Anti-DNA meets NMDA in neuropsychiatric lupus

Alterations of the gut microbiota in the lupus nephritis: a systematic review

BACKGROUND

Emerging evidence suggests that gut microbiota dysbiosis may play a critical role in the development of lupus nephritis (LN). However, the specific characteristics of the gut microbiota in individuals with LN have not been fully clarified.

METHODS

The PubMed, Web of Science, and Embase databases were systematically searched for clinical and animal studies related to the relationship between LN and gut microbiota from inception until October 1, 2023. A semiquantitative analysis was used to assess the changes in gut microbial profiles.

RESULTS

A total of 15 clinical studies were selected for analysis, which included 138 LN patients, 441 systemic lupus erythematosus patients, and 1526 healthy controls (HCs). Five different types of LN mouse models were included in 5 animal studies. The alpha diversity was decreased in LN patients compared to HCs. A significant decrease in the Firmicutes/Bacteroidetes (F/B) ratio is considered a hallmark of pathological conditions. Specifically, alterations in the abundance of the phylum Proteobacteria, genera Streptococcus and Lactobacillus, and species Ruminococcus gnavus and Lactobacillus reuteri may play a critical role in the pathogenesis of LN. Remarkably, the gut taxonomic chain Bacteroidetes-Bacteroides-Bacteroides thetaiotaomicron was enriched in LN patients, which could be a crucial characteristic of LN patients. The increased level of interleukin-6, imbalance of regulatory T cells and T helper 17 cells, and decreased level of the intestinal tight junction proteins zonula occludens-1 and claudin-1 also might be related to the pathogenesis of LN.

CONCLUSIONS

Specific changes in the abundance of gut microbiota such as decreased F/B ratio, and the level of inflammatory indicators, and markers of intestinal barrier dysfunction may play a crucial role in the pathogenesis of LN. These factors could be effective diagnostic and potential therapeutic targets for LN.

Differential impact of environmental factors on systemic and localized autoimmunity

The influence of environmental factors on the development of autoimmune disease is being broadly investigated to better understand the multifactorial nature of autoimmune pathogenesis and to identify potential areas of intervention. Areas of particular interest include the influence of lifestyle, nutrition, and vitamin deficiencies on autoimmunity and chronic inflammation. In this review, we discuss how particular lifestyles and dietary patterns may contribute to or modulate autoimmunity. We explored this concept through a spectrum of several autoimmune diseases including Multiple Sclerosis (MS), Systemic Lupus Erythematosus (SLE) and Alopecia Areata (AA) affecting the central nervous system, whole body, and the hair follicles, respectively. A clear commonality between the autoimmune conditions of interest here is low Vitamin D, a well-researched hormone in the context of autoimmunity with pleiotropic immunomodulatory and anti-inflammatory effects. While low levels are often correlated with disease activity and progression in MS and AA, the relationship is less clear in SLE. Despite strong associations with autoimmunity, we lack conclusive evidence which elucidates its role in contributing to pathogenesis or simply as a result of chronic inflammation. In a similar vein, other vitamins impacting the development and course of these diseases are explored in this review, and overall diet and lifestyle. Recent work exploring the effects of dietary interventions on MS showed that a balanced diet was linked to improvement in clinical parameters, comorbid conditions, and overall quality of life for patients. In patients with MS, SLE and AA, certain diets and supplements are linked to lower incidence and improved symptoms. Conversely, obesity during adolescence was linked with higher incidence of MS while in SLE it was associated with organ damage. Autoimmunity is thought to emerge from the complex interplay between environmental factors and genetic background. Although the scope of this review focuses on environmental factors, it is imperative to elaborate the interaction between genetic susceptibility and environment due to the multifactorial origin of these disease. Here, we offer a comprehensive review about the influence of recent environmental and lifestyle factors on these autoimmune diseases and potential translation into therapeutic interventions.

Gut Microbiota in Systemic Lupus Erythematosus and Correlation With Diet and Clinical Manifestations

Despite the existing studies relating systemic lupus erythematosus (SLE) to changes in gut microbiota, the latter is affected by external factors such as diet and living environment. Herein, we compared the diversity and composition of gut microbiota in SLE patients and in their healthy family members who share the same household, to link gut microbiota, diet and SLE clinical manifestations. The study cohort included 19 patients with SLE and 19 of their healthy family members. Daily nutrition was assessed using a food frequency questionnaire (FFQ). Microbiota was analyzed using amplicons from the V4 regions of the 16S rRNA gene, to obtain microbiota diversity, taxa relative abundances and network analysis. The gut microbiota in the SLE group had lower alpha diversity and higher heterogeneity than the control group. SLE patients had decreased Acidobacteria, Gemmatimonadetes, Nitrospirae and Planctomycetes at the phylum level, and increased Streptococcus, Veillonella, Clostridium_XI, and Rothia at the genus level. Streptococcus was extremely enriched among patients with lupus nephritis. Lactobacillus, Clostridium_XlVa, Lachnospiracea_incertae_sedis and Parasutterella OTUs were associated with diet and clinical features of SLE. Finally, the gut microbiota of SLE patients remained different from that in healthy controls even after accounting for living conditions and diet.

The dietary supplement ephedrine induces b-adrenergic mediated exacerbation of systemic lupus erythematosus in NZM391 mice

The dietary supplement and adrenergic receptor agonist ephedrine has been a controversial topic as its safety has been questioned. b-adrenergic receptor (b-AR) activation causes immunomodulation, which may contribute to promotion of autoimmune pathology. This report investigated the ability of ephedrine to exacerbate processes associated with autoimmune disease in a lupus-prone mouse model. To mimic human supplementation, ephedrine was administered to NZM391 (lupus-prone) and BALB/c (nonlupus prone) mice orally twice a day for three months at a dose of 50 and 100 mg/day. Some ephedrine-treated NZM391 mice also were preadministered the b-AR antagonist propranolol to investigate b-AR involvement. Mice were bled monthly, and sera were assayed for a variety of lupus manifestations and immunological measurements. In NZM391 males and females, both doses of ephedrine significantly increased lupus manifestations, including IgG production and organ-directed autoantibody titers, and significantly lowered the ratio of IgG2a/IgG1 compared to controls. Ephedrine significantly decreased female lifespan and significantly increased circulating populations of plasma cells (CD38hi CD19lo cytoplasmic IgG+) and CD40+ B1a cells, while preventing an age-related decrease in the B1a cell population expressing a high level of CD5. While ephedrine induced gender-specific immunomodulation in BALB/c mice, increases in the lupus manifestations of anti-dsDNA titers and serum urea nitrogen were not detected. Preadministration of propranolol decreased lupus manifestations and serum levels of IgG and IgE in ephedrine-treated mice, but did not block the shift towards IgG1 production. These findings indicate that ephedrine via b-AR can exacerbate lupus symptoms in NZM391 mice and that blockade of the b-ARs on B cells, and not T cells, apparently was of greater importance as the inhibition of lupus symptoms corresponded to an inhibition of immunoglobulin levels, not a change of Th1/Th2 balance.

Cambridge Neuropsychological Test Automated Battery in assessment of cognitive parameters in patients with systemic lupus erythematosus in relation to autoantibody profile

Objectives

To relate the cognitive parameters of systemic lupus erythematosus (SLE) patients in remission to their profile of autoantibodies.

Material and methods

The study included 32 patients with SLE in remission, with mild disease activity as indicated by SELENA-SLEDAI < 6. For neuropsychological assessment, the Cambridge Neuropsychological Test Automated Battery (CANTAB) was applied, using motor screening (MOT), big little circle (BLC), paired associated learning (PAL), stockings of Cambridge (SOC), and graded naming tests (GNT). Detection of autoantibodies against dsDNA, nucleosome (aNuc), Sm, and anticardiolipin (aCL: IgG and IgM) was performed with immunoassays.

Results

The SLE patients demonstrated standard scores below norms, matched according to age and gender, in the following tests: GNT (–0.87 ±0.85), SOC PSMM (–0.47 ±0.97), PAL (–1.88 ±3.58), and BLC (–0.31 ±1.90). GNT scores under –0.5 were found significantly more frequently in SLE patients, seen in roughly 66% of test subjects. Values for PAL and mean subsequent thinking time of stockings of Cambridge (SOC MSTT) were found to be lower than –0.5 in approximately half of the patients. Mean error of motor screening (MOT ME) was found to negatively correlate with mean latency of motor screening (MOT ML) (r = –0.55). PAL significantly correlated with SOC MSTT (r = 0.38) and with GNT (r = 0.36). Anti-dsDNA antibody level correlated negatively with MOT ME (r = –0.46). Anti-Nuc antibodies correlated with MOT ML (r = 0.41) but negatively correlated with MOT ME (r = –0.58). The levels of anti-Sm, anti-CL IgM and IgG did not correlate significantly with the outcomes of CANTAB. The age of the patients correlated negatively with MOT ME (r = –0.36), positively with BLC (r = 0.53) and negatively with SOC MSTT (r = –0.43). The level of anti-Nuc antibodies correlated with anti-dsDNA level (r = 0.62) and of anti-CL IgM with anti-Sm (r = 0.39) and anti-CL IgG (r = 0.87).

Conclusions

CANTAB reveals a decrease in selected cognitive functions in patients with SLE. ACL IgG and anti-dsDNA antibodies indicated SLE patients prone to develop a decrease in cognitive functions.

Memory impairment associated with neurometabolic abnormalities of the hippocampus in patients with non-neuropsychiatric systemic lupus erythematosus

Objective: Memory impairment is common in patients with systemic lupus erythematosus (SLE). This study examined hippocampal volumes and neurometabolic alterations in relation to memory function in SLE patients without a history of neuropsychiatric syndromes (nonNPSLE).

Methods: Subjects included 81 nonNPSLE patients and 34 healthy controls. Volumetric magnetic resonance imaging and magnetic resonance spectroscopy of the right and left hippocampal areas (RH, LH) were performed. Verbal and visual memory tests were administered and a Memory Impairment Index (MII) was derived from standardized tests.

Results: Higher memory impairment (MII) was correlated with lower RH glutamate + glutamine/creatine ( p = 0.009) and lower RH N-acetylaspartic acid/creatine ( p = 0.012) in nonNPSLE patients. A trend for a negative correlation between RH and LH volumes and MII was evident for absolute hippocampal volumes. Lower RH glutamate + glutamine/creatine was also correlated with worse performance in a mean visual memory index ( p = 0.017).

Conclusions: An association between reduced memory and lower N-acetylaspartic acid/creatine in the RH suggests neuronal damage in nonNPSLE patients with very mild and early disease. Alterations in glutamate + glutamine/creatine further indicate early metabolic changes in nonNPSLE are related to memory impairment, a finding that might suggest that memory impairment relates to presynaptic glutamatergic dysfunction in the hippocampus.

[Anti-NMDA-receptor encephalitis. An interdisciplinary clinical picture]

Anti-NMDA-receptor encephalitis is a severe and considerably underdiagnosed form of encephalitis with characteristic clinical features including psychiatric symptoms, decreased levels of consciousness, hypoventilation, epileptic seizures, autonomic dysfunction and dyskinesias. Most patients are primarily seen by psychiatrists, often on the assumption of a drug-induced psychosis. Anti-NMDA-receptor encephalitis had initially been described in young women with ovarian teratoma, but is also common in women without tumour, in men and in children. The diagnosis is based on the characteristic clinical picture, supporting findings of brain MRI, electroencephalogram and cerebrospinal fluid (CSF), and the presence of highly specific autoantibodies directed against the NR1 subunit of NMDA-type glutamate receptors in the serum or CSF. In particular, anti-NMDA-receptor encephalitis must be excluded in patients with 'encephalitis of unknown cause'. In principle, the prognosis is favourable and recovery from symptoms can be expected even after prolonged intensive care treatment and mechanical ventilation. However, improvement correlates with prompt identification of the disorder, early immunotherapy and - in the case of a malignancy - with complete tumour removal. Patient care requires an interdisciplinary approach including neurologists, psychiatrists, paediatricians, oncologists and gynaecologists.

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.

Selective involvement of the amygdala in systemic lupus erythematosus

BACKGROUND

Antibodies specifically affect the amygdala in a mouse model of systemic lupus erythematosus (SLE). The aim of our study was to investigate whether there is also specific involvement of the amygdala in human SLE.

METHODS AND FINDINGS

We analyzed a group of 37 patients with neuropsychiatric SLE (NP-SLE), 21 patients with SLE, and a group of 12 healthy control participants with diffusion weighted imaging (DWI). In addition, in a subset of eight patients, plasma was available to determine their anti-NMDAR antibody status. From the structural magnetic resonance imaging data, the amygdala and the hippocampus were segmented, as well as the white and gray matter, and the apparent diffusion coefficient (ADC) was retrieved. ADC values between controls, patients with SLE, and patients with NP-SLE were tested using analysis of variance with post-hoc Bonferroni correction. No differences were found in the gray or white matter segments. The average ADC in the amygdala of patients with NP-SLE and SLE (940 x 10(-6) mm2/s; p = 0.006 and 949 x 10(-6) mm2/s; p = 0.019, respectively) was lower than in healthy control participants (1152 x 10(-6) mm2/s). Mann-Whitney analysis revealed that the average ADC in the amygdala of patients with anti-NMDAR antibodies (n = 4; 802 x 10(-6) mm2/s) was lower (p = 0.029) than the average ADC of patients without anti-NMDAR antibodies (n = 4; 979 x 10(-6) mm2/s) and also lower (p = 0.001) than in healthy control participants.

CONCLUSIONS

This is the first study to our knowledge to observe damage in the amygdala in patients with SLE. Patients with SLE with anti-NMDAR antibodies had more severe damage in the amygdala compared to SLE patients without anti-NMDAR antibodies.

Catalytic autoantibodies in clinical autoimmunity and modern medicine

Abzymes (catalytic autoantibodies) belong to an absolutely new group of physiologically active substances with dual characteristics: they represent a pool of canonical autoantibodies and possess catalytic activity. Among them, proteolytic and DNA-hydrolyzing autoantibodies are of special value. Abzymes are an important pathogenic factor in the progression of clinical autoimmunity syndrome. The presence of autoantibodies against various autoantigens is accompanied by their high catalytic potential. The increase in this activity correlates with serum levels of the autoantibodies, clinical manifestations of autoimmune disorders, disease severity and the rate of progressing disability. Abzymes are crucial for immune homeostasis regulation. They can be of practical value in the development of modern immunodiagnostic tools and schedules of immunotherapy.

Models of systemic lupus erythematosus: development of autoimmunity following peptide immunizations of noninbred pedigreed rabbits

Reported in this study are the initial results from studies to develop rabbit models of systemic lupus erythematosus (SLE) by immunizations using two distinct peptides on branched polylysine backbones (multiple Ag peptide)-peptides. Eleven rabbits received a peptide from the Sm B/B' spliceosomal complex previously shown to be immunogenic in rabbits, and 13 rabbits received a peptide from the rabbit N-methyl-d-aspartate receptor NR2b. All 24 animals in different generations of pedigreed, noninbred rabbits produced peptide-specific responses. Anti-nuclear autoantibody responses, including anti-dsDNA, were seen in 17 of 24 rabbits. To date, two rabbits have been observed to have seizure-like events and a third nystagmus. A model for eliciting development of SLE in genetically related yet heterogeneous rabbits may more closely resemble development of human SLE than do some models in inbred mice. Through selective breeding, it may also ultimately provide additional information about the genetics and etiology of SLE and serve as a model for assessing new treatment options.

Polymorphisms in the promoter region of RANTES in Han Chinese and their relationship with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex multisystem autoimmune disease afflicting more than 600,000 individuals in China. RANTES (regulated on activation, normal T cell expressed and secreted, 17q11.2-q12) is a member of the proinflammatory cytokine family known as "chemokines". It plays an important role in the attraction and recruitment of lymphocytes, monocytes and eosinophils to sites of inflammation. A total of 146 SLE patients and 159 random healthy volunteer individuals in Han Chinese patients were enrolled in this study. Genotypes of RANTES -403 locus and -28 locus were observed to be different in all racial groups. The frequency of individuals who possessed G allele at -28 locus among SLE patients was not significantly different from that among normal controls. A total of seven compound genotypes at -403 locus and -28 locus were observed in this study. The frequency of this compound genotype (-403 G/G, -28 C/C) was different between the two groups. The distribution of genotypes and alleles at RANTES-403 locus was observed to be significantly different between renal damaged group and no renal damaged group (P<0.05), while there was no significant difference in distribution of genotypes and alleles at RANTES-28 locus between the two groups. These results suggest that (a) two genetic polymorphisms in the RANTES promoter do not correlate with SLE as individual polymorphisms. (b) interaction of the polymorphisms at two loci probably exerts a risk effect against SLE and (c) polymorphism at RANTES-403 locus is probably related with renal damage.

Lowering anti-dsDNA antibodies--what's new?

Antibodies to dsDNA are specific to SLE and are pathogenic, both due to their ability to deposit in tissues through a variety of mechanisms, and to their ability, when present in immune complexes, to activate inflammatory cells. The relationship of serum anti-dsDNA antibody levels to disease activity is a complex one and the factors that determine whether or not such antibodies will be pathogenic in an individual SLE patient are incompletely understood. Although anti-dsDNA antibodies can be made by naïve B cells and B cells belonging to the B1 and marginal zone subsets, pathogenic anti-dsDNA antibodies have the hallmarks of germinal center development and exposure to T cell help, including accumulation of somatic mutations and class switching to the IgG isotype. Epitope spreading may result in aquisition of cross-reactivities with multiple target organ antigens and aquisition of a memory phenotype will allow these B cells to acquire antigen presentation functions that amplify the autoreactive response. In the early stages of disease, or after remission induction protocols, autoreactive B cells may be susceptible to treatments that target T cell costimulation or that deplete or tolerize naïve and mature B cells. Therapeutic approaches targeting innate immune responses or regulatory T cells are starting to be tested in pre-clinical models. In later disease stages, memory and plasma cell accumulation may render patients more resistant to this type of therapeutic approach. Deposition of anti-dsDNA antibodies in target tissues can stimulate an inflammatory cascade that leads to tissue damage. A number of murine models have now been developed that show that interruption of this cascade can prevent or reverse such damage. This type of approach may be beneficial for individuals with established disease. As we learn more about the specific defects that cause SLE, it may become possible to individualize therapy based on patient specific biologic markers.