Interleukin 18: a biomarker for differential diagnosis between adult-onset Still's disease and sepsis

Adult-Onset Still's Disease (AOSD): Advances in Understanding Pathophysiology, Genetics and Emerging Treatment Options

Adult-onset Still's disease (AOSD) is a multisystemic complex disorder clinically characterised by episodes of spiking fever, evanescent rash, polyarthritis or diffuse arthralgias; multiorgan involvement may develop according to the hyper-inflammatory extent. The pathogenesis of AOSD is not completely recognised. The central role of macrophage activation, which results in T helper 1 (Th1) cell cytokine activation, is well established. Pro-inflammatory cytokines such as interleukin (IL)-1, IL-6 and IL-18 play a fundamental role in disease onset and progression. The disease may develop in both children and adults with overlapping clinical features, and although several subsets depending on the clinical manifestations and the cytokines expressed have been identified, the dichotomy between systemic juvenile idiopathic arthritis (sJIA) and AOSD nowadays has been overcome, and the pathology is considered a disease continuum between ages. Various therapeutic approaches have been evaluated thus far, and different compounds are under assessment for AOSD treatment. Historically, glucocorticoids have been employed for treating systemic manifestations of Still's disease, while conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) demonstrated efficacy in controlling the articular manifestations. Currently, biological (b) DMARDs are widely employed; IL-1 inhibitors such as anakinra and canakinumab have proven to have high efficacy and an excellent safety profile and the anti-IL-6 tocilizumab is approved for sJIA, with several trials and longitudinal studies confirming its efficacy and safety. Moreover, in the light of the 'window of opportunity', new evidence showed that the earlier these treatments are initiated, the sooner clinical inactivity can be achieved. Other treatment options are being considered since several molecules involved in the disease pathophysiology can be targeted through various mechanisms. This review will provide a broad overview of AOSD pathophysiology, insights into specific organ manifestations and the currently available treatments with the identification of potential therapeutic targets involved in AOSD pathogenesis will be outlined.

Identification of discriminatory factors and construction of nomograms for differentiating AOSD and sepsis

OBJECTIVE

This study aimed to develop nomogram prediction models to differentiate between adult-onset Still's disease (AOSD) and sepsis.

METHODS

We retrospectively collected laboratory test data from 107 hospitalized patients with AOSD and sepsis at the Affiliated Hospital of Xuzhou Medical University. Multivariate binary logistic regression was used to develop nomogram models using arthralgia, WBC, APTT, creatinine, PLT, and ferritin as independent factors. The performance of the model was evaluated by the bootstrap consistency index and calibration curve.

RESULTS

Model 1 had an AUC of 0.98 (95% CI, 0.96-1.00), specificity of 0.98, and sensitivity of 0.94. Model 2 had an AUC of 0.96 (95% CI, 0.93-1.00), specificity of 0.92, and sensitivity of 0.94. The fivefold cross-validation yielded an accuracy (ACC) of 0.92 and a kappa coefficient of 0.83 for Model 1, while for Model 2, the ACC was 0.87 and the kappa coefficient was 0.74.

CONCLUSION

The nomogram models developed in this study are useful tools for differentiating between AOSD and sepsis. Key Points • The differential diagnosis between AOSD and sepsis has always been a challenge • Delayed treatment of AOSD may lead to serious complications • We developed two nomogram models to distinguish AOSD from sepsis, which were not previously reported • Our models can be used to guide clinical practice with good discrimination.

Vitamin A Promotes the Fusion of Autophagolysosomes and Prevents Excessive Inflammasome Activation in Dextran Sulfate Sodium-Induced Colitis

Vitamin A ensures intestinal homeostasis, impacting acquired immunity and epithelial barrier function; however, its role in innate immunity is mostly unknown. Here, we studied the impact of vitamin A in different dextran sulfate sodium (DSS)-induced colitis animal models. Interestingly, more severe DSS-induced colitis was observed in vitamin A-deficient (VAD) mice than in vitamin A-sufficient (VAS) mice; the same was observed in VAD severe combined immunodeficient mice lacking T/B cells. Remarkably, IL-1β production, LC3B-II expression, and inflammasome activity in the lamina propria were significantly elevated in VAD mice. Electron microscopy revealed numerous swollen mitochondria with severely disrupted cristae. In vitro, non-canonical inflammasome signaling-induced pyroptosis, LC3B-II and p62 expression, and mitochondrial superoxide levels were increased in murine macrophages (RAW 264.7) pretreated with retinoic acid receptor antagonist (Ro41-5253). These findings suggest that vitamin A plays a crucial role in the efficient fusion of autophagosomes with lysosomes in colitis.

A Streamlined Diagnostic Process Improved the Outcomes of Patients with Adult-Onset Still's Disease: A Single-Center Retrospective Observational Study

INTRODUCTION

The diagnosis of adult-onset Still's disease (AOSD) is often delayed due to its clinical heterogeneity and lack of pathognomic features. Hence, there is an unmet need for an efficient diagnostic process. The major aim of this study was to compare the differences in disease outcomes between two groups of AOSD patients with and without implementation of the streamlined diagnostic process (SDP).

METHODS

Of 172 febrile patients with skin rash and/or arthralgia, 112 individuals had AOSD. The tentative diagnosis of AOSD or non-AOSD was made with or without the SDP implementation. The selection criteria for AOSD outcomes analysis were as follows: (1) age at study entry older than 20 years, (2) fulfillment of the Yamaguchi criteria for AOSD diagnosis, and (3) a follow-up period longer than 6 months after initiation of therapy. Three outcome parameters were evaluated, including diagnosis lag period, the proportion of "early diagnosis," and the proportion of achieving disease remission after a 6-month therapy.

RESULTS

The SDP was implemented for expediting AOSD diagnosis in 41 (36%) enrolled patients (SDP-implemented group). The diagnosis lag period was significantly shorter in the SDP-implemented group (median 2.0 weeks, interquartile range [IQR] 1.0-2.5 weeks) than in the non-SDP-implemented group (4.0 weeks, IQR 2.0-6.0 weeks, p < 0.001). A significantly higher proportion of "early diagnosis" was also found in the SDP-implemented group (75.6%) compared with the non-SDP-implemented group (33.8%, p < 0.001). We revealed a significantly higher proportion of achieving remission in the SDP-implemented group (85.4%) compared with the non-SDP-implemented group (67.6%, p < 0.05). Logistic regression analysis revealed SDP implementation as a potential predictor of achieving disease remission.

CONCLUSIONS

Implementing an SDP for expediting diagnosis could improve outcomes for AOSD patients. This diagnostic process increased the early diagnosis rate and led to a higher disease remission rate. However, the beneficial effects of SDP implementation need further external validation.

Refractory adult-onset Still's disease complicated with monoclonal gammopathy of undetermined significance: A case report

RATIONALE

Adult-onset Still's disease (AOSD) is a rare inflammatory disease characterized by a classic triad of daily spike fever, arthritis, and a typical salmon-pink rash. The involvement of inflammatory cytokines by various factors such as infection, drug, or neoplasm causes refractory AOSD.

PATIENT CONCERNS

We report a 63-year-old man with a high fever, rash, hyperferritinemia, and M proteinemia. His serum levels of interleukin-6 and interleukin-18 were remarkably high at 192 and 114,250 pg/mL, respectively.

DIAGNOSIS

AOSD complicated with monoclonal gammopathy of undetermined significance was diagnosed.

INTERVENTIONS

After steroid pulse therapy followed by oral prednisolone, cyclosporin, methotrexate, and colchicine, serum ferritin levels temporarily declined, but secondary cytomegalovirus infections exacerbated AOSD's activity.

OUTCOMES

Finally, after tocilizumab induction, AOSD activity was gradually suppressed over a long period.

LESSONS

The disease activity of AOSD is exacerbated by multiple factors, including comorbidities or infections. Clinicians need to consider that monoclonal gammopathy of undetermined significance complications might become AOSD refractory by an elevation of the inflammatory cytokines. Moreover, further prospective studies are required to confirm this result.

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.

Fulminant elderly adult-onset Still disease effectively treated with tocilizumab and methotrexate: A case report

RATIONALE

Adult-onset Still disease (AOSD) is a rare inflammatory disease of unknown etiology. AOSD is common in young or middle-aged adults; however, in recent years, there have been increasing reports of elderly AOSD. Differentiating AOSD from diseases such as infections and malignancies is difficult. Moreover, rare fulminant AOSD cases with resistance to corticosteroids and immunosuppressive drugs have been reported.

PATIENT CONCERNS

An 80-year-old woman presented with flaccid fever, generalized arthralgia, and erythema of the anterior chest for 2 weeks. On day 5 of hospitalization, the patient developed pleural effusion with hypoxemia and her vital signs indicated rapid progression to shock. During the clinical course, the levels of inflammatory markers, including maximum level of ferritin and white blood cells (WBCs) were elevated (252,796 ng/mL and 86,500/μV, respectively) with disseminated intravascular coagulation syndrome (DIC) and macrophage activation syndrome (MAS).

DIAGNOSIS

The patient was diagnosed with elderly AOSD as per the Yamaguchi criteria for AOSD. The state of disease was extremely severe with rapid progression and was, thus, categorized as a fulminant form of elderly AOSD.

INTERVENTIONS

The patient was treated with prednisolone (PSL) pulse therapy (1000 mg/d) twice and plasma exchange in the intensive care unit for the primary disease and shock. Although she recovered from shock, she developed DIC and MAS. Methotrexate (MTX; 10 mg/d) improved the DIC and MAS. However, severe pleuritis recurred and the patient developed pericarditis; her primary disease was poorly controlled. Finally, tocilizumab (TCZ) was introduced using interleukin-18 (IL-18) as a surrogate marker. The IL-18 level was measured repeatedly following admission, with the peak level (170,000 pg/mL) recorded on the 75th day of hospitalization, immediately prior to introducing TCZ.

OUTCOMES

The combined use of MTX, TCZ, and PSL was effective in suppressing elderly AOSD, which was unsuccessfully controlled with MTX and PSL. Frequent monitoring of IL-18 levels proved useful for differentiating elderly AOSD from other diseases.

LESSONS

A fulminant form of elderly AOSD was treated with a combination of MTX, TCZ, and PSL. Repeated monitoring of IL-18 levels can be useful for decision-making in treating elderly AOSD.

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.

Baseline clinical features predicting macrophage activation syndrome in patients with systemic adult-onset Still's disease receiving interleukin-6 inhibitor treatment

AIM

Macrophage activation syndrome (MAS), a severe complication of systemic adult-onset Still's disease (AOSD), has been reported to occur during interleukin-6 (IL-6) inhibitor treatment. However, predictors for MAS development are unknown. Therefore, this study investigated predictive features for MAS development after starting IL-6 inhibitor treatment in systemic AOSD patients.

METHOD

In a single-center retrospective study involving systemic AOSD patients who were refractory to high-dose glucocorticoids with immunosuppressants and started IL-6 inhibitor treatment between April 2008 and March 2020, we compared the baseline clinical features between patients who developed AOSD flare with MAS features (MAS group) and those who did not (non-MAS group) during IL-6 inhibitor treatment.

RESULTS

Only tocilizumab was used as an IL-6 inhibitor. Six of 14 refractory systemic AOSD patients developed AOSD flares with MAS features during tocilizumab treatment, including 4 who developed them shortly after initiation. The MAS group had significantly lower neutrophil counts, fibrinogen, and higher IL-18/C-reactive protein (CRP) ratio at starting tocilizumab (baseline) than the non-MAS group. Before starting tocilizumab, neutrophil counts were trending downward and upward in the MAS and non-MAS groups, respectively, with significant differences in changes. Receiver operating characteristic analysis showed that baseline neutrophil counts and fibrinogen and their changes before tocilizumab treatment and baseline IL-18/CRP ratio had significant discriminatory abilities for subsequent MAS development.

CONCLUSION

We identified baseline laboratory features associated with MAS development after initiating an IL-6 inhibitor in refractory systemic AOSD patients. These features may reflect the suppression of IL-6 signaling, and further suppression of IL-6 signaling might trigger early-onset MAS.

Strategy and Challenges of Paraclinical Examinations in Adult-Onset Still’s Disease

Adult-onset Still’s disease is a complex autoinflammatory disease with a multifactorial etiology. Its presentation is less stereotypical than that of a monogenic autoinflammatory disease and is actually relatively common with few specific signs. To avoid under- or over-prescription of complementary examinations, it is useful to advance in a structured manner, taking into consideration the actual added value of each supplemental examination. In this review, we detail the different complementary tests used in adult Still’s disease. We consider them from three different angles: positive diagnostic approach, the differential diagnosis, and the screening for complications of the disease. After discussing the various tests at our disposal, we look at the classical diagnostic strategy in order to propose a structured algorithm that can be used in clinical practice. We conclude with the prospects of new complementary examinations, which could in the future modify the management of patients.

The Role of Interleukin 18/Interleukin 18-Binding Protein in Adult-Onset Still's Disease and Systemic Juvenile Idiopathic Arthritis

Interleukin 18 (IL-18) is a pro-inflammatory cytokine of the IL-1 family, whose activity is tightly controlled at the level of production, as well as signalization. Notably, it is buffered by its natural inhibitor, IL-18 binding protein (IL-18BP), which is massively present in circulation in normal and in most pathological conditions, thus preventing harmful pro-inflammatory systemic effects of IL-18. IL-18 has long been considered to be involved in the pathophysiology of various inflammatory diseases. However, a first clinical trial using recombinant IL-18BP for the treatment of rheumatoid arthritis and psoriasis gave disappointing results. Direct measurements of unbound, bioactive, free form of circulating IL-18 demonstrated that IL-18 was more specifically involved in adult-onset Still’s disease (AOSD) and systemic juvenile idiopathic arthritis (sJIA) but also in their most severe complication, macrophage activation syndrome (MAS). More importantly, administration of recombinant IL-18BP to patients with AOSD, and sJIA with MAS, showed promising results. This review summarizes available data regarding IL-18 and IL-18BP in AOSD and sJIA in mouse models and humans and shows the importance of IL-18/IL-18BP imbalance in these conditions, leading to the conclusion that IL-18, particularly free IL-18, may be a useful biomarker in these diseases and an interesting therapeutic target.

Role of mean platelet volume in differential diagnosis of adult-onset Still's disease and sepsis

OBJECTIVES

Mean platelet volume is a simple biomarker for inflammatory disease. The purpose of this study is to evaluate the role of mean platelet volume in distinguishing adult-onset Still's disease from sepsis.

METHODS

We retrospectively selected 68 patients with adult-onset Still's disease and 55 patients with sepsis between January 2015 and December 2019. Related laboratory data were collected and analyzed.

RESULTS

There were no significant differences in white blood cell counts, neutrophils, lymphocytes, and C-reactive protein between adult-onset Still's disease group and sepsis group. However, patients in adult-onset Still's disease group showed higher ferritin and platelets and lower mean platelet volume and platelet distribution width than those in sepsis group (p<0.01 for both). Receiver operating characteristic curve analysis was performed to distinguish adult-onset Still's disease and sepsis. The area under the curve of mean platelet volume was 0.761 (95%CI 0.673-0.849), with a sensitivity of 79.1%, a specificity of 63.3%, and a cutoff value of 10.9 fL. In contrast, the area under the curve of combined ferritin and mean platelet volume was 0.90l (95%CI 0.837-0.965), with higher sensitivity (82.8%) and specificity (96.2%). Therefore, mean platelet volume could be used as a supplementary indicator to distinguish adult-onset Still's disease from sepsis.

CONCLUSION

We suggest that mean platelet volume could be used as a supplementary biomarker for differential diagnosis of adult-onset Still's disease and sepsis in addition to ferritin.

Usefulness of Interleukin-18 as a Diagnostic Biomarker to Differentiate Adult-Onset Still's Disease With/Without Macrophage Activation Syndrome From Other Secondary Hemophagocytic Lymphohistiocytosis in Adults

Background

Interleukin (IL)-18 is markedly elevated in systemic inflammatory diseases that cause the ‘cytokine storm’ such as adult-onset Still’s disease (AOSD) and hemophagocytic lymphohistiocytosis (HLH). The differences in IL-18 between AOSD and HLH, especially in adults, is uncertain. Macrophage activation syndrome (MAS), a form of secondary HLH, is often difficult to differentiate cases of AOSD that include MAS from other secondary HLH. In this case-control study, we investigated whether serum IL-18 levels could be a useful biomarker for the differential diagnosis of AOSD with or without MAS (AOSD group) and other secondary HLH in adults (adult HLH group).

Patients and Methods

We enrolled 46 patients diagnosed with AOSD including 9 patients with MAS and 31 patients in the adult HLH group, which excluded AOSD-associated MAS. The clinical features and laboratory data were compared between the AOSD and adult HLH groups. In addition, we subdivided the AOSD group (with or without MAS) and the adult HLH group (whether lymphoma-associated or not) and compared the four groups. A logistic regression analysis was used to identify factors with high efficacy in differentiating the two groups, followed by a receiver operating characteristic (ROC) curve analysis to evaluate the differential diagnostic ability of IL-18. We analyzed the correlation between IL-18 and various laboratory parameters in the AOSD group.

Results

Serum IL-18 levels of patients in the AOSD groups were significantly higher than those of the adult HLH groups, and were closely correlated with ferritin, soluble interleukin-2 receptor (sIL-2R), and other laboratory data. Univariate and multivariate logistic regression analyses revealed that IL-18, sIL-2R, and ‘arthralgia or arthritis’ are independent factors useful in the differential diagnosis of AOSD from adult HLH. In the differential diagnosis of both groups, the area under the curve obtained from the ROC curve of IL-18 with a cutoff value of 18,550 pg/mL was 0.91 (95% confidence interval 0.83–1.00; sensitivity 90.3%, specificity 93.5%), and the differential diagnosis ability of IL-18 was superior to that of other laboratory data.

Conclusions

IL-18 could be a useful biomarker for the differential diagnosis of AOSD and adult HLH.

Granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-α in combination is a useful diagnostic biomarker to distinguish familial Mediterranean fever from sepsis

Objective

To identify potential biomarkers to distinguish familial Mediterranean fever (FMF) from sepsis.

Method

We recruited 28 patients diagnosed with typical FMF (according to the Tel Hashomer 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 FMF and sepsis groups in order to identify specific molecular networks. Multivariate classification (random forest analysis) and logistic regression analysis were used to rank the cytokines by importance and determine specific biomarkers for distinguishing FMF from sepsis.

Results

Fifteen of the 40 cytokines were found to be suitable for further analysis. Levels of serum granulocyte-macrophage colony-stimulating factor (GM-CSF), fibroblast growth factor 2, vascular endothelial growth factor, macrophage inflammatory protein-1b, and interleukin-17 were significantly elevated, whereas tumor necrosis factor-α (TNF-α) was significantly lower in patients with FMF compared with those with sepsis. Cytokine clustering patterns differed between the two groups. Multivariate classification followed by logistic regression analysis revealed that measurement of both GM-CSF and TNF-α could distinguish FMF from sepsis with high accuracy (cut-off values for GM-CSF = 8.3 pg/mL; TNF-α = 16.3 pg/mL; sensitivity, 92.9%; specificity, 94.4%; accuracy, 93.4%).

Conclusion

Determination of GM-CSF and TNF-α levels in combination may represent a biomarker for the differential diagnosis of FMF from sepsis, based on measurement of multiple cytokines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02644-2.

Circulating regulatory T cells in adult-onset Still's disease: Focusing on their plasticity and stability

We investigated the characteristics of regulatory T cells in adult-onset Still's disease (AOSD) with a focus on their plasticity, stability and relationship to disease severity. The proportion of circulating CD4⁺ CD25⁺ forkhead box protein 3 (FoxP3⁺ ) cells (T_regs ) and intracellular expression of effector cytokines, including interferon (IFN)-γ, interleukin (IL)-17 and IL-4, was analysed in 27 untreated patients with AOSD (acute AOSD), 11 of the 27 patients after remission and 16 healthy controls (HC) using flow cytometry. The suppressive ability of T_regs was also evaluated. Regression analyses of the results were performed. The proportion of T_regs was significantly lower in patients with acute AOSD than in the HC. The expression levels of IFN-γ, IL-17 and IL-4 in T_regs were significantly increased in patients with acute AOSD. IFN-γ and IL-4 expression levels were inversely correlated with the proportion of T_regs and positively correlated with serum ferritin levels. Decreased expression of FoxP3 in CD4⁺ CD25⁺ cells, which was correlated with increased expression of IL-17, and impaired suppressive function were observed in T_regs in acute AOSD. However, these aberrant findings in T_regs , including the reduced circulating proportion and functional ability and altered intracellular expression levels of cytokines and FoxP3, were significantly improved after remission. In acute AOSD, T_regs show plastic changes, including effector cytokine production and reductions in their proportion and functional activity. IFN-γ and IL-4 expression levels in T_regs may be associated with disease severity. Also, down-regulation of FoxP3 may be related to IL-17 expression in T_regs . Importantly, the stability of T_regs can be restored in remission.

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.

Serum Heparin-Binding Protein as a Potential Biomarker to Distinguish Adult-Onset Still's Disease From Sepsis

Adult-onset Still’s disease (AOSD) is a systemic, multifactorial, autoinflammatory disease for which the etiopathogenesis is not well understood. Given the similarities in clinical and laboratory features between this disease and sepsis, and the differences in treatment strategies for these two diseases, specific diagnostic markers are crucial for the correct diagnosis and management of AOSD. Previous studies have shown plasma heparin-binding protein (HBP) is a promising potential biomarker for AOSD; thus, this study aimed to detect serum HBP levels in patients with AOSD or sepsis to assess its potential as a biomarker for differential diagnosis. We found that serum HBP levels were significantly higher in patients with active AOSD than that in those with inactive AOSD. Patients with sepsis had higher serum HBP levels compared with those who had active or inactive AOSD. We calculated the area under the receiver operating characteristic (ROC) curve to assess whether HBP could be used to differentiate active from inactive AOSD; this was 0.811 with sensitivity 0.650, specificity 0.811, and cutoff HBP value of 35.59 ng/ml. The area under the ROC curve for HBP as a biomarker to differentiate AOSD from sepsis was 0.653, with sensitivity 0.759, and specificity 0.552, and cutoff HBP value of 65.1 ng/ml. Taken together, the results of our study suggest that serum HBP could be a useful diagnostic biomarker to evaluate disease activity in patients with AOSD, and to differentiate AOSD from sepsis.

Different Features of Interleukin-37 and Interleukin-18 as Disase Activity Markers of Adult-Onset Still's Disease

The aim of this study was to evaluate the usefulness of serum interleukin (IL)-37 and IL-18 as disease activity markers of adult-onset Still’s disease (AOSD) and to compare their related clinical features. Forty-five patients with a set of high and subsequent low disease activity status of AOSD were enrolled. Modified Pouchot (mPouchot) score and serologic disease activity markers including levels of IL-37 and IL-18 were compared between high and low disease activity status. The relationships between disease activity parameters and differences in levels of cytokines according to each disease manifestation were evaluated in high disease activity status. mPouchot score and all disease activity markers including IL-37 and IL-18 significantly declined after treatment. Though both cytokines positively correlated with mPouchot score, the two did not correlate with each other in high disease activity status. IL-18 positively correlated with ferritin, AST, and LDH while IL-37 correlated better with CRP. The expression level of IL-37 was related to leukocytosis while IL-18 was related to pleuritis, pneumonitis, abnormal LFT, and hyperferritinemia. In addition, patients in the IL-18 dominant group presented with higher LDH levels and required a higher mean corticosteroid dose. In conclusion, IL-37 and IL-18 are disease activity markers reflecting different aspects of AOSD that can complement each other.

Adult-onset Still's disease evolving with multiple organ failure and death: A case report and review of the literature

BACKGROUND

Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory disease, which is characterized by daily fever and arthritis, with an evanescent rash and neutrophilic leukocytosis. To date, there has been no definite laboratory or imaging test available for diagnosing AOSD; the diagnosis is one of exclusion, which can be very challenging. In particular, AOSD patients may experience different complications affecting their clinical picture, management, and prognosis. The treatment of AOSD remains largely empirical and involves therapeutic agents.

CASE SUMMARY

We report the case of a 36-year-old woman who presented with fever, red rash, arthralgia, and sore throat. Her serum ferritin level and white blood cell count were markedly elevated, and the first diagnosis 22 years prior was "juvenile rheumatoid arthritis of systemic type". The patient was treated with prednisone, sulfasalazine, methotrexate, and leflunomide. After remission of her symptoms, the patient stopped taking the medications, and the disease recurred. Ultimately, the patient was diagnosed with adult-onset Still's disease. Relapse occurred several times due to self-medication withdrawal, and an interleukin-6 antagonist (tocilizumab/Actemra) was administered to control the disease. Recently, she was hospitalized because an incision did not heal, and the patient suddenly developed high fever and diarrhea during hospitalization. The patient's disease progressed violently and quickly developed into macrophage activation syndrome, disseminated intravascular coagulation, shock, and multiple organ failure. The patient had sudden cardiac arrest, and she died despite emergency rescue efforts.

CONCLUSION

AOSD patients need regular follow-up in the long-term treatment process, and must press formulary standard medication, and do not voluntarily withdraw or reduce the dose. Otherwise it may cause disease back-and-forth or serious life-threatening complications. Meanwhile, strict management of trauma, infections, tumors, and other diseases may contribute to improved outcomes in patients with complications.

A Cohort Study of Liver Involvement in Patients With Adult-Onset Still's Disease: Prevalence, Characteristics and Impact on Prognosis

Objective: Adult-onset Still's disease (AOSD) is a systemic disorder commonly accompanied by liver involvement. This study aims to illustrate the detailed information of liver abnormalities in patients with AOSD and evaluate the impact on the prognosis.

Methods: A total number of 128 hospitalized patients, who met the Yamaguchi criteria of AOSD in the Department of Rheumatology and Immunology, Ruijin Hospital from July 2016 to August 2019 were consecutively enrolled and followed up. The demographic characteristics, clinical features, laboratory tests, treatments and prognosis were recorded. Correlations of liver function tests (LFTs) with disease activity and laboratory parameters were analyzed by the Spearman test. Risk factors of the refractory AOSD were evaluated by multivariate logistic regression analysis.

Results: Liver involvement was presented in 104 (81.3%) patients with AOSD. We observed that 34 (32.7%) patients were with mild elevation, 32 (30.8%) patients were with moderate elevation, and 38 (36.5%) patients were with severe elevation. The majority of elevated ALT, AST and ALP decreased to normal within the range of 2 months, except for GGT. Furthermore, the LFTs were found significantly correlated with disease activity. Besides, we found patients with higher levels of LFTs tended to require more intensive treatments and suffered from poorer prognosis. Multivariate logistic regression analysis showed ALP ≥ 141 IU/L and GGT ≥ 132 IU/L are independent risk factors of refractory AOSD.

Conclusion: Liver involvement is common in patients with AOSD, the levels of LFTs are associated with disease activity and related to the treatment strategies and prognosis.

An Unusual Presentation of Adult-Onset Still's Disease as Hemophagocytic Lymphohistiocytosis in a Male Patient

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and potentially fatal condition characterized by immune activation and multi-organ dysfunction. HLH can be inherited in an autosomal recessive fashion, but can also be secondary to infections, malignancy, immunosuppression, and autoimmune conditions. Adult-onset Still’s disease (AOSD) is an autoimmune disorder that can predispose patients to HLH. AOSD, similar to other autoimmune conditions, is more common in females than males. However, the occurrence of AOSD in males and subsequent predisposition to HLH is rarely reported. We report the case of a 23-year-old male patient who presented with fever, joint pain, and rash for 20 days. On evaluation, he fulfilled the diagnostic criteria for AOSD and HLH, and a diagnosis of HLH secondary to AOSD was made. He was treated with pulse dose steroids and gradually tapered. AOSD and HLH have overlapping clinical and laboratory features and hence their co-occurrence poses diagnostic challenges. The mortality rate of HLH is high and hence prompt initiation of treatment is of utmost importance.

Combination value of biomarkers in discriminating adult onset Still's disease and sepsis

BACKGROUND

Lymphocyte and plateletcrit (PCT) as proportions of routine complete blood count tests, have been studied as simple biomarkers for inflammatory diseases. The aim of our study was to investigate whether blood routine parameters, especially platelet parameters could be a useful tool to distinguish Adult onset Still's disease (AOSD) from sepsis.

METHODS

We retrospectively reviewed 58 patients with AOSD and 55 sepsis patients diagnosed at the First Affiliated Hospital of Nanjing Medical University between January, 2015 to December 2018. Laboratory data including ferritin, blood routine parameters and C‑reactive protein (CRP) level were collected, and the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte (PLR) were calculated.

RESULTS

The results showed that AOSD patients showed higher ferritin, lymphocyte and PCT (all P < 0.01) and these factors are independent risk factors for predicting AOSD. In receiver operating characteristic (ROC) curve analysis of LY, PCT and ferritin for distinguish of AOSD, the area under the curve (AUC) was 0.676 (0.576-0.777); 0.706 (95% CI = 0.596-0.816); 0.715 (0.617-0.814). Meanwhile, the AUC of the combination of lymphocyte, PCT and ferritin was 0.836 (0.737-0.909) with sensitivity 67.3, specificity 92.3, and the difference was significant.

CONCLUSIONS

Thus we suggest that lymphocyte, PCT may be a useful tool to make a distinction between AOSD and sepsis, as supplementary biomarkers to ferritin.

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.

Adult-Onset Still’s Disease

Adult-onset Still’s disease (AoSD) is a rare but clinically well-known, polygenic, systemic autoinflammatory disease. It is typically characterized by four main (cardinal) symptoms: spiking fever ≥39 °C, arthralgia or arthritis, skin rash, and hyperleukocytosis (≥10,000 cells/mm³). However, many other clinical features are possible, and it can appear in all age groups with potentially severe inflammatory onset accompanied by a broad spectrum of disease manifestation and complications. Hence, it remains a diagnostic challenge, and the clinician should first rule out infectious, tumoral, or inflammatory differential diagnoses. Determination of the total and glycosylated ferritin levels, although not pathognomonic, can help in diagnosis. New biomarkers have recently been described, but they need to be validated. The disease evolution of AoSD can be monocyclic, polycyclic, or chronic. In chronic disease, a joint involvement is often predominant, and erosions are noted in one-third of patients. Many progresses have been made in the understanding of the pathogenesis over the last decades. This chapter provides a comprehensive insight into the complex and heterogeneous nature of AoSD describing the identified cytokine signaling pathways and biomarkers. It also discusses the current evidence for the usage of biologics in AoSD to provide guidance for treatment decisions, taking into account both the efficacy and the safety of the different therapeutic options.

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.

Mechanisms, biomarkers and targets for adult-onset Still's disease

Adult-onset Still’s disease (AoSD) is a rare but clinically well-known, polygenic, systemic autoinflammatory disease. Owing to its sporadic appearance in all adult age groups with potentially severe inflammatory onset accompanied by a broad spectrum of disease manifestation and complications, AoSD is an unsolved challenge for clinicians with limited therapeutic options. This Review provides a comprehensive insight into the complex and heterogeneous nature of AoSD, describing biomarkers of the disease and its progression and the cytokine signalling pathways that contribute to disease. The efficacy and safety of biologic therapeutic options are also discussed, and guidance for treatment decisions is provided. Improving the approach to AoSD in the future will require much closer cooperation between paediatric and adult rheumatologists to establish common diagnostic strategies, treatment targets and goals.

Adult-onset Still’s disease (AoSD) is not easily diagnosed, and treatment options are limited. This Review provides an overview of the disease and its pathogenesis, clinical trial results, therapeutic options and a plan to diagnose and clinically manage these patients.

Similar to systemic-onset juvenile idiopathic arthritis, adult-onset Still’s disease (AoSD) is a rare systemic autoinflammatory disease with potentially severe inflammatory onset accompanied by a broad spectrum of disease manifestation and complications.

AoSD should be considered in patients with persistent fever, and the diagnosis is based on the combination of clinical and laboratory findings as well as the exclusion of other inflammatory conditions.

Central to the pathogenesis of AoSD is the intense activation of innate immune cells and overproduction of several pro-inflammatory cytokines including IL-1, IL-6 and IL-18.

Two IL-1 antagonists have been approved for treatment of AoSD, and growing evidence suggests that other biologic agents are therapeutic options, such as anti-IL-6 and anti-IL-18 therapeutics.

As a reliable prediction of response and outcome is not possible, therapeutic decisions have to be made on the basis of clinical, biological or imaging characteristics of disease.

A close cooperation between paediatric and adult rheumatologists is required to establish common diagnostic strategies, treatment targets and goals.

Synovial fluid interleukin-16, interleukin-18, and CRELD2 as novel biomarkers of prosthetic joint infections

Objectives

Prosthetic joint infection (PJI) diagnosis is a major challenge in orthopaedics, and no reliable parameters have been established for accurate, preoperative predictions in the differential diagnosis of aseptic loosening or PJI. This study surveyed factors in synovial fluid (SF) for improving PJI diagnosis.

Methods

We enrolled 48 patients (including 39 PJI and nine aseptic loosening cases) who required knee/hip revision surgery between January 2016 and December 2017. The PJI diagnosis was established according to the Musculoskeletal Infection Society (MSIS) criteria. SF was used to survey factors by protein array and enzyme-linked immunosorbent assay to compare protein expression patterns in SF among three groups (aseptic loosening and first- and second-stage surgery). We compared routine clinical test data, such as C-reactive protein level and leucocyte number, with potential biomarker data to assess the diagnostic ability for PJI within the same patient groups.

Results

Cut-off values of 1473 pg/ml, 359 pg/ml, and 8.45 pg/ml were established for interleukin (IL)-16, IL-18, and cysteine-rich with EGF-like domains 2 (CRELD2), respectively. Receiver operating characteristic curve analysis showed that these factors exhibited an accuracy of 1 as predictors of PJI. These factors represent potential biomarkers for decisions associated with prosthesis reimplantation based on their ability to return to baseline values following the completion of debridement.

Conclusion

IL-16, IL-18, and CRELD2 were found to be potential biomarkers for PJI diagnosis, with SF tests outperforming blood tests in accuracy. These factors could be useful for assessing successful debridement based on their ability to return to baseline values following the completion of debridement.Cite this article: M-F. Chen, C-H. Chang, L-Y. Yang, P-H. Hsieh, H-N. Shih, S. W. N. Ueng, Y. Chang. Synovial fluid interleukin-16, interleukin-18, and CRELD2 as novel biomarkers of prosthetic joint infections. Bone Joint Res 2019;8:179-188. DOI: 10.1302/2046-3758.84.BJR-2018-0291.R1.

Comparative study of Interleukin-18 (IL-18) serum levels in adult onset Still's disease (AOSD) and systemic onset juvenile idiopathic arthritis (sJIA) and its use as a biomarker for diagnosis and evaluation of disease activity

Background

Signs and symptoms establish the diagnosis of adult onset Still’s disease (AOSD) as well as of systemic onset juvenile idiopathic arthritis (sJIA). The published data regarding the importance of IL-18 as a marker for diagnosis and disease activity so far are conflicting. The aim of this study was to clarify the role of IL-18 as a diagnostic and disease activity marker in AOSD and sJIA.

Methods

Thirty adult patients diagnosed with AOSD and twenty children diagnosed with sJIA were included in the study. Clinical and laboratory data were obtained retrospectively for each patient visit whenever IL-18 serum levels were determined. IL-18 levels were determined by ELISA. Sixty-five adults and twenty-three children presenting with fever and/or arthritis who did not meet the criteria for a diagnosis of AOSD or sJIA served as comparison groups. Rau’s criteria and CRP values were used to evaluate disease activity.

Results

IL-18 levels were significantly elevated in patients with active AOSD compared to AOSD patients in remission and to the comparison group with a median of 16,327 pg/ml, 470 pg/ml, and 368 pg/ml, respectively (p < 0.001). Analogous to AOSD in active sJIA, the median IL-18 serum level was significantly higher with 21,512 pg/ml than in the comparison group with 2580 pg/ml (p < 0.001).

At our cut-off point of 5000 pg/ml, the calculated specificity of IL-18 to establish the diagnosis of AOSD was 96.9%, and the sensitivity 63.3% (AUC = 0.870, p < 0.001). For the diagnosis of sJIA, a cut-off value of 10,000 pg/ml was chosen with a specificity of 100% and a sensitivity of 60% (AUC = 0.774, p = 0.003). At a cut-off value of 5000 pg/ml, the specificity was 62% and the sensitivity 65%.

Conclusions

This study gives further evidence to earlier publications of elevated IL-18 serum levels in active AOSD and sJIA, with up to 1000-fold higher concentrations compared to other rheumatic diseases. A clear association of IL-18 serum levels with disease activity in AOSD was found. The results support the use of IL-18 as an important biomarker in AOSD and sJIA.

Electronic supplementary material

The online version of this article (10.1186/s41927-019-0053-z) contains supplementary material, which is available to authorized users.

Red blood cell distribution width is useful in discriminating adult onset Still's disease and sepsis within 24 hours after hospitalization

BACKGROUND/AIMS

Red blood cell distribution width (RDW) is a value representing the heterogeneity in the size of red blood cell, and it is usually used in distinguishing types of anaemia. Recently, it was reported that it could reflect the burden of inflammation in diverse diseases and their prognosis. Hence, in this study, we investigated whether RDW may contribute to discriminating adult onset Still's disease (AOSD) from sepsis in serious febrile patients within 24 hours after hospitalization.

METHODS

We reviewed the medical records and enrolled 21 AOSD patients, 27 sepsis patients and 30 matched healthy controls. We collected at least two laboratory results of variables including RDW within 24 hours after hospitalization, and we calculated their mean values.

RESULTS

Sepsis patients showed the significantly increased median white blood cell count, compared to AOSD patients (14,390.0/mm3 vs. 12,390.0/mm3 , p = 0.010). The median RDW in sepsis patients was higher than that in AOSD patients (15.0% vs. 13.3%, p = 0.001), and furthermore, the median RDW in both patient-groups was significantly higher than that in healthy controls. In contrast, the median ferritin level in sepsis patients was lower than that in AOSD patients (544.0 mg/dL vs. 3,756.6 mg/dL, p = 0.001). In multivariate analysis, RDW ≥ 14.8% (odds ratio, 17.549) and ferritin < 2,251.0 mg/dL (odds ratio, 32.414) independently suggested sepsis more than AOSD in patients initially presenting with fever requiring hospitalization.

CONCLUSION

RDW might be a rapid and helpful marker for a differential diagnosis between AOSD from sepsis at an early phase.

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.

Interleukin-18 as a diagnostic marker of adult-onset Still's disease in older patients: a case report and review of the literature

BACKGROUND

Adult onset Still's disease is a systemic auto-inflammatory condition of unknown etiology characterized by intermittent spiking high fever, an evanescent salmon-pink or erythematous maculopapular skin rash, arthralgia or arthritis, and leukocytosis. Recently, a high level of interleukin-18 has been reported as a new characteristic marker. On the other hand no reports have been published on high interleukin-18 as a marker in older patients. We report a case of adult onset Still's disease in an older patient successfully treated with steroids in which interleukin-18 was a useful marker of disease activity.

CASE PRESENTATION

A 66-year-old Asian woman presented to our hospital with fever and arthralgia. We diagnosed adult onset Still's disease based on Yamaguchi criteria and a history of a high spiking fever, salmon-colored rash, and bilateral pain to shoulders, knees, and wrists. In this case, a high serum level of interleukin-18 was a diagnostic parameter. Administration of 40 mg of prednisolone followed by subcutaneous administration of 200 mg cyclosporine daily resulted in a dramatic resolution of our patient's febrile episodes 2 months after admission. Prednisolone was tapered to 5 mg/day every 2 weeks and cyclosporine 200 mg/day was continued. Her serum interleukin-18 level was prominently decreased, and she was discharged 3 months after treatment.

CONCLUSIONS

Serum interleukin-18 level may be a good diagnostic biomarker to monitor adult onset Still's disease activity in older patients, measuring levels in both the acute and convalescent phases.

Severe Adult-onset Still Disease with Constrictive Pericarditis and Pleuritis That Was Successfully Treated with Tocilizumab in Addition to Corticosteroids and Cyclosporin A

Adult-onset Still disease (AOSD) is a systemic inflammatory disease characterized by fever, arthritis and rash. Corticosteroids represent a promising therapeutic option for AOSD; however, some resistant cases require immunosuppressants and biologic agents. We herein report the case of a 29-year-old Japanese man with severe AOSD, accompanied by constrictive pericarditis (CP) and pleuritis. Although 2 courses of steroid pulse and subsequent high-dose of prednisolone and cyclosporine A improved the patient's CP and pleuritis, his fever and inflammatory responses persisted. Tocilizumab (TCZ) was added to his treatment, which resulted in a rapid remission. This case suggests the usefulness of TCZ in the treatment of severe AOSD with CP and pleuritis.

Open-label, multicentre, dose-escalating phase II clinical trial on the safety and efficacy of tadekinig alfa (IL-18BP) in adult-onset Still's disease

Objectives

Adult-onset Still’s disease (AOSD) is a rare systemic autoinflammatory disease; its management is largely empirical. This is the first clinical study to determine if interleukin (IL)-18 inhibition, using the recombinant human IL-18 binding protein, tadekinig alfa, is a therapeutic option in AOSD.

Methods

In this phase II, open-label study, patients were ≥18 years with active AOSD plus fever or C reactive protein (CRP) levels ≥10 mg/L despite treatment with prednisone and/or conventional synthetic disease-modifying antirheumatic drugs (DMARDs). Previous biological DMARD treatment was permitted. Patients received tadekinig alfa 80 mg or 160 mg subcutaneously three times per week for 12 weeks; those receiving 80 mg not achieving early predicted response criteria (reduction of ≥50% CRP values from baseline and fever resolution) were up-titrated to 160 mg for a further 12 weeks. The primary endpoint was the occurrence of adverse events (AEs) throughout the study.

Results

Ten patients were assigned to receive 80 mg tadekinig alfa and 13 patients to the 160 mg dose. One hundred and fifty-five treatment-emerging AEs were recorded, and 47 were considered related to the study drug. Most AEs were mild and resolved after drug discontinuation. Three serious AEs occurred, one possibly related to treatment (toxic optic neuropathy). At week 3, 5 of 10 patients receiving 80 mg and 6 of 12 patients receiving 160 mg achieved the predefined response criteria.

Conclusions

Our results indicate that tadekinig alfa appears to have a favourable safety profile and is associated with early signs of efficacy in patients with AOSD.

Trial registration number

NCT02398435.

H-ferritin and proinflammatory cytokines are increased in the bone marrow of patients affected by macrophage activation syndrome

Macrophage activation syndrome (MAS) is hyperinflammatory life-threatening syndrome, associated typically with high levels of serum ferritin. This is an iron storage protein including heavy (H) and light (L) subunits, categorized on their molecular weight. The H-/L subunits ratio may be different in tissues, depending on the specific tissue and pathophysiological status. In this study, we analysed the bone marrow (BM) biopsies of adult MAS patients to assess the presence of: (i) H-ferritin and L-ferritin; (ii) CD68⁺ /H-ferritin⁺ and CD68⁺ /L-ferritin⁺ ; and (iii) interleukin (IL)-1β, tumour necrosis factor (TNF) and interferon (IFN)-γ. We also explored possible correlations of these results with clinical data. H-ferritin, IL-1β, TNF and IFN-γ were increased significantly in MAS. Furthermore, an increased number of CD68⁺ /H-ferritin⁺ cells and an infiltrate of cells co-expressing H-ferritin and IL-12, suggesting an infiltrate of M1 macrophages, were observed. H-ferritin levels and CD68⁺ /H-ferritin⁺ cells were correlated with haematological involvement of the disease, serum ferritin and C-reactive protein. L-ferritin and CD68⁺ /L-ferritin⁺ cells did not correlate with these parameters. In conclusion, during MAS, H-ferritin, CD68⁺ /H-ferritin⁺ cells and proinflammatory cytokines were increased significantly in the BM inflammatory infiltrate, pointing out a possible vicious pathogenic loop. To date, H-ferritin and CD68⁺ /H-ferritin⁺ were associated significantly with haematological involvement of the disease, suggesting biomarkers assessing severity of clinical picture.

A Pilot Study on Tocilizumab for Treating Refractory Adult-Onset Still's Disease

To investigate the efficacy and safety of Tocilizumab (TCZ) in patients with refractory adult-onset Still’s disease (AOSD). We enrolled 8 female patients from October 2013 to July 2014. All patients fulfilled Japan’s Yamaguch AOSD classification and recognized as refractory AOSD. All Patients received TCZ treatment 4–8 mg/kg every 4 weeks. Evaluation of efficacy was conducted after 3 months and 6 months, including clinical manifestations of AOSD patients, improvement of inflammatory markers as well as glucocorticoids dosage adjustments. Treatment-related adverse events were also recorded. Patients treated with Tocilizumab with average age 41.1 years old, the average disease duration 23.6 months. Two patients drop off due to infusion side effects. Others were followed at least 6 months. After 3 months of follow-up, remission rates of fever, arthritis and rashes from 8 patients were 87.5%, 100% and 87.5%. White blood cell counts, erythrocyte sedimentation rate, C-reactive protein and ferritin levels were decreased (P < 0.01) significantly compared to treatment before. Furthermore, the average dose of prednisone was reduced from 51.7 ± 38.4 mg/d to 12.9 ± 7.7 mg/d (P < 0.01). Our findings suggest that tocilizumab could alleviate the clinical manifestations of refractory AOSD rapidly and efficiently.

Upregulation of circulating microRNA-134 in adult-onset Still's disease and its use as potential biomarker

Adult-onset Still’s disease (AOSD) is a multi-systemic inflammatory disorder of unknown etiology. To date, no single diagnostic test is available for AOSD. Herein, we investigated the pathogenic role of microRNAs in AOSD. MicroRNA profiles in plasma from AOSD patients and healthy controls were analyzed by microarray analysis, followed by quantitative reverse transcription PCR validation. The biological functions of microRNAs were evaluated using in vitro cell-based assay. Among the differentially expressed microRNAs, microRNA-134 (miR-134) expression was positively correlated with AOSD activity scores and significantly decreased after effective treatment. An increased miR-134 level is significantly associated with the activation of Toll-like receptor 3 (TLR3). The reporter assay identified IL-18 binding protein (IL-18BP) as the target of miR-134. A negative correlation between miR-134 expression and IL-18BP mRNA levels were detected in peripheral blood cells following TLR3 ligand treatment. Lower plasma IL-18BP levels and higher IL-18 levels were also observed in active AOSD patients who had higher miR-134 expression than inactive patients. Upregulation of circulating miR-134 was associated with elevated IL-18 levels by targeting IL-18BP in AOSD patients and was positively correlated with disease activity, suggesting its involvement in AOSD pathogenesis. MiR-134 may be a novel activity indicator or potential prognostic biomarker in AOSD.

Response to Interleukin-1 Inhibitors in 140 Italian Patients with Adult-Onset Still's Disease: A Multicentre Retrospective Observational Study

Background: Interleukin (IL)-1 plays a crucial role in the pathogenesis of Adult onset Still's disease (AOSD). Objectives: To evaluate the efficacy and safety of anakinra (ANA) and canakinumab (CAN) in a large group of AOSD patients. Methods: Data on clinical, serological features, and concomitant treatments were retrospectively collected at baseline and after 3, 6, and 12 months from AOSD patients (Yamaguchi criteria) referred by 18 Italian centers. Pouchot's score was used to evaluate disease severity. Results: One hundred forty patients were treated with ANA; 4 were subsequently switched to CAN after ANA failure. The systemic pattern of AOSD was identified in 104 (74.2%) of the ANA-treated and in 3 (75%) of the CAN-treated groups; the chronic-articular type of AOSD was identified in 48 (25.8%) of the ANA-treated and in 1 (25%) of the CAN-treated groups. Methotrexate (MTX) was the most frequent disease modifying anti-rheumatic drug (DMARD) used before beginning ANA or CAN [91/140 (75.8%), 2/4 (50%), respectively]. As a second-line biologic DMARD therapy in 29/140 (20.7%) of the patients, ANA was found effective in improving all clinical and serological manifestations (p < 0.0001), and Pouchot's score was found to be significantly reduced at all time points (p < 0.0001). No differences in treatment response were identified in the ANA-group when the patients were stratified according to age, sex, disease pattern or mono/combination therapy profile. ANA primary and secondary inefficacy at the 12-month time point was 15/140 (10.7%) and 11/140 (7.8%), respectively. Adverse events (AEs) [mainly represented by in situ (28/47, 59.5%) or diffuse (12/47, 25.5%) skin reactions and infections (7/47, 14.8%)] were the main causes for discontinuation. Pouchot's score and clinical and serological features were significantly ameliorated at all time points (p < 0.0001) in the CAN-group, and no AEs were registered during CAN therapy. Treatment was suspended for loss of efficacy only in one case (1/4, 25%). Conclusion: This is the largest retrospective observational study evaluating the efficacy and safety of IL-1 inhibitors in AOSD patients. A good response was noted at 3 months after therapy onset in both the ANA- and CAN-groups. Skin reaction may nevertheless represent a non-negligible AE during ANA treatment.

Adult-Onset Still's Disease: Still a Serious Health Problem (a Case Report and Literature Review)

Patient: Female, 53

Final Diagnosis: Adult-onset Still’s Disease

Symptoms: Abdominal pain • fever

Medication: —

Clinical Procedure: —

Specialty: Rheumatology

Elevated serum levels of free interleukin-18 in adult-onset Still's disease

OBJECTIVE

IL-18 is a pro-inflammatory cytokine of the IL-1 family that is naturally inhibited by IL-18 binding protein (IL-18BP). High levels of IL-18 have been described in the serum of adult-onset Still's disease (AOSD) patients, but only total IL-18 levels (including inactive IL-18 bound to IL-18BP) have been measured. With a specific immunoassay, we aimed to measure free IL-18 serum levels in AOSD patients and other rheumatic diseases.

METHODS

An ELISA was developed to measure free IL-18. Its sensitivity and specificity were tested by spiking recombinant IL-18 or IL-18BP in serum and PBS supplemented with 5% BSA. The binding affinity of IL-18 to IL-18BP was calculated by titration experiments using the ELISA and by Biacore analysis. Sera of 37 AOSD patients and 138 controls (40 healthy controls, 30 RA, 29 SLE, 21 AS and 18 PsA) were assayed for free IL-18, IL-18BP, total IL-18 and other cytokines. Correlations were performed between free IL-18 and markers of disease activity in AOSD patients.

RESULTS

Free IL-18 serum levels were significantly higher in AOSD patients (median 8.89 pg/ml) than in healthy and disease controls (1.37 pg/ml; P < 0.01). Free IL-18 serum levels correlated with AOSD activity. The affinity of IL-18 to IL-18BP was found to be much higher than previously described, with a dissociation constant ranging from 30 to 50 pM.

CONCLUSION

Free IL-18 levels are specifically elevated in AOSD compared with other inflammatory diseases, suggesting that IL-18 represents a potential target for the treatment of AOSD.