Mendelian randomization analyses reveal no genetic causal effects of major adipokines on systemic lupus erythematosus.

Epidemiological studies have shown that the levels of serum adipokine such as leptin and resistin are associated with the risk of developing systemic lupus erythematosus (SLE). Nevertheless, whether either leptin or resistin has causal impacts on the risk of SLE is still unknown. In this study, two-sample univariable MR analyses and multivariable MR analysis were performed to explore the causal relationships between adipokines and SLE. Additionally, the potential causal effects of SLE on major adipokines were evaluated using reverse MR analyses. The results of inverse-variance weighted (IVW), weighted median, weighted mode and MR‒Egger methods concordantly supported that major adipokines have no causal effects on the risk of SLE. In the multivariable MR IVW analysis with leptin and resistin as covariates, neither leptin (odds ratio (OR) = 3.093, P = 0.067) nor resistin (OR = 0.477, P = 0.311) was identified as an independent risk factor for SLE, which is in line with the univariable MR results. In conclusion, our analyses revealed no evidence to support that these three major adipokines are risk factors for SLE.

An interactive web application for exploring systemic lupus erythematosus blood transcriptomic diversity.

In the field of complex autoimmune diseases such as systemic lupus erythematosus (SLE), systems immunology approaches have proven invaluable in translational research settings. Large-scale datasets of transcriptome profiling have been collected and made available to the research community in public repositories, but remain poorly accessible and usable by mainstream researchers. Enabling tools and technologies facilitating investigators' interaction with large-scale datasets such as user-friendly web applications could promote data reuse and foster knowledge discovery. Microarray blood transcriptomic data from the LUPUCE cohort (publicly available on Gene Expression Omnibus, GSE49454), which comprised 157 samples from 62 adult SLE patients, were analyzed with the third-generation (BloodGen3) module repertoire framework, which comprises modules and module aggregates. These well-characterized samples corresponded to different levels of disease activity, different types of flares (including biopsy-proven lupus nephritis), different auto-antibody profiles and different levels of interferon signatures. A web application was deployed to present the aggregate-level, module-level and gene-level analysis results from LUPUCE dataset. Users can explore the similarities and heterogeneity of SLE samples, navigate through different levels of analysis, test hypotheses and generate custom fingerprint grids and heatmaps, which may be used in reports or manuscripts. This resource is available via this link: https://immunology-research.shinyapps.io/LUPUCE/. This web application can be employed as a stand-alone resource to explore changes in blood transcript profiles in SLE, and their relation to clinical and immunological parameters, to generate new research hypotheses.

Diagnosis of neuropsychiatric systemic lupus erythematosus by label-free serum microsphere-coupled SERS fingerprints with machine learning.

Surface-enhanced Raman spectroscopy (SERS) is a powerful optical technique for non-invasive and label-free bioanalysis of liquid biopsy, facilitating to diagnosis of potential diseases. Neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the subgroups of systemic lupus erythematosus (SLE) with serious manifestations for a high mortality rate. Unfortunately, lack of well-established gold standards results in the clinical diagnosis of NPSLE being a challenge so far. Here we develop a novel Raman fingerprinting machine learning (ML-) assisted diagnostic method. The microsphere-coupled SERS (McSERS) substrates are employed to acquire Raman spectra for analysis via convolutional neural network (CNN). The McSERS substrates demonstrate better performance to distinguish the Raman spectra from serums between SLE and NPSLE, attributed to the boosted signal-to-noise ratio of Raman intensities due to the multiple optical regulation in microspheres and AuNPs. Eight statistically-significant (p-value <0.05) Raman shifts are identified, for the first time, as the characteristic spectral markers. The classification model established by CNN algorithm demonstrates 95.0% in accuracy, 95.9% in sensitivity, and 93.5% in specificity for NPSLE diagnosis. The present work paves a new way achieving clinical label-free serum diagnosis of rheumatic diseases by enhanced Raman fingerprints with machine learning.

When Should I Get My Next COVID-19 Vaccine? Data From the Surveillance of Responses to COVID-19 Vaccines in Systemic Immune-Mediated Inflammatory Diseases (SUCCEED) Study.

OBJECTIVE: To determine how serologic responses to coronavirus disease 2019 (COVID-19) vaccination and infection in immune-mediated inflammatory disease (IMID) are affected by time since last vaccination and other factors. METHODS: Post-COVID-19 vaccination, data, and dried blood spots or sera were collected from adults with rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, ankylosing spondylitis and spondylarthritis, and psoriasis and psoriatic arthritis. The first sample was collected at enrollment, then at 2 to 4 weeks and 3, 6, and 12 months after the latest vaccine dose. Multivariate generalized estimating equation regressions (including medications, demographics, and vaccination history) evaluated serologic response, based on log-transformed anti-receptor-binding domain (RBD) IgG titers; we also measured antinucleocapsid (anti-N) IgG. RESULTS: Positive associations for log-transformed anti-RBD titers were seen with female sex, number of doses, and self-reported COVID-19 infections in 2021 to 2023. Negative associations were seen with prednisone, anti-tumor necrosis factor agents, and rituximab. Over the 2021-2023 period, most (94%) of anti-N positivity was associated with a self-reported infection in the 3 months prior to testing. From March 2021 to February 2022, anti-N positivity was present in 5% to 15% of samples and was highest in the post-Omicron era, with antinucleocapsid positivity trending to 30% to 35% or higher as of March 2023. Anti-N positivity in IMID remained lower than Canada's general population seroprevalence (> 50% in 2022 and > 75% in 2023). Time since last vaccination was negatively associated with log-transformed anti-RBD titers, particularly after 210 days. CONCLUSION: Ours is the first pan-Canadian IMID assessment of how vaccine history and other factors affect serologic COVID-19 vaccine responses. These findings may help individuals personalize vaccination decisions, including consideration of additional vaccination when > 6 months has elapsed since last COVID-19 vaccination/infection.

B- and T-Lymphocyte Attenuator in Systemic Lupus Erythematosus Disease Pathogenesis.

B- and T-lymphocyte attenuator (BTLA; CD272) is an immunoglobulin superfamily member and part of a family of checkpoint inhibitory receptors that negatively regulate immune cell activation. The natural ligand for BTLA is herpes virus entry mediator (HVEM; TNFRSF14), and binding of HVEM to BTLA leads to attenuation of lymphocyte activation. In this study, we evaluated the role of BTLA and HVEM expression in the pathogenesis of systemic lupus erythematosus (SLE), a multisystem autoimmune disease. Peripheral blood mononuclear cells from healthy volunteers (N = 7) were evaluated by mass cytometry by time-of-flight to establish baseline expression of BTLA and HVEM on human lymphocytes compared with patients with SLE during a self-reported flare (N = 5). High levels of BTLA protein were observed on B cells, CD4+, and CD8+ T cells, and plasmacytoid dendritic cells in healthy participants. HVEM protein levels were lower in patients with SLE compared with healthy participants, while BTLA levels were similar between SLE and healthy groups. Correlations of BTLA-HVEM hub genes' expression with patient and disease characteristics were also analyzed using whole blood gene expression data from patients with SLE (N = 1,760) and compared with healthy participants (N = 60). HVEM, being one of the SLE-associated genes, showed an exceptionally strong negative association with disease activity. Several other genes in the BTLA-HVEM signaling network were strongly (negative or positive) correlated, while BTLA had a low association with disease activity. Collectively, these data provide a clinical rationale for targeting BTLA with an agonist in SLE patients with low HVEM expression.

Elevated serum soluble CD27 levels are associated with both disease activity and humoral immune activity in patients with rheumatoid arthritis.

OBJECTIVES: To investigate the serum level of soluble CD27 (sCD27) and its potential clinical significance in rheumatoid arthritis (RA). METHODS: Serum sCD27 levels in RA patients, idiopathic inflammatory myopathy (IIM) patients, systemic lupus erythematosus (SLE) patients and healthy controls (HCs) were detected by enzyme-linked immunosorbent assay. The medical information and laboratory data of the patients were collected. Serum sCD27 levels in RA patients with different clinical features were analysed, as was the correlation between the clinical data and serum sCD27 levels. Independent samples t test, the Mann-Whitney U-test or Wilcoxon signed-rank test, and Spearman correlation were used for statistical analysis. RESULTS: Levels of sCD27 were elevated in RA patients (3898 [2525, 5834] pg/mL) compared with IIM patients (2467 [1939, 3324] pg/mL) or HCs (1659 ± 648 pg/mL) (p 0.001). In addition, serum sCD27 levels correlated with age, erythrocyte sedimentation rate, C-reactive protein (CRP), rheumatoid factor (RF), immunoglobulin A, immunoglobulin G, complement 4 and disease activity score in 28 joints in RA patients. Levels of sCD27 were higher in RF-positive RA patients (6054 ± 5842 pg/mL) than in RF-negative patients (3902 ± 2098 pg/mL), and a similar finding was also observed in anti-cyclic citrullinated peptide (anti-CCP) antibody-positive (5810 ± 5671 pg/mL) and anti-CCP-negative (4183 ± 2187 pg/mL) RA patients. Serum ESR, RF, IgA, IgG levels and DAS28-CRP were elevated in RA patients with higher sCD27 levels than in those with lower sCD27 levels (p<0.01). CONCLUSIONS: Serum sCD27 might be a promising biomarker that reflects both disease activity and humoral immunity activity in RA.

Vascular Endothelial Growth Factor and Its Soluble Receptor in Systemic Lupus Erythematosus Patients.

Vascular endothelial growth factor (VEGF) is a major regulator of physiological and pathological angiogenesis. Its soluble receptor (sVEGFR) is a potent VEGF antagonist. Systemic lupus erythematosus (SLE) is an autoimmune disease with a diverse array of clinical manifestations that affect virtually any organ. We aimed to analyze the relationship of VEGF and sVEGFR with SLE disease-related features including disease activity, damage, and severity. Serum levels of VEGF165 isoform and sVEGFR (receptor 1) were assessed in 284 well-characterized patients with SLE. Linear regression analysis was performed to analyze the relationship of disease characteristics with both VEGF and sVEGFR. Patients with a disease damage index (SLICC score) equal to or greater than 1 had significantly elevated serum levels of VEGF and sVEGFR. Regarding disease-specific features, musculoskeletal manifestations were the disease feature most commonly associated with the upregulation of both VEGF and sVEGFR. SLE disease damage is associated with higher levels of VEGF and sVEGFR.

Serum Calprotectin - a NET Product - as a Biomarker of Disease Activity in Patients with Systemic Lupus Erythematosus: A Single-Center Case-Control Study from Poland.

BACKGROUND Calprotectin (S100A8/A9 or myeloid-related protein 8/14) is a heterodimeric S100 complex expressed in leukocytes. Calprotectin participates in development of the inflammatory response by binding to receptors for advanced glycation end-products (RAGE) and Toll-like receptors (TLR). The clinical activity of systemic lupus erythematosus (SLE) is evaluated using the Systemic Lupus International Collaborating Clinics (SLICC) criteria and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). This Polish single-center case-control study aimed to evaluate serum levels of calprotectin as a rapid diagnostic biomarker of SLE (59 patients with SLE were compared with 52 healthy controls). MATERIAL AND METHODS Calprotectin concentration was measured with the use of enzyme-linked immunosorbent assay (ELISA). The SLE activity of the patients was assessed by the SLEDAI scale. Statistical analysis of the results was carried out using MedCalc 15.8 software. P<0.05 was considered statistically significant. RESULTS A significantly higher concentration of calprotectin was found in the study group compared to the control group (medians: 3.11 vs 2.45 ng/ml; P=0.0013). We found that calprotectin has high sensitivity (89.83%) and specificity (53.85%) in differentiating between SLE patients and healthy volunteers. We found that calprotectin has very high sensitivity (100%) and specificity (82.46%) in detection of patients with moderate and severe SLE assessed using SLEDAI. CONCLUSIONS Consistent with previous studies, serum calprotectin level was revealed to have potential as a rapid diagnostic biomarker of disease activity in patients with SLE.

B-cell activating factor and A proliferation-inducing ligand in relation to intima-media thickness as biomarkers of premature atherosclerosis in systemic lupus erythematosus patients.

BACKGROUND: The aim of this study was to assess the correlation of the serum B-cell activating factor (BAFF), A proliferation-inducing ligand (APRIL) and interleukin (IL)-21 with carotid intima-media thickness (cIMT) to evaluate their efficacy as non-invasive biomarkers for the risk of premature development of atherosclerosis. METHODS: ELISA test was used to quantify serum BAFF, APRIL and IL-21 in 40 patients with systemic lupus erythematosus (SLE) and 20 healthy controls (HCs). The obtained results were correlated with disease duration, anti-double stranded DNA, complement proteins levels, lipid profile, cIMT and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). RESULTS: Serum BAFF, APRIL and IL-21 were significantly increased in SLE compared to HCs. Positive correlation was recorded between BAFF (r = 0.51) and APRIL (r = 0.52) with the cIMT. IL-21 correlated positively with SLEDAI (r = 0.33) and negatively with BAFF (r = -0.37) and APRIL (r = -0.44). According to the multiple logistic regression analysis, we found that low-density lipoprotein, serum BAFF and APRIL values were independent factors for cIMT in SLE. To discriminate premature atherosclerosis in patients with SLE, BAFF ≥455 pg/ml yielded 88.9% sensitivity with 100% specificity while APRIL ≥600 pg/ml yielded 95% sensitivity with 100% specificity. IL-21 ≥240 pg/ml yielded 66.7% sensitivity and 100% specificity. CONCLUSIONS: Circulating BAFF and APRIL in patients with SLE were correlated to disease activity and cIMT, suggesting that they could be used as a peripheral blood biomarker for the occurrence of premature atherosclerosis in SLE.

Serum cytokines to predict systemic lupus erythematosus clinical and serological activity.

We aimed to explore the role of interleukin (IL)-6, interferon-gamma (IFNγ), IL-10, and tumor necrosis factor (TNF) as predictors of systemic lupus erythematosus (SLE) clinical and serological activity, and their correlation with the treatment received. We performed a retrospective analysis of 77 patients with SLE according to the 2012 Systemic Lupus International Collaborative Clinics (SLICC) criteria. The outcomes were serological activity (SA), active disease (AD), complete remission (CR), the low-disease activity state (LDAS), and immunosuppressive treatment. SA was present in 17.1%, AD in 17.3%, CR in 13%, and LDAS in 64.9% of patients. IL-6 values were higher in patients in SA, in AD, in those receiving steroids alone, and in patients without CR or LDAS (p < 0.05). IFNγ was associated with anti-double stranded DNA (dsDNA) antibodies positivity and immunosuppression, whereas IL-10 values were higher in patients with CR (p < 0.05). The IL6-IFN product was able to predict anti-double stranded DNA (anti-dsDNA) antibodies positivity (area under the receiver operating characteristic curve [AUC-ROC] = 0.705, 95% confidence interval [CI] 0.563-0.847), SA (AUC-ROC = 0.720, 95% CI 0.542-0.899), AD (AUC-ROC = 0.701, 95% CI 0.520-0.882), steroid treatment (AUC-ROC = 0.751, 95% CI 0.622-0.879), and the absence of LDAS (AUC-ROC = 0.700, 95% CI 0.558-0.834). The IL6-IFN/IL10 ratio predicted AD (AUC-ROC = 0.742, 955 CI 0.540-0.944), steroid treatment (AUC-ROC = 0.721, 95% CI 0.572-0.870), and the absence of LDAS (AUC-ROC = 0.694, 95% CI 0.536-0.853). In conclusion, IL-6, IL-10, and IFNγ might help to assess SLE serological and clinical activity. Their combination in the IL-6-IFN product and the IL-6xIFN to IL-10 ratio results in novel tools to determine and predict SA, AD, and LDAS. Prompt detection of SLE activity might allow a rapid intervention to avoid established or chronic damage.

Involvement of N6-methyladenosine modifications of long noncoding RNAs in systemic lupus erythematosus.

BACKGROUND: LncRNAs are potential biomarkers for SLE, but the epigenetic regulatory mechanisms of N6-methyladenosine (m6A) modification in SLE remain largely unclear. METHODS: In this study, we established m6A modification profile and investigated the potential roles of m6A-related lncRNAs in SLE. The m6A modification profile of SLE was established using MeRIP-seq. Four potential m6A related-lncRNAs (linc02446, linc01410, Xist, and PSMB8-AS1) were selected for validation using qRT-PCR, and their expression and association with clinical characteristics with SLE were evaluated. RESULTS: Overall, m6A level was lower in patients with SLE than in controls. Compared with controls, the expression of the two m6A related-lncRNAs (Xist and PSMB8-AS1) was downregulated in patients with SLE (all P < 0.05); the linc02446 was up-regulated in PBMCs of patients with SLE (Z=-2.738, P = 0.006), while it was not differentially expressed in T cells (Z=-0.387, P = 0.699). No significant alteration in linc01410 expression was observed in patients (Z=-0.940, P = 0.347). The lower expression levels of Xist and PSMB8-AS1 were associated with many clinical manifestations in patients with SLE (all P < 0.05). Additionally, mRNAs co-expressed with m6A related-lncRNAs (Xist, linc02446, and PSMB8-AS1) also participated in SLE. CONCLUSION: These results suggest that m6A methylation and m6A related-lncRNAs might be involved in the pathogenesis of SLE. Thus, our findings provide some clues on the potential function of lncRNAs that m6A modification may target in novel therapeutic or diagnostic strategies for SLE.

Belimumab Decreases Autophagy and Citrullination in Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus.

Belimumab (BLM) is a B lymphocyte stimulator (BLyS) inhibitor approved for the treatment of systemic lupus erythematosus (SLE). Autophagy is a cell survival mechanism involved in the pathogenesis of SLE. Citrullination is a post-translational modification catalyzed by peptidylarginine deiminase (PAD) enzymes. Autophagy and citrullination may generate neoepitopes, evoking an autoimmune response. No previous studies have investigated the connection of these processes, and how BLM could affect them, in SLE. Ex vivo autophagy and protein citrullination were analyzed by western blot in lysates from 26 SLE patients' PBMCs at baseline and after 2, 4, and 12 weeks of BLM administration, and from 16 healthy donors' PBMCs. Autophagic PBMCs were identified by the immunofluorescent detection of the autophagy-associated proteins LC3B (LC3 puncta) and LAMP-1. Autophagosome accumulation was evaluated in CD14- (PBLs) and CD14+ (monocytes) SLE cells. The presence of the BLyS receptors BAFF-R, BCMA, and TACI on SLE CD4+, CD8+ T cells and monocytes, as well as serum IL-18 levels, was also assessed. Following BLM administration, we observed a decrease in autophagy and citrullination, with a lowering of LC3-II, citrullinated vimentin, and PAD4 expression levels in PBMCs from SLE patients. LC3-II levels showed a correlation with the SLE Disease Activity Index 2000 (SLEDAI-2K) after 12 weeks of therapy. The LC3B/LAMP-1 analysis confirmed the reduction in autophagy. A lesser autophagosome accumulation occurred in PBLs and monocytes which, in turn, seemed to be the main cellular populations contributing to autophagy. A reduction in patients' serum IL-18 concentrations occurred. CD4+ and CD8+ cells weakly expressed BAFF receptors; monocytes expressed only BAFF-R. BLM could impact on autophagy and citrullination, offering an opportunity for a deeper understanding of these mechanisms in SLE, and a possible tool for the clinical management of SLE.

Adenosine receptor 2a agonists target mouse CD11c+T-bet+ B cells in infection and autoimmunity.

CD11c+T-bet+ B cells are recognized as an important component of humoral immunity and autoimmunity. These cells can be distinguished from other B cells by their higher expression of the adenosine receptor 2a. Here we address whether A2A receptor activation can affect CD11c+T-bet+ B cells. We show that administration of the A2A receptor agonist CGS-21680 depletes established CD11c+T-bet+ B cells in ehrlichial-infected mice, in a B cell-intrinsic manner. Agonist treatment similarly depletes CD11c+T-bet+ B cells and CD138+ B cells and reduces anti-nuclear antibodies in lupus-prone mice. Agonist treatment is also associated with reduced kidney pathology and lymphadenopathy. Moreover, A2A receptor stimulation depletes pathogenic lymphocytes and ameliorates disease even after disease onset, highlighting the therapeutic potential of this treatment. This study suggests that targeting the adenosine signaling pathway may provide a method for the treatment of lupus and other autoimmune diseases mediated by T-bet+ B cells.

IL-1ß, IL-10 and TNF-α polymorphisms may affect systemic lupus erythematosus risk and phenotype.

OBJECTIVES: Systemic lupus erythematosus (SLE) is an autoimmune disease, and IL-1ß, IL-10, and TNF-α genes are important in the pathogenesis of this disease. We studied the impact of IL-1ß-511, IL-1ß +3953, IL-10 -592, IL-10 -1082, TNF-α -308, TNF-α -238, and TNF-α +489 polymorphisms on SLE risk and phenotype in SLE patients and healthy controls. METHODS: We genotyped SLE patients and healthy controls by real-time PCR on QuantStudio 5 (Applied Biosystems) and measured levels of cytokines by enzyme-linked immunosorbent assay (ELISA). RESULTS: We indicated that TNF-α -308, IL-10 -592, IL-10 -1082, IL-1ß-511 and IL-1ß +3953 polymorphisms affect SLE risk. Furthermore, we exposed that some of the TNF-α +489, TNF-α -238, IL-10 -1082 and IL-1ß +3953 genotypes are connected with the SLE phenotype. Moreover, we discovered the linking between specific genotypes and the serum concentrations of TNF-α, IL-1ß, and IL-10. CONCLUSIONS: In conclusion, our study revealed that IL-1ß-511, IL-1ß +3953, IL-10 -592, IL-10 -1082, and TNF-α -308 polymorphisms may affect SLE risk and phenotype.

From Telemedicine to the ICU-Fever and Rash in a 9-Year-Old Girl.

A 9-year-old girl presented to her primary care pediatrician via telemedicine during the initial months of the coronavirus disease 2019 pandemic because of 4 days of warmth perceived by her mother, decreased energy, and a new rash on her upper extremities. After 10 additional days of documented fever >38°C, worsening fatigue, and 1 day of nausea, vomiting, and diarrhea, she was allowed to schedule an in-person visit with her pediatrician after testing negative for severe acute respiratory syndrome coronavirus 2. She appeared ill on arrival to clinic, and her pediatrician recommended evaluation in an emergency department. Her initial laboratory testing revealed nonspecific elevation in several inflammatory markers and leukopenia, and she responded well to intravenous hydration. Over the next 2 weeks, her fever persisted, constitutional symptoms worsened, and she developed progressively painful cervical lymphadenopathy and pancytopenia. She was evaluated in clinic by several specialists and eventually was urged to present to the emergency department again, at which time she was admitted to the PICU. After consulting additional specialists and waiting for laboratory results, the team reached a definitive diagnosis and initiated therapy; however, she experienced rapid clinical decline shortly thereafter. The specialists who assisted with identification of the underlying etiology of her symptoms were able to work together to manage the subsequent complications.

Advanced Glycation End-Products (AGEs) and Their Soluble Receptor (sRAGE) in Women Suffering from Systemic Lupus Erythematosus (SLE).

Systemic lupus erythematosus (SLE) is characterized by abnormal action of the immune system and a state of chronic inflammation. The disease can cause life-threatening complications. Neoepitopes arising from interdependent glycation and oxidation processes might be an element of SLE pathology. The groups included in the study were 31 female SLE patients and 26 healthy female volunteers (the control group). Blood serum samples were obtained to evaluate concentrations of advanced glycation end-products (AGEs), carboxymethyllysine (CML), carboxyethyllysine (CEL), pentosidine, and a soluble form of the receptor for advanced glycation end-products (sRAGE). Compared to a healthy control group, the SLE patients exhibited a higher concentration of AGEs and a lower concentration of sRAGE in serum. There were no statistically significant differences in serum CML, CEL, and pentosidine concentrations between the groups. Therefore, SLE patients could be at risk of intensified glycation process and activation of the proinflammatory receptor for advanced glycation end-products (RAGE), which could potentially worsen the disease course; however, it is not clear which compounds contribute to the increased concentration of AGEs in the blood. Additionally, information about the cigarette smoking and alcohol consumption of the study participants was obtained.

Physical Fitness Attenuates the Impact of Higher Body Mass and Adiposity on Inflammation in Women With Systemic Lupus Erythematosus.

Aims: Higher body mass and adiposity represent independent contributors to the systemic low-grade inflammatory state often observed in patients with systemic lupus erythematosus (SLE). This study assessed the role of physical fitness in the association of body mass and adiposity with inflammation in women with SLE. Methods: A total of 77 women with SLE were included in this cross-sectional study. We obtained body mass index, waist-to-height ratio, and body fat percentage as indicators of body mass and adiposity. Inflammation was assessed through Serum levels of C-reactive protein, interleukin 6, and leptin. Cardiorespiratory fitness was assessed with the 6-minute walk test, range of motion with the back-scratch test, and muscular strength with handgrip dynamometry. Results: Cardiorespiratory fitness attenuated the association of both body mass index and body fat percentage with interleukin 6 (all, P<0.05). Range of motion attenuated the association of body mass index with interleukin 6 (P<0.05) and the association of body fat percentage with C-reactive protein (P<0.05). These interactions indicated that higher fitness was associated with a lower increase in inflammation per unit increase of body mass or adiposity. Muscular strength showed a non-significant trend to attenuate the association of body fat percentage with interleukin 6 (P=0.057) but potentiated the association of body fat percentage with leptin (P<0.05). Conclusion: These findings suggest that higher levels of cardiorespiratory fitness and range of motion might attenuate the impact of higher body mass and adiposity on inflammation in women with SLE. The role of muscular strength requires further investigation.

Serum procalcitonin and C-reactive protein levels as diagnostic markers for distinguishing bacterial infections from lupus flares in systemic lupus erythematosus: A systematic review and meta­analysis.

PURPOSE: To systematically evaluate the diagnostic performance of procalcitonin (PCT) and C-reactive protein (CRP) for distinguishing bacterial infections from lupus flares in systemic lupus erythematosus (SLE) via meta-analysis. METHODS: Electronic databases were comprehensively searched. The pooled standard mean difference (SMD) and 95% confidence interval (CI) were calculated to estimate the differences of serum PCT and CRP levels between bacterial infections and flares in SLE. Sensitivity, specificity and summary receiver operating characteristics (SROC) curve were used to assess the diagnostic values of PCT and CRP. The use of fixed or random effects model depended on heterogeneity. RESULTS: Fifteen studies were included in the analysis. Serum PCT and CRP levels were significantly higher in SLE patients with bacterial infections compared to SLE patients with flares (PCT: SMD = 1.035, 95 %CI = 0.708 to 1.362; CRP: SMD = 1.000, 95 %CI = 0.758 to 1.242). The overall sensitivity, specificity, area under the SROC curve, positive likelihood ratios (PLR) and negative likelihood ratios (NLR) of PCT were 0.62, 0.88, 0.862, 6.63 and 0.36, respectively, while the same indicators for CRP were 0.72, 0.70, 0.784, 2.45 and 0.38, respectively. CONCLUSION: Serum PCT and CRP levels were significantly increased in SLE with bacterial infections. PCT had a better diagnostic performance than CRP. PCT had a high value of PLR and could serve as a rule-in marker, while CRP testing may result in a high false-positive rate due to low PLR; both markers had a suboptimal value of NLR and are not appropriate for ruling out bacterial infections.

AIM2 deficiency in B cells ameliorates systemic lupus erythematosus by regulating Blimp-1-Bcl-6 axis-mediated B-cell differentiation.

Absent in melanoma 2 (AIM2) has been reported to be a component of inflammasomes in innate immune cells. Surprisingly, AIM2 is expressed by B cells, and higher AIM2 expression is observed in the B cells from lupus patients. To date, the inflammasome-independent function of AIM2 in B cells remains unclear. Here, we report increased expression of AIM2 in human tonsil memory and germinal center (GC) B cells and in memory B cells and plasma cells from the circulation and skin lesions of lupus patients. Conditional knockout of AIM2 in B cells reduces the CD19+ B-cell frequency in lymph nodes and spleens, and dampens KLH-induced IgG1-antibody production. In a pristane-induced mouse model of lupus, AIM2 deficiency in B cells attenuates lupus symptoms and reduces the frequency of GC B cells, T follicular helper (Tfh) cells, plasmablast cells, and plasma cells. Furthermore, the loss of AIM2 in human B cells leads to the increased expression of Blimp-1 and reduces the expression of Bcl-6. However, the silencing of Blimp-1 and Bcl-6 has no significant effect on AIM2 expression, indicating that AIM2 might be the upstream regulator for Blimp-1 and Bcl-6. In addition, IL-10 is found to upregulate AIM2 expression via DNA demethylation. Together, our findings reveal that AIM2 is highly expressed in the B cells of lupus patients and promotes B-cell differentiation by modulating the Bcl-6-Blimp-1 axis, providing a novel target for SLE treatment.

Association of the PINX1 Variant rs6984094, Which Lengthens Telomeres, with Systemic Lupus Erythematosus Susceptibility in Chinese Populations.

A recent genome-wide association study (GWAS) of Asian ancestry reported that single nucleotide polymorphism (SNP) in TERT (telomerase reverse transcriptase) was associated with systemic lupus erythematosus (SLE). TERT has a critical role in maintaining the chromosomal stability and the length of telomere. Given that only a small portion of the genetic heritability of SLE has been explained so far, we aimed to identify novel loci in telomere-related genes responsible for SLE susceptibility in Chinese populations. We performed a comprehensive genetic association analysis of SLE with telomere-related genes. To identify functional significance, we analyzed the publicly available HaploReg v4.1 and RegulomeDB databases. Differential gene expression analysis was also performed using ArrayExpress. A novel signal of PINX1 rs6984094 was identified (P discovery = 4.13 × 10-2, OR = 0.58, 95% CI 0.35-0.98) and successfully replicated (P replication = 5.73 × 10-3, OR = 0.45, 95% CI 0.26-0.81). Multiple layers of functional analysis suggested that the PINX1 rs6984094 risk T allele exhibited increased nuclear protein binding. We also observed an increased expression of PINX1 mRNA in peripheral blood mononuclear cells from SLE patients compared with healthy controls. Overall, we observed a novel genetic association between PINX1 (encodes the PinX1 protein, an inhibitory telomerase enzyme that lengthens telomeres) and SLE susceptibility in Chinese populations.