Still\'s disease is frequently a condition of exclusion for patients with an unidentified cause of fever. Accompanying symptoms typically include fever, arthralgia, and a transient skin rash. The underlying pathophysiology indicates an autoimmune origin. Diagnosis is primarily clinical, often utilizing the Yamaguchi criteria. The case in question involves a 19-year-old male presenting with high-grade fever and paralytic ileus. The patient received intravenous glucocorticoids and cyclophosphamide, resulting in a rapid clinical improvement. During the follow-up, tofacitinib was initiated based on the clinical response observed.

OBJECTIVE: Still\'s disease is a rare autoinflammatory disorder characterized by systemic inflammation, fever, rash, and arthritis. The term \"Still\'s disease\" covers the pediatric subtype systemic Juvenile Idiopathic Arthritis (sJIA) and adult-onset Still\'s disease (AOSD), which affects adults. Biological drugs, including anti-interleukin-1 agents anakinra, canakinumab, rilonacept, and the interleukin-6 antagonist tocilizumab, are used in the management of Still\'s disease.
METHODS: We conducted a systematic review and network meta-analysis of randomized controlled trials, and the study protocol was registered in PROSPERO (CRD42023450442). MEDLINE, EMBASE, and CENTRAL were screened from inception until September 17, 2023. We included patients with Still\'s disease who received placebo or biological drugs: anakinra, canakinumab, rilonacept, or tocilizumab. The primary efficacy and safety outcomes were achievement of ACR50 response and occurrence of serious adverse events, respectively. The interventions were ranked using rankograms and SUCRA values.
RESULTS: Nine trials with 430 patients were included. All biological drugs were associated with greater odds of ACR50 response compared with placebo. There was no statistically significant association between biological drugs and serious adverse events. The multivariate meta-analysis found no difference between biological drugs. As per SUCRA rankings, anakinra was the most effective and safe option with respect to ACR50 response and occurrence of serious adverse events.
CONCLUSIONS: This is the first systematic review and meta-analysis to assess the efficacy and safety of biological drugs in pediatric and adult patients with Still\'s disease. Biological drugs were effective in achieving ACR response and demonstrated a low adverse event profile in the management of Still\'s disease.

UNASSIGNED: Systemic juvenile idiopathic arthritis (sJIA) is a severe inflammatory condition with onset in childhood. It is sporadic, but elements of its stereotypical innate immune responses are likely genetically encoded by both common variants with small effect sizes and rare variants with larger effects.
UNASSIGNED: Genomic investigations have defined the unique genetic architecture of sJIA. Identification of the class II HLA locus as the strongest sJIA risk factor for the first time brought attention to T lymphocytes and adaptive immune mechanisms in sJIA. The importance of the human leukocyte antigen (HLA) locus was reinforced by recognition that HLA-DRB1*15 alleles are strongly associated with development of drug reactions and sJIA-associated lung disease (sJIA-LD). At the IL1RN locus, genetic variation relates to both risk of sJIA and may also predict non-response to anakinra. Finally, rare genetic variants may have critical roles in disease complications, such as homozygous LACC1 mutations in families with an sJIA-like illness, and hemophagocytic lymphohistiocytosis (HLH) gene variants in some children with macrophage activation syndrome (MAS).
UNASSIGNED: Genetic and genomic analysis of sJIA holds great promise for both basic discovery of the course and complications of sJIA, and may help guide personalized medicine and therapeutic decision-making.

OBJECTIVE: We aimed to review the literature on the clinical presentation, renal pathology, treatment, and outcome of renal manifestations in adult-onset Still\'s disease (AOSD).
METHODS: We used PRISMA guidelines for our systematic review and included all English-language original articles from inception till September 15, 2023, on AOSD and kidney involvement in any form. Data on patient demographics, diagnostic criteria, clinical presentation, renal pathology, treatment employed including dialysis, outcome, cause of death were collected and analyzed.
RESULTS: The median age at the diagnosis of renal issues was 37, with a higher prevalence among females (58.1%). Among the cases, 28 experienced renal problems after being diagnosed with AOSD, 12 had simultaneous diagnoses of renal issues and AOSD, and in 4 cases, renal problems appeared before AOSD diagnosis. Out of the 44 cases, 36 underwent renal biopsy, revealing various pathology findings including AA amyloidosis (25%), collapsing glomerulopathy (11.4%), thrombotic microangiopathy (TMA) (11.4%), IgA nephropathy (9.1%), minimal change disease (6.8%), and others. Some cases were clinically diagnosed with TMA, proximal tubular dysfunction, or macrophage activation syndrome-related acute kidney injury. Treatment approaches varied, but glucocorticoids were commonly used. Renal involvement was associated with increased mortality and morbidity, with 6 out of 44 patients passing away, 4 progressing to end-stage renal disease (ESRD), and data on 2 cases\' outcomes not available.
CONCLUSIONS: Renal manifestations in AOSD are diverse but rarely studied owing to the rarity of the disease. Studies with larger data would be essential to study further on the pathogenesis and implications.

UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

BACKGROUND: Adult-onset Still\'s disease (AOSD) and systemic juvenile idiopathic arthritis (sJIA) resemble a continuum of a rare, polygenic IL-1β-driven disease of unknown etiology.
OBJECTIVE: In the present study we sought to investigate a potential role of recently described autoantibodies neutralizing the interleukin-1(IL-1)-receptor antagonist (IL-1-Ra) in the pathogenesis of Still\'s disease.
METHODS: Serum or plasma samples from Still\'s disease patients (AOSD, n = 23; sJIA, n = 40) and autoimmune and/or inflammatory disease controls (n = 478) were analyzed for autoantibodies against progranulin (PGRN), IL-1Ra, IL-18 binding protein (IL-18BP), and IL-36Ra, as well as circulating IL-1Ra and IL-36Ra levels by ELISA. Biochemical analyses of plasma IL-1Ra were performed by native Western blots and isoelectric focusing. Functional activity of the autoantibodies was examined by an in vitro IL-1β-signaling reporter assay.
RESULTS: Anti-IL-1-Ra IgG were identified in 7 (27%) out of 29 Still\'s disease patients, including 4/23 with AOSD and 3/6 with sJIA and coincided with a hyperphosphorylated isoform of endogenous IL-1Ra. Anti-IL-36Ra antibodies were found in 2 AOSD patients. No anti-PGRN or anti-IL-18BP antibodies were detected. Selective testing for anti-IL-1Ra antibodies in an independent cohort (sJIA, n = 34) identified 5 of 34 (14.7%) as seropositive. Collectively, 8/12 antibody-positive Still\'s disease patients were either new-onset active disease or unresponsive to IL-1 blocking drugs. Autoantibody-seropositivity associated with decreased IL-1Ra plasma/serum levels. Seropositive plasma impaired in vitro IL-1Ra bioactivity, which could be reversed by anakinra or canakinumab treatment.
CONCLUSIONS: Autoantibodies neutralizing IL-1Ra may represent a novel patho-mechanism in a subgroup of Still\'s disease patients, which is sensitive to high-dose IL-1 blocking therapy.

Currently, the criteria used to classify patients with SJIA are different from those used for AOSD. However, it has been recognized that the existing terms are too narrow, subdividing the Still\'s population unnecessarily between pediatric-onset and adult-onset disease and excluding an appreciable group of children in whom overt arthritis is delayed or absent. Government regulators and insurers rely upon the guidance of subject experts to provide disease definitions, and when these definitions are flawed, to provide new and better ones. The classification session at the NextGen 2022 conference helped to serve this purpose, establishing the need for a revised definitional system that transcends the fault lines that remain in existing definitions.

BACKGROUND: Adult-onset Still\'s disease (AOSD) is a challenging diagnosis because of the variability in clinical presentation and lack of gold-standard diagnostic investigations. Even after diagnosis, the treatment is challenging, especially when the disease is refractory to first-line therapy. Multiple pharmacotherapeutic options exist for refractory AOSD, but treatment failures still occur. Etanercept, a Tumor necrosis factor (TNF)-alpha inhibitor, is one of the options that has been rarely used for refractory AOSD, with various outcomes ranging from no response to complete remission.
METHODS: In this case, we highlight how a previously healthy lady had refractory AOSD to glucocorticoids, methotrexate, and hydroxychloroquine combination therapy. There was no response to interleukin (IL)-1 therapy, which necessitated a switch to a combination of etanercept, low-dose methotrexate, and low-dose glucocorticoids with complete remission for a total of three- -year follow-up.
CONCLUSIONS: The combination of methotrexate and Etanercept can maintain remission in patients with refractory AOSD.

Systemic juvenile idiopathic arthritis (sJIA) is a complex, systemic inflammatory disorder driven by both innate and adaptive immunity. Improved understanding of sJIA pathophysiology has led to recent therapeutic advances including a growing evidence base for the earlier use of IL-1 or IL-6 blockade as first-line treatment. We conducted a retrospective case notes review of patients diagnosed with sJIA over a 16-year period (October 2005-October 2021) at Great Ormond Street Hospital for Children. We describe the clinical presentation, therapeutic interventions, complications, and remission rates at different timepoints over the disease course. We examined our data, which spanned a period of changing therapeutic landscape, to try and identify potential therapeutic signals in patients who received biologic treatment early in the disease course compared to those who did not. A total of 76-children (female n = 40, 53%) were diagnosed with sJIA, median age 4.5 years (range 0.6-14.1); 36% (27/76) presented with suspected or confirmed macrophage activation syndrome. A biologic disease-modifying anti-rheumatic drug (bDMARD) alone was commenced as first-line treatment in 28% (n = 21/76) of the cohort; however, at last review, 84% (n = 64/76) had received treatment with a bDMARD. Clinically inactive disease (CID) was achieved by 88% (n = 67/76) of the cohort at last review; however, only 32% (24/76) achieved treatment-free CID. At 1-year follow-up, CID was achieved in a significantly greater proportion of children who received treatment with a bDMARD within 3 months of diagnosis compared to those who did not (90% vs. 53%, p = 0.002). Based on an ever-increasing evidence base for the earlier use of bDMARD in sJIA and our experience of the largest UK single-centre case series described to date, we now propose a new therapeutic pathway for children diagnosed with sJIA in the UK based on early use of bDMARDs. Reappraisal of the current National Health Service commissioning pathway for sJIA is now urgently required.

OBJECTIVE: Adult-onset Still\'s disease (AOSD) is a rare condition characterized by fevers, rash, and arthralgia/arthritis; most doctors treating AOSD in the Netherlands treat <5 patients per year. Currently, there is no internationally accepted treatment guideline for AOSD. The objectives of this study were to conduct a Delphi panel aimed at reaching consensus about diagnostic and treatment strategies for patients with AOSD and to use the outcomes as a basis for a treatment algorithm.
METHODS: The Delphi panel brought together 18 AOSD experts: rheumatologists, internists and paediatricians. The Delphi process consisted of three rounds. In the first two rounds, online lists of questions and statements were completed. In the third round, final statements were discussed during a virtual meeting and a final vote took place. Consensus threshold was set at 80%. Two targeted literature searches were performed identifying the level of evidence of the consensus-based statements.
RESULTS: Consensus was reached on 29 statements, including statements related to diagnosis and diagnostic tests, definition of response and remission, the therapy, the use of methotrexate and tapering of treatment. The panel consented on reduction of the use of glucocorticoids to avoid side effects, and preferred the use of biologics over conventional treatment. The role of IL-1 and IL-6 blocking agents was considered important in the treatment of AOSD.
CONCLUSIONS: In this Delphi panel, a high level of consensus was achieved on recommendations for diagnosis and therapy of AOSD that can serve as a basis for a treatment guideline.