Updating on the pathogenesis of systemic lupus erythematosus

Identification of RSAD2 as a Key Biomarker Linking Iron Metabolism and Dendritic Cell Activation in Systemic Lupus Erythematosus Through Bioinformatics and Experimental Validation

Background

Systemic lupus erythematosus (SLE) is characterized by aberrant immune activation and disrupted iron metabolism, yet the molecular mediators that govern both processes remain unclear. This study aims to identify pivotal genes that modulate immune responses and iron metabolism, and to delineate their contributions to SLE pathogenesis.

Methods

Differentially expressed genes related to iron metabolism (IM-DEGs) were identified using datasets (GSE72326, GSE110169, GSE126307, and GSE50772) from the GEO database and the MSigDB. Functional enrichment analyses were performed on the iron metabolism related genes (IM-Genes). A weighted gene co-expression network analysis was constructed to identify hub genes, which were further refined as potential biomarkers using the least absolute shrinkage and selection operator method. The predictive value of these biomarkers was validated using receiver operating characteristic (ROC) curves and the nomogram. CIBERSORT was employed to evaluate immune cell infiltration in SLE. Additionally, the expression and function of RSAD2 were confirmed using RNA interference, quantitative real-time PCR, and Western blotting techniques.

Results

Bioinformatics analyses identified 4 potential biomarkers: RSAD2, MT2A, LCN2, and LTF. RSAD2 exhibited the highest clinical validity (AUC = 0.927) and was closely associated with classic diagnostic indicators. Its diagnostic potential was confirmed through ROC curve and nomogram, highlighting its role in SLE pathogenesis. Elevated RSAD2 expression was observed in peripheral blood mononuclear cells of SLE patients, positively correlating with activated dendritic cells (DCs). Notably, Rsad2 knockdown markedly impaired the function of activated DCs, as evidenced by suppressed expression of inflammatory mediators and iron metabolism-related genes.

Conclusion

Our findings suggest that RSAD2 is a potential diagnostic biomarker and therapeutic target for SLE, elucidating the intricate relationship between immune dysregulation and aberrant iron metabolism in activated DCs, which exacerbates SLE.

Clinical characteristics and risk factors of cardiovascular disease in systemic lupus erythematosus patients

To analyze the clinical characteristics of cardiovascular disease in systemic lupus erythematosus (SLE) patients and identify risk factors for predicting the occurrence of cardiovascular disease in SLE patients. Clinical data of 110 SLE patients were randomly selected from the Tongde Hospital of Zhejiang Province clinical medical record database, including 50 patients with cardiovascular disease and 60 patients without. Clinical data, blood biochemistry indicators, antibody detection results, and complement levels were collected. The receiver operating characteristic (ROC) curve was used to analyze the efficacy of these differential indicators in predicting the occurrence of cardiovascular disease in SLE patients. Univariate logistic regression analysis and multivariate logistic regression analysis showed that anti-ribosomal P protein, RNP/sm, IgG, IgM, serum creatinine, uric acid, and lipoprotein a were independent risk factors for cardiovascular disease in SLE patients (P < 0.05). The area under the curve (AUC) for predicting cardiovascular disease in SLE patients using IgG was 0.67, with low sensitivity of 44% and high specificity of 88.48%. The AUC for predicting cardiovascular disease in SLE patients using IgM was 0.67, with sensitivity of 76% and specificity of 55.17%. The AUC for predicting cardiovascular disease in SLE patients using serum creatinine was 0.73, with sensitivity of 68% and specificity of 78.33%. The AUC for predicting cardiovascular disease in SLE patients using uric acid was 0.69, with sensitivity of 52% and specificity of 81.67%. The AUC for predicting cardiovascular disease in SLE patients using lipoprotein a was 0.96, with high sensitivity of 96% and specificity of 91.67%. Levels of anti-ribosomal P protein, RNP/sm, IgG, IgM, serum creatinine, uric acid, and lipoprotein A are significantly altered in SLE patients with cardiovascular disease. These indicators can be used to predict the risk of cardiovascular disease in SLE patients.

Detection of genetic mutations underlying early-onset systemic lupus erythematosus

OBJECTIVE

We aimed to investigate the presence of monogenic causes of systemic lupus erythematosus (SLE) in our early-onset SLE patients.

METHODS

Fifteen pediatric SLE cases who had early disease onset (≤6 years) were enrolled in this study. All patients fulfilled the Systemic Lupus International Collaborating Clinics (SLICC) criteria. Genomic DNA was used for whole exome sequencing (WES). Pathogenic variants were confirmed by Sanger sequencing.

RESULTS

The median age at diagnosis of 15 early-onset SLE patients included in the study was 4 (2-6) years (F/M = 12/3). Significant gene mutations were detected in five of these patients (33.3%). Patients 1 and 2 with homozygous DNASE1L3 mutations [c.320+4_320+7del and G188 A (c.563 G>C) variants] had skin involvement and oral ulcers. One of them (patient 1) had arthritis and nephritis, and another (patient 2) had nonscarring alopecia and thrombocytopenia. They are currently clinically inactive but have positive serological findings. Patient 3 with homozygous pathogenic ACP5 mutation [G109 R (c.325 G>A) variant] had arthritis, nephritis, short stature, and skeletal dysplasia. Patient 4 with a heterozygote novel IFIH1 mutation [L809 F (c.2425 C>T) variant] had skin findings and leukopenia. Patient 5 with novel C1S variant [homozygous C147 W (c.441 C>G) variant] had marked skin findings, oral ulcers, nonscarring alopecia, pancytopenia, and low total hemolytic complement CH50 level. All patients have responded to the treatments and have low Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, on therapy.

CONCLUSION

Genetic causes should be investigated in early-onset SLE, for better management and genetic counseling. On the other hand, multicenter studies may help to further define genotype-phenotype associations.

Is systemic lupus erythematosus linked to Immunoglobulin G4 Autoantibodies?

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder characterized by a hyperactive immune system with multiple abnormalities in B-cell proliferation, antibody production, T-cell regulation, and immune complex (IC) formation. In humans, Immunoglobulin (Ig) G is found in four subclasses. IgG1-IgG4, which are distinguished by both structural and biological differences. Fab-arm Exchange (FAE), specific biases in the IgG4 response repertoire, and a decreased capacity to induce effector functions mediated by interactions in the fragment crystallizable (Fc) region are just a few of the distinctive characteristics of IgG4. The recent finding of the presence of double-stranded DNA (dsDNA) and antinuclear antibody (ANA)-IgG4 has raised attention to this IgG subclass and its possible role in SLE. IgG4 was previously believed to just have anti-inflammatory effects by inhibiting immune responses, but recent studies have shown that these antibodies can also play a role in the onset and development of some clinical disorders. To consider the clinical effects of IgG4 presence, it is necessary to discuss its characteristics, which could underlie the potential role it can play in SLE. Therefore, this study aimed to comprehensively review the role of IgG4 in SLE to elucidate the collective incidence of high IgG4 levels reported in some SLE patients.

The multifaceted role of autophagy in skin autoimmune disorders: a guardian or culprit?

Autophagy is a cellular process that functions to maintain intracellular homeostasis via the degradation and recycling of defective organelles or damaged proteins. This dynamic mechanism participates in various biological processes, such as the regulation of cellular differentiation, proliferation, survival, and the modulation of inflammation and immune responses. Recent evidence has demonstrated the involvement of polymorphisms in autophagy-related genes in various skin autoimmune diseases. In addition, autophagy, along with autophagy-related proteins, also contributes to homeostasis maintenance and immune regulation in the skin, which is associated with skin autoimmune disorders. This review aims to provide an overview of the multifaceted role of autophagy in skin autoimmune diseases and shed light on the potential of autophagy-targeting therapeutic strategies in dermatology.

Autophagy: a necessary evil in cancer and inflammation

Autophagy, a highly regulated cellular process, assumes a dual role in the context of cancer. On the one hand, it functions as a crucial homeostatic pathway, responsible for degrading malfunctioning molecules and organelles, thereby maintaining cellular health. On the other hand, its involvement in cancer development and regression is multifaceted, contingent upon a myriad of factors. This review meticulously examines the intricacies of autophagy, from its molecular machinery orchestrated by Autophagy-Related Genes (ATG) initially discovered in yeast to the various modes of autophagy operative within cells. Beyond its foundational role in cellular maintenance, autophagy reveals context-specific functions in processes like angiogenesis and inflammation. Our analysis delves into how autophagy-related factors directly impact inflammation, underscoring their profound implications for cancer dynamics. Additionally, we extend our inquiry to explore autophagy's associations with cardiovascular conditions, neurodegenerative disorders, and autoimmune diseases, illuminating the broader medical relevance of this process. Furthermore, this review elucidates how autophagy contributes to sustaining hallmark cancer features, including stem cell maintenance, proliferation, angiogenesis, metastasis, and metabolic reprogramming. Autophagy emerges as a pivotal process that necessitates careful consideration in cancer treatment strategies. To this end, we investigate innovative approaches, ranging from enzyme-based therapies to MTOR inhibitors, lysosomal blockers, and nanoparticle-enabled interventions, all aimed at optimizing cancer treatment outcomes by targeting autophagy pathways. In summary, this comprehensive review provides a nuanced perspective on the intricate and context-dependent role of autophagy in cancer biology. Our exploration not only deepens our understanding of this fundamental process but also highlights its potential as a therapeutic target. By unraveling the complex interplay between autophagy and cancer, we pave the way for more precise and effective cancer treatments, promising better outcomes for patients.

Intestinal permeability and inflammatory features of juvenile age correlate with the eventual systemic autoimmunity in lupus-prone female SWR × NZB F1 (SNF1) mice

The incidence of systemic lupus erythematosus (SLE) is about nine times higher in women than in men, and the underlying mechanisms that contribute to this gender bias are not fully understood. Previously, using lupus-prone (SWR × NZB)F1 (SNF1) mice, we have shown that the intestinal immune system could play a role in the initiation and progression of disease in SLE, and depletion of gut microbiota produces more pronounced disease protection in females than in males. Here, we show that the gut permeability features of lupus-prone female SNF1 mice at juvenile ages directly correlate with the expression levels of pro-inflammatory factors, faecal IgA abundance and nAg reactivity and the eventual systemic autoantibody levels and proteinuria onset. Furthermore, we observed that the disease protection achieved in female SNF1 mice upon depletion of gut microbiota correlates with the diminished gut inflammatory protein levels, intestinal permeability and circulating microbial DNA levels. However, faecal microbiota transplant from juvenile male and females did not result in modulation of gut inflammatory features or permeability. Overall, these observations suggest that the early onset of intestinal inflammation, systemic autoantibody production and clinical stage disease in lupus-prone females is linked to higher gut permeability in them starting at as early as juvenile age. While the higher gut permeability in juvenile lupus-prone females is dependent on the presence of gut microbes, it appears to be independent of the composition of gut microbiota.

The functional TNFAIP3 rs2230926T/G (Phe127Cys) variant confers risk to systemic lupus erythematosus in a Latin American population

TNFAIP3 is a classical systemic lupus erythematosus (SLE)-associated risk locus identified by genome-wide association studies (GWASs) and replicated by candidate gene association studies primarily in Caucasians and Asians. However, in Latin American populations, its role on SLE susceptibility is not known. We conducted a case-control study to evaluate whether the TNFAIP3 rs2230926T/G (Phe127Cys) variant is associated with risk of developing SLE in a cohort of Mexican patients. The TNFAIP3 rs2230926T/G variant was analyzed in 561 patients with SLE and 499 control subjects, using TaqMan probes. We found that the G allele was associated with susceptibility to SLE under the allelic (OR 2.09, p = 0.005) and genotypic (OR 2.14, p = 0.004) models. In conclusion, our results show that TNFAIP3 rs2230926T/G is a risk factor for the development of SLE in the Mexican population.

A Interacting Model: How TRIM21 Orchestrates with Proteins in Intracellular Immunity

Tripartite motif-containing protein 21 (TRIM21), identified as both a cytosolic E3 ubiquitin ligase and FcR (Fragment crystallizable receptor), primarily interacts with proteins via its PRY/SPRY domains and promotes their proteasomal degradation to regulate intracellular immunity. But how TRIM21 involves in intracellular immunity still lacks systematical understanding. Herein, it is probed into the TRIM21-related literature and raises an interacting model about how TRIM21 orchestrates proteins in cytosol. In this novel model, TRIM21 generally interacts with miscellaneous protein in intracellular immunity in two ways: For one, TRIM21 solely plays as an E3, ubiquitylating a glut of proteins that contain specific interferon-regulatory factor, nuclear transcription factor kappaB, virus sensors and others, and involving inflammatory responses. For another, TRIM21 serves as both E3 and specific FcR that detects antibody-complexes and facilitates antibody destroying target proteins. Correspondingly delineated as Fc-independent signaling and Fc-dependent signaling in this review, how TRIM21's interactions contribute to intracellular immunity, expecting to provide a systematical understanding of this important protein and invest enlightenment for further research on the pathogenesis of related diseases and its prospective application is elaborated.

Effects of N-acetylcysteine on systemic lupus erythematosus disease activity and its associated complications: a randomized double-blind clinical trial study

BACKGROUNDS

N-acetylcysteine (NAC) has broadly been used as an anti-oxidant agent in various types of diseases. This study aimed to assess the effect of NAC on the systemic lupus erythematosus (SLE) disease activity and outcome.

METHODS

In this randomized, double-blind clinical trial study, 80 SLE patients were recruited that were classified into two groups: 40 patients received NAC (1800 mg/day; 3 times per day with 8-h intervals) for 3 months and 40 patients as the control group received normal therapies. Laboratory measurements and disease activity based on the British Isles Lupus Assessment Group (BILAG) and SLE Disease Activity Index (SLEDAI) were determined before the initiation of treatment and after the study time period.

RESULTS

A statistically significant decrease in BILAG (P= 0.023) and SLEDAI (P= 0.034) scores after receiving NAC for a 3-month period was observed. BILAG (P= 0.021) and SLEDAI (P= 0.030) scores were significantly lower in NAC-receiving patients compared to the control group after 3 months. The disease activity in each organ based on BILAG score after treatment indicated a significant decrease in the NAC group compared to the baseline level in general (P=0.018), mucocutaneous (P=0.003), neurological (P=0.015), musculoskeletal (P=0.048), cardiorespiratory (P=0.047), renal (P=0.025), and vascular (P=0.048) complications. Analysis indicated a significant increase in CH50 level in the NAC group after treatment compared to the baseline level (P=0.049). No adverse event was reported by the study subjects.

CONCLUSIONS

It appears that the administration of 1800 mg/day NAC to SLE patients can decrease the SLE disease activity and its complications.

ATG5: A central autophagy regulator implicated in various human diseases

Autophagy, an intracellular conserved degradative process, plays a central role in the renewal/recycling of a cell to maintain the homeostasis of nutrients and energy within the cell. ATG5, a key component of autophagy, regulates the formation of the autophagosome, a hallmark of autophagy. ATG5 binds with ATG12 and ATG16L1 resulting in E3 like ligase complex, which is necessary for autophagosome expansion. Available data suggest that ATG5 is indispensable for autophagy and has an imperative role in several essential biological processes. Moreover, ATG5 has also been demonstrated to possess autophagy-independent functions that magnify its significance and therapeutic potential. ATG5 interacts with various molecules for the execution of different processes implicated during physiological and pathological conditions. Furthermore, ATG5 genetic variants are associated with various ailments. This review discusses various autophagy-dependent and autophagy-independent roles of ATG5, highlights its various deleterious genetic variants reported until now, and various studies supporting it as a potential drug target.

Fecal immunoglobulin A (IgA) and its subclasses in systemic lupus erythematosus patients are nuclear antigen reactive and this feature correlates with gut permeability marker levels

Systemic lupus erythematosus (SLE) is characterized by the production of anti-nuclear autoantibodies. Here, for the first time, we show that the abundances of gut permeability marker Zonulin and IgA1- and IgA2- subclasses are significantly higher in the fecal samples of SLE patients compared to HCs. Importantly, IgA-total, and IgA1- and IgA2-subclasses from SLE patients showed higher nAg reactivity titers. Notably, we found that not only the nuclear antigen (nAg) reactive fecal IgA1:IgA2 ratio is higher in SLE patients, but also the abundance and nAg reactivity of fecal IgA and subclasses, IgA1 particularly, correlate with the fecal levels of Zonulin, which is produced primarily in the small intestine. These observations that higher amounts of nAg-reactive IgA and gut permeability marker are produced, particularly, in the proximal gut suggest a compromised epithelial barrier function and pro-inflammatory characteristics of small intestine in SLE patients.

miRNA-binding site polymorphism in IL-15RA gene in rheumatoid arthritis and systemic lupus erythematosus: correlation with disease risk and clinical characteristics

INTRODUCTION/OBJECTIVES

MiRSNPs may interfere with mRNA stability through effects on microRNAs (miRNAs)-mRNA interactions via direct changes in miRNA binding site or effect on the secondary structure of this region and changes in accessibility of this region to miRNAs. Studies have confirmed that an elevated level of interleukin-15 receptor alpha (IL-15RA) has an important role in the pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In the present study, for the first time, we aimed to evaluate the possible correlation between a miRSNP, rs2296135, in IL-15RA gene with the risk of SLE and RA.

METHODS

In this case-control study, 100 SLE patients, 100 RA patients, and 110 healthy participants were enrolled to assess rs2296135 genotypes with real-time PCR high-resolution melting method.

RESULTS

According to our findings, AA genotype and A allele of rs2296135 were considerably associated with enhanced risk of RA (for AA genotype, OR = 2.29; 95% CI [1.06-5.02]; for A allele, OR = 1.65; 95% CI [1.10-2.48]). However, this common variant was not significantly correlated with SLE risk in population under study. Stratification analysis in the RA group verified that patients with the A allele had considerably higher serum concentrations of C-reactive protein (CRP) (P < 0.001). In SLE subjects, the frequency of arthritis (P: 0.021) and renal involvement (P: 0.025) in patients with A allele was significantly higher than in other SLE individuals.

CONCLUSION

The current study proposes a substantial association between rs2296135 polymorphism in IL-15RA gene with augmented risk of RA and some clinical characteristics in RA and SLE patients.

Novel Anti Double-Stranded Nucleic Acids Full-Length Recombinant Camelid Heavy-Chain Antibody for the Detection of miRNA

The discovery that certain diseases have specific miRNA signatures which correspond to disease progression opens a new biomarker category. The detection of these small non-coding RNAs is performed routinely using body fluids or tissues with real-time PCR, next-generation sequencing, or amplification-based miRNA assays. Antibody-based detection systems allow an easy onset handling compared to PCR or sequencing and can be considered as alternative methods to support miRNA diagnostic in the future. In this study, we describe the generation of a camelid heavy-chain-only antibody specifically recognizing miRNAs to establish an antibody-based detection method. The generation of nucleic acid-specific binders is a challenge. We selected camelid binders via phage display, expressed them as VHH as well as full-length antibodies, and characterized the binding to several miRNAs from a signature specific for dilated cardiomyopathy. The described workflow can be used to create miRNA-specific binders and establish antibody-based detection methods to provide an additional way to analyze disease-specific miRNA signatures.

Preclinical stage abundance and nuclear antigen reactivity of fecal Immunoglobulin A (IgA) varies among males and females of lupus-prone mouse models

Systemic lupus erythematosus (SLE) is characterized by the production of pathogenic autoantibodies with nuclear antigen (nAg) specificity. Using (SWRxNZB)F1 (SNF1) mice, we showed higher levels of IgA production in the intestine and the nAg reactivity of fecal IgA under lupus susceptibility. Here, we determined if the fecal IgA abundance and nAg reactivity are higher in, different among, various lupus-prone preclinical models (MRL/lpr, NZBxNZW-F1, SNF1, NZM2410 and NZM2328). We also determined if the fecal IgA nAg reactivity at pre-seropositive ages correlates with the eventual serum autoantibody levels in males and females of these mouse models. We show that age dependent increase in the abundance and nAg reactivity of fecal IgA can vary among different lupus-prone mouse models. Importantly, fecal IgA in these mice show significant levels of nAg reactivity, starting as early as at juvenile age. Furthermore, the pre-seropositive stage nAg reactivity of fecal IgA in most lupus-prone strains correlates well with that of eventual, seropositive stage systemic autoantibody levels. Gender differences in serum autoantibody levels were preceded by similar differences in the fecal IgA abundance and nAg reactivity. These observations suggest that fecal IgA features, nAg reactivity particularly, could serve as a biomarker for early prediction of the eventual systemic autoimmunity in lupus-prone subjects.

Semaphorin 3A Levels in Lupus With and Without Secondary Antiphospholipid Antibody Syndrome and Renal Involvement

OBJECTIVE

The aim of this study is to evaluate semaphorin 3A levels in patients with systemic lupus erythematosus (SLE) with and without renal involvement and secondary antiphospholipid antibody syndrome (APS).

METHODS

Patients with SLE were grouped according to the presence of secondary APS or renal involvement. The control group consisted of age-matched, nonsmoking, healthy volunteers. Semaphorin 3A levels were compared among groups. All patients with SLE were regrouped according to the presence of thrombotic events, miscarriages, and proteinuria, and semaphorin 3A levels were investigated. Finally, semaphorin 3A levels of all patients with SLE as a single group were compared to those of the control patients.

RESULTS

The mean semaphorin 3A values were 16.16 ± 2.84 ng/mL in the control group, 9.05 ± 5.65 ng/mL in patients with SLE without nephritis and APS, 11.28 ± 5.23 ng/mL in the SLE with APS group, and 8.53 ± 5.11 ng/mL in the lupus nephritis group. When all 3 patient groups were examined as a single group, the mean semaphorin 3A value was significantly lower than that of the control group. Semaphorin 3A was reduced in patients with SLE with thromboembolism and/or history of miscarriage.

CONCLUSION

Semaphorin 3A levels were lower in all patient groups compared to the control group. Moreover, the reduced semaphorin 3A levels in patients with a history of thromboembolism and/or miscarriage suggest that semaphorin 3A may play an important role in the pathogenesis of vasculopathy.

Can anticarbamylated protein antibodies be used to support the diagnosis of systemic lupus erythematosus?

Aim: Autoantibody development plays an important role in the pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In this study, we aimed to determine the diagnostic value of anticarbamylated protein antibody (anti-CarP) antibody in SLE and RA patients and its relationship with disease prognosis. Material & method: Fifty-seven SLE patients (F/M 50/7; median age 40.9 ± 13.7; median disease duration 2 years) who met the 2012 SLICC SLE diagnostic criteria were included in the study. A total of 46 RA patients selected according to the 2010 ACR/EULAR diagnostic criteria (F/M 38/8; median age 54.2 ± 12.4; median disease duration 2 years) were included. A total of 30 healthy individuals were selected as the control group. The anti-CarP antibody was studied by using human anticarbamylated protein antibody ELISA Kit (SunRedBio, Shanghai, China). Results: Anti-CarP antibody positivity was found to be 17.4% in RA patients (p < 0.001), 54.4% in SLE patients (p < 0.001) and 3.3% in the healthy control group. The anti-CarP antibody was determined to predict SLE patients with 54.4% sensitivity and 96.7% specificity compared with the healthy control group (area under the curve: 0.755; p < 0.001). Conclusion: Anti-CarP antibody positivity was significantly higher in the SLE patients compared with the healthy control and RA group. It has significant sensitivity and specificity in both SLE and RA patients compared with the healthy controls.

Effect of Cytokine Gene Polymorphisms on Eltrombopag Reactivity in Japanese Patients with Immune Thrombocytopenia

BACKGROUND

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by low platelet counts resulting from antiplatelet autoantibodies. Analysis of polymorphisms in cytokine-encoding genes is important for understanding the pathophysiology of ITP and selecting appropriate treatments. We investigated associations between polymorphisms in cytokine-encoding genes and responses to therapy in Japanese patients with ITP.

METHODS

The participants in this study comprised 153 patients with ITP and 70 healthy controls. We extracted data on sex, age, platelet counts, bleeding symptoms, and therapeutic responses, including those to prednisolone (PSL) and eltrombopag. Genomic DNA was isolated from peripheral blood and polymorphisms in TNF-α, IL-10, TGF-β1, and IFN-γ genes were analyzed using the PCR-SSP method.

RESULTS

Our results showed that the TGF-β1 +869 C/C genotype might be related to ITP in Japanese patients. The IL-10 -592 C/C and A/A, -819 C/C and T/T, and -1082, -819, -592 ATA/ATA genotypes might be associated with reactivity to PSL. Furthermore, the IL-10 -592 C/A -819 C/T genotypes, IL-10 ACC/ATA genotype, and TGF-β1 +869 T/T and T/C genotypes might be linked to the response to eltrombopag.

CONCLUSION

Our results indicate that analysis of polymorphisms in cytokine-encoding genes could aid in understanding PSL and eltrombopag responsiveness in Japanese patients with ITP.

Implications the Role of miR-155 in the Pathogenesis of Autoimmune Diseases

MicroRNAs (miRNAs) are small noncoding conserved RNAs containing 19 to 24 nucleotides that are regulators of post-translational modifications and are involved in the majority of biological processes such as immune homeostasis, T helper cell differentiation, central and peripheral tolerance, and immune cell development. Autoimmune diseases are characterized by immune system dysregulation, which ultimately leads to destructive responses to self-antigens. A large body of literature suggests that autoimmune diseases and immune dysregulation are associated with different miRNA expression changes in the target cells and tissues of adaptive or innate immunity. miR-155 is identified as a critical modulator of immune responses. Recently conducted studies on the expression profile of miR-155 suggest that the altered expression and function of miR-155 can mediate vulnerability to autoimmune diseases and cause significant dysfunction of the immune system.

Three functional variants in the NLRP3 gene are associated with susceptibility and clinical characteristics of systemic lupus erythematosus

OBJECTIVE

Nod-like receptor pyrin domain containing 3 (NLRP3) gene encodes an intracellular receptor whose dysregulation in systemic lupus erythematosus (SLE) has been reported in multiple studies. Activation of NLRP3 inflammasome leads to the induction of inflammatory response via cleaving and producing of specific cytokines. In the present study, we assessed the possible association between three functional polymorphisms in this gene and SLE risk in the Iranian population. These variants include two gain of function (rs4612666 and rs10754558) and one loss of function (rs6672995) which are correlated with modulation of expression of NLRP3.

METHODS

A case-control study involving 110 SLE patients and 116 control subjects was undertaken to estimate the frequency of rs4612666, rs10754558, and rs6672995 genotypes using real-time PCR high resolution melting method (HRM).

RESULTS

Our findings revealed significant associations between GG genotype and G allele of rs10754558 with increased risk of SLE (OR _{for GG genotype}= 2.82; 95%CI [1.45-5.46]/OR _{for G allele}= 1.97; 95%CI [1.36-2.87]). Although, no significant associations were recognized between allele and genotype frequencies of rs4612666 and rs6672995 polymorphisms with SLE risk (P > 0.05). Also, our analysis revealed that the C allele in rs4612666 and G allele in rs10754558 was correlated with the severity of disease activity (P < 0.001). Moreover, these common variants were associated with lower age of onset and some clinical symptoms in the patient group, such as skin manifestation, neurological symptom and, renal involvement (P < 0.05).

CONCLUSION

This study demonstrates a substantial association between NLRP3 polymorphisms with increased risk, clinical symptoms, and the severity of disease activity of SLE.

Usefulness of Cytokine Gene Polymorphisms for the Therapeutic Choice in Japanese Patients with Rheumatoid Arthritis

Background

Rheumatoid arthritis (RA) is characterized by systemic synovitis with bone erosion and joint cartilage degradation. Although the analysis of polymorphisms in cytokine-encoding genes is important or understanding the pathophysiology of RA and selecting appropriate treatment for it, few studies have examined such single-nucleotide polymorphisms (SNPs) specifically in Japanese patients. This study was established to investigate the associations between polymorphisms in cytokine-encoding genes, autoantibodies and therapeutic responses in Japanese RA patients.

Methods

The subjects in this study consisted of 100 RA patients and 50 healthy controls. We extracted data on sex, age, disease duration, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, and therapeutic responses, including to methotrexate (MTX) and biological disease-modifying antirheumatic drugs (DMARDs). Genomic DNA was isolated from peripheral blood, which was genotyped for IL-10, TNF-α, TGF-β₁, and IFN-γ polymorphisms.

Results

Regarding IL-10 (−592 C/A and −819 C/T), significant decreases in the frequencies of the IL-10 (−592) CC genotype and (−819) CC genotype were found in RA patients compared with the levels in controls. For IFN-γ (+874 T/A), a significant decrease in the frequency of the TT genotype was found in RA patients compared with that in controls. Regarding TGF-β₁ (+869 T/C), patients with positivity for anti-CCP antibody had a significantly lower frequency of the CC genotype than those with negativity for it. Furthermore, the IL-10 (−592) CC genotype and (−819) CC genotype might be related to the biological DMARD-response.

Conclusion

Our results suggest that the analysis of polymorphisms in cytokine-encoding genes may be useful when selecting treatment for Japanese RA patients.

Abundance and nuclear antigen reactivity of intestinal and fecal Immunoglobulin A in lupus-prone mice at younger ages correlate with the onset of eventual systemic autoimmunity

Our recent studies, using (SWRxNZB)F1 (SNF1) mice, showed a potential contribution of the gut microbiota and pro-inflammatory immune responses of the gut mucosa to systemic autoimmunity in lupus. Here, using this mouse model, we determined the abundance and the nAg reactivity of IgA antibody produced in the intestine under lupus susceptibility. Intestinal lymphoid tissues from SNF1 mice, females particularly, showed significantly higher frequencies of nAg (dsDNA and nucleohistone) reactive IgA producing B cells compared to B6 females. Most importantly, younger age fecal IgA -abundance and -nAg reactivity of lupus-prone mice showed a positive correlation with eventual systemic autoimmunity and proteinuria onset. Depletion of gut microbiota in SNF1 mice resulted in the diminished production of IgA in the intestine and the nAg reactivity of these antibodies. Overall, these observations show that fecal IgA features, nuclear antigen reactivity particularly, at preclinical stages/in at-risk subjects could be predictive of autoimmune progression.

Mechanisms of Environment-Induced Autoimmunity

Although numerous environmental exposures have been suggested as triggers for preclinical autoimmunity, only a few have been confidently linked to autoimmune diseases. For disease-associated exposures, the lung is a common site where chronic exposure results in cellular toxicity, tissue damage, inflammation, and fibrosis. These features are exacerbated by exposures to particulate material, which hampers clearance and degradation, thus facilitating persistent inflammation. Coincident with exposure and resulting pathological processes is the posttranslational modification of self-antigens, which, in concert with the formation of tertiary lymphoid structures containing abundant B cells, is thought to promote the generation of autoantibodies that in some instances demonstrate major histocompatibility complex restriction. Under appropriate gene-environment interactions, these responses can have diagnostic specificity. Greater insight into the molecular and cellular requirements governing this process, especially those that distinguish preclinical autoimmunity from clinical autoimmunedisease, may facilitate determination of the significance of environmental exposures in human autoimmune disease.

Discovering the signature of a lupus-related microRNA profile in the Gene Expression Omnibus repository

Lupus is one of the most prevalent systemic autoimmune diseases. It is a multifactorial disease in which genetic, epigenetic and environmental factors play significant roles. The pathogenesis of lupus is not yet well understood. However, deregulation of microRNAs (miRNAs) - one of the post-transcriptional regulators of genes - can contribute to the development of autoimmune diseases. Over the last two decades, advances in the profiling of miRNA using microarray have received much attention, and it has been demonstrated that miRNAs play a regulatory role in the pathogenesis of lupus. Therefore, dysregulated miRNAs can be considered as promising diagnostic biomarkers for lupus. This article is an overview of lupus-related miRNA profiling studies and arrays in the Gene Expression Omnibus (GEO) database. The aims of our study were to widen current knowledge of known dysregulated miRNAs as potential biomarkers of SLE and to introduce a bioinformatics approach to using microarray data and finding novel miRNA and gene candidates for further study. We identified hsa-miR-4709-5p, hsa-miR-140, hsa-miR-145, hsa-miR-659, hsa-miR-134, hsa-miR-150, hsa-miR-584, hsa-miR-409 and hsa-miR-152 as potential biomarkers by integrated bioinformatics analysis.

Genetic defects of autophagy linked to disease

Autophagy is a highly conserved lysosomal degradation pathway responsible for rapid elimination of unwanted cytoplasmic materials in response to stressful conditions. This cytoprotective function is essential for maintenance of cellular homeostasis and is mediated by conserved autophagy-related genes (ATG) and autophagic receptors. Impairment of autophagy frequently results in a wide variety of human pathologies. Recent studies have revealed direct links between diverse diseases and genetic defects of core autophagy genes, autophagy-associated genes, and genes encoding autophagic receptors. Here we provide a general description of autophagy-related genes and their mutations or polymorphisms that play a causative role in specific human disorders or may be risk factors for them.

Evidence for a pathogenic role of extrafollicular, IL-10-producing CCR6+B helper T cells in systemic lupus erythematosus

Interleukin 10 (IL-10) is an antiinflammatory cytokine, but also promotes B cell responses and plays a pathogenic role in systemic lupus erythematosus (SLE). CD4⁺CCR6⁺IL-7R⁺T cells from human tonsils produced IL-10 following stimulation by naïve B cells, which promoted B cell immunoglobulin G (IgG) production. These tonsillar CCR6⁺B helper T cells were phenotypically distinct from follicular helper T (T_FH) cells and lacked BCL6 expression. In peripheral blood, a CCR6⁺T cell population with similar characteristics was identified, which lacked Th17- and T_FH-associated gene signatures and differentiation-associated surface markers. CD4⁺CCR6⁺T cells expressing IL-10, but not IL-17, were also detectable in the spleens of cytokine reporter mice. They provided help for IgG production in vivo, and expanded systemically in pristane-induced lupus-like disease. In SLE patients, CD4⁺CCR6⁺IL-7R⁺T cells were associated with the presence of pathogenic anti-dsDNA (double-stranded DNA) antibodies, and provided spontaneous help for autoantibody production ex vivo. Strikingly, IL-10-producing CCR6⁺T cells were highly abundant in lymph nodes of SLE patients, and colocalized with B cells at the margins of follicles. In conclusion, we identified a previously uncharacterized population of extrafollicular B helper T cells, which produced IL-10 and could play a prominent pathogenic role in SLE.

JAK/STAT signaling controls the fate of CD8+CD103+ tissue-resident memory T cell in lupus nephritis

Autoimmune mediated inflammation and renal damage in lupus nephritis (LN) depends partly on the infiltration of lymphocytes in glomeruli and renal interstitium. Here we identified a population of CD8⁺ T cells with a CD103⁺-phenotype in the healthy kidneys of human and mouse. These cells were typically CD69⁺CD103⁺ tissue-resident memory T cells (T_RM) in the kidney. CD8⁺ T_RM cells were expanded in the kidneys of patients with LN or MRL/lpr mice. The expansion of renal CD8⁺ T_RM cells correlated significantly with kidney disease activity. These cells were active in producing cytokines, perforin and granzyme B in the kidney of MRL/lpr mice. Importantly, renal CD8⁺ T_RM cells underwent proliferation and self-renewal to maintain a stable T_RM pool in the kidney of MRL/lpr mice, contributing to renal inflammation and damage. JAK/STAT signaling in the MRL/lpr mice was required for renal T_RM self-renewal as well as maintenance of effector functions. Targeting JAK/STAT signaling by tofacitinib effectively suppressed effector functions and impaired the survival of renal T_RM cells in the kidney, contributing to improved kidney function in MRL/lpr mice. These results provided evidences that renal CD8⁺ T_RM cells play a role in the pathogenesis of LN. They could serve as a therapeutic target for LN.

Gut microbiota differently contributes to intestinal immune phenotype and systemic autoimmune progression in female and male lupus-prone mice

The risk of developing systemic lupus erythematosus (SLE) is about 9 times higher in women as compared to men. Our recent report, which used (SWRxNZB) F1 (SNF1) mouse model of spontaneous lupus, showed a potential link between immune response initiated in the gut mucosa at juvenile age (sex hormone independent) and SLE susceptibility. Here, using this mouse model, we show that gut microbiota contributes differently to pro-inflammatory immune response in the intestine and autoimmune progression in lupus-prone males and females. We found that gut microbiota composition in male and female littermates are significantly different only at adult ages. However, depletion of gut microbes causes suppression of autoimmune progression only in females. In agreement, microbiota depletion suppressed the pro-inflammatory cytokine response of gut mucosa in juvenile and adult females. Nevertheless, microbiota from females and males showed, upon cross-transfer, contrasting abilities to modulate disease progression. Furthermore, orchidectomy (castration) not only caused changes in the composition of gut microbiota, but also a modest acceleration of autoimmune progression. Overall, our work shows that microbiota-dependent pro-inflammatory immune response in the gut mucosa of females initiated at juvenile ages and androgen-dependent protection of males contribute to gender differences in the intestinal immune phenotype and systemic autoimmune progression.

Deltex1 suppresses T cell function and is a biomarker for diagnosis and disease activity of systemic lupus erythematosus

OBJECTIVE

Deletion of Deltex1 (DTX1) in mice caused hyperactivation of T cells and lupus-like autoimmune syndromes, however, the association of DTX1 with human autoimmune diseases is totally unknown. This study investigated the role of DTX1 in human T cell functions and its correlation with disease activity in patients with SLE.

METHODS

The influence of DTX1 on T cell function was evaluated using human primary cells. DTX1 expression in peripheral blood mononuclear cells (PBMCs) from healthy controls and SLE patients was measured by quantitative real-time PCR and the SLEDAI was used to assess disease activity.

RESULTS

After stimulation with anti-CD3 and anti-CD28, silencing of DTX1 expression enhanced IFN-γ secretion by human T cells. The expression of DTX1 in PBMCs was significantly lower in 100 SLE patients than in 50 age- and sex-matched healthy controls (DTX1/glyceraldehyde 3-phosphate dehydrogenase, 0.452 vs 1.269, P < 0.001). The area under the receiver operator characteristics curve of the model was 0.737 (95% CI 0.658, 0.815). Intriguingly, a low DTX1 level in T cells led to high IFN-γ production in SLE patients and had a correlation with severe disease activity. In addition, low DTX1 expression in SLE patients was associated with active LN, lung involvement or hypocomplementaemia.

CONCLUSION

Knockdown DTX1 expression in human T cells reduced IFN-γ secretion. DTX1 expression in the PBMCs was significantly lower in SLE patients and had an inverse correlation with disease activity, indicating that the DTX1 level may be a good disease marker of SLE.

The -675 4G/5G PAI-1 polymorphism confers genetic susceptibility to systemic lupus erythematosus, its clinical manifestations, and comorbidities in Mexican-Mestizo population

Systemic lupus erythematosus (SLE) involves a broad range of factors that contribute to the development of the disease and its comorbidities. Genetic predisposition influences the development of SLE, and the -675 4G/5G PAI-1 polymorphism has been associated with several pathologies with a chronic inflammatory component. Our objective was to investigate the genetic association between the -675 4G/5G PAI-1 polymorphism with SLE, its clinical manifestations, and comorbidities in a Mexican-Mestizo population. The -675 PAI-1 polymorphism was determined by PCR-RFLP in 716 subjects: 293 SLE patients and 423 control subjects. Significant associations for SLE genetic susceptibility were found in carriers of 4G/5G (OR = 2.63; CI 1.81-3.87; p < .001) and 4G/4G (OR = 2.70; CI 1.62-4.51; p < .001) genotype in comparison with the 5G/5G genotype; 4G allele carriers also presented genetic risk for SLE (OR = 1.63; CI 1.31-2.03; p < .001) compared to the 5G allele. Following a dominant genetic model, a similar association was found with the 4G allele to SLE (OR = 2.66; CI1.84-3.84; p < .001). The 4G/5G genotype was associated with shorter disease duration (p = .039), as well as lower levels of haemoglobin (p = .001) and haematocrit (p = .009); the need for prednisone treatment (p = .001), higher BMI (p = .03), presence of type 2 DM (p = .015), clinical activity (Mex-SLEDAI = 57%; p = .047), Chronicity (SLICC-ACR = 0; p = .015) and CRP levels (p = .015) were associated with 5G/5G genotypes. In conclusion, the -675 4G/5G and 4G/4G PAI-1genotypes were found as genetic risk markers of susceptibility for SLE in the Mexican-Mestizo population, and each genotype could influence the clinical manifestations and comorbidities differently in SLE.

Susceptibility of BAFF-var allele carriers to severe SLE with occurrence of lupus nephritis

BACKGROUND

Dysregulation of the B-cell activating factor (BAFF) system is involved in the pathogenesis of systemic lupus erythematosus (SLE). Increased serum concentrations of BAFF are related to lupus nephritis and disease activity among SLE patients. Recently, a variant of the BAFF-encoding gene, BAFF-var, was identified to be associated with autoimmune diseases, in particular SLE, and to promote the production of soluble BAFF. The present study aimed to assess the prevalence of BAFF-var in a cohort of 195 SLE patients and to analyze the association of the BAFF-var genotype (TNSF13B) with various manifestations of SLE.

METHODS

A cohort of 195 SLE patients from Central Europe, including 153 patients from the Swiss SLE Cohort Study and 42 patients from the University Hospital Essen, Germany, underwent genotyping for detection of BAFF-var allele.

RESULTS

Of the 195 patients, 18 (9.2%) tested positive for BAFF-var variant according to the minor allele frequency of 4.6%. The presence of BAFF-var was associated with the occurrence of lupus nephritis (p = 0.038) (p = 0.03 and p = 0.003). Among various organ manifestations of SLE, the presence of BAFF-var was associated with the occurrence of lupus nephritis (p = 0.038; odds ratio [OR], 2.4; 95% confidence interval [CI], 0.89-6.34) and renal activity markers such as proteinuria and hematuria (p = 0.03; OR, 2.4; 95% CI, 0.9-6.4 for proteinuria; p = 0.003; OR, 3.9; 95% CI, 1.43-10.76 for hematuria). SLE patients carrying the BAFF-var allele exhibited increased disease activity at study entry, as determined by the physician's global assessment (PGA: p = 0.002; OR, 4.8; 95% CI, 1.54-14.93) and the SLE Disease Activity Index (p = 0.012; OR, 3.5; 95% CI, 1.12-11.18). Consistent with that, the percentage of patients treated with immunosuppressive agents at study entry was higher among those carrying the BAFF-var allele than among those tested negative for BAFF-var (p = 0.006; OR, 3.7; 95% CI, 1.27-10.84).

CONCLUSIONS

Our results indicate an association between the BAFF-var genotype and increased severity of SLE. Determining the BAFF-var status of SLE patients may improve the risk stratification of patients for whom the development of lupus nephritis is more likely and thus may be helpful in the follow-up care and treatment of SLE patients.

IL-10 producing regulatory and helper T-cells in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease characterised by the production of pathogenic autoantibodies against nuclear self-antigens. The anti-inflammatory and tolerogenic cytokine Interleukin-10 appears to play a paradoxical pathogenic role in SLE and is therefore currently therapeutically targeted in clinical trials. It is generally assumed that the pathogenic effect of IL-10 in SLE is due to its growth and differentiation factor activity on autoreactive B-cells, but effects on other cells might also play a role. To date, a unique cellular source of pathogenic IL-10 in SLE has not been identified. In this review, we focus on the contribution of different CD4⁺T-cell subsets to IL-10 and autoantibody production in SLE. In particular, we discuss that IL-10 produced by different subsets of adaptive regulatory T-cells, follicular helper T-cells and extra-follicular B-helper T-cells is likely to have different effects on autoreactive B-cell responses. A better understanding of the role of IL-10 in B-cell responses and lupus would allow to identify the most promising therapies for individual SLE patients in the future.

Long-term exposure to traffic-related air pollution and systemic lupus erythematosus in Taiwan: A cohort study

Systemic lupus erythematosus (SLE) is a multi-systemic chronic autoimmune disease, the etiology of SLE is still unclear. Only a few studies evaluated the associations between air pollution and SLE. We conducted a population-based cohort study in Taiwan to examine the associations of air pollution with SLE. A total of 682,208 individuals aged 18-70 years were retrieved from National Health Insurance Research Database. We applied 1-km resolution land use regression and satellite-based models to estimate air pollutant concentrations during 2001-2010. The mixed effect Cox models with time-dependent variables were performed to estimate the associations between air pollution and SLE, as hazard ratios (HRs) with 95% confidence interval (CI). We identified 1292 newly diagnosed SLE patients with average age of 43.26 ± 13.64 years, most of them were female. There were positive associations of SLE with exposure to a 9.76 ppb increase in nitrogen dioxide (NO₂), a 0.20 ppm increase in carbon monoxide (CO), and a 10.2 μg/m³ increase in fine particles (PM_2.5) (HR = 1.21, 95% CI: 1.08-1.36, HR = 1.44, 95% CI: 1.31-1.59, and HR = 1.12, 95% CI: 1.02-1.23, respectively). Additionally, we observed negative associations with ozone (O₃) and sulfur dioxide (SO₂). According to the exposure-response relationships, exposure to NO₂ between 28 and 38 ppb, exposure to CO above 0.6 ppm, and exposure to PM_2.5 between 18 and 46 μg/m³ were positively associated with SLE. The results suggested that long-term exposure to traffic-related gaseous air pollutants (NO₂ and CO) less than current National Ambient Air Quality Standards and PM_2.5 are significantly associated with the risk of SLE.

Homocysteine levels are independently associated with damage accrual in systemic lupus erythematosus patients from a Latin-American cohort

OBJECTIVE

To determine the impact of homocysteine levels on damage accrual in systemic lupus erythematosus (SLE) patients.

METHODS

This longitudinal study was conducted in consecutive patients seen every 6 months at our Rheumatology Department since 2012. Patients with available homocysteine levels and who had at least one subsequent visit were included. Univariable and multivariable Cox regression models were done to determine if homocysteine levels were predictive of damage accrual as per the SLICC Damage Index (SDI). The multivariable model was adjusted for pertinent variables (age at diagnosis, gender, socioeconomic status, disease duration, disease activity (SLEDAI), Framingham score, antimalarial and immunosuppressive drug use, average daily dose, and exposure time to prednisone (PDN)).

RESULTS

One hundred forty-five patients were included; their mean (SD) age at diagnosis was 43.70 (12.09) years, 136 (93.8%) were female, and nearly all were Mestizo. At baseline, disease duration was 7.55 (6.73) years; patients were followed for 3.54 (1.27) years. The SLEDAI was 5.60 (4.34), and the SDI 0.97 (1.35). The average daily PDN dose was 7.30 (5.78) mg/day and the time of PDN exposure was 7.36 (6.73) years. Mean homocysteine levels were 10.07 (3.71) μmol/L. The highest tertile of homocysteine levels predicted new damage accrual in the univariable and multivariable models [HR 1.78 (95% CI, 1.042-3.039); p = 0.035 and HR 2.045 (95% CI, 1.077-3.883); p = 0.029, respectively]. Increased levels (> 15 μmol/L) were found in 12 (8.3%) patients; 75 (51.7%) patients increased ≥ 1 SDI point.

CONCLUSION

In SLE patients, homocysteine levels predicted damage accrual independently of other well-known risk factors for such occurrence.

Exploring the Role of Autophagy-Related Gene 5 (ATG5) Yields Important Insights Into Autophagy in Autoimmune/Autoinflammatory Diseases

Autophagy is a highly conserved process that degrades certain intracellular contents in both physiological and pathological conditions. Autophagy-related proteins (ATG) are key players in this pathway, among which ATG5 is indispensable in both canonical and non-canonical autophagy. Recent studies demonstrate that ATG5 modulates the immune system and crosstalks with apoptosis. However, our knowledge of the pathogenesis and regulatory mechanisms of autophagy in various immune related diseases is lacking. Thus, a deeper understanding of ATG5's role in the autophagy mechanism may shed light on the link between autophagy and the immune response, and lead to the development of new therapies for autoimmune diseases and autoinflammatory diseases. In this focused review, we discuss the latest insights into the role of ATG5 in autoimmunity. Although these studies are at a relatively early stage, ATG5 may eventually come to be regarded as a “guardian of immune integrity.” Notably, accumulating evidence indicates that other ATG genes may have similar functions.

MicroRNA-mediated immune regulation in rheumatic diseases

MicroRNAs (miRNAs) are endogenous small, non-coding RNAs that regulate genome expression at the post-transcriptional level. They are involved in a wide range of physiological processes including the maintenance of immune homeostasis and normal function. Accumulating evidence from animal studies show that alterations in pan or specific miRNA expression would break immunological tolerance, leading to autoimmunity. Differential miRNA expressions have also been documented in patients of many autoimmune disorders. In this review, we highlight the evidence that signifies the critical role of miRNAs in autoimmunity, specifically on their regulatory roles in the pathogenesis of several rheumatic diseases including systemic lupus erythematosus, rheumatoid arthritis and spondyloarthritis. The potential of miRNAs as biomarkers and therapeutic targets is also discussed. Manipulation of dysregulated miRNAs in vivo through miRNA delivery or inhibition offers promise for new therapeutic strategies in treating rheumatic diseases.

Association of TNFAIP3 and TNIP1 polymorphisms with systemic lupus erythematosus risk: A meta-analysis

OBJECT

With the development of GWAS, both TNFAIP3 and TNIP1 were revealed to be susceptibility genes of SLE. However, some other studies revealed no association between TNFAIP3, TNIP1 and SLE susceptibility. In order to estimate such association more precisely and systemically, a meta-analysis was conducted.

METHOD

Studies on the association between TNFAIP3 rs2230926, TNIP1 rs7708392 and SLE risk were carefully selected via searching 3 databases (Pubmed, Embase, and Web of Science). A fixed- or random-effect model was used according to the heterogeneity, and a subgroup analysis by ethnicity was also performed.

RESULTS

26 studies from 18 articles involving a total of 21,372 patients and 30,165 controls were analyzed for TNFAIP3 rs2230926. A significant association between the minor G allele of TNFAIP3 rs2230926 and SLE risk was found via a random-effect model (OR = 1.643, 95% CI = (1.462, 1.847), p < 0.01). In the subgroup analysis by ethnicity, significant correlations were also found in all Caucasians, Asians, and Africans (OR = 1.675, 95% CI = (1.353, 2.074), p < 0.01; OR = 1.738, 95% CI = (1.557, 1.940), p < 0.01; OR = 1.324, 95% CI = (1.029, 1.704), p < 0.05). As for TNIP1 rs7708392, 21 studies from 12 articles involving 24,716 cases and 32,200 controls were analyzed. A significant association of the minor C allele of TNIP1 rs7708392 and SLE risk was found via a random-effect model (OR = 1.247, 95% CI = (1.175, 1.323), p < 0.01). In the subgroup analysis by ethnicity, significant correlations were found in Caucasians, and Africans (OR = 1.317, 95% CI = (1.239, 1.401), p < 0.01; OR = 1.210, 95% CI = (1.108, 1.322), p < 0.01). However, there was no significant association in Asians (OR = 1.122, 95% CI = (0.953, 1.321), p > 0.05).

CONCLUSION

The minor G allele of TNFAIP3 rs2230926 was associated with increased risk of SLE in all Caucasians, Asians, and Africans. The minor C allele of TNIP1 rs7708392 was associated with the increased risk of SLE in Caucasians and Africans, while it was not associated with SLE susceptibility in Asians.

Evaluation of ATG5 polymorphisms in Italian patients with systemic lupus erythematosus: contribution to disease susceptibility and clinical phenotypes

Systemic lupus erythematosus (SLE) is a common heterogeneous autoimmune disease that is caused by the involvement both of genetic and environmental factors. There is evidence that autophagy is involved in several aspects of SLE pathogenesis. In particular, polymorphisms in the ATG5 gene have been observed to be associated with disease susceptibility. Our aim was to verify if ATG5 polymorphisms are involved in the susceptibility to disease and its clinical phenotypes in an Italian cohort of SLE patients. This study involved 315 SLE patients and 265 healthy controls. Three polymorphisms in the ATG5 gene (rs573775, rs6568431 and rs2245214) were investigated by allelic discrimination assay. A case-control association study, a genotype/phenotype correlation analysis and a haplotype study were performed. Moreover, an expression study was conducted in peripheral blood mononuclear cells from 15 SLE patients to verify a possible effect of the three SNPs on the expression of ATG5. Among the three investigated SNPs, only the rs573775 SNP was significantly associated with disease susceptibility with the variant allele conferring a higher risk of developing SLE (OR = 1.50, p = 0.018 and OR = 1.48, p = 0.007 at the genotypic and allelic level, respectively). The variant allele of rs6568431 SNP was more present in patients with anemia (OR = 1.86, p = 0.009) and renal involvement (OR = 1.63, p = 0.06), while the variant allele of rs2245214 SNP was significantly associated with a higher risk of producing anti-DNA autoantibodies (OR = 1.66, p = 0.04). Carriers of the rs6568431 variant allele showed higher messenger RNA levels compared to the carriers of the wild-type allele, suggesting also a potential variant allele dose-dependent effect on gene expression. In conclusion, our study confirms a role for ATG5 polymorphisms both in disease susceptibility and in the modulation of clinical phenotypes in an Italian SLE cohort. These results further suggest that genetic variations in autophagy genes could play a role in autoimmune diseases susceptibility and are worth further investigation.

Caffeine inhibits STAT1 signaling and downregulates inflammatory pathways involved in autoimmunity

Caffeine is a widely consumed pharmacologically active product. We focused on characterizing immunomodulatory effects of caffeine on peripheral blood mononuclear cells. Caffeine at high doses showed a robust downregulatory effect on cytokine activity and genes related to several autoimmune diseases including lupus and rheumatoid arthritis. Dose-dependent validation experiments showed downregulation at the mRNA levels of key inflammation-related genes including STAT1, TNF, IFNG, and PPARG. TNF and PPARG were suppressed even with the lowest caffeine dose tested, which corresponds to the serum concentration of caffeine after administration of one cup of coffee. Cytokine levels of IL-8, MIP-1β, IL-6, IFN-γ, GM-CSF, TNF, IL-2, IL-4, MCP-1, and IL-10 were decreased significantly with caffeine treatment. Upstream regulator analysis suggests that caffeine inhibits STAT1 signaling, which was confirmed by showing reduced phosphorylated STAT1 after caffeine treatment. Further studies exploring disease-modulating potential of caffeine in autoimmune diseases and further exploring the mechanisms involved are warranted.

Analytical variability in the determination of anti-double-stranded DNA antibodies: the strong need of a better definition of the old and new tests

Anti-dsDNA antibodies are a heterogeneous group of antibodies, quite specific for SLE. Their variability is related to the assay used, the immunoglobulin class secondary antibody, and the dsDNA source. The standardization of measuring anti-dsDNA antibodies is still poor and different methods yield different results. Several novel technologies were developed during the last decades that represent viable alternatives to the traditional methods such as the chemiluminescent immunoassay (CIA) and multiplex flow immunoassay (MFI). Additionally, positive results for anti-dsDNA antibodies can be detected in patients with inflammatory arthritis (IA) treated with different biologics reducing its clinical specificity for SLE. Anti-dsDNA antibody levels were evaluated in 246 patient samples: 70 SLE and 176 disease control (including 96 IA during treatment with different biologics), using three enzyme immunoassays (indirect enzyme immunoassay, Bio-Rad Laboratories; chemiluminescent immunoassay, Inova Diagnostics; multiplex flow immunoassay, Bio-Rad Laboratories) and three Crithidia luciliae immunofluorescence tests (CLIFT) (Euroimmun AG, Bio-Rad Laboratories, INOVA Diagnostics). Diagnostic performances were assessed both including and excluding the IA patients. Agreements, measured by the Cohen's Kappa between all methods, ranged from moderate to substantial (0.47-0.68). The clinical sensitivities for the anti-dsDNA antibody tests varied from 5.7% by CLIFT A up to 33.3% provided by EIA while the clinical specificities varied from 89.8% by MFI to 98.9% provided by CLIFT B and C. Newer technologies, such as MFI and CIA, showed great potential as a diagnostic application. Significant variations among anti-dsDNA antibody assays were observed confirming the lack of standardization.

Plasma Cell Depletion Attenuates Hypertension in an Experimental Model of Autoimmune Disease

Numerous studies show a direct relation between circulating autoantibodies, characteristic of systemic autoimmune disorders, and primary hypertension in humans. Whether these autoantibodies mechanistically contribute to the development of hypertension remains unclear. Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by aberrant immunoglobulin production, notably pathogenic autoantibodies, and is associated with prevalent hypertension, renal injury, and cardiovascular disease. Because plasma cells produce the majority of serum immunoglobulins and are the primary source of autoantibodies in SLE, we hypothesized that plasma cell depletion using the proteasome inhibitor bortezomib would lower autoantibody production and attenuate hypertension. Thirty-week-old female SLE (NZBWF1) and control (NZW [New Zealand White]) mice were injected IV with vehicle (0.9% saline) or bortezomib (0.75 mg/kg) twice weekly for 4 weeks. Bortezomib treatment significantly lowered the percentage of bone marrow plasma cells in SLE mice. Total plasma IgG and anti-dsDNA IgG levels were higher in SLE mice compared with control mice but were lowered by bortezomib treatment. Mean arterial pressure (mm Hg) measured in conscious mice by carotid artery catheter was higher in SLE mice than in control mice, but mean arterial pressure was significantly lower in bortezomib-treated SLE mice. Bortezomib also attenuated renal injury, as assessed by albuminuria and glomerulosclerosis, and reduced glomerular immunoglobulin deposition and B and T lymphocytes infiltration into the kidneys. Taken together, these data show that the production of autoantibodies by plasma cells mechanistically contributes to autoimmune-associated hypertension and suggests a potential role for patients with primary hypertension who have increased circulating immunoglobulins.

Environmental Xenobiotic Exposure and Autoimmunity

Susceptibility to autoimmune diseases is dependent on multigenic inheritance, environmental factors, and stochastic events. Although there has been substantial progress in identifying predisposing genetic variants, a significant challenge facing autoimmune disease research is the identification of the specific events that trigger loss of tolerance, autoreactivity and ultimately autoimmune disease. Accordingly, studies have indicated that a wide range of extrinsic factors including drugs, chemicals, microbes, and other environmental factors can induce autoimmunity, particularly systemic autoimmune diseases such as lupus. This review describes a class of environmental factors, namely xenobiotics, epidemiologically linked to human autoimmunity. Mechanisms of xenobiotic autoimmune disease induction are discussed in terms of human and animal model studies with a focus on the role of inflammation and the innate immune response. We argue that localized tissue damage and chronic inflammation elicited by xenobiotic exposure leads to the release of self-antigens and damage-associated molecular patterns as well as the appearance of ectopic lymphoid structures and secondary lymphoid hypertrophy, which provide a milieu for the production of autoreactive B and T cells that contribute to the development and persistence of autoimmunity in predisposed individuals.

Air pollution, oxidative stress, and exacerbation of autoimmune diseases

A number of epidemiological studies have shown a strong association between exposure to ambient airborne particulate matter (PM 2.5, PM < 1.0) and lung or cardiovascular diseases characterised by high mortality and morbidity. However, much less is known about the role of air pollution in the pathogenesis of autoimmune diseases, which constitutes a significant problem in modern society. This paper summarises the state of current research regarding the influence of PM on the development and/or progression of autoimmune diseases. A brief review of the great body of research concerning pathogenesis of autoimmune disorders is presented. Then, the scope of our review is narrowed to the research related to the impact of particulate matter on oxidative and nitrosative stress, as well as exacerbation of chronic inflammation, because they can contribute to the development of autoimmune diseases. Moreover, we discuss the impact of various components of PM (metal, organic compounds) on PM toxicity and the ability to generate oxidants.

The impact of biological treatments on the anti-dsDNA and anti-nucleosome tests

Background Anti-double stranded DNA antibodies are a very heterogeneous group of antibodies, quite specific for systemic lupus erythematosus. Newer technologies, such as addressable laser bead immunoassays (ALBIA), show great potential as a diagnostic application. The production of anti-double stranded DNA antibodies is often encountered in inflammatory arthritis; however, literature reports that the actual onset of drug induced lupus in patients treated with biological drugs is a rare event. False positive results for anti-double stranded DNA and anti-nucleosome antibodies detected in patients with inflammatory arthritis treated with different biologics prompted the investigation of full autoantibody profiles to evaluate each biomarker's diagnostic performance in systemic lupus erythematosus. The aim of the study was to compare the diagnostic performance of anti-double stranded DNA antibody and anti-nucleosome antibody methods and to evaluate the value of simultaneously measuring anti-double stranded DNA and anti-nucleosome antibodies, along with other anti-nuclear antibody analytes, as biomarkers for systemic lupus erythematosus, using a more appropriate control cohort including inflammatory arthritis patients with a non-clinical drug induced lupus. Methods Anti-double stranded DNA and anti-nucleosome antibody levels were evaluated in 247 patient samples: 70 systemic lupus erythematosus, 177 disease controls (including 97 inflammatory arthritis during treatment with different biologics) using the Bio-Rad BioPlex® 2200. Results Anti-nucleosome antibodies demonstrated greater clinical sensitivity and specificity than anti-double stranded DNA antibodies. At the manufacturers' cut-off range, considering the two markers as a single or combined test, the "anti-double stranded DNA test or anti-nucleosome antibodies" was the most sensitive combination (0.400) with the best negative likelihood ratio (0.62) and negative predictive value (0.803). Conclusion Anti-nucleosome antibodies are a more sensitive and specific biomarker of systemic lupus erythematosus than anti-double stranded DNA antibodies. Anti-nucleosome antibodies and anti-double stranded DNA antibodies are independent and complementary markers of systemic lupus erythematosus diagnosis and, therefore, are strongly suggested as combined tests (positive predictive value = 0.938). Moreover, the combined use of the two tests may help to overcome the decreased specificity percentage of the anti-double stranded DNA test, when considering an inflammatory arthritis cohort under biological therapies. The ALBIA method for anti-nuclear specificity detection allows a full autoantibody assessment, resulting in a much higher clinical specificity for systemic lupus erythematosus in the presence of ≥3 positive markers and significantly more positive likelihood ratio when ≥2 positive markers are present.

Smoking and obesity in systemic lupus erythematosus: a cross-sectional study

BACKGROUND

Both smoking and obesity have been demonstrated as risk factors in several autoimmune diseases. Little is known about the relationship between systemic lupus erythematosus (SLE) and both smoking and obesity.

OBJECTIVES

To investigate the association between SLE, tobacco consumption and body mass index (BMI).

MATERIALS AND METHODS

Using data from the largest Health Maintenance Organization (HMO) in Israel, the Clalit Health Services, we searched for an association between SLE, smoking and obesity. Chi-square and t-test were used for univariate analysis, and a logistic regression model was used for multivariate analysis. Data available from Clalit Health Services database included age, sex, BMI, smoking status, socioeconomic status (SES) and diagnoses of chronic diseases.

RESULTS

The study included 5018 patients with SLE and 25 090 age- and sex-matched controls. In multivariate analysis, we found a significant association between smoking and SLE (OR = 1·91). Conversely, there was no association between BMI and SLE.

CONCLUSION

In this study, we have shown that smoking is independently associated with SLE, whereas BMI scores were not.

Salvianolic acid A alleviates renal injury in systemic lupus erythematosus induced by pristane in BALB/c mice

The purpose of this study was to investigate the effects of salvianolic acid A (SAA) in systemic lupus erythematosus (SLE) induced by pristane in BALB/c mice. Lupus mice were established by confirming elevated levels of autoantibodies and IL-6 after intraperitoneal injection of pristane. Mice were then treated with daily oral doses of SAA for 5 months in parallel with mice treated with prednisone and aspirin as positive controls. The levels of autoantibodies were monitored at monthly intervals and nephritic symptoms observed by hematoxylin and eosin (H&E) and periodic acid–Schiff (PAS) staining. Western blot analysis of renal tissue was also employed. SAA treatment caused a significant reduction in the levels of anti-Sm autoantibodies and reduced renal histopathological changes and pathological effects. SAA treatment also significantly inhibited the phosphorylation of IKK, IκB and NFκB in renal tissues of lupus mice. In conclusion, the results suggest that SAA alleviates renal injury in pristane-induced SLE in BALB/c mice through inhibition of phosphorylation of IKK, IκB and NFκB.

Systemic lupus erythematosus in the light of the regulatory effects of galectin-1 on T-cell function

Galectin-1 is an endogenous immunoregulatory lectin-type protein. Its most important effects are the inhibition of the differentiation and cytokine production of Th1 and Th17 cells, and the induction of apoptosis of activated T-cells. Galectin-1 has been identified as a key molecule in antitumor immune surveillance, and data are accumulating about the pathogenic role of its deficiency, and the beneficial effects of its administration in various autoimmune disease models. Initial animal and human studies strongly suggest deficiencies in both galectin-1 production and responsiveness in systemic lupus erythematosus (SLE) T-cells. Since lupus features widespread abnormalities in T-cell activation, differentiation and viability, in this review the authors wished to highlight potential points in T-cell signalling processes that may be influenced by galectin-1. These points include GM-1 ganglioside-mediated lipid raft aggregation, early activation signalling steps involving p56Lck, the exchange of the CD3 ζ-ZAP-70 to the FcRγ-Syk pathway, defective mitogen-activated protein kinase pathway activation, impaired regulatory T-cell function, the failure to suppress the activity of interleukin 17 (IL-17) producing T-cells, and decreased suppression of the PI3K-mTOR pathway by phosphatase and tensin homolog (PTEN). These findings place galectin-1 into the group of potential pathogenic molecules in SLE.

Autophagy and autoimmunity

Autophagy is a highly conserved protein degradation pathway from yeasts to humans that is essential for removing protein aggregates and misfolded proteins in healthy cells. Recently, autophagy-related genes polymorphisms have been implicated in several autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, psoriasis, and multiple sclerosis. Numerous studies reveal autophagy and autophagy-related proteins also participate in immune regulation. Conditional deletions of autophagy-related proteins in mice have rendered protection from experimental autoimmune encephalomyelitis, and TNF-mediated joint destruction in animal models of multiple sclerosis and experimental arthritis respectively. As autophagy is strongly implicated in immune functions such as removal of intracellular bacteria, inflammatory cytokine secretion, antigen presentation, and lymphocyte development, in this review we summarized current understanding of the roles of autophagy and autophagy proteins in autoimmune diseases.