Synergistic Signaling of TLR and IFNα/β Facilitates Escape of IL-18 Expression from Endotoxin Tolerance

A comprehensive insight into the immunomodulatory role of MSCs-derived exosomes (MSC-Exos) through modulating pattern-recognition receptors (PRRs)

Mesenchymal stem cell-derived exosomes (MSC-Exos) are emerging as remarkable agents in the field of immunomodulation with vast potential for diagnosing and treating various diseases, including cancer and autoimmune disorders. These tiny vesicles are laden with a diverse cargo encompassing proteins, nucleic acids, lipids, and bioactive molecules, offering a wealth of biomarkers and therapeutic options. MSC-Exos exhibit their immunomodulatory prowess by skillfully regulating pattern-recognition receptors (PRRs). They conduct a symphony of immunological responses, modulating B-cell activities, polarizing macrophages toward anti-inflammatory phenotypes, and fine-tuning T-cell activity. These interactions have profound implications for precision medicine, cancer immunotherapy, autoimmune disease management, biomarker discovery, and regulatory approvals. MSC-Exos promises to usher in a new era of tailored therapies, personalized diagnostics, and more effective treatments for various medical conditions. As research advances, their transformative potential in healthcare becomes increasingly evident.

Human NLRC4 expression promotes cancer survival and associates with type I interferon signaling and immune infiltration

The immune system can control cancer progression. However, even though some innate immune sensors of cellular stress are expressed intrinsically in epithelial cells, their potential role in cancer aggressiveness and subsequent overall survival in humans is mainly unknown. Here, we show that nucleotide-binding oligomerization domain-like receptor (NLR) family CARD domain-containing 4 (NLRC4) is downregulated in epithelial tumor cells of patients with colorectal cancer (CRC) by using spatial tissue imaging. Strikingly, only the loss of tumor NLRC4, but not stromal NLRC4, was associated with poor immune infiltration (mainly DCs and CD4+ and CD8+ T cells) and accurately predicted progression to metastatic stage IV and decrease in overall survival. By combining multiomics approaches, we show that restoring NLRC4 expression in human CRC cells triggered a broad inflammasome-independent immune reprogramming consisting of type I interferon (IFN) signaling genes and the release of chemokines and myeloid growth factors involved in the tumor infiltration and activation of DCs and T cells. Consistently, such reprogramming in cancer cells was sufficient to directly induce maturation of human DCs toward a Th1 antitumor immune response through IL-12 production in vitro. In multiple human carcinomas (colorectal, lung, and skin), we confirmed that NLRC4 expression in patient tumors was strongly associated with type I IFN genes, immune infiltrates, and high microsatellite instability. Thus, we shed light on the epithelial innate immune sensor NLRC4 as a therapeutic target to promote an efficient antitumor immune response against the aggressiveness of various carcinomas.

Tofacitinib for the treatment of severe rare skin diseases: a narrative review

PURPOSE

Autoimmune bullous diseases, connective tissue diseases, and vasculitis represent a group of severe rare skin diseases. While glucocorticoids and immunosuppressive agents serve as standard treatments for these diseases, their efficacy is limited due to adverse side effects, indicating the need for alternative approaches. Biologics have been used in the management of some rare skin diseases. However, the use of biologics is associated with concerns, such as infection risk and high costs, prompting the quest for efficacious and cost-effective alternatives. This study discusses the safety issues associated with tofacitinib and its potential in treating rare skin diseases.

METHODS

This narrative review focuses on the pharmacodynamic properties of tofacitinib and its impact on the JAK/STAT pathway. In addition, we present a comprehensive discussion of the effects and mechanism of action of tofacitinib for each severe rare skin disease.

RESULTS

This role of tofacitinib in treating severe rare skin diseases has been discussed, shedding light on its promising prospects as a treatment modality. Few reports of serious adverse events are available in patients treated with tofacitinib.

CONCLUSION

We explored the mechanism of action, efficacy, and safety considerations of tofacitinib and found that it can be used as a treatment option for rare skin diseases. However, multicenter clinical studies are needed to confirm the efficacy and safety of JAK inhibitors.

Biological and clinical roles of IL-18 in inflammatory diseases

Several new discoveries have revived interest in the pathogenic potential and possible clinical roles of IL-18. IL-18 is an IL-1 family cytokine with potent ability to induce IFNγ production. However, basic investigations and now clinical observations suggest a more complex picture. Unique aspects of IL-18 biology at the levels of transcription, activation, secretion, neutralization, receptor distribution and signalling help to explain its pleiotropic roles in mucosal and systemic inflammation. Blood biomarker studies reveal a cytokine for which profound elevation, associated with detectable 'free IL-18', defines a group of autoinflammatory diseases in which IL-18 dysregulation can be a primary driving feature, the so-called 'IL-18opathies'. This impressive specificity might accelerate diagnoses and identify patients amenable to therapeutic IL-18 blockade. Pathogenically, human and animal studies identify a preferential activation of CD8+ T cells over other IL-18-responsive lymphocytes. IL-18 agonist treatments that leverage the site of production or subversion of endogenous IL-18 inhibition show promise in augmenting immune responses to cancer. Thus, the unique aspects of IL-18 biology are finally beginning to have clinical impact in precision diagnostics, disease monitoring and targeted treatment of inflammatory and malignant diseases.

Treatment of systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (sJIA) is an inflammatory disease with hallmarks of severe systemic inflammation, which can be accompanied by arthritis. Contemporary scientific insights set this paediatric disorder on a continuum with its counterpart, adult-onset Still disease (AOSD). Patients with sJIA are prone to complications, including life-threatening hyperinflammation (macrophage activation syndrome (sJIA-MAS)) and sJIA-associated lung disease (sJIA-LD). Meanwhile, the treatment arsenal in sJIA has expanded markedly. State-of-the-art therapeutic approaches include biologic agents that target the IL-1 and IL-6 pathways. Beyond these, a range of novel agents are on the horizon, some of them already being used on a compassionate use basis, including JAK inhibitors and biologic agents that target IL-18, IFNγ, or IL-1β and IL-18 simultaneously. However, sJIA, sJIA-MAS and sJIA-LD still pose challenging conundrums to rheumatologists treating paediatric and adult patients worldwide. Although national and international consensus treatment plans exist for the treatment of 'classic' sJIA, the treatment approaches for early sJIA without arthritis, and for refractory or complicated sJIA, are not well defined. Therefore, in this Review we outline current approaches for the treatment of sJIA and provide an outlook on knowledge gaps.

Type I interferon signature and cycling lymphocytes in macrophage activation syndrome

BACKGROUNDMacrophage activation syndrome (MAS) is a life-threatening complication of Still's disease (SD) characterized by overt immune cell activation and cytokine storm. We aimed to further understand the immunologic landscape of SD and MAS.METHODWe profiled PBMCs from people in a healthy control group and patients with SD with or without MAS using bulk RNA-Seq and single-cell RNA-Seq (scRNA-Seq). We validated and expanded the findings by mass cytometry, flow cytometry, and in vitro studies.RESULTSBulk RNA-Seq of PBMCs from patients with SD-associated MAS revealed strong expression of genes associated with type I interferon (IFN-I) signaling and cell proliferation, in addition to the expected IFN-γ signal, compared with people in the healthy control group and patients with SD without MAS. scRNA-Seq analysis of more than 65,000 total PBMCs confirmed IFN-I and IFN-γ signatures and localized the cell proliferation signature to cycling CD38+HLA-DR+ cells within CD4+ T cell, CD8+ T cell, and NK cell populations. CD38+HLA-DR+ lymphocytes exhibited prominent IFN-γ production, glycolysis, and mTOR signaling. Cell-cell interaction modeling suggested a network linking CD38+HLA-DR+ lymphocytes with monocytes through IFN-γ signaling. Notably, the expansion of CD38+HLA-DR+ lymphocytes in MAS was greater than in other systemic inflammatory conditions in children. In vitro stimulation of PBMCs demonstrated that IFN-I and IL-15 - both elevated in MAS patients - synergistically augmented the generation of CD38+HLA-DR+ lymphocytes, while Janus kinase inhibition mitigated this response.CONCLUSIONMAS associated with SD is characterized by overproduction of IFN-I, which may act in synergy with IL-15 to generate CD38+HLA-DR+ cycling lymphocytes that produce IFN-γ.

Diagnosis and Management of the Systemic Juvenile Idiopathic Arthritis Patient with Emerging Lung Disease

Chronic lung disease in children with systemic juvenile idiopathic arthritis (SJIA-LD) is an emerging and potentially life-threatening disease complication. Despite recent descriptions of its clinical spectrum, preliminary immunologic characterization, and proposed hypotheses regaarding etiology, optimal approaches to diagnosis and management remain unclear. Here, we review the current clinical understanding of SJIA-LD, including the potential role of biologic therapy in disease pathogenesis, as well as the possibility of drug reactions with eosinophilia and systemic symptoms (DRESS). We discuss approaches to evaluation of children with suspected SJIA-LD, including a proposed algorithm to risk-stratify all SJIA patients for screening to detect LD early. We review potential pharmacologic and non-pharmacologic treatment approaches that have been reported for SJIA-LD or utilized in interstitial lung diseases associated with other rheumatic diseases. This includes lymphocyte-targeting therapies, JAK inhibitors, and emerging therapies against IL-18 and IFNγ. Finally, we consider urgent unmet needs in this area including in basic discovery of disease mechanisms and clinical research to improve disease detection and patient outcomes.

Molecular Pathways in the Pathogenesis of Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a rare childhood chronic inflammatory disorder with risk for life-threatening complications including macrophage activation syndrome and lung disease. At onset, sJIA pathogenesis resembles that of the autoinflammatory periodic fever syndromes with marked innate immune activation, expansion of neutrophils and monocytes, and high levels of interleukin-18. Here, we review the current conceptual understanding of sJIA pathogenesis with a focus on both innate and adaptive immune pathways. Finally, we consider how recent progress toward understanding the immunologic basis of sJIA may support new therapies for refractory disease courses.

Type 1 Interferon-Stimulated Gene Expression and Disease Activity in Pediatric Rheumatic Diseases: No Composite Scores Needed?

OBJECTIVE

Rheumatic diseases are characterized by different patterns of immune overactivation. This study investigated the correlation of whole blood type 1 interferon (IFN) stimulated gene (ISG), IL18, and CXCL9 expression with clinical disease activity in pediatric rheumatic diseases and assessed the required number of ISGs to be included in a composite type 1 IFN score.

METHODS

Whole blood-derived RNA and clinical data were collected from 171 mostly pediatric patients with connective tissue diseases (CTDs), systemic autoinflammatory diseases (SAIDs), monogenic interferonopathies (IFNPs) and other inflammatory diseases, and from 38 controls. The expression of six previously established ISGs, IL18, and CXCL9 was assessed by real-time polymerase chain reaction (471 samples). Individual and composite gene expression was assessed, and correlation and threshold analyses were performed.

RESULTS

Correlation between ISG expression and clinical disease activity was strongest in CTD, especially in juvenile dermatomyositis (JDM) and IFNP, and modest in patients with SAID. Threshold ISG expression levels for the detection of at least mild clinical disease activity were substantially higher in patients with systemic lupus erythematosus compared with JDM. The correlation of expression levels of limited sets of ISGs and even individual ISGs with clinical disease activity were not inferior to a composite score of six ISGs.

CONCLUSION

In a real-world cohort, individual ISG expression levels robustly reflected clinical disease activity in CTD and IFNP, especially in JDM, which would simplify such analyses in clinical routine and be more cost-effective. Threshold levels varied across diseases, potentially reflecting different mechanisms of type 1 IFN overactivation.

ATF4 knockdown in macrophage impairs glycolysis and mediates immune tolerance by targeting HK2 and HIF-1α ubiquitination in sepsis

Strengthened glycolysis is crucial for the macrophage pro-inflammatory response during sepsis. Activating transcription factor 4 (ATF4) plays an important role in regulating glucose and lipid metabolic homeostasis in hepatocytes and adipocytes. However, its immunometabolic role in macrophage during sepsis remains largely unknown. In the present study, we found that the expression of ATF4 in peripheral blood mononuclear cells (PBMCs) was increased and associated with glucose metabolism in septic patients. Atf4 knockdown specifically decreased LPS-induced spleen macrophages and serum pro-inflammatory cytokines levels in mice. Moreover, Atf4 knockdown partially blocked LPS-induced pro-inflammatory cytokines, lactate accumulation and glycolytic capacity in RAW264.7. Mechanically, ATF4 binds to the promoter region of hexokinase II (HK2), and interacts with hypoxia inducible factor-1α (HIF-1α) and stabilizes HIF-1α through ubiquitination modification in response to LPS. Furthermore, ATF4-HIF-1α-HK2-glycolysis axis launches pro-inflammatory response in macrophage depending on the activation of mammalian target of rapamycin (mTOR). Importantly, Atf4 overexpression improves the decreased level of pro-inflammatory cytokines and lactate secretion and HK2 expression in LPS-induced tolerant macrophages. In conclusion, we propose a novel function of ATF4 as a crucial glycolytic activator contributing to pro-inflammatory response and improving immune tolerant in macrophage involved in sepsis. So, ATF4 could be a potential new target for immunotherapy of sepsis.

JAK Inhibition in Juvenile Idiopathic Arthritis (JIA): Better Understanding of a Promising Therapy for Refractory Cases

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases with probably differential underlying physiopathology. Despite the revolutionary era of biologics, some patients remain difficult to treat because of disease severity, drug adverse events, drug allergy or association with severe comorbidities, i.e., uveitis, interstitial lung disease and macrophagic activation syndrome. Janus Kinase (JAK) inhibitors are small molecules that target JAK/Signal Transducers and Activators of Transcription (STAT) pathways, which could then prevent the activity of several proinflammatory cytokines. They may provide a useful alternative in these cases of JIA or in patients actually affected by Mendelian disorders mimicking JIA, such as type I interferonopathies with joint involvement, and might be the bridge for haematopoietic stem cell transplantation in these disabling conditions. As these treatments may have side effects that should not be ignored, ongoing and further controlled studies are still needed to provide data underlying long-term safety considerations in children and delineate subsets of JIA patients that will benefit from these promising treatments.

Parishin A-loaded mesoporous silica nanoparticles modulate macrophage polarization to attenuate tendinopathy

Macrophages are involved mainly in the balance between inflammation and tenogenesis during the healing process of tendinopathy. However, etiological therapeutic strategies to efficiently treat tendinopathy by modulating macrophage state are still lacking. In this study, we find that a small molecule compound Parishin-A (PA) isolated from Gastrodia elata could promote anti-inflammatory M2 macrophage polarization by inhibiting gene transcription and protein phosphorylation of signal transducers and activators of transcription 1. Local injection or sustained delivery of PA by mesoporous silica nanoparticles (MSNs) could almost recover the native tendon's dense parallel-aligned collagen matrix in collagenase-induced tendinopathy by modulating macrophage-mediated immune microenvironment and preventing heterotopic ossification. Especially, MSNs decrease doses of PA, frequency of injection and yield preferable therapeutic effects. Mechanistically, intervention with PA could indirectly inhibit activation of mammalian target of rapamycin to repress chondrogenic and osteogenic differentiation of tendon stem/progenitor cells by influencing macrophage inflammatory cytokine secretion. Together, pharmacological intervention with a natural small-molecule compound to modulate macrophage status appears to be a promising strategy for tendinopathy treatment.

Immune dysregulation

The understanding of immune dysregulation in many different diseases continues to grow. There is increasing evidence that altered microbiome and gut barrier dysfunction contribute to systemic inflammation in patients with primary immunodeficiency and in patients with rheumatic disease. Recent research provides insight into the process of induction and maturation of pathogenic age-associated B cells and highlights the role of age-associated B cells in creating tissue inflammation. T follicular regulatory cells are shown to help maintain B-cell tolerance, and therapeutic approaches to increase or promote T follicular regulatory cells may help prevent or decrease immune dysregulation. Meanwhile, novel studies of systemic-onset juvenile idiopathic arthritis reveal a strong HLA association with interstitial lung disease and identify key aspects of the pathogenesis of macrophage activation syndrome. Studies of hyperinflammatory syndromes, including the recently described multisystem inflammatory syndrome of children, characterize similarities and differences in cytokine profiles and T-cell activation. This review focuses on recent advances in the understanding of immune dysregulation and describes potential key factors that may function as biomarkers for disease or targets for therapeutic interventions. Future trials are necessary to address the many remaining questions with regards to pathogenesis, diagnosis, and treatment of autoimmune, inflammatory, and immunodeficiency syndromes.

[Clinical analysis of 5 cases of dermatomyositis complicated with macrophage activation syndrome]

To investigate the clinical and immunological features of dermatomyositis (DM) complicated with macrophage activation syndrome (MAS). The demographic and clinical characteristics of five patients diagnosed with DM complicated with MAS hospitalized in the Department of Rheumatology and Immunology, Peking University People ' s Hospital from 2011 to 2021 were collected. The results of clinical manifestations, laboratory tests, immunological features, treatments and prognosis were analyzed and summarized. In this study, five female patients in Peking University People's Hospital with an average age of 63.8 (44.0-83.0) years and an average disease duration of 16.1 (1.5-48.0) months. All the patients had typical DM rash (such as heliotrope sign, V/shawl sign or Gottron's sign/papules). They all had muscle involvement (including myalgia or muscle weakness). Two patients had positive myositis-specific antibodies (MSAs), in which case 1 had anti-TIF1-γ antibody and case 5 had anti-NXP-2 antibody. Four patients had interstitial lung disease except case 3. All of the cases developed MAS in the active stage of DM. Common manifestations of MAS in these five patients included high-grade fever, cytopenia, decreased fibrinogen, elevated ferritin and increased soluble CD25. Case 1 presented with neutropenia (0.6×10⁹ /L), thrombocytopenia (26.0×10⁹ /L), hypofibrinogenemia (0.9 g/L), markedly elevated ferritin (26 331.0 μg/L), decreased NK cell activity. Case 2 had anaemia (hemoglobin 81.0 g/L), thrombocytopenia (55.0×10⁹ /L), hypertriglyceridemia (4.7 mmol/L), hypofibrinogenemia (1.2 g/L), elevated ferritin (>100 000.0 μg/L), hemophagocytosis in bone marrow. Case 3 had anaemia (hemoglobin 88 g/L), decreased fibrinogen (1.9 g/L), increased ferritin (>27 759.0 μg/L), splenomegaly, hemophagocytosis in bone marrow. Case 4 suffered from neutropenia(0.3×10⁹ /L), anaemia(hemoglobin 78 g/L), hypertriglyceridemia (4.2 mmol/L), hypofibrinogenemia (0.9 g/L), increased ferritin (>100 000.0 μg/L), and decreased NK cell activity. Case 5 presented anaemia (hemoglobin 60.0 g/L), thrombocytopenia (67.0×10⁹ /L), hypertriglyceridemia (12.7 mmol/L), decreased fibrinogen (1.1 g/L), and elevated ferritin (>923.0 μg/L). All the patients were treated with methylprednisone pulse therapy (200-500 mg) combined with cyclosporine while case 5 received rituximab after methylprednisone pulses. In addition, case 3 also received the combination of mycophenolate mofetil. Case 1 was given etoposide while case 4 was treated with cyclophosphamide and repeated plasmapheresis at the same time. Moreover, intravenous immunoglobulin was added meantime apart from case 3. The condition of four patients improved significantly, nevertheless case 4 experienced recurred pulmonary symptoms and died of respiratory failure. As for complications about infection, case 2 had bacterial infection with high level procalcitonin (PCT) before MAS treatment and condition was improved after empiric antibacterial therapy. Case 3 had cytomegalovirus DNAemia before diagnosis of MAS and viral titer turned negative after ganciclovir therapy. After treatment of MAS, four patients developed cytomegalovirus DNAemia except case 3, in which case 5 was co-infected with bacteria. To sum, DM complicated with MAS is relatively rare, and its patients are of ten in life-threatening condition. Early detection, treatment and prevention of infection during treatment are critical to improve the prognosis.

Lung Involvement in Systemic Juvenile Idiopathic Arthritis: A Narrative Review

Systemic juvenile idiopathic arthritis associated with lung disorders (sJIA-LD) is a subtype of sJIA characterized by the presence of chronic life-threatening pulmonary disorders, such as pulmonary hypertension, interstitial lung disease, pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia, which were exceptionally rare before 2013. Clinically, these children show a striking dissociation between the relatively mild clinical manifestations (tachypnoea, clubbing and chronic cough) and the severity of the pulmonary inflammatory process. Our review describes sJIA-LD as having a reported prevalence of approximately 6.8%, with a mortality rate of between 37% and 68%. It is often associated with an early onset (<2 years of age), macrophage activation syndrome and high interleukin (IL)-18 circulating levels. Other risk factors may be trisomy 21 and a predisposition to adverse reactions to biological drugs. The most popular hypothesis is that the increase in the number of sJIA-LD cases can be attributed to the increased use of IL-1 and IL-6 blockers. Two possible explanations have been proposed, named the “DRESS hypothesis” and the “cytokine plasticity hypothesis”. Lung ultrasounds and the intercellular-adhesion-molecule-5 assay seem to be promising tools for the early diagnosis of sJIA-LD, although high resolution computed tomography remains the gold standard. In this review, we also summarize the treatment options for sJIA-LD, focusing on JAK inhibitors.

Identification of Monocytes Associated with Severe COVID-19 in the PBMCs of Severely Infected Patients Through Single-Cell Transcriptome Sequencing

Understanding the immunological characteristics of monocytes-including the characteristics associated with fibrosis-in severe coronavirus disease 2019 (COVID-19) is crucial for understanding the pathogenic mechanism of the disease and preventing disease severity. In this study, we performed single-cell transcriptomic sequencing of peripheral blood samples collected from six healthy controls and 14 COVID-19 samples including severe, moderate, and convalescent samples from three severely/critically ill and four moderately ill patients. We found that the monocytes were strongly remodeled in the severely/critically ill patients with COVID-19, with an increased proportion of monocytes and seriously reduced diversity. In addition, we discovered two novel severe-disease-specific monocyte subsets: Mono 0 and Mono 5. These subsets expressed amphiregulin (AREG), epiregulin (EREG), and cytokine interleukin-18 (IL-18) gene, exhibited an enriched erythroblastic leukemia viral oncogene homolog (ErbB) signaling pathway, and appeared to exhibit pro-fibrogenic and pro-inflammation characteristics. We also found metabolic changes in Mono 0 and Mono 5, including increased glycolysis/gluconeogenesis and an increased hypoxia inducible factor-1 (HIF-1) signaling pathway. Notably, one pre-severe sample displayed a monocyte atlas similar to that of the severe/critical samples. In conclusion, our study discovered two novel severe-disease-specific monocyte subsets as potential predictors and therapeutic targets for severe COVID-19. Overall, this study provides potential predictors for severe disease and therapeutic targets for COVID-19 and thus provides a resource for further studies on COVID-19.

Oral Sabizabulin for High-Risk, Hospitalized Adults with Covid-19: Interim Analysis

BACKGROUND: Sabizabulin is an oral, novel microtubule disruptor that has dual antiviral and anti-inflammatory activities in preclinical models. METHODS: A randomized, multicenter placebo-controlled phase 3 clinical trial was conducted with hospitalized patients with moderate to severe Covid-19 who were at high risk for acute respiratory distress syndrome (ARDS) and death. Patients were randomly assigned (2:1) to 9 mg of oral sabizabulin or placebo daily (up to 21 days). The primary end point was all-cause mortality up to day 60. Key secondary end points were days in the intensive care unit (ICU), days on mechanical ventilation, and days in the hospital. RESULTS: A total of 204 patients were randomly assigned to treatment: 134 to sabizabulin and 70 to placebo. Baseline characteristics were similar. Sabizabulin superiority was demonstrated by a planned interim analysis for the first 150 randomized patients. Sabizabulin treatment resulted in a 24.9 percentage point absolute reduction and a 55.2% relative reduction in deaths compared with placebo (odds ratio, 3.23; 95% CI confidence interval, 1.45 to 7.22; P=0.0042). The mortality rate was 20.2% (19 of 94) for sabizabulin versus 45.1% (23 of 51) for placebo. For the key secondary end points, sabizabulin treatment resulted in a 43% relative reduction in ICU days (P=0.0013), a 49% relative reduction in days on mechanical ventilation (P=0.0013), and a 26% relative reduction in days in the hospital (P=0.0277) versus placebo. Adverse and serious adverse events were lower in the sabizabulin group compared with the placebo group. CONCLUSIONS: Sabizabulin treatment resulted in a 24.9% absolute reduction in deaths compared with placebo in hospitalized patients with moderate to severe Covid-19 at high risk for ARDS and death, with a lower incidence of adverse and serious adverse events compared with placebo. (Funded by Veru, Inc.; ClinicalTrials.gov number, NCT04842747.)

JAK inhibitors in difficult-to-treat adult-onset Still's disease and systemic-onset juvenile idiopathic arthritis

OBJECTIVES

Excessive and inappropriate production of pro-inflammatory cytokines plays a key role in Still's disease. JAK inhibitor (JAKi) agents mainly block pro-inflammatory cytokine pathways, notably IL-6 and IFN. The objective was to assess the efficacy and safety of JAKi agents in difficult-to-treat systemic juvenile idiopathic arthritis (SJIA) or adult-onset Still's disease (AOSD).

METHODS

This retrospective study was based on a national survey conducted in the departments of rheumatology, paediatric rheumatology and internal medicine of French hospitals regarding SJIA and AOSD patients who received JAKi agents. The data were collected with a standardised questionnaire and analysed at different times (treatment initiation, months 1, 3, and 6 and the end of follow-up).

RESULTS

Nine patients (7 adults) were included. All patients showed inadequate response to corticosteroids or conventional synthetic or biologic disease-modifying anti-rheumatic drugs. Baricitinib was used in 5 patients, ruxolitinib in 2, tofacitinib in 2, and upadacitinib in 1. A JAKi was used combined with corticosteroids in all but 2 patients. A JAKi was associated with anakinra and corticosteroids in one patient, and with methotrexate, anakinra and corticosteroids in another. The median follow-up was 16 [1-33] months. Two cases out 9 showed complete remission, 3/9 partial response and 4/9 treatment failure. At the last visit, corticosteroids could be decreased but not stopped. Tolerance of the JAKi was acceptable (no severe adverse events).

CONCLUSION

JAKi agents may be a therapeutic option for some patients with difficult-to-treat Still's disease, especially those with partial response to medium- or high-dose corticosteroids or biologics.

Infection-Triggered Hyperinflammatory Syndromes in Children

An association between infectious diseases and macrophage activation syndrome (MAS) has been reported, yet the exact role of infection in MAS development is still unclear. Here, a retrospective analysis of the clinical records of patients with rheumatic diseases complicated with MAS who were treated in a pediatric tertiary care center between 2011 and 2020 was performed. Any infection documented within the 30 days preceding the onset of MAS was reported. Out of 125 children in follow-up for systemic rheumatic diseases, 12 developed MAS, with a total of 14 episodes. One patient experienced three episodes of MAS. Clinical and/or laboratory evidence of infection preceded the onset of MAS in 12 events. Clinical features, therapeutic strategies, and patient outcomes were described. The aim of this study was to evaluate the possible role of infection as a relevant trigger for MAS development in children with rheumatic conditions. The pathogenetic pathways involved in the cross-talk between uncontrolled inflammatory activity and the immune response to infection deserve further investigation.

Causal Biological Network Model for Inflammasome Signaling Applied for Interpreting Transcriptomic Changes in Various Inflammatory States

Virtually any stressor that alters the cellular homeostatic state may result in an inflammatory response. As a critical component of innate immunity, inflammasomes play a prominent role in the inflammatory response. The information on inflammasome biology is rapidly growing, thus creating the need for structuring it into a model that can help visualize and enhance the understanding of underlying biological processes. Causal biological network (CBN) models provide predictive power for novel disease mechanisms and treatment outcomes. We assembled the available literature information on inflammasome activation into the CBN model and scored it with publicly available transcriptomic datasets that address viral infection of the lungs, osteo- and rheumatoid arthritis, psoriasis, and aging. The scoring inferred pathway activation leading to NLRP3 inflammasome activation in these diverse conditions, demonstrating that the CBN model provides a platform for interpreting transcriptomic data in the context of inflammasome activation.

Cardiovascular Risk After SARS-CoV-2 Infection Is Mediated by IL18/IL18R1/HIF-1 Signaling Pathway Axis

Objectives

Currently, cardiovascular risk associated with COVID-19 has been brought to people's attention, but the mechanism is not clear. The aim of this study is to elucidate the mechanisms based on multiple omics data.

Methodology

Weighted gene co-expression network analysis (WGCNA) was used to identify key pathways. Combination analysis with aneurysm and atherosclerosis related pathways, hypoxia induced factor-1 (HIF-1) signaling were identified as key pathways of the increased cardiovascular risk associated with COVID-19. ScMLnet algorithm based on scRNA-seq was used to explore the regulation of HIF-1 pathway by intercellular communication. Proteomic analysis was used to detect the regulatory mechanisms between IL18 and HIF-1 signaling pathway. Pseudo time locus analysis was used to study the regulation of HIF1 signaling pathway in macrophages and vascular smooth muscle cells (VSMC) phenotypic transformation. The Virtual Inference of protein-activity by Enriched Regulon (VIPER) analysis was used to study the activity of regulatory proteins. Epigenetic analysis based on methylation revealed epigenetic changes in PBMC after SARS-CoV-2 infection. Potential therapeutic compounds were explored by using Cmap algorithm.

Results

HIF-1 signaling pathway is a common key pathway for aneurysms, atherosclerosis and SARS-CoV-2 infection. Intercellular communication analysis showed that macrophage-derived interleukin-18 (IL-18) activates the HIF-1 signaling pathway through IL18R1. Proteomic analysis showed that IL18/IL18R1 promote NF-κB entry into the nucleus, and activated the HIF-1 signaling pathway. Macrophage-derived IL18 promoted the M1 polarization of macrophages and the syntactic phenotype transformation of VSMCs. MAP2K1 mediates the functional regulation of HIF-1 signaling pathway in various cell types. Epigenetic changes in PBMC after COVID-19 infection are characterized by activation of the type I interferon pathway. MEK inhibitors are the promising compounds for the treatment of HIF-1 overactivation.

Conclusions

The IL18/IL18R1/HIF1A axis is expected to be an therapeutic target for cardiovascular protection after SARS-CoV-2 infection. MEK inhibitors may be an choice for cardiovascular protection after SARS-COV-2 infection.

Short-term effectiveness of baricitinib in children with refractory and/or severe juvenile dermatomyositis

OBJECTIVE

To determine the short-term effectiveness safety of baricitinib in children with refractory and/or severe juvenile dermatomyositis (rsJDM) in a real-world setting.

METHODS

This was a single-center retrospective study, including 20 children with rsJDM. They were all treated using baricitinib combined with steroids and other immunosuppressive agents. The childhood myositis assessment scale (CMAS) and PRINTO remission criteria were used to evaluate the disease severity and treatment outcome at 0, 4, 12, and 24 weeks after initiation of baricitinib.

RESULTS

The skin rash improved in 95% of patients (19/20) at week 24, with a significant decrease of skin-DAS at weeks 12 (6.0 vs. 2.0, p < 0.05] and week 24 [6.0 vs. 1.0, p < 0.05) by median statistics. The CMAS score increased significantly at week 12 (41.0 [29.0, 44.0] vs. 46.0 [42.0, 52.0], p < 0.05) and week 24 (41.0 [29.0, 44.0] vs. 50.0 [45.0, 52.0], p < 0.05), as did the manual muscle testing (MMT)-8 score at week 24 (73.0 [610, 76.0] vs. 79.0 [77.0, 80.0], p < 0.05). At 24 weeks, the complete response (CR) and partial response (PR) were achieved in 75% (15/20) and 15% (3/20), respectively. The dose of corticosteroids (CS) decreased by 37% from the baseline (0.53 [0.42, 1.00] mg/kg) to week 12 (0.33 [0.18, 0.40] mg/kg) (p < 0.05), and by 49% at week 24 (p < 0.05). No serious side effects were observed.

CONCLUSION

Baricitinib combined with traditional immunosuppressants treatment was efficacious in rsJDM. Add-on therapy of baricitinib was helpful for tapering CS dose. No serious side effects were observed in this study.

Pathogenesis and Treatment of Refractory Disease Courses in Systemic Juvenile Idiopathic Arthritis: Refractory Arthritis, Recurrent Macrophage Activation Syndrome and Chronic Lung Disease

Systemic juvenile idiopathic arthritis is a distinct and heterogeneous disease presently classified under the umbrella of juvenile idiopathic arthritis, with some patients following a monophasic remitting course, whereas others have persistent disease with chronic organ- and life-threatening complications. Although biologic therapies have revolutionized treatment, recent follow-up studies report significant numbers of children with persistently active disease on long term follow-up. This review focuses on refractory disease courses, specifically refractory arthritis, systemic juvenile idiopathic arthritis with recurrent, or longstanding signs of macrophage activation syndrome, and systemic juvenile idiopathic arthritis associated with suspected, probable, or definite lung disease.

Interfering with interferons: targeting the JAK-STAT pathway in complications of systemic juvenile idiopathic arthritis (SJIA)

Systemic JIA (SJIA) is distinguished from other forms of JIA by the prevalence of the severe, life-threatening complications macrophage activation syndrome (SJIA-MAS) and lung disease (SJIA-LD). Alternative therapeutics are urgently needed, as disease pathogenesis diverges from what is observed in SJIA, and currently available biologics are insufficient. SJIA-MAS, defined by a cytokine storm and dysregulated proliferation of T-lymphocytes, and SJIA-LD which presents with lymphocytic interstitial inflammation and pulmonary alveolar proteinosis, are both thought to be driven by IFNs, in particular the type II IFN-γ. Involvement of IFNs and a possible crosstalk of type I IFNs with existing biologics indicate a distinct role for the JAK-STAT signalling pathway in the pathogenesis of SJIA-MAS and SJIA-LD. Here, we review this role of JAK-STATs and IFNs in SJIA complications and discuss how new insights of ongoing research are shaping future therapeutic advances in the form of JAK inhibitors and antibodies targeting IFNs.

Definition and validation of serum biomarkers for optimal differentiation of hyperferritinaemic cytokine storm conditions in children: a retrospective cohort study

BACKGROUND

Cytokine storm syndromes are life-threatening complications that can occur in children with rheumatic conditions (macrophage activation syndrome [MAS]), inherited cytotoxicity defects (ie, primary haemophagocytic lymphohistiocytosis [HLH]), or as a result of infection or malignancies (ie, secondary HLH). To adequately steer treatment, an early and clear discrimination of these entities is essential. We aimed to define and validate serum biomarker profiles that can differentiate between primary HLH, secondary HLH (predominantly infection-associated), and MAS associated with systemic juvenile idiopathic arthritis (systemic JIA-MAS).

METHODS

In this multicentre, retrospective, cohort study, serum samples from patients (0-18 years) with a clinical diagnosis of primary HLH, secondary HLH, or systemic JIA-MAS were analysed by immunoassays for 55 cytokines and chemokines. Serum samples were collected from patients treated at seven clinical centres in Europe and North America. 15 serum biomarkers were validated using an independent commercial assay, and the diagnostic accuracy of the best performing biomarkers was tested in an independent validation cohort.

FINDINGS

Serum samples were collected between Dec 7, 2010, and Jan 26, 2018. In the discovery cohort of 43 patients (24 girls and 19 boys) multi-marker analyses revealed distinct serum biomarker profiles associated with primary or secondary HLH versus systemic JIA-MAS. Ten biomarkers were identified that were differentially elevated in either HLH or systemic JIA-MAS and distinguished between these clinical entities, six of which were tested in an independent validation cohort of 79 patients (34 girls and 45 boys). Serum concentrations of S100A12 and interleukin-18, as well as ratios of both S100A12 and IL-18 with chemokine (C-X-C motif) ligand (CXCL)9 and CXCL10 were identified as the most promising candidates for differential diagnostics.

INTERPRETATION

At initial presentation, when it is unclear whether a patient with excessive hyperferritinaemic inflammation has primary HLH, infection-associated secondary HLH, or MAS, high serum concentrations of S100A12 indicate an initial differential diagnosis of systemic JIA-MAS, thus helping to guide subsequent treatment decisions. We therefore suggest the inclusion of serum S100A12 and IL-18 in the diagnostic investigations for hyperferritinaemic syndromes; however, the definition and introduction of universially applicable cutoff values are still required.

FUNDING

German Research Foundation, the Center for Interdisciplinary Clinical Research at University Hospital Muenster, the EU's Horizon 2020 research and innovation programme, and the Deutsche Kinderkrebsstiftung.

Biomarker screening and validation for the differentiation of bloodstream infection from adult-onset Still's disease: A prospective cohort study

OBJECTIVES

Distinguishing between bloodstream infection (BSI) and adult-onset Still's disease (AOSD) is challenging in practice due to similarities in their clinical and laboratory characteristics. We aimed to identify biomarkers in a prospective cohort of patients with BSI and AOSD for differential diagnosis and prognosis prediction.

METHODS

Sixty-four individuals were enrolled in the training set (37 with BSI, 17 with AOSD, and 10 healthy controls). Furthermore, 86 individuals were enrolled in the validation cohort (67 with BSI and 19 with AOSD). Clinical and laboratory data were collected. Blood samples were stimulated using bacteria-specific antigens and levels of several cytokines were detected in the supernatant via Luminex or enzyme-linked immunosorbent assay.

RESULTS

Escherichia coli and Klebsiella pneumoniae were the pathogens most frequently responsible for BSI. In the training cohort, the incidence of rash, arthralgia, myalgia, sore throat, lymphadenopathy, leukocytosis, and hyperferritinemia was higher in patients with AOSD than in those with BSI. Procalcitonin was significantly higher in patients with BSI than that in those with AOSD. Interleukin (IL)-6, IL-17A, C-X3-C motif chemokine ligand (CX3CL)-1, and C-X-C motif chemokine ligand 10 (CXCL10) levels were higher in patients with BSI than in those with AOSD. IL-18 was higher among patients with AOSD than in those with BSI. A decision tree analysis showed that a combination of plasma IL-18 and ferritin levels can be used to distinguish BSI from AOSD (diagnostic accuracy: 97.67%, sensitivity: 96.15%, specificity: 100%). Plasma IL-18 levels were positively correlated with ferritin, and were decreased after treatment in both BSI and ASOD groups.

CONCLUSIONS

Plasma IL-18 and ferritin levels can be used to differentiate BSI from AOSD. IL-18 may be a potential biomarker for prognosis prediction in BSI and AOSD.

Analysis of Autophagy-Related Signatures Identified Two Distinct Subtypes for Evaluating the Tumor Immune Microenvironment and Predicting Prognosis in Ovarian Cancer

Ovarian cancer (OC) is one of the most lethal gynecologic malignant tumors. The interaction between autophagy and the tumor immune microenvironment has clinical importance. Hence, it is necessary to explore reliable biomarkers associated with autophagy-related genes (ARGs) for risk stratification in OC. Here, we obtained ARGs from the MSigDB database and downloaded the expression profile of OC from TCGA database. The k-means unsupervised clustering method was used for clustering, and two subclasses of OC (cluster A and cluster B) were identified. SsGSEA method was used to quantify the levels of infiltration of 24 subtypes of immune cells. Metascape and GSEA were performed to reveal the differential gene enrichment in signaling pathways and cellular processes of the subtypes. We found that patients in cluster A were significantly associated with higher immune infiltration and immune-associated signaling pathways. Then, we established a risk model by LASSO Cox regression. ROC analysis and Kaplan-Meier analysis were applied for evaluating the efficiency of the risk signature, patients with low-risk got better outcomes than those with high-risk in overall survival. Finally, ULK2 and GABARAPL1 expression was further validated in clinical samples. In conclusion, Our study constructed an autophagy-related prognostic indicator, and identified two promising targets in OC.

Synergistic inflammatory signaling by cGAS may be involved in the development of atherosclerosis

Inappropriate activation or overactivation of cyclic GMP-AMP synthase (cGAS) by double-stranded deoxyribonucleic acid (dsDNA) initiates a regulatory signaling cascade triggering a variety of inflammatory responses, which are a great threat to human health. This study focused on identifying the role of cGAS in atherosclerosis and its potential mechanisms. The relationship between cGAS and atherosclerosis was identified in an ApoE ^-/- mouse model. Meanwhile, RNA sequencing (RNA-seq) analysis of the underlying mechanisms of atherosclerosis in RAW264.7 macrophages treated with cGAS inhibition was conducted. Results showed that cGAS was positively correlated with atherosclerotic plaque area, and was mainly distributed in macrophages. RNA-seq analysis revealed that inflammatory response, immune response and cytokine–cytokine receptor interaction may play important roles in the development of atherosclerosis. Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression of the pro-inflammatory factors, signal transducer and activator of transcription (Stat), interferon regulatory factor (Irf), toll-like receptors (Tlrs), and type I interferons (Ifns) were synergistically reduced when cGAS was inhibited. Furthermore, cGAS inhibition significantly inhibited RAW264.7 macrophage M1 polarization. These results demonstrate that cGAS may contribute to the development of atherosclerosis through synergistic inflammatory signaling of TLRs, STAT/IRF as well as IFNs, leading to macrophage M1 polarization.

Systemic juvenile idiopathic arthritis and recurrent macrophage activation syndrome due to a CASP1 variant causing inflammasome hyperactivation

OBJECTIVES

We investigated a patient with systemic juvenile idiopathic arthritis (sJIA) and recurrent macrophage activation syndrome (MAS) to discover genetic and immunological contributing factors.

METHODS

Severe recurrent MAS motivated whole exome sequencing (WES) to identify genetic variants potentially involved in disease pathogenesis. In vitro peripheral blood mononuclear cell (PBMC) stimulations for cytokine expression and caspase-1 activity assays as well as NF-κB reporter luciferase assays were performed to functionally characterize variants.

RESULTS

WES revealed an extremely rare heterozygous missense variant, c.482G>A, p.R161H in the CASP1 gene encoding pro-caspase-1. Lipopolysaccharide (LPS) stimulation of patient PBMCs induced high levels of IL-6 compared to controls, and activation of the NLRP3 inflammasome resulted in increased production of IL-1β and IL-18 as well as significantly elevated caspase-1 activity. Constitutive and inducible levels of IL-18 and IFNγ in whole blood were markedly elevated. Expression of the CASP1 variant in an NF-κB reporter luciferase assay induced increased NF-κB activation in a RIP2-dependent manner. The disease course of the patient was complicated by severe recurrent MAS. However, dual IL-1 and IL-6 blockade caused disease remission.

CONCLUSION

For the first time, we demonstrate the involvement of a CASP1 variant in sJIA and recurrent MAS. This variant is gain-of-function for both inflammasome and NF-κB activation leading to increased production of IL-6, IL-1β and IL-18. Although dual IL-1 and IL-6 blockade may be beneficial in patients, in whom single treatment is not sufficient to control MAS, caution should be practiced, since interstitial lung disease may progress despite apparent clinical and biochemical remission.

Distinct Gene Expression Signatures Characterize Strong Clinical Responders Versus Nonresponders to Canakinumab in Children With Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

Canakinumab is a human anti-interleukin-1β (anti-IL-1β) blocking agent that effectively neutralizes IL-1β-mediated signaling for treatment of systemic juvenile idiopathic arthritis (JIA). While many patients have dramatic clinical response to IL-1 blockade, approximately one-third fail to respond, but there are currently no validated clinical or immunologic predictors of response. We undertook this study to characterize distinct gene signatures for treatment response and nonresponse to canakinumab in systemic JIA patients.

METHODS

We performed a secondary analysis of whole-blood gene expression microarrays using blood samples obtained from healthy controls and systemic JIA patients at baseline and on day 3 after canakinumab treatment (GEO accession no. GSE80060). Patients were considered strong clinical responders if they met the ACR90 response (exhibited ≥90% improvement in the American College of Rheumatology [ACR] JIA response criteria; nonresponders were those who met ACR30 [exhibiting ≤30% improvement in the ACR JIA response criteria]). A random-effects model with patient identity as the random variable was used for differential expression analysis.

RESULTS

We identified a distinct gene expression signature in patients with a strong clinical response to canakinumab treatment as compared to nonresponders, mediated by up-regulation of neutrophil- and IL-1-associated genes and characterized by increasing divergence from control transcriptomes with increasing clinical response. We also identified a signature including up-regulated CD163 expression that was associated with canakinumab nonresponse. Intriguingly, canakinumab treatment induced either up- or down-regulation of type I interferon (IFN) genes, independent of clinical response.

CONCLUSION

Here, we identify a gene signature in systemic JIA patients prior to receiving treatment that distinguishes strong responders to canakinumab from nonresponders. Further prospective studies are needed to assess the utility of these insights for treatment decisions in systemic JIA and to track the association of up-regulated type I IFN signatures with systemic JIA complications.

Understanding of cytokines and targeted therapy in macrophage activation syndrome

Macrophage activation syndrome (MAS) is a potentially life-threatening complication of systemic autoinflammatory/autoimmune diseases, generally systemic juvenile idiopathic arthritis and adult-onset Still's disease. It is characterized by an excessive proliferation of macrophages and T lymphocytes. Recent research revealed that cytokine storm with elevated pro-inflammatory cytokines, including IFN-γ, IL-18, and IL-6, may be central to the pathogenesis of MAS. Though the mainstream of MAS treatment remains corticosteroids and cyclosporine, targeted therapies with anti-cytokine biologics are reported to be promising for controlling systemic inflammation in MAS.

[Successful treatment of adult Still's disease with tofacitinib in a HIV-2 positive female patient]

A 46-year-old female patient with a known HIV-2-infection suffered from adult onset Still's disease, which was initially complicated by a macrophage activation syndrome (MAS). The required glucocorticoid treatment induced a psychosis and the patient developed an aversion to glucocorticoids. After failure of treatment with anakinra, an alternative option with the JAK-inhibitor tofacitinib was introduced because of the short half-life and to reduce glucocorticoid exposure. A switch to tofacitinib was only successful after an overlapping treatment with anakinra and tofacitinib for 3 weeks. The patient is currently being treated with monotherapy with tofacitinib as well as NSAID on demand, is in stable remission and can continue working as normal.

Transcriptional Regulation of Inflammasomes

Inflammasomes are multimolecular complexes with potent inflammatory activity. As such, their activity is tightly regulated at the transcriptional and post-transcriptional levels. In this review, we present the transcriptional regulation of inflammasome genes from sensors (e.g., NLRP3) to substrates (e.g., IL-1β). Lineage-determining transcription factors shape inflammasome responses in different cell types with profound consequences on the responsiveness to inflammasome-activating stimuli. Pro-inflammatory signals (sterile or microbial) have a key transcriptional impact on inflammasome genes, which is largely mediated by NF-κB and that translates into higher antimicrobial immune responses. Furthermore, diverse intrinsic (e.g., circadian clock, metabolites) or extrinsic (e.g., xenobiotics) signals are integrated by signal-dependent transcription factors and chromatin structure changes to modulate transcriptionally inflammasome responses. Finally, anti-inflammatory signals (e.g., IL-10) counterbalance inflammasome genes induction to limit deleterious inflammation. Transcriptional regulations thus appear as the first line of inflammasome regulation to raise the defense level in front of stress and infections but also to limit excessive or chronic inflammation.

Innately Adaptive or Truly Autoimmune: Is There Something Unique About Systemic Juvenile Idiopathic Arthritis?

Systemic juvenile idiopathic arthritis (JIA) is a form of arthritis in childhood that is initially dominated by innate immunity-driven systemic inflammation and is thus considered a polygenic autoinflammatory disease. However, systemic JIA can progress toward an adaptive immunity-driven afebrile arthritis. Based on this observation of biphasic disease progression, a "window of opportunity" for optimal, individualized and target-directed treatment has been proposed. This hypothesis requires testing, and in this review we summarize current evidence regarding molecular factors that may contribute to the progression from an initially predominantly autoinflammatory disease phenotype to autoimmune arthritis. We consider the involvement of innately adaptive γδ T cells and natural killer T cells that express γδ or αβ T cell receptors but cannot be classified as either purely innate or adaptive cells, versus classic B and T lymphocytes in this continuum. Finally, we discuss our understanding of how and why some primarily autoinflammatory conditions can progress toward autoimmune-mediated disorders over the disease course while others do not and how this knowledge may be used to offer individualized treatment.