Neutrophil activation biomarker pentraxin 3 for diagnosis and monitoring of macrophage activation syndrome occurrence in adult-onset Still's disease.

Macrophage activation syndrome (MAS) is a potentially fatal consequence of adult-onset Still's disease (AOSD), driven by a cytokine storm. Efficient early diagnosis of AOSD-associated MAS requires a sensitive and specific biomarker. In this study, we demonstrated that pentraxin 3 (PTX3), an acute phase protein, was associated with AOSD disease activity and served as a biomarker for AOSD-MAS. PTX3 levels were significantly increased in AOSD patients compared to other autoimmune diseases and healthy controls. Plasma PTX3 levels showed positive correlations with inflammatory markers, the systemic score and the HScore. In active AOSD with MAS, PTX3 levels were higher compared to those in non-AOSD haemophagocytic lymphohistiocytosis (HLH) patients. Moreover, the PTX3's area under the curve value for distinguishing AOSD with MAS exceeded that of soluble interleukin-2 receptor, ferritin and C-reactive protein. Furthermore, plasma levels of PTX3 were associated with circulating NET-DNA levels. To fully understand the underlying mechanism of PTX3 prompting AOSD and AOSD-MAS progression, we discovered that neutrophils exhibited enhanced NET formation and mitogen-activated protein kinases (MAPK) pathway activation upon PTX3 stimulation. More importantly, PTX3-induced NET formation was effectively dampened by MAPK pathway inhibitors. These findings collectively revealed that PTX3 has a favorable correlation with disease activity and may serve as a potential biomarker to differentiate AOSD patients with MAS. Additionally, PTX3 induces NET release via the MAPK pathway, suggesting a pathogenic role in AOSD-MAS.

Neutrophil extracellular trap-induced intermediate monocytes trigger macrophage activation syndrome in adult-onset Still's disease.

BACKGROUND: Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disease characterized by innate immune system activation, with a high risk for macrophage activation syndrome (MAS). MAS development is associated with monocyte/macrophage activation and cytokine storm. Monocytes consist of three different subsets, classical monocytes (CMs, CD14brightCD16 -), intermediate monocytes (IMs, CD14brightCD16 +), and non-classical monocytes (NCMs, CD14dimCD16 +), each has distinct roles in inflammatory regulation. However, the frequencies and regulatory mechanism of monocyte subsets in AOSD patients have not been identified. METHODS: We performed flow cytometry, RNA sequencing, phagocytosis analysis, and enzyme-linked immunosorbent assay to evaluate monocyte subsets, cell functions, and potential biomarkers. The effect of neutrophil extracellular traps (NETs) on monocytes was determined by evaluating mRNA levels of DNA sensors, surface CD16 expression, and inflammasome pathway activation. RESULTS: Higher proportions of intermediate monocytes (IMs) were identified in active AOSD patients. IMs displayed higher expression of CD80, CD86, HLA-DR, and CD163 than CMs and NCMs. CD163 upregulation was noted on AOSD IMs, accompanied by increased phagocytic activity and elevated cytokine/chemokine production, including IL-1ß, IL-6, CCL8, and CXCL10. The frequencies of IMs were correlated with disease activity and higher in AOSD patients with MAS (AOSD-MAS). CCL8 and CXCL10 were highly expressed in RNA sequencing of monocytes from AOSD-MAS patients and plasma CXCL10 level could serve as a potential biomarker for AOSD-MAS. Moreover, DNA-sensing pathway was activated in monocytes from AOSD-MAS patients. Stimulation with NETs derived from AOSD induced DNA sensor expression, the expansion of IMs, and inflammasome pathway activation. These effects can be abrogated by DNase I treatment. CONCLUSIONS: Our results demonstrated that the proportions of IMs were elevated in AOSD and associated with MAS. The DNA component in NETs from AOSD plays an important role in the formation of IMs, shedding new light for the therapeutic target.

The landscape of innate and adaptive immune cell subsets in patients with adult-onset Still's disease.

OBJECTIVE: Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disorder. The understanding of the changes in adaptive immune cells and the crosstalk between innate and adaptive immune systems in AOSD is limited. This study aimed to examine the peripheral immune cell composition and inflammatory protein levels in AOSD patients. METHODS: Twenty-nine active AOSD patients were enrolled. Flow cytometry was used to analyze the cell populations in peripheral blood. Antibody chips were utilized to detect the protein expression profile in serum. RESULTS: In active AOSD patients, there was an increase in the percentage of classical and non-classical monocytes among peripheral blood mononuclear cells. The proportion of natural killer (NK) cells decreased, with an increase in CD56dim NK1 cells and a decrease in CD56bright NK2 cells compared with healthy controls (HC). The percentage of naïve central memory T cells was decreased, while the percentage of effector and effector memory T cells was increased among adaptive lymphocytes. The proportion of naïve B and memory B cells was decreased, while plasma cells were increased in AOSD patients, indicating activation of the adaptive immune system. Additionally, the serum levels of 40 proteins were elevated in AOSD patients, primarily involved in cytokine-cytokine receptor interaction, inflammatory response, and regulation of MAPK cascade. CONCLUSION: Our findings showed the activation of the innate and adaptive immune system in AOSD. The protein-protein interaction analysis suggested potential communication between innate and adaptive cell subsets. These findings provide new insights into the pathogenesis of the disease and the development of targeted therapies.

Inactivated SARS-CoV-2 vaccine does not increase the risk of relapse in patients with clinically inactive adult-onset Still's disease.

OBJECTIVE: A succession of cases have reported flares of adult-onset Still's disease (AOSD) after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), raising concerns. We aimed to investigate the impact of inactivated SARS-CoV-2 vaccines on disease activity in patients with AOSD. METHODS: We prospectively enrolled clinically inactive AOSD patients visiting the outpatient clinics of our department. The patients received SARS-CoV-2 vaccines (BBIBP-CorV, Sinopharm, Beijing, China) voluntarily. The occurrence of relapse in the participants was recorded during the follow-up period, and a propensity score matching (PSM) method was used to compare the relapse rates between vaccinated and unvaccinated patients. Localized and systemic symptoms were assessed in the vaccinated patients. RESULTS: A total of 122 patients with inactive AOSD were included, of which 49.2% (n = 60) voluntarily received the inactivated SARS-CoV-2 vaccine. The relapse rate did not increase significantly in vaccinated patients in comparison with unvaccinated patients (after PSM: 6.8% vs 6.8%), and no relapse occurred within 1 month after vaccination. No obvious adverse reactions were reported in 75.0% of the participants, and none of the patients reported severe reactions. CONCLUSION: Increased disease activity or relapse following vaccination with inactivated SARS-CoV-2 was rare in patients with inactive AOSD. Local and systemic adverse reactions were found to be mild and self-limiting. These safety profiles of inactivated SARS-CoV-2 vaccines in patients with AOSD may assist in eliminating vaccine hesitancy and increase the vaccination rate against SARS-CoV-2.

COVID-19 vaccine affects neither prothrombotic antibody profile nor thrombosis in primary anti-phospholipid syndrome: a prospective study.

OBJECTIVE: To explore whether inactivated coronavirus disease 2019 vaccine influences the profile of prothrombotic autoantibodies and induces thrombotic events in primary APS patients. METHODS: We enrolled 39 primary APS patients who received two doses of inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (BBIBPCorV, Sinopharm, Beijing, China) voluntarily in this prospective cohort. Prothrombotic autoantibodies were determined before vaccination and 4 weeks after the second dose of vaccination. Thrombotic disorders were evaluated via hospital site visits and assessments. RESULTS: There was no significant difference in the presence of all 11 autoantibodies detected before and 4 weeks after vaccination: for aCL, IgG (14 vs 16, P = 0.64), IgM (13 vs 19, P = 0.34), IgA (2 vs 3, P = 0.64); anti-ß2GP1, IgG (12 vs 12, P = 1.00), IgM (5 vs 8, P = 0.36), IgA (4 vs 3, P = 0.69); anti-PS/PT IgG (13 vs 16, P = 0.48), IgM (17 vs 22, P = 0.26); LAC (22 vs 28, P = 0.16); aPF4-heparin (0 vs 0, P = 1.00) and ANA (23 vs 26, P = 0.48). Notably, the distribution of the aPL profile in the pre- and post-vaccination cohorts was not affected by SARS-CoV-2 vaccination: for patients with a low-risk aPL profile (11 vs 10, P = 0.799) and patients with a high-risk aPL profile (28 vs 29, P = 0.799), respectively. Furthermore, no case exhibited symptoms of the thrombotic disorder during a minimum follow-up period of 12 weeks. There was no adjustment to the ongoing treatment regimens following SARS-CoV-2 vaccination. CONCLUSION: Inactivated SARS-CoV-2 vaccine does not influence the profile of anti-phospholipid antibodies and anti-PF4-heparin antibodies nor induces thrombotic events in primary APS patients.

Research trends in the field of retinitis pigmentosa from 2002 to 2021: a 20 years bibliometric analysis.

PURPOSE: To analyze publication trends for the past 20 years and identify potential research trends in the retinitis pigmentosa (RP) research field. METHODS: We extracted data from the Web of Science Core Collection and conducted a bibliometric analysis. All records related to RP from 2002 to 2021 were analyzed. The co-occurrence maps of keywords were generated by VOSviewer v.1.6.17 to identify knowledge structure and research trends in the RP research field. RESULTS: Totally 1976 publications from 2002 to 2021 were included in this study. The United States ranked first in the number of publications, citations and H-index. INVESTIGATIVE OPHTHALMOLOGY VISUAL SCIENCE was the most prolific journal in the RP research field. LEAGUE OF EUROPEAN RESEARCH UNIVERSITIES LERU had the greatest output in the RP research field. Tsang SH contributed to the highest number of publications in the RP research field. All keywords were divided into three clusters: (1) gene mutations, (2) pathophysiological changes, and (3) diagnosis and management in the RP research field. Average appearing years of keywords were evaluated and most of the recently appearing keywords focused on the pathophysiological changes. CONCLUSIONS: By bibliometric analysis, the knowledge structure of RP research field was identified. It may help clinicians to comprehensively understand the hotspots and guide the research trends in the RP research field.

Performance of the modified Systemic Manifestation Score for systemic juvenile idiopathic arthritis in Adult-onset Still's disease.

OBJECTIVES: To compare the ability of the modified Systemic Manifestation Score (mSMS) and the mPouchot score to distinguish adult-onset Still's disease (AOSD) with high disease severity in a large cohort. METHODS: We scored the disease severity of 174 patients and categorized them into high and low disease severity states. The correlation of mSMS and mPouchot score with ESR, CRP, ferritin, liver function tests, and serum cytokines was investigated. Receiver operator characteristic (ROC) curve and logistic regression analysis were performed to compare the ability of mSMS and mPouchot to distinguish patients with severe AOSD. RESULTS: Both mSMS and mPouchot score were positively correlated with ESR (both P < 0.001), CRP (both P < 0.0001), and serum ferritin (both P < 0.0001). Moreover, both mSMS and mPouchot score are significantly associated with liver dysfunction and high IL-18 (both P < 0.0001) and IL-6 (both P < 0.01) levels in AOSD patients. Furthermore, the area under curve (AUC) value of mSMS was significantly less than of mPouchot score (0.71 for mSMS, 0.81 for mPouchot score, P < 0.0001). Compared with mPouchot score, mSMS had higher sensitivity (75.64% vs 74.36%) and lower specificity (55.06% vs 76.40%). And mSMS had a worse performance in assessing high disease severity than mPouchot score in logistic analysis. CONCLUSION: Both scores are proven as effective to assess disease severity of AOSD. By contrast, mSMS perform worse in assessing high disease severity of AOSD patients than mPouchot score. Key Points • Both modified Systemic Manifestation Score (mSMS) and modified Pouchot score (mPouchot score) positively correlated with ESR, CRP, and serum ferritin of AOSD patients. • Both scores are significantly associated with impaired liver function and high serum cytokine levels. • mSMS had lower discriminative ability than mPouchot score to distinguish high disease severity of AOSD patients.

Ferritin triggers neutrophil extracellular trap-mediated cytokine storm through Msr1 contributing to adult-onset Still's disease pathogenesis.

Hyperferritinemic syndrome, an overwhelming inflammatory condition, is characterized by high ferritin levels, systemic inflammation and multi-organ dysfunction, but the pathogenic role of ferritin remains largely unknown. Here we show in an animal model that ferritin administration leads to systemic and hepatic inflammation characterized by excessive neutrophil leukocyte infiltration and neutrophil extracellular trap (NET) formation in the liver tissue. Ferritin-induced NET formation depends on the expression of peptidylarginine deiminase 4 and neutrophil elastase and on reactive oxygen species production. Mechanistically, ferritin exposure increases both overall and cell surface expression of Msr1 on neutrophil leukocytes, and also acts as ligand to Msr1 to trigger the NET formation pathway. Depletion of neutrophil leukocytes or ablation of Msr1 protect mice from tissue damage and the hyperinflammatory response, which further confirms the role of Msr1 as ferritin receptor. The relevance of the animal model is underscored by the observation that enhanced NET formation, increased Msr1 expression and signalling on neutrophil leukocytes are also characteristic to adult-onset Still's disease (AOSD), a typical hyperferritinemic syndrome. Collectively, our findings demonstrate an essential role of ferritin in NET-mediated cytokine storm, and suggest that targeting NETs or Msr1 may benefit AOSD patients.

Enhanced type I interferon signature induces neutrophil extracellular traps enriched in mitochondrial DNA in adult-onset Still's disease.

Adult-onset Still's disease (AOSD) is a rare but clinically well-known auto-inflammatory disorder. Cytokine storm, the hallmark of AOSD, is mediated by neutrophil hyperactivation and enhanced neutrophil extracellular trap (NET) formation. Type I interferons (IFNs), having a primary role in the initiation of proinflammation responses, can induce subsequent inflammatory cytokine production. However, the role of type I IFNs in AOSD is unclear. Indeed, high levels of IFN-α and IFN-ß expression are presented by AOSD patients. In this investigation, hierarchical unsupervised clustering was performed on IFN-α and IFN-ß data to identify a cluster of AOSD patients who had a serious condition. Neutrophils from treatment-naïve active AOSD patients showed very strong enrichment in their IFN-α response, as shown by RNA-seq and confirmed by the IFN score. Whether IFN-α stimulates NET formation was also tested. IFN-α had the ability to form NETs that contained oxidized mitochondrial DNA (ox-mtDNA). Moreover, the JAK inhibitor could be used to dampen type I IFN-induced NET formation and eventually control ox-mtDNA release. Our results demonstrated the important roles of type I IFNs in the pathogenesis of AOSD through their promotion of NET formation, as characterized by the enhanced level of ox-mtDNA. The findings open up new avenues of research into therapeutic approaches for AOSD.

Serum VEGF-C as an evaluation marker of disease activity in adult-onset Still's disease.

In view of the possible involvement of vascular endothelial growth factor-C (VEGF-C) in pathogenesis of adult-onset Still's disease (AOSD) based on our previous genome-wide association study (GWAS) results, the primary objective of this study, therefore, was to investigate the correlations between the content of VEGF-C in serum and clinical and biochemical markers of AOSD. Blood samples were collected from 80 patients with AOSD, 26 with rheumatoid arthritis (RA), 30 with systemic lupus erythematosus (SLE) and 31 healthy control subjects. The serum VEGF-C levels were determined using an enzyme-linked immunosorbent assay (ELISA). Statistical analysis and comparisons were conducted. A significantly higher serum VEGF-C level was observed in patients with AOSD than in HC. Serum VEGF-C levels had high AUC value of 0.8145 for distinguishing AOSD group from healthy group with sensitivity of 0.7097 and specificity of 0.8250. It also showed good diagnostic value to differentiate AOSD from other autoinflammatory diseases with sensitivity of 0.7500 and specificity of 0.5500. AOSD patients with fever, arthralgia, skin rash, sore throat, lymphadenopathy, splenomegaly hepatomegaly and pleuritis, had a higher level than those who did not have these symptoms (p = 0.0012, p = 0.0092, p = 0.0056, p = 0.0123, p = 0.0068, p = 0.0030, p = 0.0020, and p = 0.0018, respectively). The serum VEGF-C levels were also positively correlated with laboratory features and several cytokines related to AOSD disease activity. In conclusion, our study unveiled a close association between serum VEGF-C levels and AOSD including disease activity and clinical hematological manifestations, suggesting the potential utility of VEGF-C as a candidate biomarker to assess disease activity in AOSD.

Plasma exchange therapy in refractory inflammatory myopathy with anti-signal recognition particle antibody: a case series.

OBJECTIVES: To explore the efficacy of plasma exchange (PE) therapy in refractory idiopathic inflammatory myopathy (IIM) patients with positive anti-signal recognition particle (SRP) antibody. METHODS: Nine refractory IIM patients with positive anti-SRP antibody were enrolled, who received PE therapy at Ruijin Hospital from October 2017 to December 2020. The clinical manifestations, laboratory tests, chest CT and lower extremity MRI images before and after PE therapy were compared. The treatment response was evaluated by the 2016 ACR/EULAR myositis response criteria. RESULTS: A total of 88.9% (8/9) of subjects had achieved improvement by 3 weeks after PE therapy, with 55.6% (5/9) minimal improvement and 33.3% (3/9) moderate improvement. There were statistically significant improvements between baseline and after PE therapy at 3 weeks on the core set measures: physician global activity, patient global activity, HAQ, manual muscle testing (MMT), extramuscular disease activity, and muscle enzymes activity including creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST), except for alanine transaminase (ALT). Moreover, the chest CT showed regression of ground glass opacities and irregular linear opacities after PE therapy in four patients with interstitial lung disease. The MRI images of lower extremity in four patients showed reduction of muscle oedema after the therapy. CONCLUSION: PE therapy is effective for refractory IIM patients with positive anti-SRP antibody. It should be considered as an alternative treatment for those patients who are resistant to the combined therapy of glucocorticoids and immunosuppressive agents.

Methylenetetrahydrofolate Reductase 677T Allele Is a Risk Factor for Arterial Thrombosis in Chinese Han Patients with Antiphospholipid Syndrome.

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by the persistent presence of antiphospholipid antibodies (aPL) and thrombotic or obstetric events. Given the heterogeneity of the clinical manifestations, it is likely that genetic and acquired factors are involved in the pathogenesis of APS. The inherited polymorphisms of the thrombophilic gene, including methylenetetrahydrofolate reductase (MTHFR) C677T, type 1 plasminogen activator inhibitor (PAI-1) 4G/5G, factor V Leiden (FVL) G1691A, prothrombin (PT) G20210A, antithrombin (AT), and fibrinogen (Fg) polymorphisms, were analyzed in 67 aPL(+) patients from the Chinese Han population, including 41 APS patients and 26 persistent aPL carriers. The MTHFR C677T genotypes of 105 healthy controls, and the PAI-1 4G/5G polymorphism of 120 healthy controls, from the Chinese Han population were acquired for this study. Both the MTHFR C677T genotype (χ2 = 10.67, p = 0.004) and C/T allele distribution (χ2 = 5.92, p = 0.019) between the aPL(+) patients and healthy controls were found to be significantly different. Furthermore, we observed that the patients with at least one T allele had a higher risk of arterial thrombosis (CT vs. CC, OR 11.00, p= 0.025; CT + TT vs. CC, OR 10.27, p = 0.018). The C677T mutation of MTHFR is a risk factor for arterial thrombosis in Chinese Han patients with APS.

Urine Proteomics Differentiate Primary Thrombotic Antiphospholipid Syndrome From Obstetric Antiphospholipid Syndrome.

Antiphospholipid syndrome (APS) is a multisystem disorder characterized by thrombosis and/or recurrent fetal loss. This clinical phenotype heterogeneity may result in differences in response to treatment and prognosis. In this study, we aimed to identify primary thrombotic APS (TAPS) from primary obstetric APS (OAPS) using urine proteomics as a non-invasive method. Only patients with primary APS were enrolled in this study from 2016 to 2018 at a single clinical center in Shanghai. Urine samples from 15 patients with TAPS, 9 patients with OAPS, and 15 healthy controls (HCs) were collected and analyzed using isobaric tags for relative and absolute quantification (iTRAQ) labeling combined with liquid chromatography-tandem mass spectrometry analysis to identify differentially expressed proteins. Cluster analysis of urine proteomics identified differentiated proteins among the TAPS, OAPS, and HC groups. Urinary proteins were enriched in cytokine and cytokine receptor pathways. Representative secreted cytokines screened out (fold change >1.20, or <0.83, p<0.05) in these differentiated proteins were measured by enzyme-linked immunosorbent assay in a validation cohort. The results showed that the levels of C-X-C motif chemokine ligand 12 (CXCL12) were higher in the urine of patients with TAPS than in those with OAPS (p=0.035), while the levels of platelet-derived growth factor subunit B (PDGFB) were lower in patients with TAPS than in those with OAPS (p=0.041). In addition, correlation analysis showed that CXCL12 levels were positively correlated with immunoglobulin G anti-ß2-glycoprotein I antibody (r=0.617, p=0.016). Our results demonstrated that urinary CXCL12 and PDGFB might serve as potential non-invasive markers to differentiate primary TAPS from primary OAPS.

Current and emerging biological therapy in adult-onset Still's disease.

Adult-onset Still's disease (AOSD) is a rare, but characteristic non-familial, multi-genic systemic auto-inflammatory disorder, characterized by high spiking fever, salmon-like evanescent skin rash, polyarthritis, sore throat, hyperferritinemia and leucocytosis. The hallmark of AOSD is a cytokine storm triggered by dysregulation of inflammation. Nowadays, with advances in anti-cytokine biologic agents, the treatment of AOSD is no longer limited to NSAIDs, glucocorticoids or conventional synthetic DMARDs. In this review, we focussed on the roles of these cytokines in the pathogenesis of AOSD and summarized the current and emerging biological therapy.

Total metabolic lesion volume of lymph nodes measured by 18F-FDG PET/CT: a new predictor of macrophage activation syndrome in adult-onset Still's disease.

BACKGROUND: To investigate the potential utility of quantitative parameters obtained by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the assessment of disease severity and the occurrence of macrophage activation syndrome (MAS) in adult-onset Still's disease (AOSD). METHODS: Fifty-seven patients with AOSD who underwent pre-treatment 18F-FDG PET/CT were recruited in this study and compared with 60 age- and sex-matched healthy controls. Clinical features and laboratory data were recorded. The systemic score was assessed to determine the disease severity. The maximal standardized uptake value (SUVmax), metabolic lesion volume (MLV), and total lesion glycolysis (TLG) were used to evaluate the involved organs and tissues that abnormally accumulated 18F-FDG. Multivariate analysis was performed to identify the PET/CT-derived risk factors contributing to the AOSD-related MAS, and their diagnostic efficiency was evaluated. RESULTS: High 18F-FDG accumulation was observed in the bone marrow (SUVmax median, 5.10), spleen (SUVmax median, 3.70), and lymph nodes (LNs, SUVmax median, 5.55). The SUVmax of the bone marrow (rho = 0.376, p = 0.004), SUVmax of the spleen (rho = 0.450, p < 0.001), TLGtotal of LNs (rho = 0.386, p = 0.017), and MLVtotal of LNs (rho = 0.391, p = 0.015) were correlated with the systemic score. The SUVmax of the spleen (p = 0.017), TLGtotal of LNs (p = 0.045), and MLVtotal of LNs (p = 0.012) were higher in patients with MAS than in those without MAS. A MLVtotal of LNs > 62.2 (OR 27.375, p = 0.042) was an independent predictive factor for MAS with a sensitivity of 80.0% and a specificity of 93.9%. CONCLUSIONS: The glucose metabolic level of the spleen could be an effective and easy-to-use imaging indicator of disease severity, and MLVtotal of LNs > 62.2 was a strong predictor of MAS occurrence in patients with AOSD.

Neutrophil-derived lipocalin-2 in adult-onset Still's disease: a novel biomarker of disease activity and liver damage.

OBJECTIVE: Liver damage is a common manifestation and can be life-threatening in adult-onset Still's disease (AOSD), an autoinflammatory disease. The hallmark of AOSD is activation of neutrophils, whose infiltration in liver is suspected to promote tissue injury. Here we aimed to identify a candidate biomarker and to validate its association with liver damage in AOSD. METHODS: Transcriptome analysis of neutrophils from treatment-naïve active AOSD patients and healthy donors was performed. Lipocalin-2 (LCN2) expression was assessed in neutrophils, plasma and liver biopsies of AOSD. The correlations of LCN2 with different variables and its ability to identify liver damage from AOSD patients were analysed. RESULTS: LCN2, a novel biomarker in hepatic inflammation, was found to be upregulated in AOSD neutrophils by RNA sequencing and confirmed at the mRNA and protein levels. Plasma levels of LCN2 were significantly higher in AOSD patients than healthy controls, RA and SLE patients. Plasma LCN2 levels were closely correlated with inflammatory markers, systemic score, HScore and cytokines. Moreover, LCN2 levels were increased in active AOSD with liver involvement and independently associated with liver dysfunction. Enhanced expression of LCN2 was detected in liver biopsies from three patients with ongoing liver injury. Furthermore, the area under the curve value of LCN2 for identifying AOSD with liver injury from other liver diseases was 0.9694. CONCLUSION: Our results reveal that neutrophils-derived LCN2 is higher in plasma and liver tissue in AOSD patients than in healthy controls, and it could serve as a potent biomarker for identifying AOSD with systemic inflammation, especially liver damage caused by hyperinflammation.

Association of the Leukocyte Immunoglobulin-like Receptor A3 Gene With Neutrophil Activation and Disease Susceptibility in Adult-Onset Still's Disease.

OBJECTIVE: Adult-onset Still's disease (AOSD) is a severe autoinflammatory disease. Neutrophil activation with enhanced neutrophil extracellular trap (NET) formation is involved in the pathogenesis of AOSD. Functional leukocyte immunoglobulin-like receptor A3 (LIR-A3; gene name LILRA3) has been reported to be associated with many autoimmune diseases. We aimed to investigate the association of LILRA3 with disease susceptibility and neutrophil activation in AOSD. METHODS: The LILRA3 deletion polymorphism and its tagging single-nucleotide polymorphism rs103294 were genotyped in 164 patients with AOSD and 305 healthy controls. The impact of LILRA3 on clinical features and messenger RNA expression was evaluated. Plasma levels of LIR-A3 were detected using enzyme-linked immunosorbent assay (ELISA), and the correlation between LIR-A3 plasma levels and disease activity and levels of circulating NET-DNA was investigated. LIR-A3-induced NETs were determined using PicoGreen double-stranded DNA dye and immunofluorescence analysis in human neutrophils and a neutrophil-like differentiated NB4 cell line transfected with LIR-B2 small interfering RNA. RESULTS: The findings from genotyping demonstrated that functional LILRA3 was a risk factor for AOSD (11% in AOSD patients versus 5.6% in healthy controls; odds ratio 2.089 [95% confidence interval 1.030-4.291], P = 0.034), and associated with leukocytosis (P = 0.039) and increased levels of circulating neutrophils (P = 0.027). Functional LILRA3 messenger RNA expression was higher in the peripheral blood mononuclear cells (P < 0.0001) and neutrophils (P < 0.001) of LILRA3+/+ patients. Plasma levels of LIR-A3 were elevated in patients with AOSD (P < 0.0001) and correlated with disease activity indicators and levels of circulating NET-DNA complexes. Finally, enhanced NET formation was identified in neutrophils from healthy controls and patients with inactive AOSD after stimulation of the neutrophils with LIR-A3. Moreover, NET formation was impaired in NB4 cells after knockdown of LILRB2 gene expression. CONCLUSION: Our study provides the first evidence that functional LILRA3 is a novel genetic risk factor for the development of AOSD and that functional LIR-A3 may play a pathogenic role by inducing formation of NETs.

Pregnancy Outcomes in Patients With Adult-Onset Still's Disease: A Cohort Study From China.

Objective: Adult-onset Still's disease (AOSD) is an autoinflammatory disease with a higher prevalence rate in young females. The purpose of this study is to investigate whether AOSD has an adverse impact on pregnancy outcomes, or conversely exacerbated by pregnancy. Methods: The outcomes of 191 pregnancies were evaluated in 86 female patients with AOSD. The generalized linear mixed model and propensity score matching method were conducted to evaluate the influence of AOSD on pregnancy outcomes. A dependent sample sign test was applied to assess the impact of pregnancy on the relapse of AOSD. Results: The results showed that the post-AOSD group had a lower proportion of normal delivery (25.0 vs. 52.4%, p = 0.036) and a higher proportion of spontaneous abortion (STA) (18.8 vs. 0.6%, p = 0.002) compared with the pre-AOSD group. Moreover, pregnancy after being diagnosed with AOSD was a significant high risk factor of STA (adjusted OR = 4.577, 95% CI: 4.166-845.119; p = 0.003). Disease flare upon conception was observed in one of 16 post-AOSD pregnancies (p = 1.000). There were 11 patients with new-onset AOSD during gestation or postpartum, among which five (45.4%) evolved into the polycyclic course. Conclusions: AOSD patients might suffer from a higher risk of STA, however, pregnancy might not be related with the exacerbation of diagnosed AOSD. New-onset AOSD during gestation or postpartum tend to evolve into the polycyclic course.

Circulating Neutrophil Extracellular Traps Signature for Identifying Organ Involvement and Response to Glucocorticoid in Adult-Onset Still's Disease: A Machine Learning Study.

Adult-onset Still's disease (AOSD) is an autoinflammatory disease with multisystem involvement. Early identification of patients with severe complications and those refractory to glucocorticoid is crucial to improve therapeutic strategy in AOSD. Exaggerated neutrophil activation and enhanced formation of neutrophil extracellular traps (NETs) in patients with AOSD were found to be closely associated with etiopathogenesis. In this study, we aim to investigate, to our knowledge for the first time, the clinical value of circulating NETs by machine learning to distinguish AOSD patients with organ involvement and refractory to glucocorticoid. Plasma samples were used to measure cell-free DNA, NE-DNA, MPO-DNA, and citH3-DNA complexes from training and validation sets. The training set included 40 AOSD patients and 24 healthy controls (HCs), and the validation set included 26 AOSD patients and 16 HCs. Support vector machines (SVM) were used for modeling and validation of circulating NETs signature for the diagnosis of AOSD and identifying patients refractory to low-dose glucocorticoid treatment. The training set was used to build a model, and the validation set was used to test the predictive capacity of the model. A total of four circulating NETs showed similar trends in different individuals and could distinguish patients with AOSD from HCs by SVM (AUC value: 0.88). Circulating NETs in plasma were closely correlated with systemic score, laboratory tests, and cytokines. Moreover, circulating NETs had the potential to distinguish patients with liver and cardiopulmonary system involvement. Furthermore, the AUC value of combined NETs to identify patients who were refractory to low-dose glucocorticoid was 0.917. In conclusion, circulating NETs signature provide added clinical value in monitoring AOSD patients. It may provide evidence to predict who is prone to be refractory to low-dose glucocorticoid and help to make efficient therapeutic strategy.

Urinary Proteomics Identifying Novel Biomarkers for the Diagnosis of Adult-Onset Still's Disease.

Adult-onset Still's disease (AOSD) is a systemic, multigenic autoinflammatory disease, and the diagnosis of AOSD must rule out neoplasms, infections, and other autoimmune diseases. Development of a rapid and efficient but non-invasive diagnosis method is urgently needed for improving AOSD therapy. In this study, we first performed a urinary proteomic study using isobaric tags for relative and absolute quantification (iTRAQ) labeling combined with liquid chromatography-tandem mass spectrometry analysis in patients with AOSD and healthy control (HC) subjects. The urinary proteins were enriched in pathways of the innate immune system and neutrophil degranulation, and we identified that the α-1-acid glycoprotein 1 (LRG1), orosomucoid 1 (ORM1), and ORM2 proteins were highly expressed in patients with AOSD. The elevated urine levels of LRG1, ORM1, and ORM2 were further validated by enzyme-linked immunosorbent assay in active patients with AOSD, disease controls, and HC subjects. Receiver operating characteristic curves showed that the areas under the curve of LRG1, ORM1, and ORM2 were 0.700, 0.837, and 0.736, respectively (all p < 0.05). Furthermore, we found that the urine levels of LRG1, ORM1, and ORM2 were positively correlated with the systemic score and erythrocyte sedimentation rate and that the urine levels of LRG1 were positively correlated with interleukin 1ß (IL-1ß), IL-6, and IL-18 levels, whereas the urine levels of ORM1 were positively correlated with the IL-1ß level. Together, our study identified novel urinary markers for non-invasive and simple screening of AOSD.