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Objective: Systemic lupus erythematosus (SLE) is a systemic autoimmune syndrome characterized by autoreactive responses to nucleic acids, dysregulation of the type I interferon (IFN-I) pathway, and accelerated atherosclerosis. The stimulator of IFN genes (STING), a cytosolic DNA sensor, has pathogenic implications in various inflammatory diseases. However, its specific role in SLE pathogenesis, particularly in tissue damage, remains unclear. This study aimed to elucidate the role of STING in murine models of Toll-like receptor 7 (TLR7)-driven lupus and atherosclerosis., Methods: A TLR7-driven lupus model was induced using imiquimod (IMQ) in wild-type (WT) and STING knockout (Sting1 -/- ) mice on a B6 background. Mice were assessed for organ involvement, serum autoantibodies, and innate and adaptive immune responses. Additionally, Sting1 -/- mice were backcrossed to apolipoprotein E knockout (Apoe -/- ) mice, and both Apoe -/- and Apoe -/- Sting1 -/- mice were fed a high-fat chow diet to induce atherosclerosis. Phenotypic assessments were conducted., Results: Compared with IMQ-treated WT mice, Sting1 -/- mice exhibited reduced disease severity in the lupus-like phenotype, characterized by decreased splenomegaly, lower renal immune complex deposition and renal damage, diminished expansion of myeloid cells, and reduced activation of T and B lymphocytes. IMQ-induced DNA release associated with IFN-β production and subsequent IFN-induced responses were attenuated in Sting1 -/- mice. DNase I treatment mitigated IMQ-induced proinflammatory responses in WT mice but had no effect in Sting1 -/- mice. Furthermore, STING deficiency conferred protection against vascular damage and reduced atherosclerosis burden, accompanied by decreased IFN-I production. Human monocyte-derived macrophages treated with IFN-I significantly internalized more acetylated low-density lipoprotein when compared with untreated cells, whereas an association between oxidized nucleic acids and disease activity and vascular damage was found in human SLE., Conclusion: These findings highlight a pathogenic role of STING and downstream IFN responses in TLR7-driven autoimmunity, vascular damage and atherosclerosis, supporting a therapeutic potential for STING inhibition in SLE treatment. Further research is warranted to elucidate the mechanisms underlying STING's involvement in these processes and to explore the feasibility of targeting STING as a therapeutic strategy in SLE and related autoimmune disorders., (© 2024 The Author(s). Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Objective: Latino patients are overrepresented among cases of coronavirus disease 2019 (COVID-19) and are at an increased risk of severe disease. Prevalence of COVID-19 in Latinos with rheumatic diseases is poorly reported. This study was undertaken to characterize COVID-19 clinical features and outcomes in Latino patients with rheumatic diseases., Methods: We conducted a retrospective study of Latino patients with rheumatic diseases from an existing observational cohort in the Washington, DC area. Patients seen between April 1, 2020 and October 15, 2020 were analyzed in this study. We reviewed demographic characteristics, body mass index (BMI), comorbidities, and use of immunomodulatory therapies. An exploratory classification and regression tree (CART) analysis along with logistic regression analyses were performed to identify risk factors for COVID-19 and rheumatic disease flare., Results: Of 178 Latino patients with rheumatic diseases, 32 (18%) were identified as having COVID-19, and the incidence rate of infection was found to be 3-fold higher than in the general Latino population. No patients required intensive care unit-level care. A CART analysis and multivariable logistic regression analysis identified a BMI of >30.35 as a risk factor for COVID-19 (odds ratio [OR] 3.37 [95% confidence interval (95% CI) 1.5-7.7]; P = 0.004). COVID-19 positivity was a risk factor for rheumatic disease flare (OR 4.57 [95% CI 1.2-17.4]; P = 0.02)., Conclusion: Our findings indicate that Latino patients with rheumatic diseases have a higher rate of COVID-19 compared with the general Latino population. Obesity is a risk factor for COVID-19, and COVID-19 is a risk factor for rheumatic disease flare. Latino patients with risk factors should be closely followed up, especially post-COVID-19 in anticipation of disease flare., (Published 2021. This article is a U.S.Government work and is in the public domain in the USA.)

Objective: To develop new classification criteria for systemic lupus erythematosus (SLE) jointly supported by the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR)., Methods: This international initiative had four phases. 1) Evaluation of antinuclear antibody (ANA) as an entry criterion through systematic review and meta-regression of the literature and criteria generation through an international Delphi exercise, an early patient cohort, and a patient survey. 2) Criteria reduction by Delphi and nominal group technique exercises. 3) Criteria definition and weighting based on criterion performance and on results of a multi-criteria decision analysis. 4) Refinement of weights and threshold scores in a new derivation cohort of 1,001 subjects and validation compared with previous criteria in a new validation cohort of 1,270 subjects., Results: The 2019 EULAR/ACR classification criteria for SLE include positive ANA at least once as obligatory entry criterion; followed by additive weighted criteria grouped in 7 clinical (constitutional, hematologic, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal) and 3 immunologic (antiphospholipid antibodies, complement proteins, SLE-specific antibodies) domains, and weighted from 2 to 10. Patients accumulating ≥10 points are classified. In the validation cohort, the new criteria had a sensitivity of 96.1% and specificity of 93.4%, compared with 82.8% sensitivity and 93.4% specificity of the ACR 1997 and 96.7% sensitivity and 83.7% specificity of the Systemic Lupus International Collaborating Clinics 2012 criteria., Conclusion: These new classification criteria were developed using rigorous methodology with multidisciplinary and international input, and have excellent sensitivity and specificity. Use of ANA entry criterion, hierarchically clustered, and weighted criteria reflects current thinking about SLE and provides an improved foundation for SLE research., (© 2019, American College of Rheumatology.)

Objective: Autoreactive IgE antibodies have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). We hypothesize that omalizumab, a monoclonal antibody binding IgE, may improve SLE activity by reducing type I interferon (IFN) production by hampering plasmacytoid dendritic cells and basophil activation. This study was undertaken to assess the safety, tolerability, and clinical efficacy of omalizumab in mild to moderate SLE., Methods: Sixteen subjects with SLE and a Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score of ≥4 and elevated autoreactive IgE antibody levels were randomized to receive omalizumab or placebo (2:1) for 16 weeks, followed by 16 weeks of open-label treatment and a 4-week washout period. The SLEDAI-2K score, British Isles Lupus Assessment Group index (BILAG 2004) score, and physician's global assessment of disease activity were recorded at each visit. The type I IFN-induced gene signature was determined using quantitative polymerase chain reaction., Results: Omalizumab was well tolerated with no allergic reactions, and mostly mild adverse events comparable to those experienced with placebo treatment. SLEDAI-2K scores improved in the omalizumab group compared to the placebo group at week 16 (P = 0.038), as well as during the open-label phase in subjects initially receiving placebo (P = 0.02). No worsening in BILAG scores or the physician's global assessment was detected. There was a trend toward a reduction in IFN gene signature in subjects treated with omalizumab (P = 0.11), especially in subjects with a high baseline IFN signature (P = 0.052)., Conclusion: Our findings indicate that omalizumab is well tolerated in SLE and is associated with improvement in disease activity. Larger randomized clinical trials will be needed to assess the efficacy of omalizumab in patients with SLE., (© 2018, American College of Rheumatology.)

Objective: Anticytokine autoantibodies occur across a range of hematologic, pulmonary, and infectious diseases. However, systematic investigation of their presence and significance in autoimmune diseases is lacking. This study was undertaken to examine the distinct functions of anticytokine autoantibodies in patients with systemic lupus erythematosus (SLE) compared to patients with other rheumatic diseases and healthy controls., Methods: Serum samples from patients with SLE (n = 199), patients with primary Sjögren's syndrome (SS) (n = 150), patients with rheumatoid arthritis (RA) (n = 149), and healthy controls (n = 200) were screened for 24 anticytokine autoantibodies using a multiplex bead-based assay. To evaluate the biologic activity of anticytokine autoantibodies, their ability to block cytokine-induced signal transduction or protein expression was measured. RNA sequencing was performed on whole blood in a subset of healthy controls and patients with SLE., Results: Patients with SLE and those with SS had a striking excess of autoantibodies against interferons and the interferon-responsive chemokine interferon-inducible protein 10 (IP-10). Only autoantibodies against type I interferon, interleukin-12 (IL-12), and IL-22 exhibited neutralizing activity. In SLE, the presence of anti-interferon-γ autoantibodies was correlated with more severe disease activity, higher levels of anti-double-stranded DNA antibodies, and elevated expression of interferon-α/β-inducible genes. Conversely, in SLE patients with blocking anti-interferon-α autoantibodies, the type I interferon gene expression signature was normalized. Anti-type III interferon autoantibodies (λ2, λ3) and anti-IP-10 autoantibodies were newly recognized in SLE patient serum, and autoantibodies against macrophage-colony stimulating factor, IL-4, IL-7, IL-17, and IL-22, none of which have been previously identified in rheumatic conditions, were discovered., Conclusion: Anticytokine autoantibodies are associated with distinct patterns of disease in SLE, SS, and RA. Anti-interferon autoantibodies are overrepresented in patients with SLE and those with SS, and fall into distinct functional classes, with only a subset of anti-type I interferon antibodies exhibiting neutralizing activity. Anti-interferon-γ autoantibodies are correlated with increased disease activity and interferon-related gene expression, suggesting that such autoantibodies may contribute to the pathogenesis of SLE., (© 2016, American College of Rheumatology.)

Objective: Systemic lupus erythematosus (SLE) is characterized by increased cardiovascular risk in adult-onset and childhood-onset SLE. Type I interferons (IFNs) appear to play a prominent role in premature vascular damage in adult-onset SLE, at least in part, by inducing impairments in the phenotype and function of endothelial progenitor cells (EPCs), thereby hampering vascular repair. It is not clear whether EPC dysfunction is present in childhood-onset SLE in association with a type I IFN signature., Methods: The phenotype and numbers of EPCs were quantified in patients with childhood-onset SLE, patients with juvenile idiopathic arthritis (JIA), and matched healthy control subjects. In a separate cohort of patients with childhood-onset SLE, markers of subclinical atherosclerosis and endothelial dysfunction were quantified using standardized protocols and analyzed for associations with serum type I IFN activity., Results: EPC numbers and function were significantly decreased in patients with childhood-onset SLE compared with patients with JIA and healthy control subjects. Serum from patients with childhood-onset SLE impaired differentiation of EPCs into mature endothelial cells in healthy controls, and this effect was blocked by inhibition of the type I IFN pathway. Type I IFN activity in serum was not significantly associated with subclinical atherosclerosis and endothelial function in patients with childhood-onset SLE., Conclusion: As in adult-onset SLE, childhood-onset SLE is characterized by phenotypic and functional EPC abnormalities, which are likely triggered by type I IFNs. Although cross-sectional analysis revealed no global association between type I IFN signatures and vascular measures of subclinical atherosclerosis, longitudinal assessments are needed to evaluate whether progression of vascular damage in patients with childhood-onset SLE is associated with type I IFNs, as observed in patients with adult-onset SLE., (© 2015, American College of Rheumatology.)

Objective: Oxidative stress and oxidized high-density lipoprotein (HDL) are implicated as risk factors for cardiovascular disease (CVD) in systemic lupus erythematosus (SLE). Yet, how HDL is oxidized and rendered dysfunctional in SLE remains unclear. Neutrophil extracellular traps (NETs), the levels of which are elevated in lupus, possess oxidant-generating enzymes, including myeloperoxidase (MPO), NADPH oxidase (NOX), and nitric oxide synthase (NOS). We hypothesized that NETs mediate HDL oxidation, impairing cholesterol efflux capacity (CEC)., Methods: Plasma MPO levels and CEC activity were examined in controls and lupus patients, and 3-chlorotyrosine (MPO specific) and 3-nitrotyrosine (derived from reactive nitrogen species) were quantified in human HDL. Multivariable linear models were used to estimate and test differences between groups. HDL was exposed to NETs from control and lupus neutrophils in the presence or absence of MPO, NOX, NOS inhibitors, and chloroquine (CQ). Murine HDL oxidation was quantified after NET inhibition in vivo., Results: SLE patients displayed higher MPO levels and diminished CEC compared to controls. SLE HDL had higher 3-nitrotyrosine and 3-chlorotyrosine content than control HDL, with site-specific oxidation signatures on apolipoprotein A-I. Experiments with human and murine NETs confirmed that chlorination was mediated by MPO and NOX, and nitration by NOS and NOX. Mice with lupus treated with the NET inhibitor Cl-amidine displayed significantly decreased HDL oxidation. CQ inhibited NET formation in vitro., Conclusion: Active NOS, NOX, and MPO within NETs significantly modify HDL, rendering the lipoprotein proatherogenic. Since NET formation is enhanced in SLE, these findings support a novel role for NET-derived lipoprotein oxidation in SLE-associated CVD and identify additional proatherogenic roles of neutrophils and putative protective roles of antimalarials in autoimmunity., (Published 2014. This article is a U.S. Government work and is in the public domain in the USA.)