Elevated Expression of the NLRP3 Inflammasome and Its Correlation with Disease Activity in Adult-onset Still Disease

Deep Immunophenotyping of Circulating T and B Cells in Relapsing Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD) is a complex systemic inflammatory disorder, categorized as an 'IL-1 driven' inflammasomapathy. Despite this, the interaction between T and B cells remains poorly understood. We conducted a study, enrolling 7 patients with relapsing AOSD and 15 healthy control subjects, utilizing deep flow cytometry analysis to examine peripheral blood T- and B-cell subsets. T-cell and B-cell subsets were significantly altered in patients with AOSD. Within CD4+ T cells, Th2 cells were decreased. Additionally, Th17 cell and follicular Th cell subsets were altered within CD45RA-CD62L+ and CD45RA-CD62L- Th cells in patients with AOSD compared to healthy controls. We identified changes in CD8+ T cell maturation and 'polarization' in AOSD patients, with an elevated presence of the TEMRA CD8+ T cell subset. Furthermore, the percentage of Tc1 cells was decreased, while the frequency of CCR6-CXCR3- Tc2 cells was elevated. Finally, we determined that the frequency of CD5+CD27- B cells was dramatically decreased in patients with AOSD compared to healthy controls. Further investigations on a large group of patients with AOSD are required to evaluate these adaptive immunity cells in the disease pathogenesis.

Flow-Induced Shear Stress Primes NLRP3 Inflammasome Activation in Macrophages via Piezo1

The NLRP3 inflammasome is a crucial component of the innate immune system, playing a pivotal role in initiating and regulating the body's inflammatory response to various pathogens and cellular damage. Environmental stimuli, such as temperature, pH level, and nutrient availability, can influence the behavior and functions of innate immune cells, including immune cell activity, proliferation, and cytokine production. However, there is limited understanding regarding how mechanical forces, like shear stress, govern the intrinsic inflammatory reaction, particularly the activation of the NLRP3 inflammasome, and how shear stress impacts NLRP3 inflammasome activation through its capacity to induce alterations in gene expression and cytokine secretion. Here, we investigated how shear stress can act as a priming signal in NLRP3 inflammasome activation by exposing immortalized bone marrow-derived macrophages (iBMDMs) to numerous physiologically relevant magnitudes of shear stress before chemically inducing inflammasome activation. We demonstrated that shear stress of large magnitudes was able to prime iBMDMs more effectively for inflammasome activation compared to lower shear stress magnitudes, as quantified by the percentage of cells where ASC-CFP specks formed and IL-1β secretion, the hallmarks of inflammasome activation. Testing this in NLRP3 and caspase-1 knockout iBMDMs showed that the NLRP3 inflammasome was primarily primed for activation due to shear stress exposure. Quantitative polymerase chain reaction (qPCR) and a small-molecule inhibitor study mechanistically determined that shear stress regulates the NLRP3 inflammasome by upregulating Piezo1, IKKβ, and NLRP3. These findings offer insights into the mechanistic relationship among physiological shear stresses, inflammasome activation, and their impact on the progression of inflammatory diseases and their interconnected pathogenesis.

Neutrophil extracellular traps and neutrophilic dermatosis: an update review

Neutrophils have both antimicrobial ability and pathogenic effect in the immune system, neutrophil extracellular traps (NETs) formation is one of the representative behaviors of their dual role. NETs formation was triggered by pathogen-related components and pathogen non-related proteins as cytokines to exert its effector functions. Recent studies indicate that the pathogenicity of NETs contributed to several skin diseases such as psoriasis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and neutrophilic dermatosis. Especially in neutrophilic dermatosis, a heterogeneous group of inflammatory skin disorders characterized with sterile neutrophilic infiltrate on dermis, NETs formation was reported as the way of participation of neutrophils in the pathogenesis of these diseases. In this review, we describe the different processes of NETs formation, then summarized the most recent updates about the pathogenesis of neutrophilic dermatosis and the participation of NETs, including pyoderma gangrenosum and PAPA syndrome, Behçet syndrome, hidradenitis suppurativa, Sweet Syndrome, pustular dermatosis and other neutrophilic dermatosis. Furthermore, we discuss the link between NETs formation and the development of neutrophilic dermatosis.

The NLRP3 Inflammasome as a Pathogenic Player Showing Therapeutic Potential in Rheumatoid Arthritis and Its Comorbidities: A Narrative Review

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by chronic synovitis and the progressive destruction of cartilage and bone. RA is commonly accompanied by extra-articular comorbidities. The pathogenesis of RA and its comorbidities is complex and not completely elucidated. The assembly of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activates caspase-1, which induces the maturation of interleukin (IL)-1β and IL-18 and leads to the cleavage of gasdermin D with promoting pyroptosis. Accumulative evidence indicates the pathogenic role of NLRP3 inflammasome signaling in RA and its comorbidities, including atherosclerotic cardiovascular disease, osteoporosis, and interstitial lung diseases. Although the available therapeutic agents are effective for RA treatment, their high cost and increased infection rate are causes for concern. Recent evidence revealed the components of the NLRP3 inflammasome as potential therapeutic targets in RA and its comorbidities. In this review, we searched the MEDLINE database using the PubMed interface and reviewed English-language literature on the NLRP3 inflammasome in RA and its comorbidities from 2000 to 2023. The current evidence reveals that the NLRP3 inflammasome contributes to the pathogenesis of RA and its comorbidities. Consequently, the components of the NLRP3 inflammasome signaling pathway represent promising therapeutic targets, and ongoing research might lead to the development of new, effective treatments for RA and its comorbidities.

Biallelic mutations in the CFHR genes underlying atypical hemolytic uremic syndrome in a patient with catastrophic adult-onset Still's disease and recurrent macrophage activation syndrome: A case report

We report the fatal case of a 20-year-old woman with refractory adult-onset Still's disease (AOSD) accompanied by fulminant macrophage activation syndrome (MAS) and atypical hemolytic uremic syndrome (aHUS). Anakinra and tocilizumab temporarily controlled AOSD. In 2021, she presented to ICU with generalized tonic-clonic seizure, lymphocytic aseptic meningitis, and acute kidney injury. Despite hemodialysis and methylprednisolone, she developed another seizure, MAS, and disseminated intravascular coagulation (DIC). Following brief control, MAS flares -reflected by increased plasma CXCL9 and CXCL10- re-emerged and were controlled through dexamethasone, etoposide, cyclosporin and tofacitinib. No mutations were detected in haemophagocytic lymphohistiocytosis (HLH)-associated genes, nor in genes associated with periodic fever syndromes. Post-mortem genetic testing revealed loss-of-function biallelic deletions in complement factor H-related proteins (CFHR) genes, predisposing aHUS. This case underscores the importance of prompt genetic assessment of complement-encoding alleles, in addition to HLH-related genes, in patients with severe AOSD with recurrent MAS and features of thrombotic microangiopathy (TMA).

Thymoquinone, a Novel Multi-Strike Inhibitor of Pro-Tumorigenic Breast Cancer (BC) Markers: CALR, NLRP3 Pathway and sPD-L1 in PBMCs of HR+ and TNBC Patients

Breast cancer (BC) is not only a mass of malignant cells but also a systemic inflammatory disease. BC pro-tumorigenic inflammation has been shown to promote immune evasion and provoke BC progression. The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is activated when pattern recognition receptors (PRRs) sense danger signals such as calreticulin (CALR) from damaged/dying cells, leading to the secretion of interleukin-1β (IL-1β). CALR is a novel BC biological marker, and its high levels are associated with advanced tumors. NLRP3 expression is strongly correlated with an elevated proliferative index Ki67, BC progression, metastasis, and recurrence in patients with hormone receptor-positive (HR+) and triple-negative BC (TNBC). Tumor-associated macrophages (TAMs) secrete high levels of IL-1β promoting endocrine resistance in HR+ BC. Recently, an immunosuppressive soluble form of programmed death ligand 1 (sPD-L1) has been identified as a novel prognostic biomarker in triple-negative breast cancer (TNBC) patients. Interestingly, IL-1β induces sPD-L1 release. BC Patients with elevated IL-1β and sPD-L1 levels show significantly short progression-free survival. For the first time, this study aims to investigate the inhibitory impact of thymoquinone (TQ) on CALR, the NLRP3 pathway and sPD-L1 in HR+ and TNBC. Blood samples were collected from 45 patients with BC. The effect of differing TQ concentrations for different durations on the expression of CALR, NLRP3 complex components and IL-1β as well as the protein levels of sPD-L1 and IL-1β were investigated in the peripheral blood mononuclear cells (PBMCs) and TAMs of TNBC and HR+ BC patients, respectively. The findings showed that TQ significantly downregulated the expression of CALR, NLRP3 components and IL-1β together with the protein levels of secreted IL-1β and sPD-L1. The current findings demonstrated novel immunomodulatory effects of TQ, highlighting its potential role not only as an excellent adjuvant but also as a possible immunotherapeutic agent in HR+ and TNBC patients.

Upregulation of immunoproteasome PSMB8 is associated with Parkinson's disease

BACKGROUND

Immunoproteasome, a part of ubiquitin-proteasome system, is involved in immune response as well as protein degradation. However, the relationship between immunoproteasome and Parkinson's disease (PD) was not evaluated clearly. We hypothesized that the shift of immunoproteasome attributes to PD pathogenesis due to its role in inflammation and protein homeostasis.

OBJECTIVE

To determine whether immunoproteasome in peripheral blood mononuclear cells (PBMC) and brain is expressed differently between patients with PD and healthy controls (HC).

METHODS

Blood samples were collected from 19 HC to 40 patients with PD of comparable ages. Peripheral blood mononuclear cells were isolated and followed by RT-qPCR to measure the mRNA levels of three catalytic subunits of immunoproteasome, namely, PSMB8, PSMB9, and PSMB10. Then, the protein levels of each subunit were measured by western blot. Finally, we confirmed the altered immunoproteasome subunit in the post-mortem human brain of PD.

RESULTS

In PBMCs, PSMB8 mRNA expression of PD group significantly increased compared to HC (p = 0.004), whereas PSMB9 and PSMB10 mRNA were not different between the PD and HC. The ratio of PSMB10 and PSMB8 mRNA (PSMB10/8 ratio) also reflected the significant difference between the PD and HC (p = 0.002). The PSMB10/8 ratio was well correlated with the UPDRS total and Part III score in the early stage of PD (Hoehn and Yahr ≤2.5) or drug-naïve PD subgroups. In terms of the protein level of immunoproteasome subunits in PBMCs, the increase of PSMB8 protein was observed in PD compared to HC (p = 0.0009), while PSMB9 and PSMB10 were not different between groups. Finally, we confirmed that immunoproteasome PSMB8 was expressed abundantly in the postmortem PD brain compared with normal control.

CONCLUSION

Our novel findings implicate that immunoproteasome PSMB8 is engaged in PD pathomechanism.

Dermatologic Manifestations of Noninflammasome-Mediated Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) arise from disturbances that alter interactions of immune cells and tissues. They give rise to prominent (auto)inflammation in the absence of aberrant autoantibodies and/or autoreactive T cells. AIDs that are predominantly caused by changes in the inflammasome pathways, such as the NLRP3- or pyrin-associated inflammasome, have gained substantial attention over the last years. However, AIDs resulting primarily from other changes in the defense system of the innate immune system are less well-studied. These noninflammasome-mediated AIDs relate to, for example, disturbance in the TNF or IFN signaling pathways or aberrations in genes affecting the IL-1RA. The spectrum of clinical signs and symptoms of these conditions is vast. Thus, recognizing early cutaneous signs constitutes an important step in differential diagnoses for dermatologists and other physicians. This review provides an overview of the pathogenesis, clinical presentation, and available treatment options highlighting dermatologic aspects of noninflammasome-mediated AIDs.

High-titer anti-interferon-γ neutralizing autoantibodies linked to opportunistic infections in patients with adult-onset still's disease

Objective

Neutralizing anti-interferon (IFN)-γ autoantibodies are linked to opportunistic infections (OIs). To explore the association between anti-IFN-γ autoantibodies and OIs in patients with adult-onset Still's disease (AOSD), we aimed to examine the ability of these autoantibodies to blockade signal transducer and activator of transcription (STAT1)-phosphorylation and chemokines production.

Methods

Serum titers of anti-IFN-γ autoantibodies were quantified using ELISA in 29 AOSD and 22 healthy controls (HC). The detectable autoantibodies were verified with immunoblotting assay, and their neutralizing capacity against IFN-γ-signaling was evaluated with flow-cytometry analysis and immunoblotting. IFN-γ-mediated production of supernatant chemokines, including monocyte chemoattractant protein-1 (MCP-1) and IFN-γ inducible protein-10 (IP-10), were measured by ELISA.

Results

Among 29 AOSD patients, high titers of anti-IFN-γ neutralizing autoantibodies were detectable in two patients with OIs. Immunoblotting assay revealed more effective inhibition of STAT1-phosphorylation in THP-1 cells treated with sera from autoantibody-positive AOSD patients (56.7 ± 34.79%) compared with those from HC (104.3 ±29.51%), which was also demonstrated in flow-cytometry analysis (47.13 ± 40.99 vs. 97.92 ± 9.48%, p < 0.05). Depleted serum IgG from anti-IFN-γ autoAbs-positive AOSD patients with OIs restored phosphorylated STAT-1 upon IFN-γ treatment. Sera from autoantibody-positive AOSD patients more effectively inhibited IFN-γ-mediated production of MCP-1 (45.65 pg/ml) and IP-10 (22.44 pg/ml) than sera from HC (263.1 pg/ml and 104.0 pg/ml, both p < 0.05). Serum samples showing the strongest inhibition of IFN-γ-signaling were from two patients with high-titer autoantibodies and OIs.

Conclusion

AOSD patients have a high positive rate and titers of anti-IFN-γ autoantibodies. The remarkable blockade effect of high-titer autoantibodies on IFN-γ-mediated STAT1-phosphorylation and chemokines could make these patients susceptible to OIs.

New insights on multigenic autoinflammatory diseases

Autoinflammatory diseases are disorders of the innate immune system, which can be either monogenic due to a specific genetic mutation or complex multigenic due to the involvement of multiple genes. The aim of this review is to explore and summarize the recent advances in pathogenesis, diagnosis, and management of genetically complex autoinflammatory diseases, such as Schnitzler's syndrome; adult-onset Still's disease; synovitis, acne, pustulosis, hyperostosis, osteitis syndrome/chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis; Adamantiades-Behçet's disease; Yao syndrome; and periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome. The PubMed database was screened for relevant articles using free text words and specific search strings. The search was limited to English-language articles, reporting the results of studies in humans, published through March 2021. Evidence from literature suggest that these rare multigenic autoinflammatory diseases can present with different clinical features and the diagnosis of these diseases can be challenging due to a combination of nonspecific manifestations that can be seen in a variety of other conditions. Diagnostic delays and disease complications may occur due to low disease awareness and the lack of pathognomonic markers. The pathogeneses of these diseases are complex and in some cases precise pathogenesis is not clearly understood. Conventional treatments are commonly used for the management of these conditions, but biologics have shown promising results. Biologics targeting proinflammatory cytokines including IL-1, IL-6, TNF-α, IL-17A and IL-18 have been shown to ameliorate signs and symptoms of different multigenic autoinflammatory diseases.

Adult-onset Still’s disease: A disease at the crossroad of innate immunity and autoimmunity

Adult-onset Still’s disease (AOSD) is a rare disease affecting multiple systems and organs with unknown etiology, and the clinical symptoms are usually described as spiking fever, arthritis, evanescent salmon-pink eruptions, lymphadenopathy, splenomegaly, and other manifestations. The laboratory indicators are not specific, often presenting as increased leukocyte counts and neutrophil percentage, elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), hyperferritinemia, and increased inflammatory factors. ANA, ENA, and RF are negative. According to those unspecific clinical presentations and laboratory findings, infection, tumor, connective tissue disease, and other diseases must be ruled out before diagnosis. The diagnosis of AOSD is a great challenge for clinicians. The mechanism of AOSD pathogenesis is complicated and still being studied. There is a new opinion that atypical persistent skin eruptions (APSEs) with specific histological manifestations are unique for AOSD, and APSEs might be on a spectrum with classical evanescent eruptions. Studies on APSEs showed that IL-1β and IFN-γ are strongly correlated with the pathogenesis of necrosis keratinocytes in APSEs. IL-1β is strongly involved in inflammatory disease when it is abnormal, and plays an important role in the pathogenesis of neutrophil dermatosis. In the early stage of AOSD, skin lesions appear to be evanescent urticaria-like eruptions accompanied by fever, and only neutrophils infiltrate around the blood vessels in the dermis pathologically. As the course of the disease progresses, IL-1β is gradually released. Through the stimulation of other inflammatory factors and the influence of unknown factors, IL-1β gradually infiltrates into the stratum corneum and finally accumulates around the necrotic keratinocytes of the stratum corneum. However, the detailed mechanism is still unknown. IFN-γ could play a pro-inflammatory or regulatory role in some disorders. IL-1β can enhance the expression of IFN-γ, and IFN-γ can cause keratinocyte apoptosis by activating the autocrine of caspase. Also, several pieces of evidence indicate that adaptive immunity is also involved in the pathogenesis of AOSD. Increased α-soluble receptors of IL-2 may suggest T-cell activation and proliferation in AOSD patients. Increased IL-4- and IFN-γ-producing T cells were found in active AOSD and related to disease severity. Frequencies of Treg cells in AOSD were significantly lower and were inversely correlated with disease severity. According to these, more and more researchers have reached a consensus that AOSD is a disease at the crossroads of innate immunity and autoimmunity. In this review, we will provide a comprehensive insight into AOSD, describing research progress and the immunological mechanism contribution to the disease. In the meantime, different treatment options and the efficacy and safety of various biologic agents are also discussed. A further understanding of AOSD requires closer cooperation among doctors from different departments, and this review will provide a new idea for diagnosis and therapeutic options.

Bibliometrics analysis on the research status and trends of adult-onset Still’s disease: 1921-2021

Objectives

The aim of this research is to discuss the research status, hotspots, frontiers and development trends in the field of adult-onset Still’s disease (AOSD) based on bibliometrics and visual analysis by CiteSpace software.

Methods

The relevant research articles on AOSD from 1921 to 2021 were retrieved from the Scopus database. CiteSpace software was used to form a visual knowledge map and conduct analysis for the countries/regions, journals, authors, keywords, clusters, research hotspots and frontiers of the included articles.

Results

There were 2,373 articles included, and the number of articles published during 1921-2021 is increasing. The country with the highest number of articles published was Japan (355, 14.96%), followed by the United States (329, 13.86%) and France (215, 9.06%). The author with the highest number of publications is Ansell, Barbara M. (30, 1.26%), and the author with the highest co-citation frequency is Yamaguchi, Masaya (703). Clinical Rheumatology is the journal with the highest publication frequency. The top five cluster groups were “joint”, “differential diagnosis”, “prednisolone”, “methotrexate” and “macrophage activation syndrome”. The diagnosis, treatment and pathogenesis of AOSD form the main research fields, and prognosis and complications are the research hotspots and trends.

Conclusions

The global research field in AOSD has expanded in the past 100 years. The complications and new pathogenesis of AOSD are hotspots in this field and need further study in the future.

Interleukin-18: a biomarker with therapeutic potential in adult-onset Still's disease

INTRODUCTION

Adult-onset Still's disease (AOSD) is an autoinflammatory disease driven by the innate immune response. Given the ambiguity in clinical presentation and lack of specific diagnostic biomarkers, AOSD diagnosis is usually delayed in the early stage. Because AOSD is a rare disease with clinical heterogeneity, there is no consensus on its treatment currently. This review summarizes the current research evidence regarding the pathogenic role and the diagnostic or therapeutic potential of interleukin (IL)-18 in AOSD.

AREAS COVERED

We searched the MEDLINE database using the PubMed interface and reviewed English-language literature from 1971 to 2022. This review focusing on IL-18 discusses its pathogenic role and clinical implications in AOSD.

EXPERT OPINION

NLRP3-inflammasome activation with IL-18 overproduction plays a pathogenic role in AOSD. IL-18 is closely linked to the clinical manifestations and disease activity of AOSD and may be a diagnostic biomarker. Given its pathogenic role in AOSD, IL-18 could become a potential therapeutic target. IL-18 binding protein (IL-18BP) negatively regulates the biological activity of IL-18 by inhibiting IL-18 signaling, and a clinical trial revealed that IL-18BP (Tadekinig alfa) treatment was well-tolerated and effective for AOSD. Recently, monoclonal antibodies against IL-18 have been under evaluation in a phase 1b trial.

Elevated expression of TLR2 and its correlation with disease activity and clinical manifestations in adult-onset Still's disease

This study investigated the role of Toll-like receptor 1 (TLR1), TLR2, TLR4, TLR7, and TLR9 in patients with adult-onset Still’s disease (AOSD). This study included 20 patients with AOSD and 15 healthy controls (HCs). TLR expression in the peripheral blood was quantified using flow cytometry; TLR expression pattern, in the skin lesions and lymph nodes (LNs) of patients with AOSD, was evaluated immunohistochemically. Significantly higher mean intensities of cells presenting TLR2 and TLR7 from whole blood were observed in patients with AOSD than in HCs. TLR2 expression in whole cells correlated with systemic scores, levels of lactate dehydrogenase and ferritin and serum levels of interleukin-1β (IL-1β), IL-6, and IL-18. The percentage of TLR2-positive inflammatory cells was higher in skin biopsy samples from patients with AOSD than those in HCs. TLR9-expressing positive inflammatory cell counts were higher in skin lesions from patients with AOSD than those in the HC, eczema, and psoriasis groups. The expression levels of TLR1, TLR4, TLR7, and TLR9 were higher in LNs of patients with AOSD than in those with T cell lymphoma and reactive lymphadenopathy. Circulating TLR2- and TLR7-positive cells may contribute to the pathogenesis of AOSD. Furthermore, immunohistochemical staining for TLRs in skin lesions and LNs may aid in differentiating AOSD from similar conditions.

Bibliometrics and Visual Analysis of Adult-onset Still Disease (1976–2020)

Background

Adult-onset Still Disease (AoSD) is a rare disorder without standardized diagnostic criteria. People are paying more and more attention to its research. At present, no published studies have assessed the AoSD field using bibliometric tools. This study aimed to analyze research hotspots and frontiers through bibliometrics to provide a scientific and accurate reference for new and existing researchers.

Methods

Data were obtained from the Web of Science core database and analyzed by CiteSpace, VOSviewer, and Microsoft Excel.

Results

Involving 86 countries and regions, a total of 11,121 authors published 2,199 articles in 676 journals. These studies were published from 1976 to 2020. The United States published the most related articles (397). The United States, France, Italy, and Germany were the top four countries with a high H-index. Authors and institutions with high number of published articles and high citations are mainly located in France and Italy. High-frequency keywords include classification, criteria, diagnosis, and therapy method. Keyword clustering covers the connection between AoSD and rheumatoid arthritis, disease diagnosis, classification, and risk factors.

Conclusions

The research on AoSD focuses on the diagnosis and differential diagnosis of the disease. Targeted therapy will become a research hotspot in the future, and relevant clinical research needs to appropriately expand the sample size and improve the credibility of the conclusions. The data reported in this study can serve as a useful resource for researchers studying AoSD.

PM2.5 activated NLRP3 inflammasome and IL-1β release in MH-S cells by facilitating autophagy via activating Wnt5a

Particulate matter 2.5 (PM2.5)-induced pulmonary inflammation is an important issue worldwide. NLRP3 inflammasome activation has been found to be involved in pulmonary inflammation development. However, whether PM2.5 induces pulmonary inflammation by activating the NLRP3 inflammasome has not yet been fully elucidated. This study researched whether PM2.5 induces the NLRP3 inflammasomes activation to trigger pulmonary inflammation.

Mice and MH-S cells were exposed to PM2.5, BOX5, and Rapamycin. Hematoxylin and eosin staining was performed on the lung tissues of mice. M1 macrophage marker CD80 expression in the lung tissues of mice and LC3B expression in MH-S cells was detected by immunofluorescence. IL-1β level in the lavage fluid and MH-S cells were detected by enzyme-linked immunosorbent assay. Protein expression was detected by Western blot. Autophagy assay in MH-S cells was performed by LC3B-GFP punctae experiment.PM2.5 exposure induced the lung injury of mice and increased NLRP3, P62, Wnt5a, LC3BII/I, and CD80 expression and IL-1β release in the lung tissues. PM2.5 treatment increased NLRP3, pro-caspase-1, cleaved caspase-1, Pro-IL-1β, Pro-IL-18, P62, LC3BII/I, and Wnt5a expression, IL-1β release, and LC3B-GFP punctae in MH-S cells. However, BOX5 treatment counteracted this effect of PM2.5 on lung tissues of mice and MH-S cells. Rapamycin reversed the effect of BOX5 on PM2.5-induced lung tissues of mice and MH-S cells.PM2.5 activated the NLRP3 inflammasome and IL-1β release in MH-S cells by facilitating the autophagy via activating Wnt5a. The findings of this study provided a new clue for the treatment of pulmonary inflammation caused by PM2.5.

The clinical heterogeneity of adult onset Still's disease may underlie different pathogenic mechanisms. Implications for a personalised therapeutic management of these patients

Adult-onset Still's disease (AOSD) is a rare inflammatory disease of unknown aetiology usually affecting young adults and manifesting with a clinical triad of spiking fever, arthritis, and evanescent cutaneous rash. AOSD may be considered a highly heterogeneous disease, despite a similar clinical presentation, the disease course may be completely different. Some patients may have a single episode of the disease whereas others may evolve toward a chronic course and experience life-threatening complications. On these bases, to dissect the clinical heterogeneity of this disease, four different subsets were identified combining the manifestations at the beginning with possible diverse outcomes over time. Each one of these derived subsets would be characterised by a prominent different clinical feature from others, thus proposing dissimilar underlying pathogenic mechanisms, at least partially. Consequently, a distinct management of AOSD may be suggested to appropriately tailor the therapeutic strategy to these patients, according to principles of the precision medicine. These findings would also provide the rationale to recognise a different genetic and molecular profile of patients with AOSD. Taking together these findings, the basis for a precision medicine approach may be suggested in AOSD, which would drive a tailored therapeutic approach in these patients. A better patient stratification may also help in arranging specific designed studies to improve the management of patients with AOSD. Behind these different clinical phenotypes, distinct endotypes of AOSD may be suggested, probably differing in pathogenesis, outcomes, and response to therapies.

Increased Lipid Peroxidation May Be Linked to Ferritin Levels Elevation in Adult-Onset Still's Disease

Lipid peroxidation (LPO) and hyper-ferritinemia are involved in inflammatory responses. Although hyper-ferritinemia is a characteristic of AOSD, its link to LPO remains unclear. We investigated the association between LPO and ferritin expression, and evaluated the relationship between LPO-related metabolites and inflammatory parameters. Mean fluorescence intensity (MFI) of LPO (C11-Biodipy^581/591)-expressing PBMCs/monocytes in AOSD patients and healthy control (HC) subjects was determined by flow-cytometry analysis. Expression of ferritin and cytokines on PBMCs/macrophages was examined by immunoblotting. Plasma levels of LPO-related metabolites and cytokines were determined by ELISA and the MULTIPLEX platform, respectively. LPO MFI on PBMCs/monocytes were significantly higher in patients (median 4456 and 9091, respectively) compared with HC (1900, p < 0.05, and 4551, p < 0.01, respectively). Patients had higher ferritin expression on PBMCs (mean fold, 1.02) than HC (0.55, p < 0.05). Their ferritin expression levels on PBMCs stimulated with LPO inducers erastin or RSL3 (2.47 or 1.61, respectively) were higher than HC (0.84, p < 0.05, or 0.74, p < 0.01). Ferritin expression on erastin-treated/IL-1β-treated macrophages from patients were higher than those from HC (p < 0.001). The elevated levels of LPO-related metabolites, including malondialdehyde and 4-hydroxyalkenals, were positively correlated with disease activity scores, suggesting LPO involvement in AOSD pathogenesis. Increased ferritin expression on PBMCs/macrophages stimulated with LPO inducers indicates a link between LPO and elevated ferritin.

Distinct Effects of Interleukin-1β Inhibition upon Cytokine Profile in Patients with Adult-Onset Still's Disease and Active Articular Manifestation Responding to Canakinumab

Adult-onset Still’s disease (AOSD) is a systemic auto-inflammatory disease characterized by the presence of immunologically mediated inflammation and deficient resolution of inflammation. Canakinumab is an approved IL-1β inhibitor in the treatment of AOSD with a balanced efficacy and safety profile. Since inflammatory cytokines play a major role in the pathogenesis of AOSD, we investigated the effects of canakinumab on the cytokine profile of AOSD patients from a randomized controlled trial. Multiplex analysis and ELISA were used to test the concentrations of several cytokines at three time points—week 0 (baseline), week 1 and week 4—in two patient groups—placebo and canakinumab. Two-way repeated-measures analysis of variance revealed a significant temporal effect on the concentrations of MRP 8/14, S100A12, IL-6 and IL-18 with a significant decrease at week 4 in the canakinumab group exclusively. Comparing responders with non-responders to canakinumab showed a significant decrease in MRP 8/14, IL-1RA, IL-18 and IL-6 in responders at week 4, while S100A12 levels decreased significantly in responders and non-responders. In summary, canakinumab showed a striking effect on the cytokine profile in patients with AOSD, exhibiting a clear association with clinical response.

The effectiveness of tocilizumab in treating refractory adult-onset Still's disease with dichotomous phenotypes: IL-18 is a potential predictor of therapeutic response

OBJECTIVE

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder with clinical heterogeneity. Although tocilizumab (TCZ), an interleukin (IL)-6 receptor inhibitor, is an effective treatment for AOSD, the evidence regarding its efficacy on systemic or articular subtypes is conflicting. Furthermore, the predictors of therapeutic response are still elusive and worthy of exploration.

METHODS

This two-center retrospective study analyzed the effectiveness and safety profile of TCZ treatment in 28 patients with refractory AOSD. The 28-joint disease activity score (DAS28) and systemic activity score were assessed before and during TCZ treatment period at weeks 12, 24, 36, and 48. Plasma levels of proinflammatory cytokines at baseline were determined using ELISA method.

RESULTS

Among the systemic subtype patients, 10 (58.8%), 13 (76.5%), 14 (82.4%), and 15 (88.2%) patients achieved complete remission at week 12, 24, 36, and 48, respectively, in comparison to 2 (22.2%), 5 (55.6%), 6 (66.7%), and 7 (77.8%) who achieved disease remission (DAS28 < 2.6) at weeks 12, 24, 36, and 48, respectively, among articular subtype patients. The systemic activity scores and inflammatory parameters were significantly decreased after 12-week TCZ therapy, and TCZ could significantly reduce corticosteroid dose in AOSD patients. Multivariate analysis reveals that baseline IL-18 level is a significant predictor of poor therapeutic response at week 24 (odds ratio 7.86, p < 0.05).

CONCLUSION

AOSD patients refractory to high-dose corticosteroids and methotrexate may respond well to TCZ treatment with a steroid-sparing effect and an acceptable safety. A high baseline IL-18 level may be a predictor of poor therapeutic response. Key Points • Tocilizumab may be effective and well-tolerated in refractory AOSD patients regardless of disease subtypes. • High plasma levels of IL-18 may predict poor response to tocilizumab in AOSD patients.

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.

MicroRNA-223 inhibits neutrophil extracellular traps formation through regulating calcium influx and small extracellular vesicles transmission

Modulation of miRNAs and neutrophil extracellular traps (NETs) formation are both implicated in inflammatory disorders. Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disease with neutrophilic leukocytosis and unknown etiology. Although the NETs formation is elevated in AOSD patients, the regulatory roles of miRNAs in NETs formation in AOSD remains unclear. We revealed that the circulating levels of IL-18, NETs, and miR-223 were significantly higher in active AOSD patients, compared with inactive AOSD patients or healthy controls (P < 0.005). Moreover, IL-18 increased calcium influx into neutrophils, which led to mitochondrial ROS (mROS) production and NETs formation. Elevated levels of NETs-DNA could induce miR-223 expression in neutrophils through activating Toll-like receptor 9. The upregulated miR-223 expression in neutrophils suppressed mROS production by blocking calcium influx, and subsequently inhibited IL-18-mediated NETs formation. Besides, the increased neutrophil-derived exosomal miR-223 levels were observed in active AOSD patients compared with healthy controls (P < 0.005). Our in vitro assays demonstrated that the neutrophil-derived small extracellular vesicles carried miR-223, which could repress IL-18 production in macrophages. Together, these results suggest a fine-tuned mechanism between inflammatory (IL-18 induced NETs) and anti-inflammatory (miR-223) factors in AOSD. MiR-223, mROS inhibitors, and calcium channel blockers are the potential therapeutics for autoinflammatory diseases such as AOSD.

The cytokine storms of COVID-19, H1N1 influenza, CRS and MAS compared. Can one sized treatment fit all?

An analysis of published data appertaining to the cytokine storms of COVID-19, H1N1 influenza, cytokine release syndrome (CRS), and macrophage activation syndrome (MAS) reveals many common immunological and biochemical abnormalities. These include evidence of a hyperactive coagulation system with elevated D-dimer and ferritin levels, disseminated intravascular coagulopathy (DIC) and microthrombi coupled with an activated and highly permeable vascular endothelium. Common immune abnormalities include progressive hypercytokinemia with elevated levels of TNF-α, interleukin (IL)-6, and IL-1β, proinflammatory chemokines, activated macrophages and increased levels of nuclear factor kappa beta (NFκB). Inflammasome activation and release of damage associated molecular patterns (DAMPs) is common to COVID-19, H1N1, and MAS but does not appear to be a feature of CRS. Elevated levels of IL-18 are detected in patients with COVID-19 and MAS but have not been reported in patients with H1N1 influenza and CRS. Elevated interferon-γ is common to H1N1, MAS, and CRS but levels of this molecule appear to be depressed in patients with COVID-19. CD4+ T, CD8+ and NK lymphocytes are involved in the pathophysiology of CRS, MAS, and possibly H1N1 but are reduced in number and dysfunctional in COVID-19. Additional elements underpinning the pathophysiology of cytokine storms include Inflammasome activity and DAMPs. Treatment with anakinra may theoretically offer an avenue to positively manipulate the range of biochemical and immune abnormalities reported in COVID-19 and thought to underpin the pathophysiology of cytokine storms beyond those manipulated via the use of, canakinumab, Jak inhibitors or tocilizumab. Thus, despite the relative success of tocilizumab in reducing mortality in COVID-19 patients already on dexamethasone and promising results with Baricitinib, the combination of anakinra in combination with dexamethasone offers the theoretical prospect of further improvements in patient survival. However, there is currently an absence of trial of evidence in favour or contravening this proposition. Accordingly, a large well powered blinded prospective randomised controlled trial (RCT) to test this hypothesis is recommended.

Interleukin-18 Is a Potential Biomarker to Discriminate Active Adult-Onset Still's Disease From COVID-19

Background

Hyperinflammation with dysregulated production of galectins and cytokines may develop in COVID-19 or adult-onset Still's disease (AOSD). Given the similar clinical features in both diseases, it is necessary to identify biomarkers that can differentiate COVID-19 from AOSD. However, the related data remain scarce currently.

Methods

In this cross-sectional study, plasma levels of galectin-3, galectin-9, and soluble TIM-3 (sTIM-3) were determined by ELISA in 55 COVID-19 patients (31 non-severe and 24 severe), 23 active AOSD patients, and 31 healthy controls (HC). The seropositivity for SARS-CoV-2 was examined using an immunochromatographic assay, and cytokine profiles were determined with the MULTIPLEX platform.

Results

Significantly higher levels of galectin-3, galectin-9, IL-1β, IL-1Ra, IL-10, IFN-α2, IL-6, IL-18, and TNF-α were observed in severe COVID-19 and active AOSD patients compared with HC (all p<0.001). AOSD, but not COVID-19, showed significantly higher IFN-γ and IL-17A compared with HC (both p<0.01). Moreover, active AOSD patients had 68-fold higher IL-18 levels and 5-fold higher ferritin levels than severe COVID-19 patients (both p<0.001). IL-18 levels at the cut-off value 190.5pg/mL had the highest discriminative power for active AOSD and severe COVID-19, with AUC 0.948, sensitivity 91.3%, specificity 95.8%, and accuracy of 91.5% (p<0.005). Multivariate regression analysis revealed IL-18 as a significant predictor of active AOSD (p<0.05).

Conclusion

Active AOSD patients share features of hyperinflammation and cytokine storm with severe COVID-19 patients but possess a distinct cytokine profile, including elevated IL-18, IL-6, IFN-γ, and IL-17A. IL-18 is a potential discriminator between AOSD and COVID-19 and may significantly predict active AOSD.

Interleukin-6 inhibition: a therapeutic strategy for the management of adult-onset Still's disease

Introduction:Patients with adult-onset Still's disease have markedly elevated serum levels of proinflammatory cytokines, such as IL-1β, IL-6, and IL-18, suggesting the potential of these molecules as therapeutic targets. IL-6 accelerates macrophage and cytotoxic T-cell differentiation and neutrophil and macrophage chemotaxis and is one of the most important cytokines in the pathogenesis of adult-onset Still's disease.Areas covered:The review summarizes the importance of IL-6 in the pathogenesis of adult-onset Still's disease and clinical aspects of IL-6 inhibition from retrospective and prospective studies.Expert opinion:Adult-onset Still's disease is a systemic inflammatory disease of unknown etiology and characterized by elevated various proinflammatory cytokines. In particular, serum concentrations of IL-6 is significantly high in patients with active adult-onset Still's disease, and many case reports, cohort studies and one randomized, placebo-controlled trail have shown the efficacy of IL-6 blockade in patients with adult-onset Still's disease who were refractory to glucocorticoids and other immunosuppressive treatments. IL-6 inhibition is effective for both systemic and joint manifestations with arthritis improving slowly. There is still a concern over the triggering of macrophage activation syndrome; however, the IL-6 inhibition strategy has introduced better management of adult-onset Still's disease.

An Update on the Pathogenic Role of Macrophages in Adult-Onset Still's Disease and Its Implication in Clinical Manifestations and Novel Therapeutics

Increasing evidence indicates a pivotal role of macrophages in innate immunity, which contributes to the pathogenesis of adult-onset Still's disease (AOSD). Despite the available reviews that summarized the pathogenic role of proinflammatory cytokines in AOSD, a systematic approach focusing on the crucial role of macrophages in this disease is still lacking. This review summarizes the updated functions of macrophages in AOSD and their implication in clinical manifestations and therapeutics. We searched the MEDLINE database using the PubMed interface and reviewed the English-language literature as of 31 March 2021, from 1971 to 2021. We focus on the existing evidence on the pathogenic role of macrophages in AOSD and its implication in clinical characteristics and novel therapeutics. AOSD is an autoinflammatory disease mainly driven by the innate immune response. Among the innate immune responses, macrophage activation is a hallmark of AOSD pathogenesis. The pattern recognition receptors (PRRs) on macrophages recognize pathogen-associated molecular patterns and damage-associated molecular patterns and subsequently cause overproduction of proinflammatory cytokines and recruit adaptive immunity. Some biomarkers, such as ferritin and gasdermin D, reflecting macrophage activation were elevated and correlated with AOSD activity. Given that macrophage activation with the overproduction of proinflammatory cytokines plays a pathogenic role in AOSD, these inflammatory mediators would be the therapeutic targets. Accordingly, the inhibitors to interleukin- (IL-) 1, IL-6, and IL-18 have been shown to be effective in AOSD treatment. Gaining insights into the pathogenic role of macrophages in AOSD can aid in identifying disease biomarkers and therapeutic agents for this disease.

CARD8 SNP rs11672725 Identified as a Potential Genetic Variant for Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD), an autoinflammatory disorder, is related to the dysregulation of NLR3-containing a pyrin domain (NLRP3)-inflammasome signaling. We aimed to investigate the associations of genetic polymorphisms of NLRP3-inflammasome signaling with AOSD susceptibility and outcome and to examine their functional property. Fifty-three candidate single-nucleotide polymorphisms (SNPs) involved in NLRP3-inflammasome response were genotyped using Sequenom MassArray on the samples from 66 AOSD patients and 128 healthy controls. The significant SNPs were validated by direct sequencing using a TaqMan SNP analyzer. Serum levels of associated gene products were examined by ELISA. One SNP rs11672725 of CARD8 gene was identified to be significantly associated with AOSD susceptibility by using MassArray and subsequent replication validation (p = 3.57 × 10^-7; odds ratio 3.02). Functional assays showed that serum CARD8 levels were significantly lower in AOSD patients (median, 10,524.6 pg/mL) compared to controls (13,964.1 pg/mL, p = 0.005), while levels of caspase-1, IL-1β and IL-18 were significantly higher in patients (107.1 pg/mL, 2.1 pg/mL, and 1495.8 pg/mL, respectively) than those in controls (99.0 pg/mL, 1.0 pg/mL, and 141.4 pg/mL, respectively). Patients carrying rs11672725CC genotype had significantly higher serum caspase-1 and IL-18 levels (121.3 pg/mL and 1748.6 pg/mL) compared to those with CT/TT genotypes (72.6 pg/mL, p = 0.019 and 609.3 pg/mL, p = 0.046). A higher proportion of patients with rs11672725CC genotype had a systemic pattern of disease outcome, which was linked to low CARD8 levels. A novel variant, rs11672725, of the CARD8 gene was identified as a potential genetic risk for AOSD. Patients carrying the rs11672725CC genotype and C allele had low CARD8 levels, and were predisposed to a systemic pattern with an elevated expression of inflammasome signaling.

Adult-Onset Still's Disease: Clinical Aspects and Therapeutic Approach

Adult-onset Still's disease (AoSD) is a rare systemic autoinflammatory disease characterized by arthritis, spiking fever, skin rash and elevated ferritin levels. The reason behind the nomenclature of this condition is that AoSD shares certain symptoms with Still's disease in children, currently named systemic-onset juvenile idiopathic arthritis. Immune dysregulation plays a central role in AoSD and is characterized by pathogenic involvement of both arms of the immune system. Furthermore, the past two decades have seen a large body of immunological research on cytokines, which has attributed to both a better understanding of AoSD and revolutionary advances in treatment. Additionally, recent studies have introduced a new approach by grouping patients with AoSD into only two phenotypes: one with predominantly systemic features and one with a chronic articular disease course. Diagnosis presupposes an extensive diagnostic workup to rule out infections and malignancies. The severe end of the spectrum of this disease is secondary haemophagocytic lymphohistiocytosis, better known as macrophage activation syndrome. In this review, we discuss current research conducted on the pathogenesis, diagnosis, classification, biomarkers and complications of AoSD, as well as the treatment strategy at each stage of the disease course. We also highlight the similarities and differences between AoSD and systemic-onset juvenile idiopathic arthritis. There is a considerable need for large multicentric prospective trials.

Cytokine Storm in Coronavirus Disease 2019 and Adult-Onset Still's Disease: Similarities and Differences

The catastrophic outbreak of coronavirus disease 2019 (COVID-19) is currently a public emergency. Adult-onset Still’s disease (AOSD) is an autoinflammatory disease characterized by life-threatening complications. Systemic hyperinflammation and cytokine storm play a critical role in the pathogenesis of both COVID-19 and AOSD. We aimed to compare the similarities and differences focusing on ferritin and cytokine levels between severe COVID-19 and active AOSD. A literature search was performed using the databases PubMed, EMBASE, and Web of Science to collect the levels of cytokine including IL-1β, IL-6, IL-18, TNF-α, IL-10, and ferritin in severe COVID-19 patients. After extracting available data of indicators of interest, we acquired these statistics with a single-arm meta-analysis. Furthermore, a comparison was conducted between 52 patients with active AOSD in our center and severe COVID-19 patients from databases. The levels of IL-6 and IL-10 were higher in severe COVID-19 compared with those in active AOSD. There were no significant differences on the cytokine of IL-1β and TNF-α. Fold changes of IL-18 were defined as the mean expression level ratio of severe COVID-19 to healthy controls in the COVID-19 study and active AOSD to healthy controls in our study, individually. Although the fold change of IL-18 in patients with AOSD was significantly higher than patients with severe COVID-19 (fold change: 594.00 vs 2.17), there was no statistical comparability. In addition, the level of ferritin was higher in active AOSD in comparison with severe COVID-19. Our findings suggest that severe COVID-19 and active AOSD have differences in cytokine panel and ferritin level, indicating the pathogenic role of ferritin in overwhelming inflammation. And it paves the way to make efficacy therapeutic strategy targeting the hyperinflammatory process in COVID-19 according to AOSD management, especially in severe COVID-19.

Roles of Interactions Between Toll-Like Receptors and Their Endogenous Ligands in the Pathogenesis of Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease

Systemic juvenile idiopathic arthritis (JIA) and adult-onset Still’s disease (AOSD) are systemic inflammatory disorders that manifest as high-spiking fever, joint pain, evanescent skin rash, and organomegaly. Their pathogenesis is unclear, but inflammation is triggered by activation of the innate immune system with aberrant production of proinflammatory cytokines. Along with extrinsic factors, intrinsic pathways can trigger an unexpected immune response. Damage-associated molecular patterns (DAMPs) induce the activation of innate immune cells, leading to sterile inflammation in systemic JIA and AOSD. These endogenous proteins interact with Toll-like receptors (TLRs), which are pattern recognition receptors, and mediate immune signaling following stimulation by pathogen-associated molecular patterns and DAMPs. Several DAMPs, such as S100 proteins, play a role in the development or severity of systemic JIA and AOSD, in which their interactions with TLRs are altered. Also, the expression levels of genes encoding DAMPs contribute to the susceptibility to systemic JIA and AOSD. Herein, we review reports that TLR and DAMP signaling initiates and/or maintains the inflammatory response in systemic JIA and AOSD, and their correlations with the clinical characteristics of those diseases. In addition, we assess their utility as biomarkers or therapeutics for systemic JIA and AOSD.

Autoinflammatory Pathogenesis and Targeted Therapy for Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD) is a rare multisystem autoinflammatory disorder of unknown etiology. AOSD is generally characterized by high spiking fever, arthralgia or arthritis, skin rash, leukocytosis, and hyperferritinemia. Traditionally, AOSD has been treated with non-steroidal anti-inflammatory drugs, corticosteroids, and immunosuppressants. An increasing number of studies have shown that proinflammatory cytokines, such as interleukin-1β, -18, -6, and tumor necrosis factor-α, play key roles in AOSD and may serve as therapeutic targets. In the current review, we provided insights into the roles of these cytokines in the pathogenesis of AOSD and also provided a commentary on the clinical studies of biologic therapy against AOSD.

Pro-inflammatory properties of H-ferritin on human macrophages, ex vivo and in vitro observations

Ferritin is an iron-binding molecule, which comprises 24 subunits, heavy (FeH) and light (FeL) subunits, suggested to have a pathogenic role by the 'hyperferritinemic syndrome'. In this work, we tested (1) FeH and FeL in bone marrow (BM) and sera in patients with macrophage activation syndrome (MAS); (2) pro-inflammatory effects of ferritin, FeL, and FeH on macrophages; (3) ability of FeH-stimulated macrophages to stimulate the proliferation of peripheral blood mononuclear cells (PBMCs); (4) production of mature IL-1β and IL-12p70 in extracellular compartments of FeH-stimulated macrophages. Immunofluorescence analysis and liquid chromatography mass spectrometry (LC-MS/MS) based proteomics were performed to identify FeL and FeH in BM and sera, respectively, in the same patients. Macrophages were stimulated with ferritin, FeH, and FeL to assess pro-inflammatory effects by RT-PCR and western blot. The proliferation of co-cultured PBMCs with FeH-stimulated macrophages was tested. Immunofluorescence showed an increased FeH expression in BMs, whereas LC-MS/MS identified that FeL was mainly represented in sera. FeH induced a significant increase of gene expressions of IL-1β, IL-6, IL-12, and TNF-α, more marked with FeH, which also stimulated NLRP3. FeH-stimulated macrophages enhanced the proliferation of PBMCs. The ELISA assays showed that mature form of IL-1β and IL-12p70 were increased, in extracellular compartments of FeH-stimulated macrophages. Our results showed FeH in BM biopsies of MAS patients, whereas, LC-MS/MS identified FeL in the sera. FeH showed pro-inflammatory effects on macrophages, stimulated NLRP3, and increased PBMCs proliferation.

Interleukin-18 and fibroblast growth factor 2 in combination is a useful diagnostic biomarker to distinguish adult-onset Still's disease from sepsis

OBJECTIVE

To identify potential biomarkers to distinguish adult-onset Still's disease (AOSD) from sepsis.

METHOD

We recruited 70 patients diagnosed with AOSD according to the Yamaguchi criteria, 22 patients with sepsis, and 118 age-matched controls. Serum levels of 40 cytokines were analyzed using multi-suspension cytokine array. We performed a cluster analysis of each cytokine in the AOSD and sepsis groups in order to identify specific molecular networks. Further, multivariate classification (random forest analysis) and logistic regression analysis were used to rank the cytokines by their importance and determine specific biomarkers for distinguishing AOSD from sepsis.

RESULTS

Seventeen of the 40 cytokines were found to be suitable for further analyses. The serum levels of eleven were significantly higher in patients with AOSD than healthy controls. Levels of serum fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor (VEGF), granulocyte colony-stimulating factor (G-CSF), and interleukin (IL)-18 were significantly elevated in patients with AOSD compared with those with sepsis, and cytokine clustering patterns differed between these two groups. Multivariate classification followed by logistic regression analysis revealed that measurement of both FGF-2 and IL-18 could distinguish AOSD from sepsis with high accuracy (cutoff value for FGF-2 = 36 pg/mL; IL-18 = 543 pg/mL, sensitivity 100%, specificity 72.2%, accuracy 93.8%).

CONCLUSION

Determination of FGF-2 and IL-18 levels in combination may represent a biomarker for the differential diagnosis of AOSD from sepsis, based on the measurement of multiple cytokines.

Elevated Expression of C-Type Lectin Domain Family 5-Member A (CLEC5A) and Its Relation to Inflammatory Parameters and Disease Course in Adult-Onset Still's Disease

C-type lectin domain family 5-member A (CLEC5A) associates with adaptor DAP12 (DNAX activation protein 12) to form receptor complexes involved in inflammatory responses. We postulated a potential role of CLEC5A in the pathogenesis of adult-onset Still's disease (AOSD) and aimed to investigate CLEC5A expression and its association with activity parameters and disease course. In 34 AOSD patients and 12 healthy controls (HC), circulating levels of CLEC5A-expressing monocytes or granulocytes were determined by flow cytometry analysis, the mRNA expression of CLEC5A and DAP12 on PBMCs by quantitative PCR, and plasma levels of proinflammatory cytokines by ELISA. AOSD patients had significantly higher percentages and mean fluorescence intensity (MFI) of CLEC5A-expressing monocytes (median 62.1% and 3.20, respectively) or granulocytes (72.6% and 3.22, respectively) compared with HC (in monocytes: 17.0% and 0.65, both p < 0.001; in granulocytes: 67.3%, p < 0.05 and 0.90, p < 0.001; respectively). Patients also had significantly higher levels of CLEC5A mRNA expression on PBMCs compared with HC (median 1.77 vs. 0.68, p < 0.05). The levels of CLEC5A-expressing monocytes or granulocytes were positively associated with activity scores and levels of IL-1β and IL-18 in AOSD patients. The patients with a systemic pattern had significantly higher levels of CLEC5A-expressing granulocytes and IL-18 compared to those with a chronic articular pattern of disease course. After 6 months of therapy, levels of CLEC5A-expressing monocytes and granulocytes significantly declined, paralleling the decrease of AOSD activity. Elevated CLEC5A levels and their positive association with activity parameters suggest that CLEC5A is involved in the pathogenesis and may serve as an activity indicator of AOSD.

Pathogenesis, disease course, and prognosis of adult-onset Still's disease: an update and review

OBJECTIVE

Adult-onset Still's disease (AOSD) is a rare but clinically well-known polygenic systemic autoinflammatory disease. In this review, we aim to present frontiers in the pathogenesis, clinical features, diagnosis, biomarkers, disease course, prognosis, and treatment in AOSD.

DATA SOURCES

We retrieved information from the PubMed database up to July 2019, using various search terms and relevant words, including AOSD and Still's disease.

STUDY SELECTION

We included data from peer-reviewed journals. Both basic and clinical studies were selected.

RESULTS

Pathogenesis of AOSD involves genetic background, infectious triggers, and immunopathogenesis, mainly the activation of macrophages and neutrophils followed by a cytokine storm. Diagnosis and prognosis evaluation of AOSD is still challenging; therefore, there is an urgent need to identify better biomarkers. Biologic agents, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α antagonists in the treatment of AOSD, have good prospect.

CONCLUSION

This review highlights the advances in pathogenesis, potential biomarkers, disease course, and treatment in AOSD.

Elevated serum levels of interleukin-10 in adult-onset Still's disease are associated with disease activity

To evaluate the serum levels of the anti-inflammatory cytokine interleukin-10 (IL-10) in patients with adult-onset Still's disease (AOSD), a rare, systemic, and multigenic inflammatory disease. The serum levels of IL-10, IL-1β, IL-6, IL-18, and TNF-α were examined by electrochemiluminescence assay. The serum levels of IL-10 were higher in AOSD patients than in healthy controls and positively correlated with systemic score, erythrocyte sedimentation rate (ESR), C-reactive protein level (CRP), ferritin, and inflammatory cytokine (IL-1β, IL-6, IL-18, and TNF-α) levels. Moreover, the levels of IL-10 were significantly higher in AOSD patients who had fever, sore throat, rash, lymphadenopathy, splenomegaly, pneumonia, and arthralgia than in patients who did not. IL-10 was increased in AOSD patients and correlated with disease activity. KEY POINTS: • In this manuscript, we confirmed the elevated serum levels of the anti-inflammatory cytokine IL-10 in AOSD patients, which was previously poorly defined. • We revealed for the first time that the levels of IL-10 were correlated with disease activity and inflammatory cytokine levels in AOSD.

Plasma microRNA Profiles as a Potential Biomarker in Differentiating Adult-Onset Still's Disease From Sepsis

Adult-onset Still's disease (AOSD) is a systemic inflammatory disease characterized by cytokine storm. However, a diagnostic test for AOSD in clinical use is yet to be validated. The aim of our study was to identify non-invasive biomarkers with high specificity and sensitivity to diagnosis of AOSD. MicroRNA (miRNA) profiles in PBMC from new-onset AOSD patients without any treatment and healthy controls (HCs) were analyzed by miRNA deep sequencing. Plasma samples from 100 AOSD patients and 60 HCs were used to validated the expression levels of miRNA by qRT-PCR. The correlations between expression levels of miRNAs and clinical manifestations were analyzed using advanced statistical models. We found that plasma samples from AOSD patients showed a distinct miRNA expression profile. Five miRNAs (miR-142-5p, miR-101-3p, miR-29a-3p, miR-29c-3p, and miR-141-3p) were significantly upregulated in plasma of AOSD patients compared with HCs both in training and validation sets. We discovered a panel including 3 miRNAs (miR-142-5p, miR-101-3p, and miR-29a-3p) that can predict the probability of AOSD with an area under the receiver operating characteristic (ROC) curve of 0.8250 in training and validation sets. Moreover, the expression levels of 5 miRNAs were significantly higher in active AOSD patients compared with those in inactive patients. In addition, elevated level of miR-101-3p was found in AOSD patients with fever, sore throat and arthralgia symptoms; the miR-101-3p was also positively correlated with the levels of IL-6 and TNF-α in serum. Furthermore, five miRNAs (miR-142-5p, miR-101-3p, miR-29c-3p, miR-29a-3p, and miR-141-3p) expressed in plasma were significantly higher in AOSD patients than in sepsis patients (P < 0.05). The AUC value of 4-miRNA panel (miR-142-5p, miR-101-3p, miR-29c-3p, and miR-141-3p) for AOSD diagnosis from sepsis was 0.8448, revealing the potentially diagnostic value to distinguish AOSD patients from sepsis patients. Our results have identified a specific plasma miRNA signature that may serve as a potential non-invasive biomarker for diagnosis of AOSD and monitoring disease activity.

Increased neutrophil extracellular traps activate NLRP3 and inflammatory macrophages in adult-onset Still's disease

Background

Adult-onset Still’s disease (AOSD) is a systemic inflammatory disease characterized by neutrophilia and NLRP3 inflammasome and macrophage activation. We investigated the role of neutrophil extracellular traps (NETs) in the pathogenesis of AOSD, and explored the effect of NETs on activating NLRP3 inflammasome and proinflammatory macrophages.

Methods

The sera of 73 AOSD patients and 40 healthy controls were used to detect the level of cell-free DNA and NET-DNA complexes. NET formation ex vivo was analyzed using immunofluorescence and flow plates. The activation of NLRP3 inflammasome in THP-1 cells and proinflammatory macrophages stimulated with DNA purified from NETs was measured using RT-PCR, ELISA, Western blotting and flow cytometry.

Results

The levels of cell-free DNA and NET-DNA complexes were significantly increased in the circulation of patients with AOSD compared with healthy controls, and freshly isolated neutrophils from patients with AOSD were predisposed to high levels of spontaneous NET release. Interestingly, enhanced NET release was abrogated with NADPH oxidase inhibitors and a mitochondrial scavenger. Furthermore, DNA purified from AOSD NETs activated NLRP3 inflammasomes. NET DNA from AOSD also exerted a potent capacity to accelerate the activation of CD68⁺CD86⁺ macrophages and increased the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. Finally, the copy number of mitochondrial DNA (mtDNA) in NETs and plasma was significantly increased in AOSD patients, suggesting that mtDNA may be involved in the activation of NLRP3 and inflammatory macrophages.

Conclusions

These findings implicate accelerated NET formation in AOSD pathogenesis through activation of NLRP3 and proinflammatory macrophages, and identify a novel link between neutrophils and macrophages by NET formation in AOSD.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1800-z) contains supplementary material, which is available to authorized users.

Anakinra Therapy for Non-cancer Inflammatory Diseases

Interleukin-1 (IL-1) is the prototypical inflammatory cytokine: two distinct ligands (IL-1α and IL-1β) bind the IL-1 type 1 receptor (IL-1R1) and induce a myriad of secondary inflammatory mediators, including prostaglandins, cytokines, and chemokines. IL-1α is constitutively present in endothelial and epithelial cells, whereas IL-1β is inducible in myeloid cells and released following cleavage by caspase-1. Over the past 30 years, IL-1-mediated inflammation has been established in a broad spectrum of diseases, ranging from rare autoinflammatory diseases to common conditions such as gout and rheumatoid arthritis (RA), type 2 diabetes, atherosclerosis, and acute myocardial infarction. Blocking IL-1 entered the clinical arena with anakinra, the recombinant form of the naturally occurring IL-1 receptor antagonist (IL-1Ra); IL-1Ra prevents the binding of IL-1α as well as IL-1β to IL-1R1. Quenching IL-1-mediated inflammation prevents the detrimental consequences of tissue damage and organ dysfunction. Although anakinra is presently approved for the treatment of RA and cryopyrin-associated periodic syndromes, off-label use of anakinra far exceeds its approved indications. Dosing of 100 mg of anakinra subcutaneously provides clinically evident benefits within days and for some diseases, anakinra has been used daily for over 12 years. Compared to other biologics, anakinra has an unparalleled record of safety: opportunistic infections, particularly Mycobacterium tuberculosis, are rare even in populations at risk for reactivation of latent infections. Because of this excellent safety profile and relative short duration of action, anakinra can also be used as a diagnostic tool for undefined diseases mediated by IL-1. Although anakinra is presently in clinical trials to treat cancer, this review focuses on anakinra treatment of acute as well as chronic inflammatory diseases.

A comprehensive review on adult onset Still's disease

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder of unknown etiology usually affecting young adults; spiking fever, arthritis and evanescent rash are commonly observed during the disease. Other frequently observed clinical features include sore throat, hepatomegaly, splenomegaly, lymphadenopathy and serositis. Furthermore, AOSD patients may experience different life-threating complications. Macrophage activation syndrome (MAS) has been reported up to 15% of AOSD patients and it is considered to be the most severe complication of the disease being characterised by high mortality rate. During AOSD, laboratory tests reflect the systemic inflammatory process showing high levels of erythrocyte sedimentation rate and C-reactive protein. In addition, the ferritin levels are typically higher than those observed in other autoimmune, inflammatory, infectious, or neoplastic diseases. Analysing AOSD disease course, 3 different clinical patterns of AOSD have been identified: i. monocyclic pattern, characterised by a systemic single episode; ii. polycyclic pattern, characterised by multiple, ≤ 1 year lasting, flares, alternating with remissions; iii. chronic pattern, related to a persistently active disease with associated polyarthritis. At present, AOSD therapeutic strategy is aimed at targeting pro-inflammatory signs and symptoms, preventing organ damage and life-threating complications and minimising adverse effects of treatment. However, the treatment of AOSD remains largely empirical, lacking controlled clinical trials. High dosages of corticosteroids are usually the first line therapy when the systemic symptoms predominate. Despite this treatment, a large percentage of patients experiences several flares with an evolution toward the chronic disease course and up to 16% of patients die during the follow up, due to AOSD-related complications. On these bases, in the last years, biological agents have been successfully used in refractory cases. Finally, multiple recent lines of evidence have suggested new insights in AOSD pathogenesis unmasking further therapeutic targets. In fact, small molecules, used in experimental MAS models, might represent new therapeutic options.

Impaired autophagic flux and its related inflammation in patients with adult-onset Still's disease

The pathogenic role of autophagic immune regulation in adult-onset Still’s disease (AOSD) is unclear. We investigated the relative levels of autophagy in AOSD patients and healthy controls, its association with disease activity or course, and the change in autophagy after 6 months of therapy. Autophagosome levels were determined from the mean fluorescence intensity of autophagosomotropic dye incorporated into circulating immune cells. The fluorescent signal from lymphocytes, monocytes, and granulocytes from AOSD patients was greater than from controls. Levels of p62 fluorescence measured using flow cytometry in lymphocytes and granulocytes from AOSD patients was greater than in the corresponding cells from healthy controls. Expression of Atg5 and LC3-II mRNA and protein levels of p62 and LC3-II were elevated in AOSD patients. Moreover, AOSD activity scores correlated positively with autophagosome levels in monocytes and granulocytes, p62 levels in circulating immune cells, and levels of Beclin-1, Atg5, and LC3-II mRNA. Autophagosome levels and Atg mRNA expression decreased with disease remission in AOSD patients. Elevated autophagosome formation and p62 levels suggest impaired autophagic flux in AOSD.