A case of dupilumab combination therapy for exacerbation of atopic dermatitis in a patient with eosinophilic granulomatosis with polyangiitis treated with mepolizumab

We report a 60-year-old male with eosinophilic granulomatosis with polyangiitis (EGPA) complicated with atopic dermatitis (AD). The patient was initially treated with prednisolone, cyclosporine A, and mepolizumab (MEPO). Due to worsening skin symptoms after prednisolone tapering, dupilumab (DUP) was added as an adjunctive therapy for AD confirmed by skin biopsy. The combination therapy of MEPO and DUP resulted in rapid improvement of skin symptoms, suggesting it may be an effective therapeutic option for patients with EGPA and AD. This case report emphasises the importance of a multidisciplinary approach in treating complex diseases such as EGPA and AD.

Involvement of the complement system in immune thrombocytopenia: review of the literature

Immune thrombocytopenia (ITP) is a thrombocytopenic condition induced by autoimmune mechanisms and includes secondary ITP with underlying diseases such as connective tissue diseases (CTD). In recent years, it has been elucidated that the subsets of the ITP are associated with complement abnormalities but much remains unclear. To perform a literature review and identify the characteristics of complement abnormalities in ITP. PUBMED was used to collect the literature published up to June 2022 related to ITP and complement abnormalities. Primary and secondary ITP (CTD-related) were examined. Out of the collected articles, 17 were extracted. Eight articles were related to primary ITP (pITP) and 9 to CTD-related ITP. Analysis of the literature revealed that the ITP severity was inversely correlated with serum C3, C4 levels in both ITP subgroups. In pITP, a wide range of complement abnormalities was reported, including abnormalities of initial proteins, complement regulatory proteins, or the end products. In CTD-related ITP, reported complement abnormalities were limited to the initial proteins. Activation of the early complement system, mainly through activation of C3 and its precursor protein C4, was reported for both ITPs. On the other hand, more extensive complement activation has been reported in pITP.

Real-world efficacy of belimumab in achieving remission or low-disease activity in systemic lupus erythematosus: A retrospective study

OBJECTIVES

We investigated the effect of belimumab (BEL) on achieving low disease activity (LDA) and remission as an additive molecular-targeting agent to standard of care (SoC) in patients with SLE.

METHODS

Clinical information was retrospectively collected from patients with SLE who received BEL additive to SoC (BEL+SoC), and from patients treated with SoC alone as a control arm. Disease activity was measured by SLE-disease activity score (SLE-DAS). The proportion of patients in LDA and remission at 12 months was compared after propensity score matching. The factors contributing to LDA and remission achievement was identified by Cox proportional hazard model.

RESULTS

BEL+SoC significantly reduced SLE-DAS at 6 months, with a significantly higher proportion of patients achieving LDA and remission at 12 months compared to SoC alone. The presence of arthritis at baseline was significantly associated with achieving LDA and remission. Additionally, both treatment groups experienced a significant reduction in daily glucocorticoid dose.

CONCLUSIONS

Adding BEL to SoC was beneficial for patients with arthritis, leading to higher proportion of achieving LDA and remission, while also reducing their glucocorticoid dose. Our results indicate the utility of BEL in a treat-to-target approach for SLE patients in a real-world setting.

The pathogenic role of lupus-specific autoantibodies and Interleukin-6 on demyelination of the brainstem and spinal cord in systemic lupus erythematosus

OBJECTIVES

Demyelinating syndromes that result in brainstem and/or spinal cord lesions similar to those observed in neuromyelitis optica spectrum disorder (NMOSD) as neuropsychiatric syndromes in systemic lupus erythematosus (NPSLE) occasionally develop in patients with SLE. Cerebrospinal fluid (CSF) interleukin (IL)-6 is a known biomarker for NMOSD; however, its application in patients with SLE with brainstem and/or spinal cord lesions is unknown. Additionally, the breakdown of blood-brain barrier (BBB) integrity by autoantibodies is another mechanism of NMOSD; however, it is not elucidated in SLE. Therefore, this study was designed to clarify the use of CSF IL-6 and investigate whether autoantibodies contribute to BBB breaches and the development of brainstem and/or spinal cord lesions.

METHODS

Data from patients with NPSLE who had NMOSD-like demyelinating lesions in the central nervous system (CNS), including brainstem and/or spinal cord lesions, were retrospectively analyzed. We retrospectively investigated the interval changes in CSF IL-6 and clinical and serological factors related to BBB permeability using CSF/serum albumin ratio (QAlb).

RESULTS

Twelve patients with NPSLE who had demyelinating lesions in the brainstem and/or spinal cord were recruited. Before treatment, CSF IL-6 levels were 29.1 pg/mL and significantly decreased to 3.8 pg/mL by treatment (p = 0.008). Before treatment, CSF IL-6 was significantly correlated with the anti-dsDNA antibody titer (p = 0.027). Furthermore, before treatment, QAlb was significantly correlated with the serum anti-Smith antibody titer. In patients with atypical NMOSD who had specific lesions defined in the NMOSD diagnostic criteria but were negative for antiaquaporin four antibody, a significant correlation was observed between the serum anti-Smith antibody titer and CSF IL-6 (p = 0.025) and QAlb (p = 0.033) values before treatment.

CONCLUSION

CSF IL-6 could be a surrogating marker for disease activity, and serum anti-Smith antibody permeabilizes the BBB in patients with NPSLE, supporting the development of NMOSD-like CNS lesions.

Neuropilin-1 (NRP1) expression distinguishes self-reactive helper T cells in systemic autoimmune disease

Pathogenic T helper cells (Th cells) that respond to self-antigen cannot be easily distinguished from beneficial Th cells. These cells can generate systemic autoimmune disease in response to widely expressed self-antigens. In this study, we have identified neuropilin-1 (NRP1) as a cell surface marker of self-reactive Th cells. NRP1⁺ Th cells, absent in non-regulatory T cell subsets in normal mice, appeared in models of systemic autoimmune disease and strongly correlated with disease symptoms. NRP1⁺ Th cells were greatly reduced in Nr4a2 cKO mice, which have reduced self-reactive responses but showed normal responses against exogenous antigens. Transfer of NRP1⁺ Th cells was sufficient to initiate or accelerate systemic autoimmune disease, and targeting NRP1-expressing Th cells therapeutically ameliorated SLE-like autoimmune symptoms in BXSB-Yaa mice. Peripheral NRP1⁺ Th cells were significantly increased in human SLE patients. Our data suggest that self-reactive Th cells can be phenotypically distinguished within the Th cell pool. These findings offer a novel approach to identify self-reactive Th cells and target them to treat systemic autoimmune disease.

Pathogenic neuropsychiatric effect of stress-induced microglial interleukin 12/23 axis in systemic lupus erythematosus

OBJECTIVES

The central nervous system disorder in systemic lupus erythematosus (SLE), called neuropsychiatric lupus (NPSLE), is one of the most severe phenotypes with various clinical symptoms, including mood disorder, psychosis and delirium as diffuse neuropsychological manifestations (dNPSLE). Although stress is one of the aggravating factors for neuropsychiatric symptoms, its role in the pathogenesis of dNPSLE remains to be elucidated. We aimed to investigate stress effects on the neuropsychiatric pathophysiology in SLE using lupus-prone mice and patients' data.

METHODS

Sleep disturbance stress (SDS) for 2 weeks was placed on 6-8-week-old female MRL/lpr and control mice. Behavioural phenotyping, histopathological analyses and gene and protein expression analyses were performed to assess SDS-induced neuroimmunological alterations. We also evaluated cytokines of the cerebrospinal fluid and brain regional volumes in patients with dNPSLE and patients with non-dNPSLE.

RESULTS

SDS-subjected MRL/lpr mice exhibited less anxiety-like behaviour, whereas stressed control mice showed increased anxiety. Furthermore, stress strongly activated the medial prefrontal cortex (mPFC) in SDS-subjected MRL/lpr. A transcriptome analysis of the PFC revealed the upregulation of microglial activation-related genes, including Il12b. We confirmed that stress-induced microglial activation and the upregulation of interleukin (IL) 12/23p40 proteins and increased dendritic spines in the mPFC of stressed MRL/lpr mice. IL-12/23p40 neutralisation and tyrosine kinase 2 inhibition mitigated the stress-induced neuropsychiatric phenotypes of MRL/lpr mice. We also found a higher level of cerebrospinal fluid IL-12/23p40 and more atrophy in the mPFC of patients with dNPSLE than those with non-dNPSLE.

CONCLUSIONS

The microglial IL-12/23 axis in the mPFC might be associated with the pathogenesis and a promising therapeutic target for dNPSLE.

A Patient with Castleman's Disease Initially Manifesting Symmetrical Synovitis with Pitting Edema

Castleman's disease (CD), especially multicentric CD (MCD) has been known to manifest a variety of clinical features such as fatigue, anemia, fever and hypergammaglobulinemia. Here, we report a 72-year-old female patient who had complicated severe synovitis, as an initial manifestation of the disease, lastly diagnosed as MCD. Initially, she had been diagnosed as remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome because of bilateral leg pitting edema with significant c-reactive protein and matrix metalloproteinase-3 elevation but no disease-specific autoantibodies. Promptly, corticosteroid (CS) and additionally weekly methotrexate (MTX) was introduced, but her leg edema and inflammatory findings did not adequately come to be a remission. A lymph node biopsy from the groin region was performed because multiple lymph node swelling in ultrasound examination appeared even after introducing treatments, which revealed mixed-type CD. Multiple lymphadenopathies were observed in the axilla and inguinal region, finally, we diagnosed her as idiopathic MCD and introduced tocilizumab (TCZ) which significantly improved leg edema as well as inflammatory findings. As is shown in this case, manifestations included in RS3PE syndrome could be one of the clinical phenotypes in MCD, which should be considered as a differential diagnosis of MCD.

Anti-ribosomal P protein antibodies in patients with systemic lupus erythematosus is associated with hyperferritinemia

AIM

Anti-ribosomal P protein antibodies (anti-ribo P) have been reported as one of the specific autoantibodies in patients with systemic lupus erythematosus (SLE) and has been demonstrated to bind and activate macrophages in vitro. Clinically, hyperferritinemia has been known to be a biomarker for macrophage activation. The aim of this study is to clarify the relationship of anti-ribo P and clinical characteristics and biomarkers including serum ferritin in patients with SLE.

METHODS

Clinical parameters and laboratory data were measured in patients with active SLE (N = 127) in our university hospital. The risk factors affected by anti-ribo P were retrospectively calculated by logistic regression analysis, and the correlation of anti-ribo P and clinical factors was demonstrated.

RESULTS

Anti-ribo P was significantly elevated in active SLE compared to non-SLE diseases (P < .0001). Sensitivity and the specificity of anti-ribo P in patients with SLE were 32.0% and 99.3%, respectively. Patients positive for anti-ribo P had the highest risk for elevated serum ferritin (odds ratio: 8.432). Accordingly, anti-ribo P positive patients had significantly elevated serum ferritin compared to negative patients (P = .024). A significant positive correlation was observed between the anti-ribo P titer and the serum ferritin level (r²  = .07, t = 5.22, P = .0081), but not serum interleukin (IL)-6 in SLE patients.

CONCLUSION

The presence of anti-ribo P is a risk factor for higher ferritin levels that is independent of systemic inflammation regulated by IL-6. We speculate that anti-ribo P could be directly associated with macrophage activation leading to hyperferritinemia in patients with SLE.

Haemophilus influenzae Non-type b Infection in an Adult Patient with Systemic Lupus Erythematosus

A 40-year-old man with systemic lupus erythematosus taking consecutive oral corticosteroids developed a high-grade fever and disorder of consciousness following acute rhinitis. Haemophilus influenzae type f (Hif) was found and isolated from the blood and cerebrospinal fluid by culture, leading to a diagnosis of meningitis. The prevalence of H. influenzae type b (Hib) infections has decreased due to routine immunization. As a result, the prevalence of invasive non-Hib, including Hif infection, is increasing as a common H. influenzae infection in children and adults. Physicians should be aware of non-Hib H. influenzae infection, even though the Hib vaccine is widely used in Japan.

Serological comparison of systemic lupus erythematosus with neuropsychiatric lupus using synthetic nucleic acid antigens

Neuropsychiatric systemic lupus erythematosus is an autoimmune disorder characterized by an irregular exchange between the central nervous system and the immune system, leading to the outbreak of neurological conditions with possible disabling effects. Although neuropsychiatric systemic lupus erythematosus is the most common expression of lupus condition, it is still poorly understood. In this study, we focus on the development of an advantageous method based on the application of synthetic nucleic acids and protein-based antigen arrays in order to characterize autoreactive antibodies in neuropsychiatric systemic lupus erythematosus. We confirmed the benefits of using synthetic oligonucleotides such as assay reproducibility, elevated affinity and specificity to autoreactive antibodies. We also demonstrated presence of autoantibodies towards three particular synthetic double stranded antigens and verify similarity of antinuclear antibody patterns in ordinary lupus and neuropsychiatric systemic lupus erythematosus.

A case of anti-MDA5 antibody-positive dermatomyositis developing reversible cerebral vasospasm syndrome successfully treated by multi-immunosuppressant combination including mycophenolate mofetil

A 39-year-old woman admitted with multiple joint pain, hand rashes, and shortness of breath was diagnosed with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM) with interstitial pneumonia (IP). Because of progressive dyspnoea and hypoxaemia, her IP was considered rapidly progressive interstitial lung disease. Initially, prednisolone 60 mg/day, cyclosporine A (CyA), and intravenous cyclophosphamide (IVCY) were initiated. A few days following the initiation of treatment, she experienced massive thunderclap headache, which was diagnosed as reversible cerebral vasospasm syndrome based on the findings of contraction in cerebral arteries with brain magnetic resonance imaging. Treatment with CyA and IVCY was discontinued, and diltiazem and mycophenolate mofetil (MMF) were initiated as an alternative immunosuppressant. Considering IVCY as the cause of Reversible cerebral vasospasm syndrome based on her clinical course, tacrolimus was commenced, which improved both DM and IP. DM patients who are anti-MDA5 antibody-positive are considered to have poor prognosis and require aggressive immunosuppressive treatments. In patients experiencing adverse events with standard IVCY, MMF with high-dose steroids and alternative calcineurin inhibitor should be considered.

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.

Synergistic enhancement of production of proinflammatory cytokines of human peripheral blood monocytes by anti-Sm and anti-RNP antibodies

The present study was performed to elucidate the roles of serum anti-Sm antibodies in the pathogenesis of systemic lupus erythematosus (SLE). Highly purified peripheral blood monocytes obtained from healthy donors were cultured in the presence of monoclonal anti-Sm antibody (anti-Sm mAb), monoclonal anti-U1-RNP antibody (anti-RNP mAb) or control murine IgG1 or IgG3. After various periods of incubation, levels of IL-6 and TNF-α in the culture supernatants were measured by ELISA and the expression of mRNA for various molecules in monocytes was determined using RT-PCR. Flow cytometry analysis confirmed the bindings of anti-Sm mAb and anti-RNP mAb on viable human monocytes. Both anti-Sm mAb and anti-RNP mAb significantly increased the production of IL-6 and TNF-α of human monocytes in a dose-dependent manner, although the latter was more potent than the former. Of note, anti-Sm mAb synergistically enhanced the production and mRNA expression of IL-6 and TNF-α of human monocytes in the presence of anti-RNP mAb. Notably, anti-RNP mAb, but not anti-Sm mAb, significantly enhanced the mRNA expression of RelA in human monocytes. Finally, anti-Sm mAb still up-regulated the IL-6 production of monocytes in the presence of anti-RNP mAb under the influence of N-acetyl cysteine or pyrrolidine dithiocarbamate that totally abrogated the IL-6 production provoked by anti-Sm mAb alone in the absence of anti-RNP mAb. These results demonstrate that anti-Sm and anti-RNP antibodies synergistically up-regulate the expression of IL-6 and TNF-α in human monocytes. The data also suggest that the effect of anti-Sm in the synergy with anti-RNP might not involve NFkB activation.

Role of serum autoantibodies in blood brain barrier damages in neuropsychiatric systemic lupus erythematosus

OBJECTIVES

The present study was carried out to elucidate the roles of serum autoantibodies in the development of blood-brain barrier (BBB) damages in neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Paired serum and CSF samples were obtained from 101 SLE patients when they presented active neuropsychiatric manifestations (69 patients with diffuse psychiatric/neuropsychological syndromes [diffuse NPSLE] and 32 patients with neurologic syndromes or peripheral neuropathy [focal NPSLE]). IgG anti-NR2 subunit of NMDA receptor (anti-NR2), anti-Sm, anti-ribosomal P and IgG anti-cardiolipin in sera and albumin in CSF and sera were measured by ELISA. Blood-brain barrier (BBB) function was evaluated by Q albumin (CSF/serum albumin quotient x 1,000).

RESULTS

Q albumin was significantly higher in acute confusional state (ACS) than in non-ACS diffuse NPSLE (anxiety disorder, cognitive dysfunction, mood disorder and psychosis) or in focal NPSLE. Anti-Sm, but not anti-NR2, anti-P or anticardiolipin, was significantly elevated in ACS compared with the other 2 groups of NPSLE, although serum anti-NR2 was significantly higher in ACS than that in focal NPSLE. Multiple regression analysis confirmed the significant contribution of anti-Sm (p=0.0040), but not anti-NR2 (p=0.5023), anti-P (p=0.2651), or anti-cardiolipin (p=0.6769) in the elevation of Q albumin.

CONCLUSIONS

The data demonstrate that serum anti-Sm antibodies play a most important role in the disruption of BBB in NPSLE.

Clinical significance of anti-DNA/N-methyl-D-aspartate receptor 2 antibodies in de novo and post-steroid cases with neuropsychiatric systemic lupus erythematosus

BACKGROUND

Anti-DNA/N-methyl-D-aspartate receptor 2 (NR2) antibodies (anti-DNA/NR2 antibodies) are a subset of anti-DNA autoantibodies that cross-react with the extracellular domain of the GluN2A/GluN2B subunits of NR2. These antibodies induce apoptosis of hippocampus neurons and psychiatric disorder in mice and humans. Neuropsychiatric system lupus erythematosus (NPSLE) can develop after initiation of corticosteroids (post-steroid neuropsychiatric manifestation: PSNP) or before treatment (de novo NPSLE); however, pathophysiological differences between these subtypes remain unclear. The objective of this study was to clarify the prevalence of anti-DNA/NR2 antibodies in patients with NPSLE.

METHODS

This study involved a cohort of patients with NPSLE admitted to our hospital. NPSLE patients were classified into two groups, de novo NPSLE and PSNP-SLE. Serum anti-DNA antibodies and anti-DNA/NR2 antibodies were measured by enzyme-linked immunosorbent assays.

RESULTS

Serum samples were obtained from 24 patients with de novo NPSLE, 25 with PSNP-SLE and 76 healthy controls (HC). The level of anti-DNA/NR2 antibodies in patients with de novo NPSLE and PSNP-SLE were also higher than those in HC. Positive correlation between anti-DNA antibodies and anti-DNA/NR2 antibodies were found in PSNP-SLE, but was not significant in de novo NPSLE.

CONCLUSION

The levels of anti-DNA/NR2 antibodies in PSNP-SLE were similar to those in de novo NPSLE. Anti-DNA/NR2 antibodies in PSNP-SLE were suggested as a dominant subset of anti-DNA antibodies, indicating that anti-DNA/NR2 antibodies may be a predictive factor in PSNP-SLE.

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.

Lupus antibodies induce behavioral changes mediated by microglia and blocked by ACE inhibitors

Nestor et al. examine how lupus antibodies that enter the brain cause neuronal dysfunction and cognitive impairment. The results show that activated microglia are critical for neuronal damage and that inhibiting them can preserve neuronal function and cognition.

Cognitive impairment occurs in 40–90% of patients with systemic lupus erythematosus (SLE), which is characterized by autoantibodies to nuclear antigens, especially DNA. We discovered that a subset of anti-DNA antibodies, termed DNRAbs, cross reacts with the N-methyl-d-aspartate receptor (NMDAR) and enhances NMDAR signaling. In patients, DNRAb presence associates with spatial memory impairment. In a mouse model, DNRAb-mediated brain pathology proceeds through an acute phase of excitotoxic neuron loss, followed by persistent alteration in neuronal integrity and spatial memory impairment. The latter pathology becomes evident only after DNRAbs are no longer detectable in the brain. Here we investigate the mechanism of long-term neuronal dysfunction mediated by transient exposure to antibody. We show that activated microglia and C1q are critical mediators of neuronal damage. We further show that centrally acting inhibitors of angiotensin-converting enzyme (ACE) can prevent microglial activation and preserve neuronal function and cognitive performance. Thus, ACE inhibition represents a strong candidate for clinical trials aimed at mitigating cognitive dysfunction.

Effects of CTLA4-Ig on human monocytes

Background

Abatacept, a CTLA4-Ig fusion protein attenuates T cell activation by inhibiting the CD80/86-CD28 costimulatory pathway that is required for the proper T cell activation and thus displays beneficial effects in the treatment of rheumatoid arthritis (RA). Although some studies have disclosed the in vitro effects of this biological agent on the immune-competent cells, the precise mechanisms of action in RA still remain unclear. The current studies were therefore undertaken to explore the effects of abatacept on monocytes in detail.

Methods

Monocytes from healthy donors were cultured in the presence of staphylococcal enterotoxin B (SEB) with pharmacologically attainable concentrations of abatacept or control IgG-Fc. The expression of CD80 and CD86 and the induction of apoptosis of monocytes were measured by flow cytometry. The expression of CD80 and CD86 messenger RNA (mRNA) was determined by quantitative RT-PCR.

Results

Abatacept promoted apoptosis of SEB-stimulated monocytes. The induction of apoptosis of monocytes by these biological agents was reversed by the addition of IgG, but not IgG-F(ab′)₂ fragments. Furthermore, abatacept significantly suppressed the expression of CD80, but not that of CD86 at protein levels. Finally, abatacept significantly suppressed the expression of mRNA for CD80 of monocytes stimulated with SEB, but not that of CD86.

Conclusions

These results demonstrate that one of the mechanisms of action of abatacept involves the induction of apoptosis of monocytes, which involves interaction with Fc receptor on monocytes. Moreover, the data also demonstrate that abatacept selectively suppresses the expression of CD80 at mRNA levels.

Differential influences of Fc gamma receptor blocking on the effects of certolizumab pegol and infliximab on human monocytes

OBJECTIVES

To compare the effects of certolizumab pegol (CZP) and infliximab (IFX) on human monocytes.

METHODS

Highly purified monocytes from healthy donors were cultured with CZP, IFX, control IgG1, or polyethylene glycol (PEG) at pharmacological attainable concentrations in culture medium with 10% autologous normal human serum (NHS) or with fetal bovine serum (FBS) for 24 h, after which the supernatants were replaced by fresh culture medium containing LPS. After additional 24 h of incubation, the supernatants were assayed for TNF-α and IL-6. In some experiments, the cells were harvested after 1 h of stimulation with LPS for analysis of mRNA for TNF-α by quantitative PCR.

RESULTS

Pre-incubation of monocytes with CZP or IFX reduced the production of TNF-α in subsequent cultures stimulated by LPS in a dose-dependent manner. The suppressive effects of IFX on the TNF-α production were significantly diminished, but those of CZP were rather enhanced, in cultures with autologous NHS compared with in cultures with FBS. Addition of IgG, but not IgG F(ab')₂ fragments, significantly inhibited the suppressive effects of IFX on the production of TNF-α and IL-6, whereas either IgG or IgG F(ab')₂ fragments had no significant influences on the suppressive effects of CZP. Furthermore, pre-incubation with CZP or IFX significantly inhibited the expression of mRNA for TNF-α and IL-6 in monocytes compared with PEG or IgG.

CONCLUSION

These results indicate that the mechanism of action of CZP is different from that of IFX. Thus, CZP suppresses the production of proinflammatory cytokines independently of Fc receptors, whereas the suppressive effects of IFX on human monocytes are almost totally dependent on the interaction with Fc receptors.

Immune-mediated brain pathology: from autoantibodies to microglia

Cells and molecules of the immune system contribute to brain pathology as well as to brain homeostasis. We suggest that there are numerous anti-brain antibodies that can cause acute neuronal dysfunction if they penetrate brain parenchyma. Many of these acute immune-mediated insults may alter the homeostatic mechanisms in the brain and initiate pathologic events that no longer depend on the presence of the inciting antibody, but rather on microglial cell activation. This paradigm, if correct, suggests that there may be two potential moments of therapeutic intervention. The first moment is when antibody contacts cells of the central nervous system and the second is when microglia become activated and impair normal neuronal functions. In this review, we discuss data that support this model for immune-mediated pathology in both the adult brain and the developing fetal brain.

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.

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.

Fatal complication of Legionella pneumophila pneumonia in a tocilizumab-treated rheumatoid arthritis patient

We herein report a fatal case of Legionella pneumophila pneumonia in a tocilizumab-treated rheumatoid arthritis patient who was in a state of shock on admission but remained afebrile even during severe pneumonia. Legionella antigen was detected in the urine and neutrophil CD64 expression was highly elevated. Despite undergoing intensive treatment, the patient developed sepsis and died 12 days after admission. An autopsy indicated that while the Legionella infection had almost been controlled, a subarachnoid hemorrhage was the ultimate cause of death.

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.

Effects of anti-IL-6 receptor antibody on human monocytes

OBJECTIVE

To explore the effects of anti-IL-6 receptor antibody, tocilizumab on function of human monocytes.

METHODS

Monocytes from healthy donors were cultured in the presence of staphylococcal enterotoxin B (SEB) with pharmacologically attainable concentrations of tocilizumab or control IgG. The expression of IL-6 mRNA was determined using quantitative RT-PCR. The expression of CD80 and CD86 and the induction of apoptosis of monocytes were measured using flow cytometry.

RESULTS

Tocilizumab promoted apoptosis of SEB-stimulated monocytes. The induction of apoptosis of monocytes by tocilizumab were reversed by addition of IgG, but not IgG F(ab')₂ fragments. Tocilizumab significantly suppressed the expression of CD80, but not that of CD86, on SEB- stimulated monocytes. Finally, tocilizumab significantly suppressed the expression of mRNA for IL-6 of monocytes stimulated with SEB.

CONCLUSIONS

These results demonstrate that one of the mechanism of action of tocilizumab involves the induction of apoptosis of monocytes, which requires interaction with Fc receptor on monocytes. Moreover, the data also indicate that tocilizumab inhibit IL-6 production of monocytes at mRNA levels.

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.

[Case of immunosuppressant-resistant amyopathic dermatomyositis with rapidly progressive interstitial pneumonia ameliorated after resection of gastric cancer]

A 59-year old woman had been suffering from myalgia, eruption and dyspnea on effort for a month. She was referred to our hospital because her symptoms were not improved by antibiotic therapy at a clinic. At first presentation she showed cutaneous manifestations including heliotrope eyelids and mechanic's hands, slightly elevated serum creatine kinase (CK), elevated serum C-reactive protein level, and interstitial pneumonia (IP), which led to a diagnosis as dermatomyositis. After admission to our hospital, her hypoxia due to IP progressed despite disappeared myalgia and normalized serum CK level. Intravenous steroid pulse therapy followed by oral cyclosporine and intravenous cyclophosphamide pulse therapy was not effective for the IP for more than a month. Gastroscopy revealed superficial depressed (0-IIc) type early gastric cancer. However, it was out of indication for endoscopic mucosal resection because of the histopathologic type (signet ring cell carcinoma) and possible submucosal invasion. In addition to those immunosuppressive therapies, proximal gastrectomy with total intravenous anesthesia was performed. One month after the operation, improvement of IP as well as cutaneous manifestations was confirmed by respiratory function test, pulmonary computed tomography, and discontinuance of oxygen inhalation. We conclude that this was a case of clinically amyopathic dermatomyositis with rapidly progressive IP and gastric cancer, which was ameliorated by a combination of medication (steroid, cyclosporine, and cyclophosphamide) and surgery (gastrectomy for early gastric cancer).

Genome, epigenome and transcriptome analyses of a pair of monozygotic twins discordant for systemic lupus erythematosus

Information to distinguish genetic and environmental factors in the pathogenesis of multifactorial diseases can be obtained by investigation of disease development in monozygotic twins. Recent reports have shown that there are genomic and epigenomic differences between monozygotic twins. Genomic/epigenomic and gene expression analyses were performed in monozygotic twins discordant for systemic lupus erythematosus (SLE) to find the genes playing important roles in SLE pathogenesis. Single nucleotide polymorphism (SNP) and copy number variation (CNV) typing, CpG methylation and gene expression were analyzed. The discordances in SNPs and CNVs were not confirmed. Both CpG methylation and gene expression levels were different for 10 genes. There were no genomic differences between monozygotic twins discordant for SLE, but epigenomic and gene expression differences were detected. These findings provide information for better understanding of SLE pathogenesis.

Association of human leukocyte antigen with interstitial lung disease in rheumatoid arthritis: a protective role for shared epitope

Introduction

Interstitial Lung Disease (ILD) is frequently associated with Rheumatoid Arthritis (RA) as one of extra-articular manifestations. Many studies for Human Leukocyte Antigen (HLA) allelic association with RA have been reported, but few have been validated in an RA subpopulation with ILD. In this study, we investigated the association of HLA class II alleles with ILD in RA.

Methods

An association study was conducted on HLA-DRB1, DQB1, and DPB1 in 450 Japanese RA patients that were or were not diagnosed with ILD, based on the findings of computed tomography images of the chest.

Results

Unexpectedly, HLA-DRB1*04 (corrected P [Pc] = 0.0054, odds ratio [OR] 0.57), shared epitope (SE) (P = 0.0055, OR 0.66) and DQB1*04 (Pc = 0.0036, OR 0.57) were associated with significantly decreased risk of ILD. In contrast, DRB1*16 (Pc = 0.0372, OR 15.21), DR2 serological group (DRB1*15 and *16 alleles) (P = 0.0020, OR 1.75) and DQB1*06 (Pc = 0.0333, OR 1.57, respectively) were significantly associated with risk of ILD.

Conclusion

HLA-DRB1 SE was associated with reduced, while DR2 serological group (DRB1*15 and *16) with increased, risk for ILD in Japanese patients with RA.

Incidence and the risk factor of malignancy in Japanese patients with systemic sclerosis

OBJECTIVE

To evaluate the incidence and risk factors for malignancy in Japanese patients with systemic sclerosis (SSc).

METHODS

A cohort of 405 Japanese patients with SSc who visited Kitasato University hospital between 1973 and 2008 was analyzed retrospectively until the end of 2009. The incidence of malignancy was compared with that of the general population, with calculation of the standardized incidence ratio (SIR) and 95% confidence interval (CI).

RESULTS

The cohort represented 4,787 person-years of total disease duration after the diagnosis of SSc. Of 27 malignancies clinically found, lung cancer (n=10, 37%), especially adenocarcinoma, was the most frequent, followed by breast (n=4, 15%) or gastric (n=3, 11%) cancer. SSc patients with overlapping CTD tended to have less malignancy. Multivariable analysis revealed heart involvement of SSc as a significant risk factor for breast cancer (RR 8.2, 95% CI 1.2-72.8). Other than gastric cancer, the calculated SIRs of malignancies in SSc patients were above 1 (SIR of overall malignancy 1.24, 95% CI 0.77-1.71), even though only lung cancer had a significantly elevated incidence (SIR 5.73, 95% CI 2.18-9.29). Every patient with lung cancer had interstitial lung disease (ILD) and every autopsy performed on patients with lung cancer found a primary lesion of lung cancer in their ILD lesion (n=4).

CONCLUSION

Lung cancer was significantly frequent in SSc patients, which could develop on the basis of complicated ILD.

[Case of rheumatic fever complicating carditis detected by a newly-developed systolic murmur in an adult woman]

A 62-year-old woman presented to a primary care doctor on January 2006 due to a sore throat and high fever, and had received medication for a common cold. She was referred to our hospital in February 2006 because of additional manifestations such as painful rashes on the lower limb similar to erythema nodosum and polyarthralgia on her feet, shoulder and finger joints. She was initially treated with an anti-inflammatory drug (NSAID) for polyarthritis but the symptoms did not improved. In addition, the serum level of anti-streptolysin O antibody (ASO) was elevated at the second visit more than that at the first visit. She was diagnosed to have rheumatic fever (RF) based on the polyarthritis, inflammatory data and an increase of the ASO level. She was treated with 10 mg a day of prednisolone (PSL) and sultamicillin tosilate. However, a systolic murmur that had been never noticed by previous auscultation appeared after the third hospital day and the mitral regurgitation was also detected on echocardiogram. She was then treated with 40 mg a day of PSL because of an appearance of the carditis due to RF. The increased PSL dose promptly improved the systolic murmur as well as the arthritis. This report presented an RF case with carditis detected by an development of the systolic murmur in an adult female.

An autopsy case of necrotizing fasciitis with rapidly progressive purpura caused by hemolytic streptococcal infection in a patient with rheumatoid arthritis

A 77-year-old woman with rheumatoid arthritis was admitted as an emergency because of pain in the right leg with purpura. She was diagnosed with severe cellulitis and sepsis and started on intravenous antibiotics; however, the lesion rapidly extended to the proximal thigh and she died only 38 h after the onset of the first symptom. Autopsy and tissue culture revealed necrotizing fasciitis caused by Streptococcus dysgalactiae subspecies equisimilis. Physicians should consider that necrotizing fasciitis may be present when soft-tissue disorder is suspected in patients receiving corticosteroid therapy, which is associated with tissue fragility and immunosuppression.

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.

Association of cerebrospinal fluid anti-NR2 glutamate receptor antibodies with diffuse neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To explore the association of antibodies directed against N-methyl-D-aspartate receptor subunit NR2 (anti-NR2) in cerebrospinal fluid (CSF) with neuropsychiatric manifestations in systemic lupus erythematosus (NPSLE).

METHODS

Paired serum and CSF specimens were obtained from 56 patients with NPSLE (38 with diffuse psychiatric/neuropsychological syndromes [diffuse NPSLE] and 18 with neurologic syndromes or peripheral neuropathy [focal NPSLE]) and from 20 control patients with noninflammatory neurologic diseases. IgG anti-NR2 antibodies were measured by enzyme-linked immunosorbent assay using synthetic peptide containing the extracellular ligand-binding domain of NR2. The binding of affinity-purified anti-NR2 to human neuroblastoma cell line SK-N-MC was examined by flow cytometry.

RESULTS

Purified anti-NR2 bound to the surface of SK-N-MC cells. Levels of anti-NR2 antibodies in CSF were significantly elevated in patients with diffuse NPSLE compared with levels in control patients or those with focal NPSLE, whereas there were no significant differences in serum anti-NR2 levels among the 3 groups. In 31 of the 38 patients with diffuse NPSLE (81.6%) and 8 of the 18 patients with focal NPSLE (44.4%), CSF anti-NR2 levels were more than 3 SD above the mean level in the control patients (P=0.0120 by chi-square test).

CONCLUSION

These results indicate that anti-NR2 is a constituent of antineuronal antibodies and, more importantly, that anti-NR2 antibodies in CSF, but not in serum, are associated with diffuse NPSLE.

Association of cerebrospinal fluid anti-ribosomal p protein antibodies with diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus

We explored the relationship of antibodies to the whole ribosomal P proteins (P0, P1, and P2) in cerebrospinal fluid (CSF) with diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus (SLE). CSF samples were obtained from 71 SLE patients (52 patients with diffuse psychiatric/neuropsychological syndromes [diffuse NP-SLE] and 19 patients with neurological syndromes or peripheral neuropathy [focal NP-SLE]) as well as from 24 patients with non-inflammatory neurological disease. Immunoglobulin G (IgG) antibodies to the C-terminal 22-amino acid ribosomal P synthetic peptide (anti-P_C22) and those to purified bovine ribosomal P proteins (P0, P1, and P2) (anti-whole P) were determined by enzyme-linked immunosorbent assay; affinity-purified IgG anti-P_C22 were used as the standard. The concentrations of antibodies to epitopes other than the C-terminal 22 amino acids of ribosomal P proteins were calculated by subtracting anti-P_C22 from anti-whole P (anti-P_EX.C22). CSF anti-whole P levels were significantly elevated in diffuse NP-SLE compared with focal NP-SLE or control patients. By contrast, there were no significant differences in CSF anti-P_C22 levels among the three groups. Of note, CSF anti-P_EX.C22 levels were significantly elevated in diffuse NP-SLE compared with the other two groups. CSF anti-P_EX.C22 levels were not significantly correlated with CSF anti-P_C22 levels, but with CSF antibodies against the recombinant ribosomal P0 protein lacking the C-terminal 22 amino acids (C22-depleted rP0). Moreover, levels of CSF anti-P_EX.C22 or CSF anti-C22-depleted rP0, but not CSF anti-P_C22, were significantly correlated with CSF anti-neuronal cell antibodies (anti-N). These results indicate that CSF IgG antibodies to the epitopes other than the C-terminal 22 amino acids of ribosomal P proteins, which might contain one of the major targets of CSF anti-N, are associated with the development of diffuse NP-SLE.