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.

Targeted Treatment of Diseases of Immune Dysregulation

Increasing molecular knowledge of autoinflammatory and autoimmune disorders has enabled more targeted treatment of these conditions. Treatment of inflammasomopathies is often aimed at interleukin-1 (IL-1) blockade, with potential use of other inhibitors targeting cytokines such as IL-18 and IL-6. Interferonopathies and some disorders with overlap features of autoimmunity and autoinflammation may improve with Janus kinase inhibition. Autoimmune conditions may also respond to inhibition of different cytokines, as well as to inhibition of T and B lymphocytes. Effective treatment is increasingly possible through targeted/precision medicine approaches.

Adult-Onset Still's Disease-A Complex Disease, a Challenging Treatment

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder with an unknown cause characterized by high-spiking fever, lymphadenopathy, hepatosplenomegaly, hyperferritinemia, and leukocytosis. The clinical course can be divided into three significant patterns, each with a different prognosis: Self-limited or monophasic, intermittent or polycyclic systemic, and chronic articular. Two criteria sets have been validated. The Yamaguchi criteria are the most generally used, although the Fautrel criteria offer the benefit of adding ferritin and glycosylated ferritin values. AOSD's pathogenesis is not yet completely understood. Chemokines and pro-inflammatory cytokines, including interferon (IFN)-γ, tumor necrosis factor α (TNFα), interleukin (IL)-1, IL-6, IL-8, and IL-18, play a crucial role in the progression of illness, resulting in the development of innovative targeted therapeutics. There are no treatment guidelines for AOSD due to its rarity, absence of controlled research, and lack of a standard definition for remission and therapy objectives. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids (CS), and conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) are used in AOSD treatment. Biological therapy, including IL-1, IL-6, IL-18, and IL-17 inhibitors, as well as TNFα or Janus-kinases (JAKs) inhibitors, is administered to patients who do not react to CS and csDMARDs or achieve an inadequate response.

New insights on multigenic autoinflammatory diseases

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

Adult-Onset Still’s Disease with Dermatopathic Lymphadenitis Clinicopathologic Features: A Rare Case Report and Review of the Literature

Adult-onset Still’s disease (AOSD) is an inflammatory disorder characterized by fever, arthritis, and a transient skin rash. It is a rare condition characterized by inflammatory multisystem changes of unknown cause. A 35-year-old woman was admitted to rheumatology department of tertiary care hospital complaining of painful wrist and skin rash as well as fever, generalized lymphadenopathy, weight loss, and fatigue. The early diagnosis of AOSD was confirmed by clinical history, examination, and laboratory tests, as well as a confirmatory skin biopsy with typical histopathological features, namely, upper epidermal dyskeratosis and dermal inflammatory neutrophilic infiltration. The patient’s condition was treated with steroids and NSAIDs, to which she responded well, and on follow-up, her symptoms regressed along with improvement in biochemical parameters. The authors suggest that skin biopsy and confirmation of histopathological diagnosis of AOSD are useful in the diagnosis and proper management of AOSD patients in cases with clinical suspicion of AOSD.

Progress in Biological Therapies for Adult-Onset Still’s Disease

Adult-onset Still’s disease (AOSD) is a rare multifactorial autoinflammatory disorder of unknown etiology, characterized by an excessive release of cytokines triggered by dysregulated inflammation and articular and systemic manifestations. The clinical spectrum of AOSD ranges from self-limiting forms with mild symptoms to life-threatening cases and presents clinical and biological similarities with the juvenile form (sJIA). Nowadays, the advances in biologic agents no longer limit the treatment to NSAIDs, glucocorticoids, or conventional synthetic DMARDs. The blockade of IL-1 and IL-6 is effective in the treatment of systemic and articular inflammation of AOSD patients; however, novel compounds with different properties and targets are now available and others are being studied. In this review, starting from the pathogenesis of AOSD, we summarized the current and emerging biological therapies, possible effective agents for achieving AOSD control and remission.

Interluekin-6 inhibitors for the treatment of adult-onset Still's disease

Adult-onset Still's disease is a systemic inflammatory disease characterized by high spiking fever, arthritis, evanescent skin rash, leukocytosis, and hyperferritinemia. The pathogenesis of adult-onset Still's disease has not been fully understood yet; however, multiple proinflammatory cytokines, such as IL-1β and IL-6, play important roles in the development of adult-onset Still's disease. IL-6 is a multifunctional cytokine that accelerates the differentiation of macrophages and cytotoxic T-cells and chemotaxis of neutrophils and macrophages. Serum concentrations of IL-6 well correlate with disease activity of adult-onset Still's disease, and blockade of IL-6 has been proven to be effective in active adult-onset Still's disease. This review will focus on the recent understanding of the role of proinflammatory cytokines of adult-onset Still's disease and the efficacy of IL-6 inhibitors for the treatment of adult-onset Still's disease.

[What is confirmed in the treatment of autoinflammatory fever diseases?]

In den letzten 20 Jahren hat die Aufklärung von monogenetisch verursachten periodischen Fiebererkrankungen zum eigenständigen Konzept der Autoinflammation geführt. In diese heterogene Gruppe werden inzwischen auch polygenetisch verursachte, komplexe Erkrankungen eingruppiert. Das Spektrum der Krankheitsbilder wächst kontinuierlich. Hauptunterschied zur Autoimmunität ist eine übermäßige Aktivierung des angeborenen Immunsystems ohne Autoantikörperbildung oder antigenspezifische T‑Zellen. Als Kardinalsymptom treten rezidivierende Fieberschübe, begleitet von Entzündungszeichen, auf; diese wechseln sich bei den periodischen Krankheitsbildern mit Intervallen allgemeinen Wohlbefindens ab. Die klassischen monogenetischen Erkrankungen werden auch als hereditäres rezidivierendes Fieber (HRF) bezeichnet. Beispiele sind das familiäre Mittelmeerfieber (FMF), das Cryopyrin-assoziierte periodische Syndrom (CAPS), das Tumor-Nekrose-Faktor-Rezeptor-1-assoziierte periodische Syndrom (TRAPS), die Adenosindesaminase(ADA2)-Defizienz und die Mevalonatkinasedefizienz (MKD; Hyper-IgD-Syndrom). Die polygenetischen Erkrankungen werden auch als nichthereditäre Fiebersyndrome bezeichnet. Hierzu zählen die adulte Form der Still-Erkrankung („adult-onset Still’s disease“, AoSD), die Adamantiades-Behçet-Erkrankung, das PFAPA-Syndrom (periodisches Fieber, aphthöse Stomatitis, Pharyngitis und zervikale Adenitis) und die Gichtarthritis. Alle autoinflammatorischen Fiebersyndrome gehen mit einem von individuellem Schweregrad und Therapieerfolg abhängigen Langzeitrisiko für die Entwicklung einer Amyloid-A-Amyloidose einher. Bei einigen Erkrankungen können z. T. schwere Komplikationen auftreten.

Current and emerging biological therapy in adult-onset Still's disease

Adult-onset Still's disease (AOSD) is a rare, but characteristic non-familial, multi-genic systemic auto-inflammatory disorder, characterized by high spiking fever, salmon-like evanescent skin rash, polyarthritis, sore throat, hyperferritinemia and leucocytosis. The hallmark of AOSD is a cytokine storm triggered by dysregulation of inflammation. Nowadays, with advances in anti-cytokine biologic agents, the treatment of AOSD is no longer limited to NSAIDs, glucocorticoids or conventional synthetic DMARDs. In this review, we focussed on the roles of these cytokines in the pathogenesis of AOSD and summarized the current and emerging biological therapy.

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

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

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

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