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

Toward a personalized therapy of still's disease based on immunologic endotypes: a narrative review

INTRODUCTION

Accumulative evidence indicates that both innate and adaptive immunity are involved in pathogenesis of Still's disease, an autoinflammatory disease. With Increasing insights into the pathogenesis of Still's disease coupled with the availability of emerging targeted therapeutics, it may be the unmet need for personalizing therapy and achieving a treat-to-target goal. We aim to summarize the available evidence regarding immunopathogenesis of Still's disease and therapeutic strategies based on immunologic endotypes.

AREAS COVERED

We searched MEDLINE database using the PubMed interface and reviewed relevant English-language literature from 1971 to 2024. This review focuses on the existing evidence on pathophysiology and immunological endotypes of Still's disease and their implications for personalized strategies for patients with this disease.

EXPERT OPINION

Targeting the complex immunopathogenesis of Still's disease, emerging new agents are available for treatment, including biologic disease-modifying anti-rheumatic drugs (bDMARDs) and targeted synthetic DMARDs (tsDMARDs) such as Janus kinase inhibitors (JAKi). According to the updated evidence, meta-analyses, and recommendations, we propose a flow chart emphasizing personalized therapeutic strategies based on immunological endotypes. Hopefully, the therapeutic strategy might help guide the optimal selection of b/tsDMARDs to achieve a 'treat-to-target' goal in Still's disease. This proposed flow chart will be updated as newer evidence emerges.

Evaluation of Myocarditis in Patients With Still Disease: Clinical Findings From the Multicenter International AIDA Network Still Disease Registry

OBJECTIVE

We aimed to (1) evaluate the cardiac involvement, with a focus on myocarditis, in patients with Still disease included in the multicenter Autoinflammatory Disease Alliance (AIDA) Network Still disease registry; and (2) assess the predictive factors for myocarditis by deriving a clinical risk patient profile for this severe manifestation.

METHODS

A multicenter observational study was established, in which consecutive patients with Still disease in the AIDA Network Still disease registry were characterized by cardiac involvement. Cardiac involvement was defined according to the presence of pericarditis, tamponade, myocarditis, and/or aseptic endocarditis.

RESULTS

In total, 73 patients with Still disease and cardiac involvement were assessed (mean age 36.3 [SD 19.9] years; male sex, 42.5%), out of which 21.9% were children. The most common cardiac manifestation was pericarditis, occurring in 90.4% of patients; patients also presented with myocarditis (26%), and less frequently endocarditis (2.7%) and tamponade (1.4%). In comparing clinical features of patients with myocarditis to those without, significantly increased frequencies of skin rash and pleuritis, as well as higher systemic scores, were seen. Further, a higher mortality rate was shown in patients with myocarditis. In regression models, skin rash and the systemic score independently predicted the myocarditis.

CONCLUSION

The characteristics of patients with Still disease and cardiac involvement were assessed in the AIDA Network. The most common feature was the pericarditis, but a more severe clinical picture was also reported in patients with myocarditis. The latter was associated with increased mortality rate and higher systemic score, identifying patients who should be carefully managed.

EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease

Systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) are considered the same disease, but a common approach for diagnosis and management is still missing.

METHODS

In May 2022, EULAR and PReS endorsed a proposal for a joint task force (TF) to develop recommendations for the diagnosis and management of sJIA and AOSD. The TF agreed during a first meeting to address four topics: similarity between sJIA and AOSD, diagnostic biomarkers, therapeutic targets and strategies and complications including macrophage activation syndrome (MAS). Systematic literature reviews were conducted accordingly.

RESULTS

The TF based their recommendations on four overarching principles, highlighting notably that sJIA and AOSD are one disease, to be designated by one name, Still's disease.Fourteen specific recommendations were issued. Two therapeutic targets were defined: clinically inactive disease (CID) and remission, that is, CID maintained for at least 6 months. The optimal therapeutic strategy relies on early use of interleukin (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid (GC). MAS treatment should rely on high-dose GCs, IL-1 inhibitors, ciclosporin and interferon-γ inhibitors. A specific concern rose recently with cases of severe lung disease in children with Still's disease, for which T cell directed immunosuppressant are suggested. The recommendations emphasised the key role of expert centres for difficult-to-treat patients. All overarching principles and recommendations were agreed by over 80% of the TF experts with a high level of agreement.

CONCLUSION

These recommendations are the first consensus for the diagnosis and management of children and adults with Still's disease.

Tailoring the treatment of inflammatory rheumatic diseases by a better stratification and characterization of the clinical patient heterogeneity. Findings from a systematic literature review and experts' consensus

Inflammatory rheumatic diseases are different pathologic conditions associated with a deregulated immune response, codified along a spectrum of disorders, with autoinflammatory and autoimmune diseases as two-end phenotypes of this continuum. Despite pathogenic differences, inflammatory rheumatic diseases are commonly managed with a limited number of immunosuppressive drugs, sometimes with partial evidence or transferring physicians' knowledge in different patients. In addition, several randomized clinical trials, enrolling these patients, did not meet the primary pre-established outcomes and these findings could be linked to the underlying molecular diversities along the spectrum of inflammatory rheumatic disorders. In fact, the resulting patient heterogeneity may be driven by differences in underlying molecular pathology also resulting in variable responses to immunosuppressive drugs. Thus, the identification of different clinical subsets may possibly overcome the major obstacles that limit the development more effective therapeutic strategies for these patients with inflammatory rheumatic diseases. This clinical heterogeneity could require a diverse therapeutic management to improve patient outcomes and increase the frequency of clinical remission. Therefore, the importance of better patient stratification and characterization is increasingly pointed out according to the precision medicine principles, also suggesting a new approach for disease treatment. In fact, based on a better proposed patient profiling, clinicians could more appropriately balance the therapeutic management. On these bases, we synthetized and discussed the available literature about the patient profiling in regard to therapy in the context of inflammatory rheumatic diseases, mainly focusing on randomized clinical trials. We provided an overview of the importance of a better stratification and characterization of the clinical heterogeneity of patients with inflammatory rheumatic diseases identifying this point as crucial in improving the management of these patients.

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.

Recent advances and evolving concepts in Still's disease

Still's disease is a rare inflammatory syndrome that encompasses systemic juvenile idiopathic arthritis and adult-onset Still's disease, both of which can exhibit life-threatening complications, including macrophage activation syndrome (MAS), a secondary form of haemophagocytic lymphohistiocytosis. Genetic insights into Still's disease involve both HLA and non-HLA susceptibility genes, suggesting the involvement of adaptive immune cell-mediated immunity. At the same time, phenotypic evidence indicates the involvement of autoinflammatory processes. Evidence also implicates the type I interferon signature, mechanistic target of rapamycin complex 1 signalling and ferritin in the pathogenesis of Still's disease and MAS. Pathological entities associated with Still's disease include lung disease that could be associated with biologic DMARDs and with the occurrence of MAS. Historically, monophasic, recurrent and persistent Still's disease courses were recognized. Newer proposals of alternative Still's disease clusters could enable better dissection of clinical heterogeneity on the basis of immune cell profiles that could represent diverse endotypes or phases of disease activity. Therapeutically, data on IL-1 and IL-6 antagonism and Janus kinase inhibition suggest the importance of early administration in Still's disease. Furthermore, there is evidence that patients who develop MAS can be treated with IFNγ antagonism. Despite these developments, unmet needs remain that can form the basis for the design of future studies leading to improvement of disease management.

The latest advances in the use of biological DMARDs to treat Still's disease

INTRODUCTION

Currently, the therapeutic management of Still's disease, a multisystemic inflammatory rare disorder, is directed to target the inflammatory symptoms and signs of patients. The treatment varies from glucocorticoids to disease-modifying antirheumatic drugs (DMARDs), both conventional synthetic and biological (bDMARDs). Usually, in refractory patients, bDMARDs are administered.

AREAS COVERED

Among bDMARDs, IL-1 and IL-6 inhibitors are frequently used, as data reported from both clinical trials and 'real-life' experiences. Recently, innovative therapeutic strategies have suggested an early administration of bDMARDs to increase the rate of clinical response and drug-free remission. Some new targets have been also proposed targeting IL-18, IFN-γ, and JAK/STAT pathway, which could be applied to Still's disease and its life-threatening evolution.

EXPERT OPINION

Many lines of evidence improved the knowledge about the therapeutic management of Still's disease with bDMARDs. However, many unmet needs may be still highlighted which could provide the basis to arrange further specific research in increasing the rate of clinical response. In fact, Still's disease remains a highly heterogeneous disease suggesting possible diverse underlying pathogenic mechanisms, at least partially, and consequent different therapeutic strategies. A better patient stratification may help in arranging specific studies to improve the long-term outcome of Still's disease.

Derivation and validation of four patient clusters in Still's disease, results from GIRRCS AOSD-study group and AIDA Network Still Disease Registry

BACKGROUND

Different patient clusters were preliminarily suggested to dissect the clinical heterogeneity in Still's disease. Thus, we aimed at deriving and validating disease clusters in a multicentre, observational, prospective study to stratify these patients.

METHODS

Patients included in GIRRCS AOSD-study group and AIDA Network Still Disease Registry were assessed if variables for cluster analysis were available (age, systemic score, erythrocyte sedimentation rate (ESR), C reactive protein (CRP) and ferritin). K-means algorithm with Euclidean metric and Elbow plot were used to derive an adequate number of clusters.

RESULTS

K-means clustering assessment provided four clusters based on means standardised according to z-scores on 349 patients. All clusters mainly presented fever, skin rash and joint involvement. Cluster 1 was composed by 115 patients distinguished by lower values of age and characterised by skin rash myalgia, sore throat and splenomegaly. Cluster 2 included 128 patients identified by lower levels of ESR, ferritin and systemic score; multiorgan manifestations were less frequently observed. Cluster 3 comprised 31 patients categorised by higher levels of CRP and ferritin, they were characterised by fever and joint involvement. Cluster 4 contained 75 patients derived by higher values of age and systemic score. Myalgia, sore throat, liver involvement and life-threatening complications, leading to a high mortality rate, were observed in these patients.

CONCLUSIONS

Four patient clusters in Still's disease may be recognised by a multidimensional characterisation ('Juvenile/Transitional', 'Uncomplicated', 'Hyperferritinemic' and 'Catastrophic'). Of interest, cluster 4 was burdened by an increased rate of life-threatening complications and mortality, suggesting a more severe patient group.

Extracellular vesicles in systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis is a chronic pediatric inflammatory disease of unknown etiology, characterized by fever, rash, hepatosplenomegaly, serositis, and arthritis. We hypothesized that intercellular communication, mediated by extracellular vesicles, contributes to systemic juvenile idiopathic arthritis pathogenesis and that the number and cellular sources of extracellular vesicles would differ between inactive and active states of systemic juvenile idiopathic arthritis and healthy controls. We evaluated plasma from healthy pediatric controls and patients with systemic juvenile idiopathic arthritis with active systemic flare or inactive disease. We isolated extracellular vesicles by size exclusion chromatography and determined total extracellular vesicle abundance and size distribution using microfluidic resistive pulse sensing. Cell-specific extracellular vesicle subpopulations were measured by nanoscale flow cytometry. Isolated extracellular vesicles were validated using a variety of ways, including nanotracking and cryo-electron microscopy. Extracellular vesicle protein content was analyzed in pooled samples using mass spectrometry. Total extracellular vesicle concentration did not significantly differ between controls and patients with systemic juvenile idiopathic arthritis. Extracellular vesicles with diameters <200 nm were the most abundant, including the majority of cell-specific extracellular vesicle subpopulations. Patients with systemic juvenile idiopathic arthritis had significantly higher levels of extracellular vesicles from activated platelets, intermediate monocytes, and chronically activated endothelial cells, with the latter significantly more elevated in active systemic juvenile idiopathic arthritis relative to inactive disease and controls. Protein analysis of isolated extracellular vesicles from active patients showed a proinflammatory profile, uniquely expressing heat shock protein 47, a stress-inducible protein. Our findings indicate that multiple cell types contribute to altered extracellular vesicle profiles in systemic juvenile idiopathic arthritis. The extracellular vesicle differences between systemic juvenile idiopathic arthritis disease states and healthy controls implicate extracellular vesicle-mediated cellular crosstalk as a potential driver of systemic juvenile idiopathic arthritis disease activity.

The administration of methotrexate in patients with Still's disease, "real-life" findings from AIDA Network Still Disease Registry

OBJECTIVES

To describe clinical characteristics of patients with Still's disease treated with methotrexate (MTX) and to assess drug effectiveness evaluating change in disease activity, reduction of inflammatory markers, and glucocorticoid (GC)-sparing effect.

METHODS

Patients with Still's disease treated with MTX were assessed among those included in AIDA Network Still Disease Registry.

RESULTS

In this registry, 171 patients with Still's disease were treated with MTX (males 43.3%, age 37.1 ± 16.0 years). They were mainly characterised by joint features and fever without a prominent multiorgan involvement. MTX was administered with GCs in 68.4% of patients, with other conventional synthetic DMARDs in 6.4%, and with biologic DMARDs in 25.1%. A significant reduction of the modified systemic score was observed, and 38.6% patients were codified as being in clinical remission at the end of follow-up. The concomitant administration of a biologic DMARD resulted a predictor of the clinical remission. Furthermore, a reduction of inflammatory markers and ferritin levels was observed following the administration of MTX. Additionally, a marked reduction of the dosage of concomitant GCs was identified, while 36.7% discontinued such drugs. Male gender appeared as a predictor of GC discontinuation. MTX was discontinued in 12.3% of patients because of adverse effects, and in 12.3% for lack of efficacy.

CONCLUSIONS

Clinical characteristics of patients with Still's disease treated with MTX were described, mainly joint features and fever without a prominent multiorgan involvement. The clinical usefulness of MTX was reported in reducing the disease activity, decreasing the inflammatory markers, and as GC-sparing agent.

Clinical characteristics of obese patients with adult-onset Still's disease. Data from a large multicentre cohort

OBJECTIVES

To evaluate the impact of obesity in patients with adult-onset Still's disease (AOSD) and to assess their clinical characteristics and disease outcomes.

METHODS

The clinical features of AOSD patients with a body mass index (BMI)≥30 were assessed among those included in the multicentre Gruppo Italiano di Ricerca in Reumatologia Clinica e Sperimentale (GIRRCS) cohort.

RESULTS

Out of 139 AOSD patients, who had BMI registered in our database, 26 (18.7%) had a BMI≥30. A lower rate of sore throat (P<0.05), pericarditis (P<0.05), and pleuritis (P<0.05) was shown in obese patients. Additionally, obese patients showed higher values of C-reactive protein (CRP) (P<0.05) and ferritin (P<0.05) than others. Furthermore, obese patients were characterised by biologic disease-modifying antirheumatic drug (bDMARD) failure in subsequent follow-up (P<0.05). They also presented higher rate of comorbidity than non-obese patients (P<0.05). Finally, obesity predicted the presence of a chronic disease course in both univariate (HR: 1.72, 95%CI: 1.03-2.51, P<0.05) and multivariate analyses (HR: 1.85, 95%CI: 1.45-2.89, P<0.05). Obesity was also a significant predictor of bDMARD failure in AOSD patients in both univariate (HR: 3.03, 95%CI: 1.42-6.45, P<0.01) and multivariate analyses (HR: 3.59, 95%CI: 1.55-8.27, P<0.01).

CONCLUSION

Obese patients at the time of diagnosis of the disease were characterised by a lower prevalence of sore throat, serositis, as well as by higher values of CRP and ferritin. Obesity was also a predictive factor for a chronic disease course and bDMARD failure, thus highlighting a subset of patients with AOSD to be carefully managed.

Systematic review on the use of biologics in adult-onset still's disease

This systematic review (SR) describes the efficacy and safety of biologic disease modifying anti-rheumatic drugs (bDMARDs) for patients with adult-onset Still's disease (AOSD). Three randomised controlled trials (RCTs), one retrospective case series of multiple interventions, and 17 case series of single interventions met the inclusion criteria for this SR. Comparisons of biologic therapy in AOSD were only available against conventional DMARDs in one RCT and against placebo in two RCTs. There was a lack of common assessment criteria, meaning treatment efficacy across studies could not be compared. Uncontrolled retrospective case series suggested that bDMARDs have an effect for patients with AOSD, but these studies did not provide comparative data to show whether bDMARDs were more effective than other interventions or, whether any bDMARD was more effective than another bDMARD. However, there was evidence that bDMARDs could reduce steroid dose. Safety data from all included studies showed that bDMARDs appear to be a safe alternative to conventional DMARDs. This SR has highlighted the need for larger comparative studies in AOSD and has shown the need to standardize the definition of therapeutic response in AOSD. This would allow comparisons between studies in order to gain clarity on which bDMARDs may be more effective treatments for AOSD.

Perspectives on the use of non-biological pharmacotherapy for adult-onset Still's disease

INTRODUCTION

The treatment of the patients with adult-onset Still's disease (AOSD) remains largely empirical and it is based on the administration of immunosuppressive drugs. In this work, we described the use of non-biological pharmacotherapies for AOSD.

AREA COVERED

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are employed during the diagnostic phase, glucocorticoids (GCs) are the first-line therapy, administered at the beginning of the disease. As second-line therapy, conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) are used when GCs do not fully control the disease and/or to reduce the dosage of concomitant GCs. Methotrexate (MTX) is the most commonly administered csDMARDs whereas calcineurin inhibitors (CNIs) are used in severe patients. The lack of achievement of clinical response may lead to the administration of biologic DMARDs, with or without csDMARDs.

EXPERT OPINION

The management of AOSD may benefit from the administration of non-biological pharmacotherapies, including GCs, MTX, and CNIs. These therapies showed efficacy in inducing a clinical response, in managing life-threatening complications, and may be well tolerated in combination with biologic DMARDs. However, further specific studies are needed to fully clarify the specific role of such drugs in clinical practice to improve the management of AOSD and to provide a more tailored treatment.