anti-dsDNA Autoantibodies Research Articles

Activation of circulating TFH17 cells associated with activated naive and double negative 2 B cell expansion, and disease activity in systemic lupus erythematosus patients

BackgroundSystemic lupus erythematosus (SLE) is the quintessential autoimmune disease, as it is characterized by hyperactivity of CD4+ T cells and subsequently drives lupus pathology. Follicular helper T (TFH) cells play an important role in B cell maturation and antibody production. However, which specific subset of cTFH cells drives B cell function and contributes to the development of anti-dsDNA antibodies and SLE pathogenesis remains unclear.MethodsPeripheral blood mononuclear cells from SLE patients with inactive (n = 11) and active (n = 21) were used to determine and detect frequencies and phenotypes of circulating TFH cells (cTFH), memory cTFH, and B cell subsets. The correlations among cTFH cell subsets and phenotypes, B cell subsets, anti-dsDNA autoantibodies, and clinical parameters were analyzed.ResultsIn subjects with active SLE, cTFH1 and cTFH17 cells were significantly expanded and activated. These expanded cTFH cells expressed memory phenotypes; cTFH1 cells were predominantly central memory (CM) type, while cTFH17 cells were largely effector memory (EM) type. Phenotyping B cell subsets in these patients showed increased frequencies of aNAV and DN2 B cells. Clinically, ICOS+ cTFH1, ICOS+ cTFH17 cells, and SLEDAI-2k scores were found to be correlated. Analysis of cTFH-B cell relationship revealed positive correlations among ICOS+ cTFH1 cells, aNAV B cells, and anti-dsDNA antibodies. Activation of ICOS+ cTFH17 cells was significantly related to the expansion of aNAV and DN2 B cells. The presence of CM cells in cTFH1 and cTFH17 subsets was correlated with aNAV and DN2 B cell frequencies.ConclusionSLE cTFH cells were found to be polarized toward cTFH1 and cTFH17 cells; activation of these cTFH subsets was significantly associated with disease activity score, aNAV, DN2 B cell expansion, and anti-dsDNA antibody level. Thus, the interactions among cTFH1, cTFH17, and B cells likely contribute to the development of autoantibodies and the pathogenesis in SLE.

Regulation of monocyte apoptosis and DNA extrusion in monocyte extracellular traps by PSGL-1: Relevance in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease characterized by severe organ damage and lacking curative treatment. While various immune cell types, especially dysfunctional B and T cells and neutrophils, have been related with disease pathogenesis, limited research has focused on the role of monocytes in SLE. Increased DNA extracellular traps, apoptosis and necrosis have been related to lupus pathogenesis. Our goal is to analyze the contribution of P-selectin glycoprotein ligand 1 (PSGL-1) in SLE monocytes to disease pathogenesis by investigating the control exerted by PSGL-1 on monocyte apoptosis and DNA extrusion in extracellular traps (METs). Monocytes from active disease patients (aSLE) exhibited reduced levels of PSGL-1. Importantly, lower PSGL-1 levels in SLE monocytes associated with several clinical characteristics, including anti-dsDNA autoantibodies, lupus anticoagulant, clinical lung involvement, and anemia. Monocytes from SLE patients showed higher susceptibility to apoptosis than healthy donors (HD) monocytes and PSGL-1/P-selectin interaction decreased secondary necrosis in HD but not in aSLE monocytes. Regarding METs, aSLE monocytes exhibited higher susceptibility to generate METs than HD monocytes. The interaction of HD monocytes with P-selectin induced Syk activation and reduced the levels of DNA extruded in METs. However, in aSLE monocytes, PSGL-1/P-selectin interaction did not activate Syk or reduce the amount of extruded DNA. Our data suggest a dysfunctional PSGL-1/P-selectin axis in aSLE monocytes, unable to reduce secondary necrosis or the amount of DNA released into the extracellular medium in METs, potentially contributing to lupus pathogenesis.

Insights into systemic lupus erythematosus: a retrospective observational study of clinical features, autoantibodies, and gender-related differences.

This study aims to analyze the clinical and immunologic features of SLE in Jordan, while also investigating the impact of age and gender on disease presentation. The study included 275 patients diagnosed with SLE. Data were collected through meticulous patient interviews and thorough examination of patient hospital records. The cohort exhibited a mean age of 36.8 ± 12.9years, with an average disease duration of 7.0 ± 7.8years. The mean age at diagnosis was 29.9 ± 12.1years, and the female to male ratio was 7.8:1. The most frequently observed symptoms were arthralgia (90.2%), fatigue (80.7%), hematologic manifestations (62%), photosensitivity (60.7%), Raynaud's phenomenon (53.5%), and malar rash (50.9%). The frequencies of various autoantibodies were as follows: ANA (96.7%), anti-dsDNA (39.6%), anti-SSA/Ro (32.8%), anti-Sm (21.8%), anti-U1-RNP (20.6%), and anti-SSB/La (15.5%). Male patients tended to receive a diagnosis at a younger age and exhibited a higher likelihood of experiencing severe manifestations compared to females. Additionally, juvenile onset patients demonstrated an increased likelihood of fever, photosensitivity, myositis, and anti-dsDNA autoantibodies, while adult onset patients were more predisposed to having anti-Ro, anti-La, and RF autoantibodies. This study reveals that the most prevalent manifestations of SLE in the Jordanian cohort encompassed arthralgia, fatigue, and hematologic manifestations. The prevalence of alopecia and Raynaud's phenomenon exceeded that observed in other published cohorts, while arthritis and discoid rash were less frequently encountered. The study highlights that males are more susceptible to developing severe manifestations of SLE compared to females.

Evaluation of a novel particle-based assay for detecting SLE-related autoantibodies

Anti-dsDNA, anti-Sm, and anti-ribosomal-P autoantibodies are hallmarks of systemic lupus erythematosus (SLE), being anti-dsDNA and anti-Sm included in 2019-ACR/EULAR SLE-Classification Criteria. Enzyme-linked (ELISA) and chemiluminescence assays (CIA) are widely established in immunology laboratories, but new technologies, such as particle-based multi-analyte technology (PMAT), are nowadays available. The present study aimed to compare the presence of anti-dsDNA and anti-Sm autoantibodies measured by CIA and PMAT and analyze diagnostic and clinical SLE activity performance. Anti-ribosomal-P autoantibodies by PMAT were also included. Consequently, anti-dsDNA and anti-Sm detected by CIA showed substantial agreement with PMAT (Cohen's kappa = 0.662 and 0.671, respectively). Anti-dsDNA autoantibodies measured by PMAT showed a positive correlation with clinical SLEDAI-2K (p < 0.001) and a negative correlation with complement consumption (p < 0.001). Anti-Sm and anti-ribosomal-P autoantibodies showed a positive correlation with SLEDAI-2K (p < 0.001 and p = 0.001, respectively) and a negative correlation with complement consumption (p < 0.001 and p = 0.001, respectively). Finally, anti-Sm autoantibodies were associated with renal involvement (p < 0.05).

B cell-intrinsic IL-27 and IFNγ receptor signaling drive PD-L1 expression, IgG2a autoantibody production, VEGF-dependent tumor angiogenesis and cancer progression

Abstract B effector cells produce Abs and autoantibodies, while B regulatory cells use cytokines and transmembrane proteins to fine tune immune functions. Our lab recently revealed that tumor-infiltrating B cells produce IL-27 to promote immune evasion, partly by upregulating tumoral PD-L1, including that expressed by B cells per se. To investigate the autocrine activity of IL-27 in tumor progression, we generated μMT:Il27ra–/– bone marrow chimera mice lacking the IL-27 receptor specifically in B cells. These mice displayed substantially reduced tumor growth from orthotopically engrafted ER+ E0771 breast cancer cells, as associated with only moderately decreased PD-L1 levels but, unexpectedly, severely compromised blood vessel integrity. The residual PD-L1 levels and tumor growth were virtually abolished by additional B cell-specific deficiency in IFNγ receptor signaling, as occurring in double KO μMT:Il27ra–/–Ifngr1–/– mice, in which the microvessel permeability was also worsened. Mechanistically, this aligned with our findings that IL-27-producing B cells expressed high levels of VEGFA, whose transcription in activated B cells could be further enhanced by IL-27 and IFNγ. Double KO mice also lacked anti-dsDNA IgG2a autoantibodies, as elicited by tumor engraftment. Thus, B cell-intrinsic IL-27 and IFNγ receptor signaling synergize to promote B-cell PD-L1 expression, IgG2a autoantibody production, and vascular integrity, all of which may contribute to cancer development.

Selective depletion of anti-dsDNA long-lived plasma cells in SLE

Abstract Systemic lupus erythematosus (SLE) is an autoimmune disease driven by secretion of autoantibodies including those specific for double stranded-DNA (dsDNA) by short- or long-lived plasma cells (PCs). Most SLE treatments are generally immunosuppressive and indirectly decrease short-lived PCs. New therapies are needed to selectively eliminate SLE-causing long-lived PCs while preserving immunity and avoiding side effects. Prior research fusing the model antigen ovalbumin (OVA) with an antibody specific for a PC-specific protein, CD138, showed selective depletion of anti-OVA long-lived PCs. We hypothesize that a similar fusion protein comprising anti-CD138 antibody and a dsDNA peptide mimic can selectively deplete long-lived dsDNA-specific PCs. We tested the ability of two previously reported peptide mimics, ALW and DWEYS, to competitively inhibit detection of anti-dsDNA autoantibodies from NZB/NZW mice. We found DWEYS but not ALW inhibited detection. We also validated a method to indirectly measure anti-dsDNA PCs by measuring levels of secreted antibody by ELISA. We then confirmed efficient in vivo CD138 depletion. The next step is to fuse DWEYS with anti-CD138 antibody and test for selective depletion in vitro and in vivo. Successful selective depletion of anti-dsDNA PCs using a DWEYS/anti-CD138 fusion protein may support its future development as an improved treatment for SLE patients not benefited by current treatments.

Precise Targeting of Autoantigen-Specific B Cells in Lupus Nephritis with Chimeric Autoantibody Receptor T Cells.

Despite conventional therapy, lupus nephritis (LN) remains a significant contributor to short- and long-term morbidity and mortality. B cell abnormalities and the production of autoantibodies against nuclear complexes like anti-dsDNA are recognised as key players in the pathogenesis of LN. To address the challenges of chronic immunosuppression associated with current therapies, we have engineered T cells to express chimeric autoantibody receptors (DNA-CAART) for the precise targeting of B cells expressing anti-dsDNA autoantibodies. T cells from LN patients were transduced using six different CAAR vectors based on their antigen specificity, including alpha-actinin, histone-1, heparan sulphate, or C1q. The cytotoxicity, cytokine production, and cell-cell contact of DNA-CAART were thoroughly investigated in co-culture experiments with B cells isolated from patients, both with and without anti-dsDNA positivity. The therapeutic effects were further evaluated using an in vitro immune kidney LN organoid. Among the six proposed DNA-CAART, DNA4 and DNA6 demonstrated superior selectively cytotoxic activity against anti-dsDNA+ B cells. Notably, DNA4-CAART exhibited improvements in organoid morphology, apoptosis, and the inflammatory process in the presence of IFNα-stimulated anti-dsDNA+ B cells. Based on these findings, DNA4-CAART emerge as promising candidates for modulating autoimmunity and represent a novel approach for the treatment of LN.

Clinical and laboratory characteristics of early-onset and delayed-onset lupus nephritis patients: A single-center retrospective study

BackgroundLupus nephritis (LN) manifests systemic lupus erythematosus (SLE) and is characterized by various clinical and laboratory features. This study aimed to comprehensively evaluate the characteristics of LN patients according to the time of LN diagnosis: early-onset (LN diagnosed within one year from SLE diagnosis) vs. delayed-onset (LN diagnosed more than one year after SLE diagnosis).MethodsWe conducted a retrospective analysis of medical records from all SLE patients treated at the University Hospital in Kraków, Poland, from 2012 to 2022. We collected data on demographic, clinical, and laboratory characteristics, including histological findings, treatment modalities, and disease outcomes. Statistical analyses were performed to identify factors impacting LN development and prognosis.ResultsAmong 331 LN patients, early-onset was diagnosed in 207 (62.54%) and delayed-onset was documented in 122 cases (36.86%). In 2 (0.6%) LN cases, the time of first kidney manifestation in the SLE course was unknown. Delayed-onset LN had a higher female-to-male ratio and younger age at SLE diagnosis. This group was associated with more severe clinical manifestations. In turn, studied subgroups did not differ in internist comorbidities, kidney histopathology, and family history regarding autoimmune diseases. Delayed-onset LN exhibited a higher frequency of anti-dsDNA, anti-Smith, anti-Ro, anti-RNP, and anti-cardiolipin IgG autoantibodies. During a 14-year follow-up period, 16 patients died. Mortality rate and causes of death were comparable in both analyzed subgroups.ConclusionsMore severe clinical manifestations in delayed-onset LN prompt strict monitoring of non-LN SLE patients to diagnose and treat kidney involvement early. Also, recognizing the higher frequency of autoantibodies such as anti-dsDNA or anti-Smith in delayed-onset LN underscores the potential value of autoantibody profiling as a diagnostic and prognostic tool.

CADHERIN-11 regulation of myeloid phagocytes and autoimmune inflammation in murine lupus

Background and objectiveUnderstanding the regulation of efferocytosis by myeloid phagocytes is important in identifying novel targets in systemic lupus erythematosus (SLE). Cadherin-11 (CDH11), a cell adhesion molecule, is implicated in inflammatory arthritis and fibrosis and recently been shown to regulate macrophage phagocytosis. The extent and mechanism of this regulation is unknown. Our objective was to examine the extent to which CDH11 regulates myeloid phagocytes and contributes to autoimmunity and tissue inflammation. MethodsWe analyzed efferocytosis in macrophages and dendritic cells (DCs) from WT and Cdh11−/− mice and investigated the mechanisms in vitro. We investigated the role of CDH11 in disease development in vivo using the pristane induced lupus model. To translate the clinical relevance of CDH11 in human disease, we measured serum CDH11 levels in two independent pediatric SLE (pSLE) cohorts and healthy controls. ResultsUsing bone marrow derived macrophages (BMDMs) and DCs (BMDCs), we found impaired efferocytosis in phagocytes from Cdh11−/− mice, mediated by downregulated efferocytosis receptor expression and RhoGTPase activation. Specifically, loss of CDH11 downregulated Mertk expression and Rac1 activation in BMDMs, and integrin αVβ3 expression and Cdc42 activation in BMDCs, highlighting distinct pathways. In vivo, Cdh11−/− mice displayed defective efferocytosis and increased accumulation of apoptotic debris in pristane-induced lupus. Further, Cdh11−/− mice had enhanced systemic inflammation and autoimmune inflammation with increased anti-dsDNA autoantibodies, splenomegaly, type I interferons, and inflammatory cytokines. Paradoxically, at the tissue level, Cdh11−/− mice were protected against glomerulonephritis, indicating a dual role in murine lupus. Finally, SLE patients had increased serum CDH11 compared to controls. ConclusionThis study highlights a novel role of CDH11 in regulating myeloid cells and efferocytosis and its potential as a contributor to development in autoimmunity murine lupus. Despite the increase in autoimmunity, Cdh11−/− mice developed decreased tissue inflammation and damage.

Duplex Vertical-Flow Rapid Tests for Point-of-Care Detection of Anti-dsDNA and Anti-Nuclear Autoantibodies.

The goal of this study is to develop a rapid diagnostic test for rheumatic disease and systemic lupus erythematosus (SLE) screening. A novel rapid vertical flow assay (VFA) was engineered and used to assay anti-nuclear (ANA) and anti-dsDNA (αDNA) autoantibodies from systemic lupus erythematosus (SLE) patients and healthy controls (HCs). Observer scores and absolute signal intensities from the VFA were validated via ELISA. The rapid point-of-care VFA test that was engineered demonstrated a limit of detection of 0.5 IU/mL for ANA and αDNA autoantibodies in human plasma with an inter-operator CV of 19% for ANA and 12% for αDNA. Storage stability was verified over a three-month period. When testing anti-dsDNA and ANA levels in SLE and HC serum samples, the duplex VFA revealed 95% sensitivity, 72% specificity and an 84% ROC AUC value in discriminating disease groups, comparable to the gold standard, ELISA. The rapid αDNA/ANA duplex VFA can potentially be used in primary care clinics for evaluating patients or at-risk subjects for rheumatic diseases and for planning follow-up testing. Given its low cost, ease, and rapid turnaround, it can also be used to assess SLE prevalence estimates.

The Effect of Periodontitis Treatment on Anti-DSDNA Titer in Patients with Systemic Lupus Erythematosus

Aim: Systemic Lupus Erythematosus (SLE) and periodontitis are both inflammatory diseases. It has been revealed that may be an association exists between them. Inflammation in chronic periodontitis causes gingival erosion and alveolar bone destruction. According to available sources, chronic inflammation due to periodontal disease has a negative effect on Anti-dsDNA as one of the most important laboratory indicators of SLE. The aim of this research is to evaluate the effect of periodontal treatment on Anti-dsDNA titer in patients with SLE. Materials and methods: The samples were selected from well controlled patients with SLE . In the initial visit, the laboratory factor “Anti-dsDNA” was recorded from the patients. Patients with periodontal disease were divided into case and control groups by block randomization method. For the case group, scaling was done with an ultrasonic device and oral health education was provided to all patients. The patients were asked to return 3 months after the periodontal treatment to evaluate the level of disease activity and the response to periodontal treatment. For data analysis, SPSS 18 program and Mann-Whitney non-parametric test was used. Results: The average duration of the disease in this study was 6.89 ± 6.56 years. Comparison of the average Anti-dsDNA autoantibody titer before and after treatment in the intervention group considering that there was no normality between the data and there was a statistically significant difference between the average Anti-DsDNA titer before and after the intervention in the subject group. Conclusion: Since the phase 1 of periodontal treatment as a modifiable risk factor has led to a significant change in Anti-dsDNA titer and this antibody is an indicator of disease flare, periodontal treatment is recommended separately from the reactivation of the disease and to promote the disease control.

Serum IgE anti-dsDNA autoantibodies in patients with proliferative lupus nephritis are associated with tubulointerstitial inflammation

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the overproduction of multiple autoantibodies. Lupus nephritis (LN), the most common cause of morbidity and mortality, requires early detection. However, only a limited number of serum biomarkers have been associated with the disease activity of LN. Serum IgE anti-dsDNA autoantibodies are prevalent in patients with SLE and may be associated with the pathogenesis of LN. In this study, serum samples from 88 patients with biopsy-proven proliferative LN were collected along with complete clinical and pathological data to investigate the clinical and pathological associations of anti-dsDNA IgE autoantibodies using ELISA. This study found that the prevalence of IgE anti-dsDNA autoantibodies in patients with proliferative LN was 38.6% (34/88). Patients with anti-dsDNA IgE autoantibodies were more prone to acute kidney injury (17/34 vs. 14/54; p = .025). Levels of anti-dsDNA IgE autoantibodies were associated with interstitial inflammation (r = 0.962, p = .017). Therefore, anti-dsDNA IgE autoantibody levels are associated with tubulointerstitial inflammation in patients with proliferative LN.

Lupus mice derived mesenchymal stromal cells: Beneficial or detrimental on SLE disease outcome

BackgroundSystemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by the presence of autoantibodies against nuclear genes, deposition of immune complexes, and autoimmune T cells, through which, tissue damage would ultimately occur. Furthermore, loss of immune tolerance and imbalance of Th1/Th2 cells in addition to Th17/Treg are contributed to the pathogenesis of SLE. Mesenchymal stromal cells (MSCs) infusion is a potential therapy for SLE disease. Despite a majority of SLE patients achieving clinical remission after allogeneic MSC infusion from healthy individuals, SLE patients have less benefited from autologous MSC infusion, justifying the probable compromised function of SLE patients-derived MSCs. In this study, we aim to further investigate the potential immunoregulatory mechanisms in which mesenchymal stromal cells derived from pristane-induced lupus mice, following injection into healthy and lupus mice, exert their possible effects on the lupus process. Method40 female Balb/c mice aged 3 weeks were purchased and randomly divided into six groups. First, lupus disease was induced into the lupus groups by intraperitoneal injection of pristane and then the mice were surveyed for 6 months. The body weight, anti-dsDNA autoantibody levels, serum creatinine, and Blood Urea Nitrogen (BUN) levels were measured in two-month intervals. After 6 months, the group of lupus mice was sacrificed, and lupus MSCs were isolated. Two months later, cultured lupus MSCs were intravenously injected into two groups of healthy and lupus mice. After two months, the mice were euthanized and the kidneys of each group were examined histologically by hematoxylin & eosin (H&E) staining and the immunofluorescence method was also performed to evaluate IgG and C3 deposition. The frequency of splenic Th1, Th2, Th17, and Treg cells was measured by flow cytometry. Moreover, the cytokine levels of IFN-γ, IL-4, IL-17, and TGF-β in sera were measured by ELISA method. ResultsOur results showed that the induction of lupus disease by pristane in Balb/c mice caused the formation of lipogranuloma, increased levels of anti-dsDNA autoantibodies, and impaired renal function in all pristane-induced lupus groups. In addition, the injection of lupus mesenchymal stromal cells (L-MSC) into healthy and lupus mice led to a further rise in anti-dsDNA serum levels, IgG and C3 deposition, and further dysfunction of mice renal tissue. Also, the flow cytometry results implicated that compared to the control groups, splenic Th1, Th2, and Th17 inflammatory cell subtypes and their secreted cytokines (IFN-γ, IL-4, and IL-17) in the sera of healthy and lupus mice were increased after the intake of L-MSC. Additionally, the splenic Treg cells were also significantly increased in the lupus mice receiving L-MSC. However, a decrease in serum levels of TGF-β cytokine was observed in healthy and lupus mice following L-MSC injection. In contrast, the lupus mice receiving healthy mesenchymal stem cells (H-MSC) manifested opposite results. ConclusionIn a nutshell, our results suggest that although allogeneic MSCs are encouraging candidates for SLE treatment, syngeneic MSCs may not be eligible for treating SLE patients due to their defects in regulating the immune system in addition to their capability in promoting inflammation which would consequently worsen the SLE disease status.

Regulatory T-cell deficiency leads to features of autoimmune liver disease overlap syndrome in scurfy mice.

Scurfy mice have a complete deficiency of functional regulatory T cells (Treg) due to a frameshift mutation in the Foxp3 gene. The impaired immune homeostasis results in a lethal lymphoproliferative disorder affecting multiple organs, including the liver. The autoimmune pathology in scurfy mice is in part accompanied by autoantibodies such as antinuclear antibodies (ANA). ANA are serological hallmarks of several autoimmune disorders including autoimmune liver diseases (AILD). However, the underlying pathogenesis and the role of Treg in AILD remain to be elucidated. The present study therefore aimed to characterize the liver disease in scurfy mice. Sera from scurfy mice were screened for ANA by indirect immunofluorescence assay (IFA) and tested for a wide range of AILD-associated autoantibodies by enzyme-linked immunosorbent assay, line immunoassay, and addressable laser bead immunoassay. CD4+ T cells of scurfy mice were transferred into T cell-deficient B6/nude mice. Monoclonal autoantibodies from scurfy mice and recipient B6/nude mice were tested for ANA by IFA. Liver tissue of scurfy mice was analyzed by conventional histology. Collagen deposition in scurfy liver was quantified via hepatic hydroxyproline content. Real-time quantitative PCR was used to determine fibrosis-related hepatic gene expression. Hepatic immune cells were differentiated by flow cytometry. All scurfy mice produced ANA. AILD-associated autoantibodies, predominantly antimitochondrial antibodies, were detected at significantly higher levels in scurfy sera. CD4+ T cells from scurfy mice were sufficient to induce anti-dsDNA autoantibodies and ANA with an AILD-related nuclear envelope staining pattern. Liver histology revealed portal inflammation with bile duct damage and proliferation, as in primary biliary cholangitis (PBC), and interface hepatitis with portal-parenchymal necroinflammation, as found in autoimmune hepatitis (AIH). In scurfy liver, TNFα and fibrosis-related transcripts including Col1a1, Timp1, Acta2, Mmp2, and Mmp9 were upregulated. The level of proinflammatory monocytic macrophages (Ly-6Chi) was increased, while M2-type macrophages (CD206+) were downregulated compared to wildtype controls. Despite severe hepatic inflammation, fibrosis did not develop within 25 days, which is close to the lifespan of scurfy mice. Our findings suggest that Treg-deficient scurfy mice spontaneously develop clinical, serological, and immunopathological characteristics of AILD with overlapping features of PBC and AIH.

Sirtuin 1 overexpression contributes to the expansion of follicular helper T cells in systemic lupus erythematosus and may serve as an accessible therapeutic target.

SIRT1, an NAD+-dependent deacetylase, is upregulated in CD4+ T cells from SLE patients and MRL/lpr lupus-like mice. This study aimed to explore the role of SIRT1 in follicular helper T (Tfh) cell expansion and its potential value as a therapeutic target for SLE. Frequencies of CD4+CXCR5+PD-1+ Tfh cells in peripheral blood from SLE patients and their expression of SIRT1 and B cell lymphoma 6 (BCL-6) were determined with flow cytometry. Naïve CD4+ T cells were transfected with SIRT1-expressing lentivirus and small interfering RNA (siRNA) targeting SIRT1, respectively, and then cultured under Tfh-polarizing conditions to study the impact of SIRT1 on Tfh cell differentiation. This impact was also evaluated in both CD4+ T cells and naïve CD4+ T cells by treatment with SIRT1 inhibitors (EX527 and nicotinamide) in vitro. MRL/lpr mice and pristane-induced lupus mice were treated with continuous daily intake of nicotinamide, and their lupus phenotypes (including skin rash, arthritis, proteinuria and serum anti-dsDNA autoantibodies) were compared with those of controls. Expression of SIRT1 was elevated in Tfh cells from SLE patients and was positively correlated with Tfh cell frequencies. SIRT1 expression gradually increased during Tfh cell differentiation. Overexpression of SIRT1 by lentiviral vectors significantly promoted Tfh cell differentiation/proliferation. Reciprocally, suppressing expression of SIRT1 by siRNA and inhibiting SIRT1 activity by EX-527 or nicotinamide hindered Tfh cell expansion. Continuous daily intake of nicotinamide alleviated lupus-like phenotypes and decreased serum CXCL13 in the two mouse models. SIRT1 overexpression contributed to the expansion of Tfh cells in SLE and may serve as a potential target for treatment.

Anti-SSA and Anti-dsDNA Autoantibodies in Rheumatoid Arthritis Patients and their Association with Disease Severity: A Case-Control Study in Kerbala Province

Background: Rheumatoid arthritis (RA) is a lifelong autoimmune inflammatory disease of unknown origin. An early diagnosis of RA could improve the outcome. Several autoantibodies have been found in RA patients. Objective: To evaluate the incidence of autoantibodies against Sjögren's syndrome antigen A (SSA) and double-stranded deoxyribonucleic acid (dsDNA) in RA patients and to detect the association between their presence and disease severity markers. Methods: Blood samples were drawn from participants to be used in the detection of ESR and for the simultaneous detection of rheumatoid factor (RF), anti-cyclic citrullinated protein antibodies (ACCP), anti-SSA, and anti-dsDNA by the ELISA technique. Result: The level of autoantibodies differs significantly between patients and healthy people. Anti-SSA was present in about 95.12% and 2.43% of patients and controls, respectively. Additionally, anti-dsDNA was present in 82.92% and 14.63% of patients and controls, respectively. A significant positive correlation between ESR and autoantibody levels was detected. A non-significant correlation was detected between disease activity score 28 (DAS28) and the existence of autoantibodies. Conclusion: ROC analysis demonstrated that RF, ACCP, anti-SSA, and anti-dsDNA had high discriminatory power. The mean levels of these autoantibodies vary dramatically between sick and healthy individuals. The level of RF autoantibody varies dramatically with illness duration. According to DAS28, no autoantibody levels differed considerably.

Disease in the Pld4thss/thss Model of Murine Lupus Requires TLR9.

Phospholipase D4 (PLD4) is an endolysosomal exonuclease of ssRNA and ssDNA, rather than a phospholipase as its name suggests. Human polymorphisms in the PLD4 gene have been linked by genome-wide association studies to systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, B6.129 Pld4-/- mice develop features of a distinct disease, macrophage activation syndrome, which is reversed in mice mutated in TLR9. In this article, we compare a Pld4 null mutant identified on the BALB/c background, Pld4thss/thss, which has distinct phenotypes: short stature, thin hair, and features of systemic lupus erythematosus. All phenotypes analyzed were largely normalized in Pld4thss/thssTlr9-/- mice. Thus, Pld4thss/thss represents a rare model in which mouse lupus etiology is TLR9 dependent. Compared with PLD4-deficient B6 mice, Pld4thss/thss mice had elevated levels of serum IgG, IgG anti-dsDNA autoantibodies, BAFF, and IFN-γ and elevated B cell numbers. Overall, the data suggest that PLD4 deficiency can lead to a diverse array of rheumatological abnormalities depending upon background-modifying genes, and that these diseases of PLD4 deficiency are largely driven by TLR9 recognition of ssDNA.

Endogenous erythropoietin has immunoregulatory functions that limit the expression of autoimmune kidney disease in mice.

Administration of recombinant erythropoietin (EPO), a kidney-produced hormone with erythropoietic functions, has been shown to have multiple immunoregulatory effects in mice and humans, but whether physiological levels of EPO regulate immune function in vivo has not been previously evaluated. We generated mice in which we could downregulate EPO production using a doxycycline (DOX)-inducible, EPO-specific silencing RNA (shEPOrtTAPOS), and we crossed them with B6.MRL-Faslpr/J mice that develop spontaneous lupus. We treated these B6.MRL/lpr shEPOrtTAPOS with DOX and serially measured anti-dsDNA antibodies, analyzed immune subsets by flow cytometry, and evaluated clinical signs of disease activity over 6 months of age in B6.MRL/lpr shEPOrtTAPOS and in congenic shEPOrtTANEG controls. In B6.MRL/lpr mice, Epo downregulation augmented anti-dsDNA autoantibody levels and increased disease severity and percentages of germinal center B cells compared with controls. It also increased intracellular levels of IL-6 and MCP-1 in macrophages. Our data in a murine model of lupus document that endogenous EPO reduces T- and B-cell activation and autoantibody production, supporting the conclusion that EPO physiologically acts as a counterregulatory mechanism to control immune homeostasis.

HLA-DR Association of Anti-dsDNA and Anti-Sm Autoantibodies in Bangladeshi Patients with Systemic Lupus Erythematosus

Background: Rheumatic disorders are one of the largest health problems in the world in both developed and developing countries. Among systemic rheumatic disorders, systemic lupus erythematosus (SLE) is very much common. This debilitating disease most commonly affects females, especially at a young age. Though the exact etiology for the development of SLE still remains vague but genetic factors especially, HLA-DR plays an important role particularly in the development of autoantibodies in SLE cases. Objective: This study was undertaken to find out the association of HLA-DR with anti-dsDNA and anti-Sm autoantibodies among patients with SLE. Methods: Buccal swabs for HLA-DR typing and blood samples for detection of anti-dsDNA and anti-Sm were collected from 46 SLE cases. HLA-DR typing was carried out by end point polymerase chain reaction (PCR) with sequence specific primers. Autoantibodies were detected by using ELISA. Results: Out of 46 cases with SLE 44 (95.65%) were female and 2 (4.35%) were male with female: male ratio was 22: 1. Their mean age at study entry was 27.05 ± 8.17 years (mean ± SD), ranging from 12.5-45 years. AntidsDNA was positive in 38 (82.61%) cases and negative in 8 (17.39%) cases. Anti-Sm was positive in 19 (41.30%) cases and negative in 27 (58.70%) cases. The most frequently identified HLA-DR was DR2 (86.96%). When Anti-dsDNA positive cases were compared with Anti-dsDNA negative cases significant association was found with HLA-DR2 (94.73% vs 50%, p value = 0.0044, pc = 0.044, RR = 18.0000). No positive association of HLA-DR was found with anti-Sm autoantibody in this study. The above data suggest that HLA-DR2 has a role in anti-dsDNA production in Bangladeshi patients with SLE. Bangladesh Medical Res Counc Bull 2022; 48: 138-145

Loss of interleukin-1 beta is not protective in the lupus-prone NZM2328 mouse model.

Aberrant activation of the innate immune system is a known driver of lupus pathogenesis. Inhibition of the inflammasome and its downstream signaling components in murine models of lupus has been shown to reduce the severity of disease. Interleukin-1 beta (IL-1β) is a proinflammatory cytokine released from cells following inflammasome activation. Here, we examine how loss of IL-1β affects disease severity in the lupus-prone NZM2328 mouse model. We observed a sex-biased increase in immune complex deposition in the kidneys of female mice in the absence of IL-1β that corresponds to worsened proteinuria. Loss of IL-1β did not result in changes in overall survival, anti-dsDNA autoantibody production, or renal immune cell infiltration. RNA-sequencing analysis identified upregulation of TNF and IL-17 signaling pathways specifically in females lacking IL-1β. Increases in these signaling pathways were also found in female patients with lupus nephritis, suggesting clinical relevance for upregulation of these pathways. Together, these data suggest that inhibition of the inflammasome or its downstream elements that block IL-1β signaling may need to be approached with caution in SLE, especially in patients with renal involvement to prevent potential disease exacerbation.