Immune dysregulation.

The understanding of immune dysregulation in many different diseases continues to grow. There is increasing evidence that altered microbiome and gut barrier dysfunction contribute to systemic inflammation in patients with primary immunodeficiency and in patients with rheumatic disease. Recent research provides insight into the process of induction and maturation of pathogenic age-associated B cells and highlights the role of age-associated B cells in creating tissue inflammation. T follicular regulatory cells are shown to help maintain B-cell tolerance, and therapeutic approaches to increase or promote T follicular regulatory cells may help prevent or decrease immune dysregulation. Meanwhile, novel studies of systemic-onset juvenile idiopathic arthritis reveal a strong HLA association with interstitial lung disease and identify key aspects of the pathogenesis of macrophage activation syndrome. Studies of hyperinflammatory syndromes, including the recently described multisystem inflammatory syndrome of children, characterize similarities and differences in cytokine profiles and T-cell activation. This review focuses on recent advances in the understanding of immune dysregulation and describes potential key factors that may function as biomarkers for disease or targets for therapeutic interventions. Future trials are necessary to address the many remaining questions with regards to pathogenesis, diagnosis, and treatment of autoimmune, inflammatory, and immunodeficiency syndromes.

Adult-onset Still's disease or systemic-onset juvenile idiopathic arthritis and spondyloarthritis: overlapping syndrome or phenotype shift?

OBJECTIVES: Systemic-onset JIA (SJIA) and adult-onset Still's disease (AOSD) are the same sporadic systemic auto-inflammatory disease. SpA is a group of inflammatory non-autoimmune disorders. We report the observations of eight patients with SJIA/AOSD who also presented features of SpA during their disease evolution and estimate the prevalence of SpA in SJIA/AOSD. METHODS: This was a retrospective national survey of departments of paediatric and adult rheumatology and internal medicine. To be included, SJIA patients had to fulfil the ILAR criteria, AOSD patients the Yamaguchi or Fautrel criteria, and all patients the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial or peripheral SpA, ESSG criteria for SpA or Classification Criteria for Psoriatic Arthritis (CASPAR) criteria for PsA. The data were collected with a standardized form. RESULTS: Eight patients (five adults) were identified in one paediatric and two adult departments. In all but one patient, SpA manifestations occurred several years after SJIA/AOSD onset [mean (s.d.) delay 6.2 (3.8) years]. Two patients had peripheral and three axial SpA, and four later exhibited PsA and one SAPHO syndrome. The prevalence of SpA in an adult cohort of 76 patients with AOSD was 6.58% (95% CI 2.17, 14.69), greater than the prevalence of SpA in the French general population (0.3%; 95% CI 0.17, 0.46). The prevalence of SpA in an SJIA cohort of 30 patients was 10% (95% CI 2.11, 26.53), more than that reported in the general population of industrialized countries, estimated at 0.016-0.15%. CONCLUSION: While the temporal disassociation between SpA and AOSD in most cases might suggest a coincidental finding, our work raises the possibility of an SpA/AOSD spectrum overlap that needs further study.

A case of multisystem inflammatory syndrome in children presenting as systemic onset juvenile idiopathic arthritis.

Multisystem inflammatory syndrome in children (MIS-C) is a rare and serious COVID-19 manifestation characterised by generalised inflammatory response including inflammation of the heart, blood vessels, lungs, kidneys, brain, skin, eyes and gastrointestinal system. Children usually present with fever lasting for 24 hours or more along with other symptoms such as abdominal pain, vomiting, diarrhoea, skin rash, red eyes, and swelling of the lips, tongue, hands and feet. Children with MIS-C usually have negative results for a current infection with COVID-19 but positive antibody results indicating that these children were infected with the COVID-19 virus in the past. We present the case of a 12-month-old girl with multisystem inflammatory syndrome presenting as systemic-onset juvenile idiopathic arthritis (SoJIA) and positive Covid-19 PCR. She was treated successfully with Dexamethasone and Naproxen.

Long-term surveillance of biologic therapies in systemic-onset juvenile idiopathic arthritis: data from the German BIKER registry.

OBJECTIVE: Using data from the German Biologics JIA Registry (BIKER), long-term safety of biologics for systemic-onset JIA with regard to adverse events of special interest was assessed. METHODS: Safety assessments were based on adverse event reports after first dose through 90 days after last dose. Rates of adverse event, serious adverse event and 25 predefined adverse events of special interest were analysed. Incidence rates were compared for each biologic against all other biologics combined applying a mixed-effect Poisson model. RESULTS: Of 260 systemic-onset JIA patients in this analysis, 151 patients received etanercept, 109 tocilizumab, 71 anakinra and 51 canakinumab. Patients with etanercept had higher clinical Juvenile Arthritis Disease Activity Score 10 scores, active joint counts and steroid use at therapy start. Serious adverse events were reported with higher frequency in patients receiving canakinumab [20/100 patient years (PY)] and tocilizumab (21/100 PY). Cytopenia and hepatic events occurred with a higher frequency with tocilizumab and canakinumab. Medically important infections were seen more often in patients with IL-6 or IL-1 inhibition. Macrophage activation syndrome occurred in all cohorts with a higher frequency in patients with canakinumab (3.2/100 PY) and tocilizumab (2.5/100 PY) vs anakinra (0.83/100 PY) and etanercept (0.5/100 PY). After adjustment only an elevated risk for infections in anakinra-treated patients remained significant. Three definite malignancies were reported in patients ever exposed to biologics. Two deaths occurred in patients treated with etanercept. CONCLUSION: Surveillance of pharmacotherapy as provided by BIKER is an import approach especially for patients on long-term treatment. Overall, tolerance was acceptable. Differences between several biologics were noted and should be considered in daily patient care.

Autoinflammatory diseases in childhood, part 2: polygenic syndromes.

Autoinflammatory diseases are a family of disorders characterized by aberrant stimulation of inflammatory pathways without involvement of antigen-directed autoimmunity. They can be further divided in monogenic and polygenic types. Those without an identified genetic mutation are known as polygenic and include systemic-onset juvenile idiopathic arthritis, idiopathic recurrent acute pericarditis, Behçet syndrome, chronic recurrent multifocal osteomyelitis and inflammatory bowel disease among others. Autoinflammatory diseases are characterized by recurrent flares or persistent systemic inflammation and fever, as well as lymphadenopathy and cutaneous, abdominal, thoracic and articular symptoms. Although these syndromes can mimic infections clinically, the inflammatory lesions in autoinflammatory disorders are aseptic. However, because of their infrequency, varied and nonspecific presentation, and the new genetic identification, diagnosis is usually delayed. In this article, which is Part 2 of a two-part series, the authors review the main polygenic autoinflammatory diseases that can be seen in childhood, with special emphasis wherever applicable on imaging features that may help establish the correct diagnosis. However, the major role of imaging is to delineate organ involvement and disease extent.

Tocilizumab in the treatment of systemic-onset juvenile idiopathic arthritis - single-centre experience.

OBJECTIVES: The aim of the study was to evaluate the efficacy and long-term safety of tocilizumab treatment in children with systemic-onset juvenile idiopathic arthritis in a single centre. MATERIAL AND METHODS: The study was based on a retrospective analysis of a cohort of 10 patients with systemic-onset juvenile idiopathic arthritis who were treated with tocilizumab in the period September 2011-July 2017. Their medical records were analysed taking into consideration the effectiveness of tocilizumab treatment and frequency of side effects. RESULTS: Before the initiation of treatment, 9/10 patients from the study group complained of fever and had significantly increased values of inflammatory markers, with the median CRP concentration 41.1 mg/l (norm < 5 mg/l) and ESR 37 mm/h (norm < 12 mg/l). The period of the initial 12 weeks of treatment was a quantum leap in the course of the disease: all children were afebrile, and inflammatory markers values decreased by 99.4% in the case of CRP and 91.9% in ESR. All patients fulfilled ACR Pedi 50 criteria, and 3 of them achieved ACR Pedi 70. In the next stages of treatment the response to tocilizumab was sustained, reaching 10 children achieving ACR Pedi 70 and 5 ACR Pedi 90 after one year of therapy. Tocilizumab appeared to be relatively safe in the study group. Although elevation of transaminases and neutropenia were observed in 5/10 patients, they were usually mild and transitional in their course. CONCLUSIONS: Tocilizumab is both effective and has a relatively good safety profile in children with severe systemic-onset juvenile idiopathic arthritis. It should be considered in the recommendations as a first-line treatment of this disease.

Treating inflammation by blocking interleukin-1 in humans.

IL-1 is a master cytokine of local and systemic inflammation. With the availability of specific IL-1 targeting therapies, a broadening list of diseases has revealed the pathologic role of IL-1-mediated inflammation. Although IL-1, either IL-1α or IL-1ß, was administered to patients in order to improve bone marrow function or increase host immune responses to cancer, these patients experienced unacceptable toxicity with fever, anorexia, myalgias, arthralgias, fatigue, gastrointestinal upset and sleep disturbances; frank hypotension occurred. Thus it was not unexpected that specific pharmacological blockade of IL-1 activity in inflammatory diseases would be beneficial. Monotherapy blocking IL-1 activity in a broad spectrum of inflammatory syndromes results in a rapid and sustained reduction in disease severity. In common conditions such as heart failure and gout arthritis, IL-1 blockade can be effective therapy. Three IL-1blockers have been approved: the IL-1 receptor antagonist, anakinra, blocks the IL-1 receptor and therefore reduces the activity of IL-1α and IL-1ß. A soluble decoy receptor, rilonacept, and a neutralizing monoclonal anti-interleukin-1ß antibody, canakinumab, are also approved. A monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α are in clinical trials. By specifically blocking IL-1, we have learned a great deal about the role of this cytokine in inflammation but equally important, reducing IL-1 activity has lifted the burden of disease for many patients.

Clinical improvement of renal amyloidosis in a patient with systemic-onset juvenile idiopathic arthritis who received tocilizumab treatment: a case report and literature review.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a common rheumatic disease in children and adolescents. Although JIA may cause secondary amyloidosis, this is a rare complication in patients with JIA and other rheumatic diseases. Many previous studies have revealed that common heterozygous or homozygous mutations in the MEFV gene are associated with systemic-onset JIA (SJIA). CASE PRESENTATION: We herein report a case involving a 19-year-old female patient with difficult-to-control SJIA. She developed progressive proteinuria without clinical signs or symptoms of edema. Renal amyloidosis was diagnosed by renal pathologic examination, which demonstrated deposition of eosinophilic amorphous material in the interlobular arteries, arterioles, and interstitium. Electron microscopy showed fibrillary material deposits with a diameter of 8 to 10 nm. A heterozygous E148Q mutation in the MEFV gene was identified. Conventional disease-modifying anti-rheumatic drugs and etanercept had been used to treat the SJIA, but the disease could not be controlled. Therefore, we decided to start tocilizumab to control the disease activity. However, the patient was unable to receive a standard dose of tocilizumab in the early period of treatment because of socioeconomic limitations. Her disease course was still active, and proteinuria was found. Therefore, tocilizumab was increased to a dose of 8 mg/kg every 2 weeks (standard dose of SJIA), and the patient exhibited a clinical response within 3 months. CONCLUSION: Refractory SJIA associated with renal amyloidosis is an uncommon cause of proteinuria in adolescents. Tocilizumab may be a beneficial treatment for renal amyloidosis in patients with SJIA.

Pathogenesis of systemic inflammatory diseases in childhood: "Lessons from clinical trials of anti-cytokine monoclonal antibodies for Kawasaki disease, systemic onset juvenile idiopathic arthritis, and cryopyrin-associated periodic fever syndrome".

Inflammation has often been considered to be a nonspecific response and to play a bridging role in the activation of adaptive immunity. However, it is now accepted that inflammation is the product of an independent innate immune system closely linked to the adaptive immune system. The key mediators of inflammation are inflammatory cytokines, as determined by multiple lines of evidence both in vitro and in vivo. Due to the crucial role of inflammatory cytokines in the pathogenesis of autoimmune disorders, anti-cytokine treatment has been developed as a therapy for rheumatoid arthritis, juvenile idiopathic arthritis (JIA), and inflammatory bowel diseases. We recently completed several clinical trials of anti-cytokine treatment for children with systemic inflammatory diseases: anti-IL-6 receptor monoclonal antibody (tocilizumab) for children with two subtypes of JIA (poly-JIA and systemic JIA), anti-TNF-α monoclonal antibody (infliximab) for children with Kawasaki disease, and anti-IL-1-ß monoclonal antibody (canakinumab) for children with cryopyrin-associated periodic syndrome. This review summarizes the basis of inflammation in terms of innate immunity and adaptive immunity in these systemic inflammatory diseases, clinical efficacy, and tolerability of these biologic agents, and attempts to determine the roles of individual inflammatory cytokines in disease pathogenesis.

AA amyloidosis associated with systemic-onset juvenile idiopathic arthritis.

We report a 12-year-old boy with nephrotic syndrome due to renal AA amyloidosis. The AA amyloidosis was associated with a 3-year history of systemic-onset juvenile idiopathic arthritis. The presence of serum amyloid A protein was confirmed by laser microdissection of Congo Red-positive glomeruli and vessels followed by liquid chromatography and tandem mass spectrometry; this analysis excluded hereditary and familial amyloidosis. Aggressive management of the systemic-onset juvenile idiopathic arthritis resulted in improvement in clinical and laboratory parameters. The case represents an unusual cause of nephrotic syndrome in children. Early diagnosis of renal amyloidosis and management of systemic-onset juvenile idiopathic arthritis is paramount to preventing progression of kidney disease.

Urticaria mimickers in children.

Acute urticaria is a self-limited cutaneous condition marked by transient, erythematous, and pruritic wheals. It is a hypersensitivity response that is often secondary to infection, medications, or food allergies in children. In contrast, the urticarial "mimickers" described in this review article are often seen in the context of fever and extracutaneous manifestations in pediatric patients. The differential diagnosis ranges from benign and self-limited hypersensitivity responses to multisystem inflammatory diseases. Establishing the correct diagnosis of an urticarial rash in a pediatric patient is necessary to both prevent an unnecessary work up for self-limited conditions and to appropriately recognize and evaluate multisystem inflammatory disorders. Herein, we describe two cases to illustrate the clinical manifestations, laboratory findings, histopathology and differential diagnoses for several mimickers of acute urticaria including: urticaria multiforme, serum sickness like reaction, Henoch-Schönlein purpura, acute hemorrhagic edema of infancy, systemic onset juvenile idiopathic arthritis, cryopyrin associated periodic syndromes, and urticarial vasculitis.

Case report: Success of allogeneic hematopoietic stem cell transplantation for refractory systemic-onset juvenile idiopathic arthritis.

Objectives: This study reports cases of systemic-onset juvenile idiopathic arthritis (sJIA) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at our center and reviews published outcomes of allo-HSCT in sJIA. Methods: We present a case report of two patients with sJIA who underwent allo-HSCT at a tertiary pediatric hospital. Each patient's disease course and allo-HSCT protocol/outcome are described. Outcomes of published cases of allo-HSCT in sJIA were compared to our experience. Results: Two patients with sJIA had allo-HSCT. Both failed multiple lines of disease-modifying anti-rheumatic drugs and experienced severe disease/treatment-related complications. Despite post-HSCT complications, both recovered without sequelae. Five years post-HSCT, patient 1 is in complete remission (CR) and is off medications. Patient 2 was in CR until 11 months post-HSCT after which he developed three disease flares. At 4 years post-HSCT he is currently in CR on Adalimumab monotherapy. Engraftment was excellent with a donor chimerism of 100% for patient 1 and 93% for patient 2. In the literature, the outcome of allo-HSCT is reported in 13 sJIA patients. When merging those with our 2 patients, 1/15 patients died and 13/14 achieved CR, of which 12 are off medications (median [range] follow-up: 2.2 [0.2-7.0] years). Extended follow-up data on 11 of the 13 reported sJIA patients showed that an additional 3 patients flared at 3, 4, and 10 years post-HSCT. Conclusion: We report two patients with severe/refractory sJIA who underwent successful allo-HSCT and achieved CR. Allo-HSCT is a potential curative option for severe/refractory sJIA. It should be considered only after failure of conventional sJIA treatments and when an HLA-matched donor is available in order to lower transplant-related mortality. The outcomes of reported sJIA patients who received allo-HSCT are encouraging but long-term follow-up data are needed to better characterized the risk-benefit ratio of this procedure.

Disease evolution in systemic juvenile idiopathic arthritis: an international, observational cohort study through JIRcohort.

BACKGROUND: Systemic juvenile idiopathic arthritis (systemic JIA) is a severe disease with both systemic and joint inflammation. This study aims to identify predictors of disease evolution within the systemic JIA population enrolled in the Juvenile Inflammatory Rheumatism cohort (JIRcohort). METHODS: Observational patient cohort study with 201 recruited children from 4 countries (3 European, 1 North Africa) from 2005 until 2019, using retrospectively (2005-2015) and prospectively (2015-2019) routine care collected data. RESULTS: Sixty-five patients with complete follow-up data for 24 months after first diagnosis were classified as monophasic (n = 23), polyphasic (n = 6) or persistent group (n = 36) corresponding to their evolution (unique flare, recurrent flares, or persistent disease activity respectively). The patients of the persistent group were more likely to have an earlier disease onset, before the age of 6 (OR 2.57, 95%-CI 0.70-9.46), persistence of arthritis at 12-months post-diagnosis (OR 4.45, 95%-CI 0.58-34.20) and higher use of synthetic DMARD (sDMARD, OR 5.28, 95%-CI 1.39-20.01). Other variables like global assessment by physician and by patient and C Reactive Protein levels at 12-months post-diagnosis were assessed but without any predictive value after adjusting for confounding factors. CONCLUSIONS: Our results suggest that the earlier disease onset, the persistence of arthritis throughout the first year of disease evolution and the need of sDMARD might predict a persistent disease course.

Juvenile idiopathic arthritis with systemic onset with inflammatory bone lesions: two case reports of patients successfully treated with canakinumab and experience gained from literature.

Non-bacterial osteomyelitis (NBO) is a rare chronic inflammatory bone disease related to immune system dysregulation. This disease belongs to a family of autoinflammatory diseases. It often coexists with other TNF-α-mediated immune-mediated diseases such as juvenile idiopathic arthritis (JIA) and inflammatory bowel diseases. Previously, interleukin-1-driven inflammation was described predominantly in monogenic cases of NBO, such as DIRA syndrome or Majeed syndrome. However, the association between NBO and JIA with systemic onset (soJIA) has not been described yet. Herein, we describe the cases of two patients with soJIA with inflammatory bone lesions wherein canakinumab (anti-interleukin-1ß antibodies) caused remission. Case descriptions: Patient 1-A 6-month-old boy with typical soJIA suffered a destruction of the 7th to 9th ribs and the left pubic bone. Antibiotics, IVIG, and cyclosporine proved ineffective. Corticosteroids were effective, but due to the factor of corticosteroid dependence, which has some disadvantages, canakinumab with a dosage of 4 mg/kg was initiated every 4 weeks, which completely controlled the disease and allowed to taper corticosteroids.Patient 2-A 2-year-old girl developed chronic non-bacterial osteomyelitis of the 5th rib 2 months after taking corticosteroids prescribed for typical soJIA. She underwent surgical debridement removal, and several courses of antibiotics proved ineffective. She developed macrophage activation syndrome, following which anakinra was prescribed, which resulted in only temporary improvement. Therefore, this drug was switched to canakinumab, which caused corticosteroid-free remission. Conclusion: This is the first description of a rare association of soJIA with inflammatory bone lesions with the proven efficacy of IL-1 blockade. The association of two autoinflammatory conditions should indicate IL-1-driven mechanisms and a possible genetic basis. Follow-up genetic and functional studies are required to better understand the pathogenesis of such overlapping diseases.

Efficacy of anakinra treatment in pediatric rheumatic diseases: Our single-center experience.

Objectives: This study aims to present our experience on anakinra, a recombinant interleukin-1 (IL-1) receptor antagonist, and efficacy results in pediatric rheumatic diseases in our clinic. Patients and methods: Between July 1st, 2016 and July 1st, 2020, a total of 33 pediatric patients (18 males, 15 females; mean age: 6±3.4 years; range 4 to 13 years) with pediatric rheumatic diseases who were treated with anakinra were retrospectively analyzed. The patients with over one-month treatment period and followed for at least one year were included. Demographic and clinical findings, outcomes, adverse events, prior and/or additional treatments were collected at baseline, at 3 and 12 months of therapy. Results: There were 33 patients with different pediatric rheumatic diseases (11 with systemic juvenile idiopathic arthritis [sJIA] complicated by macrophage activation syndrome [MAS], six with hyperimmunoglobulin-D syndrome, five with cryopyrin-associated periodic syndrome, five with familial Mediterranean fever, four with idiopathic recurrent pericarditis, one with NLRP12-associated periodic fever syndrome and one with unclassified systemic autoinflammatory disease), in the study group. The complete response was observed 69.7% of patients, partial response in 24.2%, and no response in 6.1% at three months of treatment. Inactive disease status was achieved in 45.5% of the patients with remission-on medication and 18.2% of the patients with remission-off medication at the end of a year. Anakinra was switched to other biological treatments in 51.5% of patients (n=17). Biological switch to canakinumab and tocilizumab were observed in 70.6% and 29.4% of these patients. Except for local reactions (n=2), no adverse events were observed in any of the patients. Conclusion: Anakinra appears to be a promising treatment alternative owing to its rapid effect as a result of its short half-life in autoinflammatory conditions. While short-term therapy seems to be sufficient for the sJIA complicated by MAS, the patients with systemic autoinflammatory diseases maintenance a more anakinra-dependent course.

Crohn's disease in a patient with systemic onset juvenile idiopathic arthritis. Association or associated side effect of treatment?

The progression of systemic-onset juvenile idiopathic arthritis (JIAs) to the different forms of presentation of inflammatory bowel disease is extremely rare. We present the first report of a patient with SJIA that progressed to Crohn's disease in which mutations have been detected in genes responsible for the adequate regulation of the innate immune system.

Refractory systemic onset juvenile idiopathic arthritis: current challenges and future perspectives.

Systemic juvenile idiopathic arthritis (SJIA) is a rare disease with distinct features not seen in other categories of juvenile idiopathic arthritis. In recent years, advances in the understanding of disease immunopathogenesis have led to improved targeted therapies with significant improvement in patient outcomes. Despite these advances, there remain subsets of SJIA with refractory disease and severe disease-associated complications. This review highlights existing options for treatment of refractory SJIA and explores potential future therapeutics for refractory disease.Key Points:Despite targeted Interleukin IL-1 and IL-6 inhibitors a subset of SJIA remains refractory to therapy. About 1 in 7 SJIA patients will be refractory to targeted IL-1 or IL-6 therapy.There is no current agreed upon definition for refractory SJIA and we propose in this review that refractory SJIA is presence of active systemic or arthritic features despite treatment with anti-IL-1 or anti-IL-6 therapy or disease requiring glucocorticoids for control beyond 6 months.SJIA disease associated complications include presence of associated macrophage activation syndrome (MAS), interstitial lung disease (ILD) or amyloidosis and management of each differs.Refractory SJIA treatment options currently include additional conventional synthetic disease modifying anti-rheumatic drugs (csDMARDS), biologic (bDMARDS), combination biologic therapy, targeted synthetic (tsDMARDS) or other immunomodulatory therapies.

Still's Disease Mortality Trends in France, 1979-2016: A Multiple-Cause-of-Death Study.

Still's disease (SD) is often considered a benign disease, with low mortality rates. However, few studies have investigated SD mortality and its causes and most of these have been single-center cohort studies. We sought to examine mortality rates and causes of death among French decedents with SD. We performed a multiple-cause-of-death analysis on data collected between 1979 and 2016 by the French Epidemiological Center for the Medical Causes of Death. SD-related mortality rates were calculated and compared with the general population (observed/expected ratios, O/E). A total of 289 death certificates mentioned SD as the underlying cause of death (UCD) (n = 154) or as a non-underlying causes of death (NUCD) (n = 135). Over the study period, the mean age at death was 55.3 years (vs. 75.5 years in the general population), with differences depending on the period analyzed. The age-standardized mortality rate was 0.13/million person-years and was not different between men and women. When SD was the UCD, the most frequent associated causes were cardiovascular diseases (n = 29, 18.8%), infections (n = 25, 16.2%), and blood disorders (n = 11, 7.1%), including six cases (54%) with macrophage activation syndrome. As compared to the general population, SD decedents aged <45 years were more likely to die from a cardiovascular event (O/E = 3.41, p < 0.01); decedents at all ages were more likely to die from infection (O/E = 7.96-13.02, p < 0.001).

Detection and Prediction of Macrophage Activation Syndrome in Still's Disease.

Distinguishing between macrophage activation syndrome (MAS) and a simple flare of Still's disease (SD) may be challenging. We sought to clarify the clinical features and outcome of MAS in SD and to explore predictive factors of MAS development. Demographic and clinical data, treatments, and outcomes were recorded in a cohort of 206 SD patients. SD patients with and without MAS were compared. To explore predictive factors for the development of MAS, patients were compared at the time of SD diagnosis. Twenty (9.7%) patients experienced MAS, which was inaugural in 12 cases. Patients with MAS were more likely to have hepatomegaly (OR, 3.71; 95% CI, 1.14-11.2; p = 0.03) and neurological symptoms (OR, 4.43; 95% CI, 1.08-15.3; p = 0.04) than patients without MAS. Cytopenias, abnormal liver tests, and coagulation disorders were significantly more frequent in patients with MAS; lactate dehydrogenase and serum ferritin levels were significantly higher. An optimized threshold of 3500 µg/L for serum ferritin yielded a sensitivity (Se) of 85% and a negative predictive value (NPV) of 97% for identifying patients with/without MAS. Survival analysis showed that a high ferritin level at the time of SD diagnosis was predictive of MAS development (p < 0.001). Specific factors, including neurological symptoms, cytopenias, elevated LDH, and coagulopathy, may contribute to the early detection of MAS. Extreme hyperferritinemia at the onset of SD is a prognostic factor for the development of MAS.