of circulating anti-N-methyl-D-aspartate receptor (NMDAR) antibodies on the severity of fatigue in patients with systemic lupus erythematosus (SLE).

METHODS

Serum samples of 426 patients with SLE were analysed for the presence of antibodies to the NR2 subunit of the NMDAR. In parallel, the severity of fatigue was determined according to the Fatigue Scale for Motor and Cognitive functions questionnaire. In a subgroup of patients with SLE, the hippocampal volume was correlated with the levels of anti-NR2 antibodies. Isolated immunoglobulin G from patients with anti-NR2 antibodies were used for murine immunohistochemical experiments and functional assays on neuronal cell lines. Treatment effects were studied in 86 patients with lupus under belimumab therapy.

RESULTS

We found a close correlation between the titre of anti-NR2 antibodies, the severity of fatigue, the clinical disease activity index (Systemic Lupus Erythematosus Disease Activity Index 2000) and anti-double stranded DNA antibodies-independently of the presence of neuropsychiatric lupus manifestations. Pathogenic effects could be demonstrated by (1) detection of anti-NR2 antibodies in the cerebrospinal fluid, (2) in situ binding of anti-NR2 antibodies to NMDAR of the hippocampus area and (3) distinct functional effects in vitro: downregulating the energy metabolism of neuronal cells without enhanced cytotoxicity. Treatment with belimumab for at least 6 months affected both the severity of fatigue and the levels of anti-NR2 antibodies.

CONCLUSION

The presence of anti-NR2 antibodies in patients with SLE with fatigue is a helpful diagnostic tool and may offer a major approach in the therapeutic management of this important disabling symptom in patients with SLE.

Antibodies and the brain: anti-N-methyl-D-aspartate receptor antibody and the clinical effects in patients with systemic lupus erythematosus

PURPOSE OF REVIEW

Neuropsychiatric manifestations are one of the fatal complications in patients with systemic lupus erythematosus (SLE). However, the diagnosis and monitoring of that aspect of SLE is still challenging, as there are no reliable biomarkers linked to central nervous system (CNS) damage. This review emphasizes potential candidate autoantibodies that appear to be associated with development of behavioral and psychiatric manifestations in SLE patients.

RECENT FINDINGS

Developments in the pathogenesis in SLE, not surprising for this immune disorder, point to specific, autoantibody toxicity. Namely, the discovery of an antibody which reacts with DNA and with the extracellular domain of N-methyl-D-aspartate (NMDA) receptor subunit GluN2A and 2B (anti-NMDA), an important receptor on neurons that is ubiquitous in the CNS, may lead to new insights into the behavioral and psychiatric manifestations in SLE. These anti-NMDA antibodies induce neuronal apoptosis and degeneration of surviving neurons in murine models. This functional antibody is also detected in SLE patients who have behavioral and psychiatric manifestations. The presence of anti-NMDA in cerebrospinal fluid but not in serum is associated significantly with overwhelming CNS abnormalities, suggesting importance of direct access of autoantibodies to brain dysfunction.

SUMMARY

As anti-NMDA autoantibodies are present in patients who develop psychiatric manifestations in SLE, it is possible that novel therapeutic approaches will depend on altering the activity of these autoantibodies.

Elevation of serum anti-glucose-regulated protein 78 antibodies in neuropsychiatric systemic lupus erythematosus

Objective

Recent studies have demonstrated that autoantibodies directed against glucose-regulated protein 78 (GRP78) on endothelial cells promote blood–brain barrier (BBB) damages. The present study examined whether serum anti-GRP78 antibodies might be involved in the pathogenesis of neuropsychiatric SLE (NPSLE).

Methods

Serum samples were obtained from 129 patients with SLE (58 patients with diffuse psychiatric/neuropsychological syndromes of NPSLE (diffuse NPSLE), 30 with neurological syndromes (focal NPSLE), 21 with lupus nephritis (LN), 20 without NPSLE or LN (SLE alone)), from 35 patients with non-SLE rheumatic diseases (non-SLE RD) and from 24 healthy controls (HC). Anti-GRP78 levels were measured with an ELISA, using recombinant GRP78 as antigens. Cerebrospinal fluid (CSF) samples were also obtained from 88 patients with NPSLE. The BBB function was evaluated by Q albumin ((CSF albumin/serum albumin)×10³).

Results

Serum anti-GRP78 levels were significantly elevated in SLE compared with non-SLE RD or HC. There were no significant differences in serum anti-GRP78 levels among NPSLE, LN and SLE alone. Of note, serum anti-GRP78 levels were significantly higher in acute confusional state (ACS) than in non-ACS diffuse NPSLE (p=0.0001) or in focal NPSLE (p=0.0002). Finally, serum anti-GRP78 levels were significantly correlated with Q albumin (r=0.294, p=0.0054) in NPSLE.

Conclusion

These results indicate that anti-GRP78 antibodies are associated with the development of diffuse NPSLE, especially ACS. Thus, the data suggest that anti-GRP78 antibodies might contribute to the development of ACS through the damages of BBB.

Anti-ribosomal P protein antibodies influence mortality of patients with diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematous involving a severe form of the disease

Objectives: The aim of this study is to clarify the effect of various autoantibodies on overall mortality in patients with diffuse psychiatric/neuropsychological syndromes in SLE (diffuse NPSLE). Methods: Fifty-five patients with diffuse NPSLE admitted from 1992 to 2017 had met inclusion criteria and were recruited for this study. The relationship of various serum autoantibodies with mortality was retrospectively analyzed based on the medical charts. Results: Of 55 patients, 14 patients [25.5%] had died during the observation period (2728 [22-8842] days (median [range])). The 5-year, 10-year, 15-year and 20-year mortality rates were 18.8%, 21.9%, 36.9% and 47.4%, respectively. Among various serum autoantibodies at the onset of diffuse NPSLE, only the presence of anti-ribosomal P protein antibodies (anti-ribo P) significantly increased the risk for death (relative risk 2.262, 95% confidence interval 1.276-4.417, p = 0.005). Of 14 fatal patients, 10 patients had died within 1 y after the onset of diffuse NPSLE. Remarkably, 7 of 10 patients with positive anti-ribo P had died of the severe complication primarily attributed to SLE except for one patient. Conclusions: The presence of anti-ribo P is a significant risk factor for overall poor prognosis in patients with diffuse NPSLE, involving a fatal complication by SLE.

The Role of Brain-Reactive Autoantibodies in Brain Pathology and Cognitive Impairment

Antibodies to different brain proteins have been recently found to be associated with an increasing number of different autoimmune diseases. They need to penetrate the blood–brain barrier (BBB) in order to bind antigens within the central nervous system (CNS). They can target either neuronal or non-neuronal antigen and result in damage either by themselves or in synergy with other inflammatory mediators. Antibodies can lead to acute brain pathology, which may be reversible; alternatively, they may trigger irreversible damage that persists even though the antibodies are no longer present. In this review, we will describe two different autoimmune conditions and the role of their antibodies in causing brain pathology. In systemic lupus erythematosus (SLE), patients can have double stranded DNA antibodies that cross react with the neuronal N-methyl-d-aspartate receptor (NMDAR), which have been recently linked to neurocognitive dysfunction. In neuromyelitis optica (NMO), antibodies to astrocytic aquaporin-4 (AQP4) are diagnostic of disease. There is emerging evidence that pathogenic T cells also play an important role for the disease pathogenesis in NMO since they infiltrate in the CNS. In order to enable appropriate and less invasive treatment for antibody-mediated diseases, we need to understand the mechanisms of antibody-mediated pathology, the acute and chronic effects of antibody exposure, if the antibodies are produced intrathecally or systemically, their target antigen, and what triggers their production. Emerging data also show that in utero exposure to some brain-reactive antibodies, such as those found in SLE, can cause neurodevelopmental impairment since they can penetrate the embryonic BBB. If the antibody exposure occurs at a critical time of development, this can result in irreversible damage of the offspring that persists throughout adulthood.

Diagnosing and attributing neuropsychiatric events to systemic lupus erythematosus: time to untie the Gordian knot?

Neurological and psychiatric syndromes, collectively referred to as NPSLE, occur frequently in SLE. The frequency of NPSLE varies from 21 to 95%; however, only 13-38% of neuropsychiatric (NP) events could be attributable to SLE in the NPSLE SLICC inception cohort. This variability in the frequency of NPSLE is attributable to the low specificity of the ACR case definitions for SLE-attributed NP syndromes, inclusion of minor NP events in the ACR nomenclature, difficulty in ascertainment of NP events and diverse experience of rheumatologists in the clinical assessment of NP events. Making the correct and early attribution of NP events to SLE is important to institute appropriate immunosuppressive treatment for favourable outcomes. Various attribution models using composite decision rules have been developed and used to ascribe NP events to SLE. This review will focus on the various clinical presentations, diagnostic work-up and attributions of the common NPSLE syndromes, including other NP events not included in the ACR nomenclature but which have come to attention in recent years.

Flares in systemic lupus erythematosus: diagnosis, risk factors and preventive strategies

Despite advances in the treatment, patients with systemic lupus erythematosus (SLE) often experience disease exacerbations (flares) of varying severity. Their diagnosis is primarily made on clinical grounds after exclusion of other diseases or disturbances, primarily infections, and can be assisted by the use of validated clinical indices. Serological tests such as serum complement fractions and anti-dsDNA autoantibodies, are helpful in monitoring SLE activity, but they lack high diagnostic accuracy. Flares are more frequent in patients with persistent immunological and clinical activity, and have been described as significant risk factor for development of irreversible end-organ damage. Accordingly, prevention of flares has been recognized as a distinct therapeutic target in SLE and involves adequate control of disease activity, use of hydroxychloroquine, maintaining immunosuppressive or biologic therapy for several years, and avoiding non-compliance issues. The future holds promise for the discovery of biomarkers that will accurately predict or diagnose SLE flares, thus allowing for the implementation of patient-tailored preventive strategies.

Review: Neuropsychiatric involvement in pediatric systemic lupus erythematosus

Neuropsychiatric (NP) manifestations are found in approximately 25% of children and adolescents with pediatric SLE (pSLE). In 70% of those, NP involvement will occur within the first year from the time of diagnosis. Headaches (66%), psychosis (36%), cognitive dysfunction (27%) and cerebrovascular disease (24%) are the most common presentations. The support of a psychiatrist is often required. Anti-phospholipid antibodies are associated with distinct NP disease entities and may be implicated in the pathogenesis of several manifestations of NP-pSLE including chorea, cerebrovascular disease and seizures. The role of novel auto-antibodies and imaging modalities is currently explored. The treatment of NP-pSLE is not based on prospective studies; however, an immunosuppressive combination therapy consisting of high doses of prednisone and a second line agent such as cyclophosphamide or azathioprine is commonly suggested for children with NP-pSLE. The role of novel therapies is currently studied. The outcome of children with NP-pSLE is relatively good. The overall survival is 95—97%, 20% of children experience a disease flare during childhood and 25% have evidence of permanent neuropsychiatric damage. Lupus (2007) 16, 564—571.

Neuropsychiatric manifestations in pediatric systemic lupus erythematosus: a 20-year study

The objective of this study was to investigate the manifestations, treatment and outcome of neuropsychiatric (NP) involvement in pediatric systemic lupus erythematosus (SLE) patients. The charts of 185 pediatric patients with SLE diagnosed between 1985 and 2005 in a tertiary referral hospital were retrospectively reviewed. NPSLE were defined using the American College of Rheumatology NPSLE case definitions. NPSLE developed in 34.6% (64/185) of the patients. The mean onset age was 15.2 years. Fourteen patients (21.9%) had NP manifestations on initial diagnosis of SLE. The median duration from the onset of SLE to NP manifestation was 11 months. The most frequent NP manifestations were seizure disorder (84.4%), ischemic stroke (28.1%) and psychosis (21.9%). However, the prevalence of manifestations of NPSLE might be underestimated by the retrospective design of our study. Higher mean C3/C4 levels, less percentage of anti-dsDNA antibodies elevation and higher percentage of elevated anticardiolipin antibodies were observed in NPSLE events than in non-NPSLE events ( P 0.05). The mortality rate of NPSLE patients decreased from 52.2% in 1985–1994 cohort to 27.8% in 1995–2005 cohort. In the past 10 years, the leading cause of death in NPSLE patients was NPSLE itself. NPSLE is common in pediatric SLE patients. It has diverse manifestations and a high mortality.

Brain MRI in patients with acute confusional state of diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus

OBJECTIVE

The objective of this study is to explore the characteristics of brain MRI abnormalities in acute confusional state (ACS) in neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Thirty-six patients with ACS admitted to our institutions from 1992 to 2015 were exhaustively enrolled. Their medical charts and brain MRI scans were reviewed.

RESULTS

Eighteen of 36 ACS patients had MRI abnormalities, mostly high-intensity lesions of various sizes in the cerebral white matter. MRI abnormalities improved after treatment in 12 of 14 patients in follow-up studies. MRI abnormalities were not correlated with ages at the onset of ACS, disease durations of SLE, the presence of anti-DNA, anti-phospholipid or anti-ribosomal P antibodies, or IL-6 levels in sera or cerebrospinal fluid. Notably, MRI abnormalities were significantly associated with the presence of serum anti-Sm antibodies (p = 0.0067). Finally, eight of the 18 patients with MRI abnormalities, but none of the other 18 patients without MRI abnormalities, died from active SLE. Thus, MRI abnormalities significantly increased the mortality in ACS (p = 0.0013, HR =10.36 [95% CI: 2.487-43.19]).

CONCLUSION

These results demonstrate that patients with ACS with MRI abnormalities have more severe diseases, resulting in poorer prognoses. The data also indicate that anti-Sm is involved in the development of MRI abnormalities in ACS.

Biomarkers for CNS involvement in pediatric lupus

CNS disease, or central neuropsychiatric lupus erythematosus (cNPSLE), occurs frequently in pediatric lupus, leading to significant morbidity and poor long-term outcomes. Diagnosing cNPSLE is especially difficult in pediatrics; many current diagnostic tools are invasive and/or costly, and there are no current accepted screening mechanisms. The most complicated aspect of diagnosis is differentiating primary disease from other etiologies; research to discover new biomarkers is attempting to address this dilemma. With many mechanisms involved in the pathogenesis of cNPSLE, biomarker profiles across several modalities (molecular, psychometric and neuroimaging) will need to be used. For the care of children with lupus, the challenge will be to develop biomarkers that are accessible by noninvasive measures and reliable in a pediatric population.

Migraine in patients with systemic lupus erythematosus is associated with reduced cerebral grey matter volume but not with measures of glial activation or anti-NR2 or anti-P antibodies

BACKGROUND AND PURPOSE

Migraine is frequent in patients with systemic lupus erythematosus (SLE), but the pathogenesis and pathophysiology are poorly understood. Migraine is assumed to be a consequence of abnormal neuronal excitability. Based on the hypothesis that the threshold for migraine is lower in SLE patients due to cerebral disturbances, whether structural abnormalities of the brain or relevant biomarkers are associated with headaches in SLE was investigated.

METHODS

Sixty-seven SLE patients and age- and gender-matched healthy subjects participated. Volumes of grey matter (GM) and white matter (WM) were estimated from cerebral magnetic resonance images with SPM8 software. Anti-NR2 and anti-P antibodies and protein S100B were measured in cerebrospinal fluid.

RESULTS

In regression analyses, larger GM volumes in SLE patients reduced the odds for headache in general [odds ratio (OR) 0.98, P = 0.048] and for migraine in particular (OR 0.95, P = 0.004). No localized loss of GM was observed. Larger WM volumes in patients increased the odds for migraine (OR 1.04, P = 0.007). These findings could not be confirmed in healthy subjects. Neither anti-NR2 and anti-P antibodies nor S100B were associated with headaches in SLE patients.

CONCLUSIONS

Systemic lupus erythematosus patients with migraine have a diffuse reduction in GM compared to patients without migraine. This finding was not observed in healthy subjects with migraine, and selected biomarkers did not indicate specific pathophysiological processes in the brain. These findings indicate that unknown pathogenic processes are responsible for the increased frequency of migraine in SLE patients.

Antibodies to microtubule-associated protein-2 in the cerebrospinal fluid are a useful diagnostic biomarker for neuropsychiatric systemic lupus erythematosus

OBJECTIVE

Previous reports indicate that serum anti-microtubule-associated protein 2 (MAP-2) antibodies are common in sera from patients with neuropsychiatric systemic lupus erythematosus (NPSLE). Differential diagnosis of NPSLE is occasionally difficult because of differential diagnosis which can mimic NPSLE. Therefore, specific biomarkers for NPSLE are needed. We conducted this study to clarify whether cerebrospinal fluid (CSF) anti-MAP-2 antibodies are a useful diagnostic biomarker for NPSLE.

METHODS

Enzyme-linked immunosorbent assay was conducted to measure CSF concentrations of anti-MAP-2 and anti-ribosomal P antibodies and of IL-6 in NPSLE patients (n = 24) and non-NPSLE controls (n = 17). The non-NPSLE controls consisted of systemic lupus erythematosus patients with neuropsychiatric symptoms caused by non-NPSLE conditions (n = 10) and patients with other connective tissue diseases (n = 7).

RESULTS

Significantly higher anti-MAP-2 antibody titers were found in the CSF of patients with NPSLE versus non-NPSLE controls. The prevalence of anti-MAP-2 antibodies was 33.3% (8/24) in NPSLE patients when a positive cutoff value was 3 standard deviations above the mean optical density of non-NPSLE controls. None of the controls had anti-MAP-2 antibodies in their CSF. Both anti-ribosomal P antibody titers and concentration of IL-6 in the CSF were significantly higher in patients with NPSLE having anti-MAP-2 antibodies than in patients with non-NPSLE controls.

CONCLUSION

Anti-MAP-2 antibodies could be detected in the CSF of 33.3% of patients with NPSLE, and its presence was highly specific for NPSLE. We propose that CSF anti-MAP-2 antibodies are a novel and useful diagnostic biomarker for NPSLE.

A Systematic Review of Peripheral and Central Nervous System Involvement of Rheumatoid Arthritis, Systemic Lupus Erythematosus, Primary Sjögren's Syndrome, and Associated Immunological Profiles

Both central (CNS) and peripheral nervous system (PNS) complications are frequent and varied in connective tissue diseases. A systematic review was conducted between 1989 and 2014 in the databases Medline, Scopus, and Cochrane Library using the search terms, peripheral and central nervous complications and immunological profiles, to identify studies in specific connective tissue disorders such as rheumatoid arthritis, systemic lupus erythematosus, and primary Sjögren's syndrome. A total of 675 references were identified, of which 118 were selected for detailed analysis and 22 were included in the final review with a total of 2338 participants. Our search focused only on studies upon connective tissue disorders such as rheumatoid arthritis, systemic lupus erythematosus, and primary Sjögren's syndrome associated with seroimmunological data. The reported prevalence of CNS involvement ranges from 9 to 92% across the reported studies. However, the association between CNS and PNS manifestations and seroimmunological profiles remains controversial. Τo date, no laboratory test has been shown as pathognomonic neither for CNS nor for PNS involvement.

Association of antibodies to the NR1 subunit of N-methyl-D-aspartate receptors with neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To determine epitope reactivity of autoantibodies to N-methyl-D-aspartate (NMDA) receptor NR1 subunit and their association with neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Paired serum and CSF specimens were obtained from 41 patients with NPSLE (22 with diffuse psychiatric/neuropsychological syndromes [diffuse NPSLE] and 19 with neurologic syndromes or polyneuropathy [focal NPSLE]), 21 patients with various rheumatic diseases other than SLE (non-SLERD). Sera were also obtained from 27 SLE patients without neuropsychiatric manifestations (non-CNS SLE). Antibodies to murine NR1 (mNR1) or to 4 different preparations of synthetic 25-amino-acid (AA) peptides of human NR1 were measured by enzyme-linked immune sorbent assay (ELISA).

RESULTS

Serum anti-mNR1 levels were significantly higher in NPSLE than in non-SLERD. Sera from NPSLE patients bound efficiently to the AA residues 19-44 from the N-terminus of NR1 (NR1-A) or 56-81 (NR1-C). Accordingly, serum anti-NR1-A and anti-NR1-C were also elevated in NPSLE compared with non-SLERD. Of note, anti-NR1-A as well as anti-NR1-C levels in CSF, but not in sera, were significantly elevated in diffuse NPSLE compared with focal NPSLE or with non-SLERD.

CONCLUSION

These results suggest that autoantibodies to NMDA receptor NR1, especially to the AA residues 19-44 and 56-81 from the N-terminus play a pivotal role in the pathogenesis of diffuse NPSLE.

Direct and indirect pathogenic roles of autoantibodies in systemic autoimmune diseases

Autoantibody (autoAb) production in patients with systemic autoimmune diseases is a hallmark of disease entity, activity and prognosis. Although a large number of autoAbs have been discovered to date, there is a limited number of autoAbs whose pathogenic roles have been clearly determined. However, intriguing evidence has recently been provided of possible pathogenic roles for anti-neutrophil cytoplasmic Abs (ANCAs) against myeloperoxidase (MPO) in ANCA-associated vasculitides (AAV) and for anti-citrullinated protein Abs (ACPAs) in rheumatoid arthritis (RA). Of note, these autoAbs are thought to display both direct and indirect effects on organ failure. Additionally, some autoAbs have been reported to play pathogenic roles in brain damage in patients with neuropsychiatric systemic lupus erythematosus (NPSLE), which is one of the most refractory autoimmune disorders. Thus the binding of autoAbs to a certain sequence of the N-methyl-D-aspartate receptor subunit NR2 (anti-NR2 Abs) may directly induce hippocampal neuronal injury. On the other hand, anti-U1 ribonucleoprotein (RNP) Abs might be pathogenic by inducing neurotoxic inflammatory mediators intrathecally. Such autoAb measurements are also clinically meaningful for treatment selection.

Brain MRI in patients with diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus

BACKGROUND

Manifestations in neuropsychiatric systemic lupus erythematosus (NPSLE), especially active diffuse NPSLE syndromes, are some of the most difficult complications of the disease. For the evaluation and the diagnosis of central nervous system manifestations, including NPSLE, MRI is a very useful tool to detect the various abnormalities. However, the relationship between brain MRI findings and clinical variables has not yet been clarified in patients with diffuse NPSLE.

OBJECTIVES

The aim of this study is to investigate the pathogenesis of diffuse NPSLE, by comparing various parameters such as serum autoantibodies and cytokines in cerebrospinal fluid (CSF) with abnormal findings revealed on brain MRIs in patients with diffuse NPSLE.

METHODS

Fifty-three patients with diffuse NPSLE admitted to our University Hospital from 1992 to 2012 were exhaustively enrolled in this study. Their medical charts and brain MRI scans were reviewed. The relationship of MRI abnormalities with various parameters was analysed.

RESULTS

As many as 25 of 53 patients (47.2%) had abnormal MRI findings. MRI findings improved after treatment in 10 of 17 patients for whom follow-up studies were available. MRI abnormalities were not correlated with age at the onset of diffuse NPSLE. However, the disease duration of SLE was significantly longer in patients with abnormal MRI findings (p=0.0009). MRI abnormalities were not significantly associated with serum autoantibodies. However, there were significant elevations of the CSF protein level (p=0.0106) and the CSF interleukin 6 level (p=0.0225) in patients with abnormal MRI findings. Patients with MRI abnormalities showed significantly higher overall mortality (p=0.0348).

CONCLUSIONS

The results revealed that MRI abnormalities in diffuse NPSLE might be heterogeneous with regard to their reversibility. These data also indicate that patients with diffuse NPSLE and MRI abnormalities have more severe inflammation in the central nervous system related to the activity of diffuse NPSLE, as evidenced by poorer prognosis.

Association of cerebrospinal fluid anti-Sm antibodies with acute confusional state in systemic lupus erythematosus

Introduction

Neuropsychiatric manifestation in systemic lupus erythematosus (NPSLE) is one of the most serious complications of the disease. Previous studies revealed the strong association between serum anti-Sm and organic brain syndrome, consisting mainly of acute confusional state (ACS) of diffuse psychiatric/neuropsychological syndromes (diffuse NPSLE). However, the precise mechanism by which anti-Sm causes diffuse NPSLE remains unclear. Of note, recent studies demonstrated that anti-U1 RNP antibodies (anti-RNP) in cerebrospinal fluid (CSF) are associated with NPSLE. The present study was designed to explore the association of anti-Sm antibodies in CSF with NPSLE.

Methods

Paired serum and CSF specimens were obtained from 72 patients with NPSLE (49 with diffuse NPSLE, 23 with neurological syndromes or peripheral neuropathy (focal NPSLE) and from 22 control patients with non-SLE neurological diseases. Sera were also obtained from 41 patients with active SLE without neuropsychiatric manifestations (non-NPSLE). Anti-Sm and anti-RNP were measured by enzyme-linked immunosorbent assay (ELISA). Blood-brain barrier (BBB) function and intrathecal anti-Sm production were evaluated by Q albumin and CSF anti-Sm index, respectively. Binding of anti-Sm to neuroblastoma cell lines SK-N-MC and Neuro2a was examined by flow cytometry and by cell ELISA.

Results

Anti-Sm and anti-RNP in CSF and sera were elevated in NPSLE compared with non-SLE control. CSF anti-Sm, but not CSF anti-RNP, was significantly elevated in ACS compared with non-ACS diffuse NPSLE or with focal NPSLE. By contrast, there were no significant differences in serum anti-Sm or anti-RNP among subsets of NPSLE and non-NPSLE. Whereas there were no significant differences in CSF anti-Sm index, Q albumin was elevated in ACS compared with non-ACS or with focal NPSLE. Notably, CSF anti-Sm was correlated with Q albumin (r = 0.2373, P = 0.0447) or with serum anti-Sm (r = 0.7185, P <0.0001) in 72 patients with NPSLE. Finally, monoclonal anti-Sm and purified human anti-Sm bound to the surface of SK-N-MC and Neuro2a.

Conclusions

These results demonstrate that the elevation of CSF anti-Sm through transudation from systemic circulation due to damaged BBB plays a critical role in the pathogenesis of ACS. More importantly, the data indicate that anti-Sm is yet another autoantibody with presumed neural toxicity, but might not be the last.

Transverse myelitis extended to disseminated encephalitis in systemic lupus erythematosus: Histological evidence for vasculitis

A 42-year-old woman was admitted due to systemic lupus erythematosus complicated with glomerulonephritis and pulmonary hypertension. During the treatment for these complications, she presented motor paresis and sensory loss caused by transverse myelitis. In spite of methyl prednisolone pulse therapy, she further developed acute confusional state due to disseminated encephalitis and fell into respiratory arrest. On laboratory examination, elevation of anti-NR2 antibodies in serum as well as in cerebrospinal fluid was noted. Although she recovered from the disseminated encephalitis after extensive treatment with high doses of corticosteroid and intravenous cyclophosphamide, she suddenly died of pulmonary hypertension. Autopsy findings confirmed the presence of liquefaction necrosis in the entire circumference of the whole spinal cord along with intimal hyperplasia and obliteration of the small arteries, accompanied by mononuclear cell infiltration and disruption of internal elastic lamina. It is therefore most likely that our patient developed longitudinal transverse myelitis through spinal cord vasculitis, which extended to brainstem and brain parenchyma, leading to the development of disseminated encephalitis.

Blood-brain barrier damages and intrathecal synthesis of anti-N-methyl-D-aspartate receptor NR2 antibodies in diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus

Introduction

Although neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the recalcitrant complications of the disease, its pathogenesis still remains unclear. Previous studies revealed that antibodies reactive with NMDA (N-methyl-D-aspartate) receptor NR2 (anti-NR2) are elevated in cerebrospinal fluid (CSF) of patients with diffuse psychiatric/neuropsychological syndromes (diffuse NPSLE), which is usually more recalcitrant than neurologic syndromes of NPSLE (focal NPSLE). Two mechanisms have been implicated for the elevation of CSF IgG, including intrathecal synthesis and transudation through the damaged blood-brain barrier (BBB). The present study was designed in order to elucidate the roles of BBB function and intrathecal synthesis of anti-NR2 in the elevation of CSF anti-NR2 with regard to the severity in NPSLE.

Methods

Paired serum and CSF samples were obtained from 81 systemic lupus erythematosus (SLE) patients when they presented active neuropsychiatric manifestations, and from 22 non-SLE control patients with non-inflammatory neurological diseases. The 81 SLE patients consisted of 55 patients with diffuse NPSLE, including 23 patients with acute confusional state (ACS), the severest form of diffuse NPSLE, and 26 patients with neurologic syndromes or peripheral nervous system involvement (focal NPSLE). IgG anti-NR2 and albumin were measured by ELISA. BBB function and intrathecal synthesis of anti-NR2 were evaluated by Q albumin and by CSF anti-NR2 index, respectively.

Results

CSF anti-NR2 levels, Q albumin and CSF anti-NR2 index were significantly higher in NPSLE than in non-SLE control. CSF anti-NR2 levels and Q albumin were significantly higher in ACS than in non-ACS diffuse NPSLE (anxiety disorder, cognitive dysfunction, mood disorder and psychosis) or in focal NPSLE, whereas there was no significant difference in CSF anti-NR2 index among the 3 groups. CSF anti-NR2 levels were significantly correlated with Q albumin in diffuse NPSLE (r = 0.3754, P = 0.0053).

Conclusions

These results demonstrate that the severity of BBB damages plays a crucial role in the development of ACS, the severest form of diffuse NPSLE, through the accelerated entry of larger amounts of anti-NR2 into the central nervous system.

Significance of antibodies against the native ribosomal P protein complex and recombinant P0, P1, and P2 proteins in the diagnosis of Chinese patients with systemic lupus erythematosus

BACKGROUND

This study aimed to evaluate autoantibodies against the native ribosomal P complex (anti-Rib-P(C)) and recombinant ribosomal P proteins (anti-Rib-P0, anti-Rib-P1, anti-Rib-P2) for their prevalence, diagnostic relevance and clinical associations in a Chinese cohort with systemic lupus erythematosus (SLE).

METHODS

Anti-Rib-P, anti-dsDNA and anti-Smith antigen (Sm) antibodies were analyzed in sera from 198 patients with SLE, 33 with rheumatoid arthritis, 61 with Sjögren's syndrome and 70 healthy individuals by means of ELISA.

RESULTS

Antibody prevalences were 29.8% (anti-Rib-P(C)), 33.3% (anti-Rib-P0), 42.9% (anti-Rib-P1) and 34.3% (anti-Rib-P2), at a specificity of 99%. Among SLE patients lacking anti-dsDNA and anti-Sm, 27.8% showed positive for at least one of the investigated anti-Rib-P types. The serological hit rate provided by anti-dsDNA/anti-Sm detection (72.7%) was increased upon parallel testing for anti-Rib-P(C) (77.3%) or anti-Rib-P0/P1/P2 (80.3%). Anti-Rib-P positivity was associated with disease activity, neuropsychiatric events, lupus nephritis, skin rash, lymphocytopenia, increased erythrocyte sedimentation rates, decreased complement C3/C4 and elevated IgA/IgG levels.

CONCLUSION

Based on these results, antibodies against ribosomal P proteins are important complementary parameters to anti-dsDNA and anti-Sm, and should be considered for inclusion in the classification criteria for SLE. The diagnostic value of anti-Rib-P0/P1/P2 is diagnostically superior to that of anti-Rib-P(C).

Neuropsychiatric features of a cohort of patients with systemic lupus erythematosus

In order to establish if neuropsychiatric systemic lupus erythematosus (NPSLE) can be identified by any characteristic other than those used to diagnose the neuropsychiatric (NP) disease itself, we retrospectively reviewed 98 systemic lupus erythematosus (SLE) patients followed over a mean period of 10 years. NPSLE was identified in 22 patients. Stroke and generalized seizures were the most frequent NP manifestations. The NPSLE and non-NPSLE groups were similar with regard to demographic characteristics, ACR criteria, serum autoantibodies, and frequency of hypertension and hypercholesterolemia. Of note, compared to the non-NPSLE group, NPSLE was associated with a higher frequency of smoking (78 versus 26%), organ damage (73 versus 34%), and cumulative mortality rate (14 versus 7%). The series of patients was further analysed according to the presence of antiphospholipid syndrome (APS). Significantly, the interval between the onset of NP disease and SLE diagnosis was shorter in the APS(-) (0.3 ± 1 years) than in the APS(+) (5 ± 7 years) groups. Recurrence and/or persistence of NP events were only documented in the APS(-) group. Overall cumulative mortality was highest in NPSLE and in APS(+) patients with inadequate anticoagulation control, identifying an aspect that requires improved vigilance and the development of novel therapeutic modalities.

Neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is the least understood, yet perhaps the most prevalent manifestation of lupus. The pathogenesis of NPSLE is multifactorial and involves various inflammatory cytokines, autoantibodies, and immune complexes resulting in vasculopathic, cytotoxic and autoantibody-mediated neuronal injury. The management of NPSLE is multimodal and has not been subjected to rigorous study. Different treatment regimens include nonsteroidal anti-inflammatory drugs, anticoagulation, and immunosuppressives such as cyclophosphamide, azathioprine, mycophenolate mofetil, and methotrexate. For refractory NPSLE, intravenous immunoglobulin (IVIG), plasmapheresis, and rituximab have been used. Adjunctive symptomatic treatment complements these therapies by targeting mood disorders, psychosis, cognitive impairment, seizures or headaches. Several new biological agents are being tested including Belimumab, a human monoclonal antibody that targets B lymphocyte stimulator. This review focuses on the pathophysiology, treatment, and new potential therapies for neuropsychiatric manifestations of systemic lupus erythematosus.

Prevalence and clinical significance of anti-ribosomal P antibody in childhood-onset systemic lupus erythematosus

Objective: To investigate the prevalence of the anti-ribosomal P (anti-P) antibodies in childhood-onset systemic lupus erythematosus patients (cSLE), healthy controls and first degree relatives. To elucidate the association between anti-P and disease activity, laboratory and treatment features in cSLE patients. Methods: We included consecutive SLE patients with disease onset before 16 years. Controls were age- and sex-matched. SLE patients were assessed for clinical and laboratory SLE manifestations, disease activity (SLE Disease Activity Index (SLEDAI)), damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI)) and current drug exposures. Mood disorders were determined through Becks Depression and Becks Anxiety Inventory. Anti-P measured by enzyme-linked immunosorbent assay. Results: We included 50 consecutive cSLE patients (mean age of 16.82 ± 3.46 years), 35 first degree relatives (mean age of 38.73 ± 3.89 years) and 20 health control (mean age of 18.3 ± 4.97 years). Anti-P was observed in 13 (26%) cSLE patients and in no first-degree relative ( p < 0.01) or control ( p < 0.01). Anti-P was more frequently observed in patients with anxiety ( p < 0.002). No other clinical, laboratory or treatment features, including SLEDAI and SDI scores were associated with the presence of anti-P in cSLE patients. Conclusion: Anti-P is frequently observed in cSLE patients and was associated with the presence of anxiety in this cohort of cSLE.

Subacute cerebellar ataxia and atrophy developed in a young woman with systemic lupus erythematosus whose cerebrospinal fluid was positive for antineuronal cell antibody

Subacute cerebellar ataxia in combination with cerebellar atrophy has rarely been reported as one of the manifestations of lupus in the central nervous system (CNS). We describe a 27-year-old woman with systemic lupus erythematosus who developed subacute cerebellar ataxia. Computed tomography and magnetic resonance imaging of her brain showed cerebellar atrophy in both hemispheres, particularly on the right side. Moreover, increased antineuronal cell antibody levels were detected in her cerebrospinal fluid. The cerebellar ataxia improved markedly following high-dose corticosteroid administration. This suggests that a relationship exists between autoantibodies and subacute atrophic processes in CNS lupus.

Histopathological analysis of cerebral hemorrhage in systemic lupus erythematosus complicated with antiphospholipid syndrome

A 53-year-old woman was admitted due to akinetic mutism and fever. On admission, brain computed tomography (CT) scan revealed a large hemorrhagic lesion in the left anterior lobe that required surgical operation for total removal. Her neuropsychiatric manifestation was not attenuated after the operation, and was gradually ameliorated by high doses of corticosteroid thereafter, suggesting a diagnosis of lupus psychosis. Histopathological examination revealed a necrotizing vasculature, sometimes with a disrupted lamina elastica interna, completely filled with thrombi and infiltrated with inflammatory cells and their debris. It is therefore suggested that the large frontal lobe hematoma in our patient was induced by thrombosis and arteritis in the subarachnoid space.

Pathogenesis, diagnosis and management of neuropsychiatric SLE manifestations

Neuropsychiatric events are common in patients with systemic lupus erythematosus (SLE), but less than one-third of these events can be directly attributed to SLE. Increased generalized SLE disease activity or damage, previous or concurrent major neuropsychiatric SLE (NPSLE) events, and persistently positive moderate-to-high antiphospholipid antibody titers are established risk factors, and their presence could facilitate proper attribution to the disease itself. Diagnostic evaluation is guided by the presenting manifestation; MRI is used to visualize brain or spinal pathologies. For neuropsychiatric events believed to reflect an immune or inflammatory process, or when these events occur in the context of active generalized disease, evidence (primarily from uncontrolled studies) supports the use of glucocorticoids alone or in combination with immunosuppressive therapy. Antiplatelet and/or anticoagulation therapy is recommended for NPSLE manifestations related to antiphospholipid antibodies, especially for thrombotic cerebrovascular disease. For the future, we anticipate that novel biomarkers and advanced neuroimaging tests will better define the underlying pathologic mechanisms of SLE-related neuropsychiatric disease, and help guide therapeutic decisions.

Identification of autoantigens specific for systemic lupus erythematosus with central nervous system involvement

Using proteomic analysis, we identified candidate autoantigens specific for central nervous system (CNS) involvement in systemic lupus erythematosus (SLE). Proteins, extracted from cultured human neuroblastoma cells, were separated both by SDS-PAGE (1-DE) and two-dimensional electrophoresis (2-DE), and transferred to membranes. Western blot analysis was performed using serum samples from 30 SLE patients with CNS involvement (CNS-Lupus) and from 30 SLE patients without CNS involvement (non-CNS-SLE). The detected autoantigens were identified using MALDI-TOF/TOF MS. On the 1-DE Western blot, we detected 32 antigenic bands in the serum samples from the CNS-Lupus patients. Among them, four bands were detected significantly more frequently in the CNS-Lupus patients than in the non-CNS-SLE patients. Three bands were detected in four or more of the CNS-Lupus patients but in only one or none of the non-CNS-SLE patients. We thus selected these seven bands for the next investigations. Next, we detected protein spots corresponding to the selected seven bands by 2-DE Western blot and identified four proteins. They are peroxiredoxin-4, ubiquitin carboxyl-terminal hydrolase isozyme L1, splicing factor arginine/serine-rich 3, and histone H2A type 1. These four candidate autoantigens for the anti-neuronal cell antibodies would be a useful marker for CNS-Lupus.

Clinical perspectives on autoimmune processes in schizophrenia

This article reviews the epidemiology of autoimmune conditions in schizophrenia, symptom manifestations of autoimmune conditions resembling schizophrenia, and the immunological changes observed in schizophrenia; and reflects on their associations with neurodevelopment, neurodegeneration, clinical course, and management of schizophrenia.

Pathogenesis of neuropsychiatric systemic lupus erythematosus and potential biomarkers

Systemic lupus erythematosus is a chronic, multisystemic, autoimmune disease that may involve the central, peripheral, and autonomic nervous systems and can present with a wide variety of neurological and psychiatric manifestations. In this article, we review the recent literature pertaining to the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE). We searched the PUBMED database with no chronological constraints using the following terms: "neuropsychiatric systemic lupus erythematosus" cross-referenced with the terms "pathogenesis" and "biomarkers" for full-text articles in English. The etiology of NPSLE is as yet unknown, though numerous autoantibodies and cytokines have been suggested as possible mediators. Of the numerous autoantibodies and biomarkers examined, anti-phospholipid, anti-ribosomal P, anti-neuronal, anti-glial fibrillary acidic protein (GFAP), anti-endothelial cell, anti-N-methyl-D: -aspartate (NMDA), microtubule-associated protein 2 (MAP-2), and matrix metalloproteinase-9 (MMP-9) appear to be elevated in patients with NPSLE. Cytokines that may be involved in the pathology of NPSLE include interleukin (IL)-2, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and interferons (IFN)-alpha and -gamma. With continued advances in immunological research, new insights into the pathophysiologic mechanisms of NPSLE may lead to the development of biomarkers and new treatment strategies.

Accuracy of cerebrospinal fluid IL-6 testing for diagnosis of lupus psychosis. A multicenter retrospective study

Psychiatric manifestations are relatively common in systemic lupus erythematosus (SLE) patients. Since there are factors causing psychiatric manifestations other than SLE, the diagnosis of lupus psychosis (LP) is often difficult. Previous studies disclosed that cerebrospinal fluid (CSF) IL-6 was elevated in SLE patients with neuropsychiatric manifestation. The current studies were therefore designed to examine the efficacy of CSF IL-6 in diagnosis of LP. Multicenter retrospective study was performed with 45 SLE patients who showed psychiatric manifestations between 1993 and 2000. The diagnosis of LP and psychosis due to causes other than SLE (non-LP) was confirmed by retrospective review of the clinical records. Thirty-two of the 45 patients were reconfirmed as LP in the retrospective study. Receiver operating characteristic curve analysis revealed that the sensitivity and specificity of CSF IL-6 for diagnosis of LP were 87.5% and 92.3%, respectively, at the cut-off value of 4.3 pg/ml. These results indicate that CSF IL-6 might be an effective measure in diagnosing LP, although exclusion of infectious meningoencephalitis and cerebrovascular accident is necessary.

Clinical and diagnostic value of ribosomal P autoantibodies in systemic lupus erythematosus

OBJECTIVE

To analyse prospectively the diagnostic sensitivity and specificity as well as the clinical relevance of ribosomal P (anti-P) autoantibodies in a large cohort of SLE patients.

METHODS

The anti-P autoantibodies were evaluated in the serum of 200 Tunisian SLE patients at disease onset and 130 various control subjects by a sensitive immunodot assay. A complete laboratory evaluation and clinical examination were performed in each SLE patient. During the follow-up, the patients were regularly monitored for clinical parameters. Global SLE activity was measured by the ECLAM.

RESULTS

The sensitivity and specificity of anti-P testing for SLE were 23.5 and 98.4%, respectively. The anti-P-positive samples 14/47 (29.8%), 27/47 (57.4%) and 5/47 (10.6%) were negative for anti-dsDNA, anti-Sm or both antibodies, respectively. The anti-P-positive patients showed more active disease activity and a much higher prevalence of arthritis. An association between IgG aCLs and anti-P antibodies was also found. However, anti-P antibodies were not associated with neuropsychiatric manifestations or lupus nephritis.

CONCLUSION

This study does not seem to confirm the described association of anti-P antibodies with neuropsychiatric manifestations of SLE. However, it supports the anti-P antibody association with arthritis and disease activity as well as the presence of aCL. Based on our study and other related studies, we propose that, akin to anti-Sm and anti-dsDNA, anti-P antibodies detected by one agreed method may be considered for inclusion as a criterion for the classification of SLE.

[Analysis of autoantigens in patients with systemic lupus erythematosus by using proteomic approach]

Analysis of autoantibodies/antigens has very important impact for investigation of the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE). Recent progress has enabled us to detect and analyze the autoantibodies/antigens easily by using a proteomics approach. By proteomics, we can directly detect proteins as gene products as well as their alterations by post-translational modification and internal abscission which are characteristically observed in proteins. For example, we pick up autoantigens of interest as spots through combination of two-dimensional electrophoresis and western blot, and identify them by analysis using mass spectrometry. These methods allow us to use clinical specimens, including various tissues as a source of autoantigens. In this review, we introduce application of proteomics approach to autoimmune diseases, referring to our study of the autoantigens detected by anti-neuronal antibodies in SLE patients with central nervous system involvement.