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

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

mCRP as a Biomarker of Adult-Onset Still's Disease: Quantification of mCRP by ELISA.

Background: C-reactive protein (CRP) is a dynamic protein that undergoes conformational changes between circulating native pentameric CRP (pCRP), pentameric symmetrical forms (pCRP*) and monomeric (or modified) CRP (mCRP) forms. mCRP exhibits strong pro-inflammatory activity and activates platelets, leukocytes, and endothelial cells. Abundant deposition of mCRP in inflamed tissues plays a role in several disease conditions, such as ischemia/reperfusion injury, Alzheimer's disease, and cardiovascular disease. Although pCRP is typically quantified rather than mCRP for clinical purposes, mCRP may be a more appropriate disease marker of inflammatory diseases. Therefore, simple methods for quantifying mCRP are needed. Methods: We developed a specific enzyme-linked immunosorbent assay (ELISA) to measure plasma levels of mCRP. Plasma mCRP concentration was measured in patients with adult-onset Still's disease (AOSD) (n=20), polymyalgia rheumatica (PMR) (n=20), rheumatoid arthritis (RA) (n=30), infection (n=50), and in control subjects (n=30) using the developed ELISA. Results: We demonstrated that mCRP is elevated in some inflammatory autoimmune diseases, particularly AOSD. The mCRP concentration was also significantly higher among AOSD patients than RA, PMR patients and controls (477 ng/ml, 77 ng/ml, 186 ng/ml, and 1.2 ng/ml, respectively). Also, the mCRP (×1,000)/pCRP ratio was significantly higher among AOSD patients than RA, PMR, and infection patients (3.5, 0.6, 1,6, and 2.0, respectively). Conclusion: The plasma mCRP levels are elevated in some autoimmune diseases, particularly AOSD. The plasma mCRP levels may therefore be a potentially useful biomarker for AOSD.

Measurement of glycosylated ferritin with Concanavalin A: Assay design, optimization and validation.

INTRODUCTION: Ferritin is the major iron-storage glycoprotein found in all tissues. Ferritin glycosylation can be assessed by the differential affinities of ferritin glycoforms for Concanavalin A (ConA), a lectin. The fraction of serum ferritin bound to ConA is called "glycosylated ferritin" (GF). Low GF reflects macrophagic activation and is an essential biomarker used in adult-onset Still's disease (AOSD), macrophage activation syndrome (MAS) and Gaucher disease diagnosis and therapeutic management. To date, no complete assay description and method validation according to the ISO 15189 standard has been published. This study aimed to describe and validate our method used for GF measurement and describe GF values observed in patients. MATERIALS AND METHODS: Ferritin glycoforms were separated based on their affinities for ConA using commercially available TRIS-barbital buffer, Sepharose and ConA/Sepharose 4B gels. Ferritin concentrations were measured on the Siemens Dimension Vista 1500®. We analysed 16,843 GF values obtained between 2000 and 2021 from our database of patients. RESULTS: Optimal separation of ferritin glycoforms was obtained by 15-min incubation of serum with ConA/Sepharose at pH 8. The optimized volume were 0.4 mL for total serum ferritin (TSF) 30-1000 µg/L and 0.5 mL for TSF 1000-2500 µg/L. Serum with higher TSF should be pre-diluted in the TRIS-barbital buffer. Reproducibility of ferritin measurement in the TRIS-barbital buffer matrix was excellent (intra-assay CV < 1%; inter-assay CV < 4%). Reproducibility of GF assay was good (intra-assay CV < 10% for low and high ferritin samples, respectively; and inter-assay CV < 10%). Inter-operator variability was 21.6% for GF < 20%. Ferritin was stable for up to 3 days in the TRIS-barbital buffer. An inter-laboratory exchange program conducted with another French hospital showed good agreement between results. In our database, <20% GF levels were scarce, compatible with the low prevalence of Still's disease, MAS, and Gaucher disease. The 95% confidence interval for GF was [26-58]%, lower than values described in the literature for healthy individuals. CONCLUSION: Thanks to good performances, this technique can become readily available for laboratories servicing patients with AOSD, MAS (including severe COVID-19 patients) and Gaucher disease patients.

Adult-Onset Still's Disease: Novel Biomarkers of Specific Subsets, Disease Activity, and Relapsing Forms.

Adult-onset Still's disease (AOSD) is a systemic inflammatory disease of unknown etiology. Recent studies have demonstrated that the hallmark of AOSD is a cytokine storm, which is characterized by the excessive production of interleukin (IL)-1, IL-6, IL-18, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), suggesting how pro-inflammatory cytokines play an important role in the pathogenesis of this disease. Actually, a certain proportion of patients (around 17-32%) with severe clinical symptoms achieves only partial remission or is resistant to both first-line corticosteroids and second-line DMARDs. These patients are defined as refractory AOSD patients, requiring higher dosage glucocorticoids, longer treatment duration, or the simultaneous introduction of immunosuppressive drugs, further leading to AOSD relapses. In this narrative review, we will analyze the latest literature data to unravel potential pathogenetic factors associated with specific patterns of AOSD disease or relapses in order to identify biomarkers that may guide clinical decisions, eventually leading to new therapeutic options.

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.

Dual effects of interleukin-10 on natural killer cells and monocytes and the implications for adult-onset Still's disease.

OBJECTIVES: We compared the serum levels of multiple cytokines in patients with adult-onset Still's disease (AOSD) and healthy controls to assess the effects of humoral factors on natural killer (NK) cells and monocytes. METHODS: We quantified the serum levels of 10 cytokines in the patients using bead-based multiplex immunoassays, along with interleukin (IL-)18 using ELISA. We then sorted NK cells and monocytes from the peripheral blood mononuclear cells (PBMCs) of healthy volunteers, cultured them in the presence or absence of cytokines that were detected in some or all of the serum samples from the AOSD patients and their combinations in vitro, and analysed the culture supernatant. RESULTS: IL-6 and IL-18 were the main cytokines increased in the serum of AOSD patients. When NK cells were cultured with the cytokines and IL-10, the combination of IL-10 and IL-18 substantially induced interferon (IFN-)γ. IL-6 had little effect on NK cells, probably because they barely expressed the IL-6 receptor and glycoprotein 130 (gp130). IFN-γ induced monocytes to produce IL-1ß, IL-6 and tumour necrosis factor (TNF-)α whereas IL-10 inhibited the induction of these proinflammatory cytokines. CONCLUSIONS: IL-10 evidently has dual effects on NK cells (stimulation) and on monocytes (inhibition). Better understanding the roles of the cytokine network would shed light on the pathogenesis of AOSD.

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

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

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

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

The Role of RIPK1/3 in Adult Onset Still's Disease Patients With Liver Damage: A Preliminary Study.

Objective: This study aimed to investigate the distributions of lymphocytes in adult onset Still's disease (AOSD) with liver dysfunction, and further prospectively explore whether receptor interacting serine/threonine kinases (RIPKs) in lymphocytes play a role in the pathogenesis of AOSD especially liver involvement. Methods: Seventy-two AOSD patients and 19 cases of healthy controls (HCs) were retrospectively reviewed, the AOSD group was then divided into liver damage (LD) group and non-liver damage (NLD) group, and the distributions of lymphocytes in peripheral blood were analyzed. Another independent 24 AOSD patients and 20 HCs were recruited for prospective study of RIPKs; the RIPKs in peripheral blood lymphocytes were detected by flow cytometry. Liver biopsy specimens were obtained from two AOSD patients and underwent immunochemistry analysis with RIPK1 and RIPK3 antibody. Results: In the retrospective study, AOSD showed significantly abnormal lymphocytes distributions, and disease activity was positively correlated with percentage of CD3+ T cells. LD patients were younger in age and showed higher disease activity score than NLD patients; they had higher frequencies of CD3+ T cells, especially higher CD8+ T cells (all p<0.05). In the prospective study, RIPKs in lymphocytes were significantly higher in AOSD patients than that of HCs, and LD patients also showed higher RIPKs expression than NLD patients. In addition, RIPKs were positively correlated with erythrocyte sedimentation rate (ESR) and disease activity in AOSD patients and LD and NLD subgroups (all p<0.05). Further, RIPKs expression was confirmed in two AOSD patients' liver. ROC curve analysis indicated that RIPKs in lymphocytes (%) could be potential biomarkers in the diagnosis of AOSD and liver damage. Conclusions: Abnormal lymphocytes distributions and RIPKs expression were detected in AOSD. Aberrant expression of RIPKs in lymphocytes might be involved in the pathogenesis of AOSD. RIPKs could be candidate markers for AOSD and liver damage.

["STILL IS NOT ENOUGH" - WHAT IS THE DIFFERENTIAL DIAGNOSIS AND THE WORKUP WHEN THE FERRITIN LEVEL IS EXTREMELY HIGH?]

INTRODUCTION: In this case-report, a young female patient presented with a systemic inflammatory disease, accompanied by an extremely elevated ferritin blood level (Hyperferritinemia).The combination of high fever with extremely elevated ferritin level is considered to be a medical emergency being associated with the following four life threating conditions: Adult-onset Still's disease, catastrophic antiphospholipid syndrome, septic shock and macrophage activating syndrome. These conditions were recently bundled under the umbrella term of Hyperferritinemia Syndrome. During the patient's hospitalization, after empiric board spectrum antibiotics did not appear to improve the patient's condition, she was diagnosed with Adult-onset Still's disease and treated with steroids and methotrexate, resulting in gradual clinical improvement. This patient exemplifies a diagnostic challenge, recurring in the patients' milieu of internal medicine departments. Therefore, we discuss the differential diagnosis of Hyperferritinemia syndrome and treatment options for refectory adult's Still disease.

Elevated plasma galectin-3 levels and their correlation with disease activity in adult-onset Still's disease.

OBJECTIVES: With galectin-3 playing an important role in inflammatory responses, elevated galectin-3 levels have been shown in patients with autoimmune diseases. However, there are limited data regarding galectin-3 expression in patients with autoinflammatory diseases such as adult-onset Still's disease (AOSD). This study aimed to investigate the extracellular galectin-3 expression and examine its association with activity parameters and disease outcome in AOSD patients. METHOD: Plasma levels of galectin-3 and inflammasome downstream cytokines including interleukin (IL)-1ß and IL-18 were determined by ELISA in 42 active AOSD patients and 20 healthy controls (HC). The protein levels of galectin-3 and cytokines were determined using immunoblotting. RESULTS: Plasma levels of galectin-3 and inflammasome downstream cytokines including IL-1ß and IL-18 were significantly higher in AOSD patients (median 5.02 ng/ml, interquartile range [IQR] 3.12-7.88 ng/ml; 3.42 pg/ml, IQR 1.48-6.70 pg/ml; and 5758 pg/ml, IQR 859-11,895 pg/ml, respectively) compared with HC (1.86 ng/ml, IQR 1.09-2.89 ng/ml; 0.99 pg/ml, IQR 0.62-1.35 pg/ml; and 129 pg/ml, IQR 71-155 pg/ml, respectively, all p < 0.001). Plasma galectin-3 levels were positively correlated with clinical activity scores, inflammatory parameters values, and the levels of IL-1ß and IL-18 in AOSD patients. AOSD patients with systemic pattern had significantly higher galectin-3 levels (median 6.08 ng/ml, IQR 4.01-9.54 ng/ml) compared with those with chronic articular pattern (3.56 ng/ml, IQR 3.04-4.98 ng/ml, p < 0.05). After 6-month therapy, galectin-3 levels significantly declined, paralleling the decreases in clinical activity scores and plasma levels of IL-1ß and IL-18. CONCLUSIONS: Elevated galectin-3 levels and their positive correlation with disease activity scores, inflammatory parameter, and inflammasome downstream cytokines suggest the involvement of galectin-3 in AOSD pathogenesis.Key Points• We revealed for the first time the association of plasma galectin-3 levels with AOSD activity parameters.• We explored the link between galectin-3 levels and NLRP3-inflammasome downstream cytokines in AOSD disease.

Juxtaposition of IL-1ß and IFN-γ expression and apoptosis of keratinocytes in adult-onset Still's disease.

Backgroud: Recently, atypical persistent skin eruptions (APSEs) have been documented as a new manifestation of adult-onset Still's disease (AOSD), with a unique pathological feature of necrotic keratinocytes in the upper third of the epidermis, but the mechanism has not been elucidated. The aim of this study was to explore the potential mechanism of the unique pathological phenomenon of APSEs.Methods: Clinical and pathological data from 26 AOSD patients with APSEs and 6 with evanescent skin eruptions (ESEs) were reviewed. Fourteen APSE biopsies and 6 ESE biopsies were selected for multi-spectrum immunohistochemistry with 5 disease controls and 5 healthy controls.Results: The unique pathological manifestation was present in all APSE patients but was hardly found in ESE patients. There were more CD4 + T-cells infiltrated in the dermis of APSEs than in the dermis of ESEs. IL-1ß and IFN-γ were specifically expressed in the upper third of the epidermis and were juxtaposed to the loci of the necrotic keratinocytes.Conclusion: Our findings showed important cellular and molecular derangements related to the APSE-specific pathological phenomena and helped to understand the pathogenesis of dyskeratosis in the epidermis. The findings could also pave a way to explore an effective intervention to this potentially life-threatening disorder.

Neutrophil Extracellular Traps May Contribute to the Pathogenesis in Adult-onset Still Disease.

OBJECTIVE: Release of neutrophil extracellular traps (NET) has been described as an effector mechanism of polymorphonuclear neutrophils in several inflammatory diseases. Thus, this study was performed to evaluate the role of NET in the pathogenesis of adult-onset Still disease (AOSD). METHODS: We determined the serum levels of NET molecules and investigated their associations with clinical disease activities in patients with AOSD. Further, we analyzed the differences in the NETosis response in AOSD patients compared to healthy controls (HC). To explore the in vivo involvement of NET in AOSD, we performed immunohistochemical analysis of skin and lymph node (LN) biopsies for proteins related to NET in patients with active AOSD. RESULTS: Serum levels of cell-free DNA, myeloperoxidase (MPO)-DNA complex, and α-defensin were significantly increased in patients with AOSD compared to HC. Serum levels of the NET molecules, cell-free DNA, MPO-DNA, and α-defensin were correlated with several disease activity markers for AOSD. In followup of patients with AOSD after treatment with corticosteroid, the levels of cell-free DNA and α-defensin decreased significantly. On immunohistochemistry, neutrophil elastase-positive and MPO-positive inflammatory cells were detected in skin and LN of patients with AOSD, and were expressed in fiber form in the lesions. The serum from patients with active AOSD induced NETosis in neutrophils from HC. NET molecules induced interleukin 1ß production in monocytes, representing a novel mechanism in the pathogenesis of AOSD. CONCLUSION: The findings presented here suggest that NET may contribute to the inflammatory response and pathogenesis in AOSD.

Cytomegalovirus Infection May Trigger Adult-Onset Still's Disease Onset or Relapses.

Previous studies have revealed that several micro-organisms, especially DNA viruses, have been associated with adult-onset Still's disease (AOSD). However, there are no studies on the relationship between the presence of viral infections in AOSD patients with disease occurrence and reactivation. In the present study, we aimed to investigate the presence of antibodies against virus, virus DNA load and nucleic acid sensors in AOSD patients. Anti-viral antibodies were measured by enzyme-linked immunosorbent assay (ELISA) in plasma samples from 100 AOSD patients and 70 healthy controls (HCs). The copy number of cytomegalovirus (CMV) DNA in 100 AOSD patients was detected by PCR. The expression levels of nucleic acid sensors interferon gamma-inducible protein 16 (IFI16) and absent in melanoma 2 (AIM2) in peripheral blood mononuclear cell (PBMC) and skin from AOSD patients and HCs were analyzed by PCR and immunohistochemistry. The levels of antibodies against CMV were significantly higher in AOSD patients compared to HCs. Moreover, the level of anti-CMV IgM antibody was significantly increased in patients with fever, sore throat, arthralgia and rash. CMV DNA was found in plasma of AOSD patients with disease new-onset and relapse. Furthermore, the copy number of CMV DNA significantly increased in patients with fever, sore throat, arthralgia and rash. And the significant associations of the CMV DNA level with the levels of leukocytes, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) were observed. Moreover, we found an upregulation of cytoplasmic DNA-sensing receptor IFI16 and AIM2 in PBMC and skin from AOSD patients. In conclusion, our results showed that CMV infection may play a role in the initiation or amplification of inflammatory responses in AOSD.

The role of damage-associated molecular pattern for pathogenesis and biomarkers in adult-onset Still's disease.

Introduction: Adult-onset Still's disease (AOSD) is a systemic inflammatory disease, which presents itself as an adult form of systemic juvenile idiopathic arthritis. Innate immune activation driven by a combination of genetic and environmental factors is the primary mechanism underlying disease pathogenesis in AOSD patients. Few biomarkers have been identified for AOSD diagnosis or for the assessment of disease activity or prediction of clinical outcomes. Damage-associated molecular patterns (DAMPs) can activate innate immunity, resulting in tissue damage. Changes in several DAMPs are associated with disease pathogenesis in AOSD patients. Areas covered: This review describes the role of DAMPs in AOSD pathogenesis and discusses their potential for use as disease biomarkers. Together with overall pathogenesis of AOSD, high-mobility group box-1, advanced glycation end products, S100 proteins, and neutrophil extracellular traps are introduced and discussed in detail. Expert opinion: The activation of macrophages and neutrophils is associated with several DAMPs, causing high concentrations of proinflammatory cytokines in AOSD patients. Involvement of certain DAMPs in AOSD patients is well documented due to the presence of sterile inflammation; however, direct evidence for some DAMPs is lacking. Further research into the role of DAMP molecules in AOSD patients may reveal new biomarkers and provide targets for disease intervention.

Refractory macrophage activation syndrome in the setting of adult-onset Still disease with hemophagocytic lymphohistiocytosis detected on skin biopsy treated with canakinumab and tacrolimus.

A 19-year-old Caucasian female with adult-onset Still disease (AOSD) presented for evaluation of an acute clinical decompensation and atypical annular papules and plaques with purpura on the lower extremities. A punch biopsy demonstrated histiocytes with engulfed degenerated erythrocytes and lymphocytes, consistent with hemophagocytic lymphohistiocytosis (HLH). HLH, clinically referred to as macrophage activation syndrome, is a rare complication of AOSD and is life-threatening. Relevant clinical, laboratory, and histologic features of this diagnosis are reviewed.

Adult-Onset Still's Disease: Molecular Pathophysiology and Therapeutic Advances.

Adult-onset Still's disease (AOSD) is a rare inflammatory disorder of unknown etiology generally characterized by persistent high spiking fever, evanescent rash, and polyarthritis. The pathogenesis of AOSD is only partially known. The pivotal role of macrophage cell activation, which leads to T-helper 1 (Th1) cell cytokine activation, is now well-established in AOSD. Moreover, pro-inflammatory cytokines such as interleukin (IL)-1, -6, and -18 seem to play a key role in this disorder, giving rise to the development of new targeted therapies. For years, treatment of AOSD has been largely empirical, using nonsteroidal anti-inflammatory drugs, corticosteroids, and disease-modifying antirheumatic drugs. Patients with steroid- and methotrexate-refractory AOSD can now benefit from efficient and well-tolerated biologic agents such as IL-1, IL-6, and tumor necrosis factor-α antagonists.

Complications of adult-onset Still's disease and their management.

INTRODUCTION: Adult-onset Still's disease (AOSD) is a rare systemic auto-inflammatory disorder in which management and treatment have considerably progressed over the past decade. Despite wide use of interleukin (IL)-1 or IL-6 inhibitors, serious complications remain possible. Areas covered: A comprehensive literature search in MEDLINE via Pubmed was performed to review AOSD's severe and sometimes life-threatening complications: reactive hemophagocytic lymphohystiocytosis, coagulation disorders, fulminant hepatitis, cardiac or pulmonary complications and amyloid A amyloidosis. Expert commentary: Early recognition and prompt management is essential to significantly decrease morbi-mortality. The key question is to determine whether the complication is related to the disease itself or related to or favored by (e.g. infection) the ongoing treatment. For all severe AOSD-related complications, high-dose corticosteroids and supportive measures remain the first-line treatment. In case of inadequate response, combination with IL-1 or IL-6 blockers is justified. Cyclosporine A and etoposide remain of interest, especially in case of reactive hemophagocytic lymphohysitocytosis. Plasma exchange may be useful in case of thrombotic microangiopathy. In the near future, new biologic or non-biologic drugs targeting IL-18 or other cytokines or kinases could be of help.

Interleukin-1 Blockade: An Update on Emerging Indications.

Interleukin (IL)-1 is a pro-inflammatory cytokine that induces local and systemic inflammation aimed to eliminate microorganisms and tissue damage. However, an increasing number of clinical conditions have been identified in which IL-1 production is considered inappropriate and IL-1 is part of the disease etiology. In autoinflammatory diseases, gout, Schnitzler's syndrome, and adult-onset Still's disease, high levels of inappropriate IL-1 production have been shown to be a key process in the etiology of the disease. In these conditions, blocking IL-1 has proven very effective in clinical studies. In other diseases, IL-1 has shown to be present in disease process but is not the central driving force of inflammation. In these conditions, including type 1 and 2 diabetes mellitus, acute coronary syndrome, amyotrophic lateral sclerosis, and several neoplastic diseases, the benefits of IL-1 blockade are minimal or absent.

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

OBJECTIVE: The dysregulation of the NLRP3 (NLR containing a pyrin domain) inflammasome is involved in autoinflammatory diseases. Adult-onset Still disease (AOSD) is regarded as an autoinflammatory disease. However, the pathogenic involvement of NLRP3 inflammasome in AOSD remains unclear and NLRP3 activators in AOSD are currently unknown. METHODS: The mRNA expression of NLRP3 inflammasome signaling in peripheral blood mononuclear cells (PBMC) from 34 patients with AOSD and 14 healthy subjects was determined using quantitative-PCR (qPCR). The changes in mRNA and protein levels of NLRP3 inflammasome signaling in PBMC treated with the potential activator [imiquimod (IMQ)] or inhibitor of NLRP3 were evaluated using qPCR and immunoblotting, respectively. The supernatant levels of interleukin (IL)-1ß and IL-18 were determined by ELISA. RESULTS: Significantly higher mRNA levels of NLRP3 inflammasome signaling were observed in patients with AOSD compared with healthy controls. NLRP3 expressions were positively correlated with disease activity in patients with AOSD. IMQ (an effective Toll-like receptor 7 ligand; 10 µg/ml and 25 µg/ml) stimulation of PBMC from patients with AOSD induced dose-dependent increases of mRNA expression of NLRP3 (mean ± standard error of the mean, 2.06 ± 0.46 and 6.05 ± 1.84, respectively), caspase-1 (1.81 ± 0.23 and 4.25 ± 0.48), IL-1ß (5.68 ± 1.51 and 12.13 ± 3.71), and IL-18 (2.32 ± 0.37 and 4.81 ± 0.51) compared with controls (all p < 0.005). IMQ stimulation of PBMC from patients similarly induced greater increases in protein expressions of NLRP3 inflammasome compared with controls. The protein expressions of NLRP3, IL-1ß, and IL-18 on PBMC significantly decreased after treatment with NLRP3 inhibitor in patients with AOSD. CONCLUSION: Increased expression of NLRP3 inflammasome and its positive correlation with disease activity in AOSD suggest its involvement in disease pathogenesis. IMQ upregulated expressions of NLRP3 inflammasome signaling, and IMQ might be an activator of NLRP3 inflammasome in AOSD.