Purtscher-Like Retinopathy Secondary to Febrile Illnesses in Pediatric Patients: A Case Series.

PURPOSE: Purtscher-like retinopathy is a rare microvascular occlusive disease that has been reported in few literature especially in pediatric patients. The ocular manifestation is associated with various systemic disorders, though its distinct pathophysiology and appropriate therapies remain unclear. This research presents three cases of Purtscher-like retinopathy secondary to febrile illnesses in pediatric patients. METHODS: Medical history and clinical findings were retrospectively collected. RESULTS: We report a series of three pediatric patients (age range, 7-13 years) who developed Purtscher-like retinopathy, secondary to febrile illnesses, including systemic juvenile idiopathic arthritis, thrombotic microangiopathy, and COVID-19 infection. All patients received steroidal therapy to control underlying conditions and ocular disease, with visual improvement in different degrees. CONCLUSIONS: Clinician awareness of Purtscher-like retinopathy is crucial for the prompt diagnosis and treatment of pediatric patients with protracted high fevers and febrile viral illnesses.

Systemic auto-inflammatory manifestations in patients with spondyloarthritis.

OBJECTIVES: (1) characterizing a group of spondyloarthritis (SpA) patients with systemic auto-inflammatory symptoms (S-SpA); (2) comparing SpA features with and without auto-inflammatory symptoms; (3) comparing the auto-inflammatory features of S-SpA and Still's disease (SD). METHODS: Retrospective observational study. Clinical data of adult and pediatric patients with S-SpA, SD or SpA were collected retrospectively and analyzed. RESULTS: Forty-one subjects with S-SpA, 39 with SD and 42 with SpA were enrolled. The median latency between systemic and articular manifestations in S-SpA was 4.4 (IQR: 7.2) years. S-SpA and SpA had similar frequency of peripheral arthritis and enthesitis (N.S.), while tenosynovitis was more frequent (P=0.01) and uveitis less frequent (P<0.01) in S-SpA. MRI showed signs of sacroiliac inflammation and damage in both S-SpA and SpA equally (N.S.). S-SpA patients had less corner inflammatory lesions (P<0.05) and inflammation at the facet joints (P<0.01), more interspinous enthesitis (P=0.01) and inter-apophyseal capsulitis (P<0.01). Compared to SD, S-SpA patients had lower-grade fever (P<0.01), less rash (P<0.01) and weight loss (P<0.05), but more pharyngitis (P<0.01), gastrointestinal symptoms (P<0.01) and chest pain (P<0.05). ESR, CRP, WBC, ANC, LDH tested higher in SD (P<0.01). Resolution of systemic symptoms was less frequent in S-SpA than SD on corticosteroid (P<0.01) and methotrexate (P<0.05) treatment. When considering all SD patients, a complete response to corticosteroids in the systemic phase significantly reduced the likelihood of developing SpA (OR=0.06, coefficient -2.87 [CI: -5.0 to -0.8]). CONCLUSIONS: SpA should be actively investigated in patients with auto-inflammatory manifestations, including undifferentiated auto-inflammatory disease and SD.

Evaluating treatment practices and challenges in systemic Juvenile Idiopathic Arthritis: a comprehensive survey analysis.

OBJECTIVE: This study aims to assess current diagnostic and management for systemic Juvenile Idiopathic Arthritis (sJIA) among physicians, evaluate the challenges encountered in diagnosis and treatment, and identify the educational needs and professional development engagements of physicians managing sJIA. METHODS: A nationwide survey was conducted from November 2023 to March 2024 across tertiary and secondary pediatric and general hospitals in China. The survey targeted physicians with at least three years of specialty experience, resulting in 310 valid responses from 25 provinces, autonomous regions, and municipalities. The survey collected data on diagnostic practices, treatment approaches, and professional development related to sJIA. Data collection was facilitated through WeChat, and statistical analysis was performed using descriptive statistics. Ethical approval was obtained from the Ethics Committee of Beijing Children's Hospital, with informed consent provided electronically by participants. RESULTS: The survey indicated that all physicians encountered suspected or confirmed cases of sJIA, highlighting its prevalence and the diagnostic challenges associated. Regarding diagnostic standards, 53.9% of physicians used the "Consensus on the Diagnosis and Treatment of sJIA and Macrophage Activation Syndrome," 18.1% followed the International League of Associations for Rheumatology (ILAR) standards, and 24.8% adhered to the Pediatric Rheumatology International Trials Organization (PRINTO) standards. In treatment strategies, glucocorticoids and IL-6 receptor monoclonal antibodies were extensively used, with the latter receiving "excellent" and "satisfactory" ratings of 46.5% and 36.1%, respectively, demonstrating high efficacy and acceptance. Main challenges included high treatment costs, complexity of diagnosis, patient compliance issues, and potential long-term side effects of biologics. Additionally, 126 doctors (40.7%) actively participated in more than three academic conferences or systematic learning courses related to sJIA, indicating a strong demand for ongoing education, particularly in new treatment developments and diagnostic skills. CONCLUSION: The findings emphasize the necessity for standardized diagnosis and customized treatment plans tailored to patient-specific conditions in managing sJIA. Key Points • The survey highlights the prevalence and clinical challenges of sJIA among physicians, emphasizing the importance of vigilant diagnosis, multi-system involvement, and differential diagnosis to improve treatment outcomes and patient quality of life.

Efficacy and safety of tocilizumab in Chinese patients with systemic juvenile idiopathic arthritis: a multicentre phase IV trial.

OBJECTIVES: Given the limited tocilizumab (TCZ) treatment data for systemic juvenile idiopathic arthritis (sJIA) in China, we evaluated the long-term efficacy and safety of TCZ in Chinese patients with sJIA. METHOD: In this multicentre, interventional Phase IV study, patients with sJIA and inadequate clinical response to non-steroidal anti-inflammatory drugs/corticosteroids received TCZ infusions every 2 weeks based on body weight (< 30 kg, 12 mg/kg; ≥ 30 kg, 8 mg/kg), over a 52-week open-label period and an 8-week safety follow-up period. The primary endpoint was the proportion of patients with a JIA American College of Rheumatology (ACR) 30 response and absence of fever at Week 12. RESULTS: Sixty-two patients were enrolled and treated (12-mg/kg group, 34; 8-mg/kg group, 28). At Week 12, 87.1% (95% confidence interval 78.8%-95.4%) of patients had JIA ACR 30 response and absence of fever; Week 52 results were similar. The proportion of JIA ACR 30/50/70/90 responders rapidly increased at Week 12, up to Week 52. High-sensitivity C-reactive protein (hsCRP) levels decreased within 4 weeks; 44/58 patients (75.9%) with elevated baseline hsCRP recovered at Week 52. Childhood Health Assessment Questionnaire pain scores, disability index scores, and mean corticosteroid dose decreased over time. Height standard deviation score changes at Week 52 indicated catch-up growth. Most adverse events (AEs) were mild (serious AE incidence, 17.7%). No deaths or macrophage activation syndrome occurred. CONCLUSION: This is the first multicentre trial to report the efficacy and safety of TCZ in Chinese patients with sJIA at 52 weeks. No new safety concerns were found.

Anti-Interferon-γ Therapy for Cytokine Storm Syndromes.

A vast body of evidence provides support to a central role of exaggerated production of interferon-γ (IFN-γ) in causing hypercytokinemia and signs and symptoms of hemophagocytic lymphohistiocytosis (HLH). In this chapter, we will describe briefly the roles of IFN-γ in innate and adaptive immunity and in host defense, summarize results from animal models of primary HLH and secondary HLH with particular emphasis on targeted therapeutic approaches, review data on biomarkers associated with activation of the IFN-γ pathway, and discuss initial efficacy and safety results of IFN-γ neutralization in humans.

Long-term efficacy of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in two patients with sJIA and recurrent episodes of MAS.

INTRODUCTION: Systemic juvenile idiopathic arthritis (sJIA), a multifaceted autoinflammatory disorder, can be complicated by life-threatening conditions such as macrophage activation syndrome (MAS) and interstitial lung disease (ILD). The management of these conditions presents a therapeutic challenge, underscoring the need for innovative treatment approaches. OBJECTIVES: to report the possible role of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in the treatment of multi-drug-resistant sJIA. METHODS: We report two patients affected by sJIA with severe and refractory MAS and high serum IL-18 levels, responding to dual blockade of IL-1ß and IL-18. RESULTS: The first patient is a 20-year-old man, presenting a severe MAS complicated by thrombotic microangiopathy, following SARS-CoV-2 infection. He was treated with MAS825, with quick improvement. Eighteen months later, the patient is still undergoing biweekly treatment with MAS825, associated with MTX, ciclosporin and low-dose glucocorticoids, maintaining good control over the systemic features of the disease.The second patient, a 10-year-old girl, presented a severe MAS case, complicated by posterior reversible encephalopathy syndrome (PRES), following an otomastoiditis. The MAS was not fully controlled despite treatment with IV high-dose glucocorticoids, anakinra and ciclosporin. She began biweekly MAS825, which led to a prompt amelioration of MAS parameters. After 10 months, the patient continues to receive MAS825 and is in complete remission. CONCLUSION: In light of the pivotal role of IL-1ß and IL-18 in sJIA, MAS and ILD, MAS825 might represent a possible valid and safe option in the treatment of drug-resistant sJIA, especially in the presence of high serum IL-18 levels.

Genetics of Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis.

Macrophage activation syndrome (MAS) is a life-threatening episode of hyperinflammation driven by excessive activation and expansion of T cells (mainly CD8) and hemophagocytic macrophages producing proinflammatory cytokines. MAS has been reported in association with almost every rheumatic disease, but it is by far most common in systemic juvenile idiopathic arthritis (SJIA). Clinically, MAS is similar to familial or primary hemophagocytic lymphohistiocytosis (pHLH), a group of rare autosomal recessive disorders linked to various genetic defects all affecting the perforin-mediated cytolytic pathway employed by NK cells and cytotoxic CD8 T lymphocytes. Decreased cytolytic activity in pHLH patients leads to prolonged survival of target cells associated with increased production of proinflammatory cytokines that overstimulate macrophages. The resulting cytokine storm is believed to be responsible for the frequently fatal multiorgan system failure seen in MAS. Whole exome sequencing as well as targeted sequencing of pHLH-associated genes in patients with SJIA-associated MAS demonstrated increased "burden" of rare protein-altering variants affecting the cytolytic pathway compared to healthy controls, suggesting that as in pHLH, genetic variability in the cytolytic pathway contributes to MAS predisposition. Functional studies of some of the novel variants have shown that even in a heterozygous state, their presence partially reduces cytolytic activity that may lead to increased cytokine production.

Criteria for Cytokine Storm Syndromes.

In the past two decades, there has been a great deal of work aimed to devise diagnostic guidelines, classification criteria, and diagnostic scores for cytokine storm syndromes (CSSs). The most notable effort has been the large-scale multinational study that led to the development of the 2016 classification criteria for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (JIA). Future studies should scrutinize the validity of the proposed criteria, particularly in systemic JIA patients treated with biologics, in children with subtle or incomplete forms of MAS, and in patients with MAS complicating other rheumatologic disorders. More generic CSS criteria are also available but often lack sensitivity and specificity in a wide variety of patient populations and CSSs of different etiologies. The coronavirus disease 2019 (COVID-19)-related lung disease led to an evolution of the concept of a "cytokine storm." Emerging and unsolved challenges in the diagnosis of the different forms of CSSs highlight the need for diagnostic tools and well-established classification criteria to enable timely recognition and correct classification of patients.

Kawasaki Disease-Associated Cytokine Storm Syndrome.

Kawasaki disease (KD) is a hyperinflammatory syndrome manifesting as an acute systemic vasculitis characterized by fever, nonsuppurative conjunctival injection, rash, oral mucositis, extremity changes, and cervical lymphadenopathy. KD predominantly affects young children and shares clinical features and immunobiology with other hyperinflammation syndromes including systemic juvenile idiopathic arthritis (sJIA) and multisystem inflammatory syndrome in children (MIS-C). Cytokine storm syndrome (CSS) is an acute complication in ~2% of KD patients; however, the incidence is likely underestimated as many clinical and laboratory features of both diseases overlap. CSS should be entertained when a child with KD is unresponsive to IVIG therapy with recalcitrant fever. Early recognition and prompt institution of immunomodulatory treatment can substantially reduce the mortality and morbidity of CSS in KD. Given the known pathogenetic role of IL-1ß in both syndromes, the early use of IL-1 blockers in refractory KD with CSS deserves consideration.

Cytokine Storm Syndrome Associated with Systemic Juvenile Idiopathic Arthritis.

The cytokine storm syndrome (CSS) associated with systemic juvenile idiopathic arthritis (sJIA) has widely been referred to as macrophage activation syndrome (MAS). In this chapter, we use the term sJIA-associated CSS (sJIA-CSS) when referring to this syndrome and use the term MAS when referencing publications that specifically report on sJIA-associated MAS.

Serum interleukin-18 levels can improve the diagnostic performance of the PRINTO and ILAR criteria for systemic juvenile idiopathic arthritis.

OBJECTIVE: Recently, the Pediatric Rheumatology International Trials Organization (PRINTO) has proposed revisions to the current International League of Associations for Rheumatology (ILAR) criteria for systemic juvenile idiopathic arthritis (s-JIA). Interleukin (IL)-18 overproduction plays a significant role in the pathogenesis of s-JIA. This study aimed to evaluate the performance of the PRINTO criteria compared with the ILAR criteria and determine whether serum IL-18 levels improve their diagnostic performances. METHODS: Overall, 90 patients with s-JIA and 27 patients with other febrile disease controls presenting with a prolonged fever of > 14 days and arthritis and/or erythematous rash were enrolled. The ILAR and PRINTO classification criteria were applied to all patients and examined with expert diagnoses. Enzyme-linked immunosorbent assay was used for measuring serum IL-18 levels. RESULTS: The PRINTO criteria had higher sensitivity but lower specificity than the ILAR criteria (sensitivity: PRINTO 0.856, ILAR 0.533; specificity: PRINTO 0.259, ILAR 0.851). With the addition of serum IL-18 levels ≥ 4,800 pg/mL, the sensitivity of the ILAR criteria and specificity of the PRINTO criteria were improved to 1.000 and 1.000, respectively. PRINTO plus serum IL-18 levels ≥ 4,800 pg/mL showed the highest value in Youden's index (sensitivity - [1 - specificity]). CONCLUSION: Serum IL-18 levels could improve the diagnostic performance of the PRINTO and ILAR criteria for s-JIA. The PRINTO criteria plus serum IL-18 levels ≥ 4,800 pg/mL could be the best diagnostic performance for s-JIA.

Systemic juvenile idiopathic arthritis with chronic recurrent multifocal osteomyelitis in an adolescent: A case report.

Chronic recurrent multifocal osteomyelitis is a rare auto-inflammatory disease in children, with only a few reports of its association with other inflammatory diseases, such as systemic juvenile idiopathic arthritis. A 15-year-old boy was admitted due to fever, skin rash, arthritis, and high inflammatory factors and was finally diagnosed with systemic juvenile idiopathic arthritis. After 6 months of recovery from the disease, the patient was referred due to local pain and swelling in the arms and left thigh. In radiography, bone lesions were seen in the shoulders, left humerus, and left femoral diaphysis. A whole-body bone scan showed increased absorption in these areas, which suggested a tumor or osteomyelitis. A biopsy of the bone lesion of the left humerus confirmed sterile osteomyelitis. Although the co-incidence of chronic recurrent multifocal osteomyelitis with systemic juvenile idiopathic arthritis is rare, it should be considered in differential diagnosis.

Efficacy and Safety of Biological Drugs in Still's Disease: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES: 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. CONCLUSION: 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.

Single center clinical analysis of macrophage activation syndrome complicating juvenile rheumatic diseases.

BACKGROUND: Macrophage activation syndrome (MAS), an example of secondary hemophagocytic lymphohistiocytosis, is a potentially fatal complication of rheumatic diseases. We aimed to study the clinical and laboratory characteristics, treatment schemes, and outcomes of different rheumatic disorders associated with MAS in children. Early warning indicators of MAS have also been investigated to enable clinicians to make a prompt and accurate diagnosis. METHODS: Fifty-five patients with rheumatic diseases complicated by MAS were enrolled between January 2017 and December 2022. Clinical and laboratory data were collected before disease onset, at diagnosis, and after treatment with MAS, and data were compared between patients with systemic juvenile idiopathic arthritis (sJIA), Kawasaki disease (KD), and systemic lupus erythematosus (SLE). A random forest model was established to show the importance score of each variable with a significant difference. RESULTS: Most (81.8%) instances of MAS occurred during the initial diagnosis of the underlying disease. Compared to the active stage of sJIA, the platelet count, erythrocyte sedimentation rate, and fibrinogen level in sJIA-MAS were significantly decreased, whereas ferritin, ferritin/erythrocyte sedimentation rate, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and D-dimer levels were significantly increased. Ferritin level, ferritin/erythrocyte sedimentation rate, and platelet count had the greatest predictive value for sJIA-MAS. The level of IL-18 in the sJIA-MAS group was significantly higher than in the active sJIA group, whereas IL-6 levels were significantly lower. Most patients with MAS were treated with methylprednisolone pulse combined with cyclosporine, and no deaths occurred. CONCLUSIONS: Thrombocytopenia, ferritin levels, the ferritin/erythrocyte sedimentation rate, and elevated aspartate aminotransferase levels can predict the occurrence of MAS in patients with sJIA. Additionally, our analysis indicates that IL-18 plays an important role in the pathogenesis of MAS in sJIA-MAS.

Efficacy and safety of an early response-based tapering regimen of tocilizumab in children with systemic juvenile idiopathic arthritis.

INTRODUCTION: Systemic juvenile idiopathic arthritis (sJIA) is a distinct disease subset, with a poorer prognosis compared with other JIA subsets. Tocilizumab has an important role in the management of sJIA refractory to standard initial therapy. However, no specific guidelines exist for the tapering of tocilizumab therapy in sJIA, which could have implications on the overall cost and side effects of treatment. METHODS: This was an observational study which included 21 children with refractory sJIA, who were initially put on injection tocilizumab every 2 weekly, with subsequent dosing tapered to 4 weekly and 6 weekly intervals based on JIA ACR 70 responses at 12 and 24 weeks, respectively. The primary outcome at week 36 included JIA ACR 30, 50, 70, and 90 response rates with other efficacy and safety measures as secondary outcomes. RESULTS: At 36 weeks, JIA ACR 30, 50, 70, and 90 responses were observed in 90.5%, 90.5%, 71.4%, and 52.4% patients respectively along with significant improvement in hematological and inflammatory parameters. The mean prednisolone dose could be reduced from 0.54 to 0.13 mg/kg/day and around 29% patients were able to discontinue steroids altogether. No serious adverse events were recorded. With drug tapering, we could curtail on 26% of the total tocilizumab dose that would have been otherwise required on the continuous 2 weekly protocol. CONCLUSIONS: Tocilizumab, used in an early response-based tapering regimen, was both safe and efficacious in children with sJIA refractory to standard therapy. Larger and longer duration studies are required to further validate our observations.

Diagnosing and Treating Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease as Part of the Still's Disease Continuum.

Aim: We have summarised the existing evidence supporting the concept that systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) are part of the same Still's disease spectrum. Methods: A PubMed/Embase database search was conducted using specific search strings and free text words to screen for relevant articles. The search was limited to studies in humans, published up to June 2023, in English-language. Summary: sJIA and AOSD are rare autoinflammatory disorders that have similar pathophysiological and clinical features. The clinical presentations of sJIA and AOSD are highly variable, with differential diagnoses that include a broad range of malignancies, infectious diseases, and autoimmune disorders, which contribute to delays in diagnosis. Several sets of classification exist to help diagnose patients in clinical practice; the International League of Associations for Rheumatology criteria for sJIA and the Yamaguchi and Fautrel criteria for AOSD are the most-used criteria. The therapeutic strategy for Still's disease aims to relieve signs and symptoms, prevent irreversible joint damage and potentially life-threatening complications, and avoid deleterious side effects of treatment. Recently, targeted therapies such as interleukin (IL)-1 and IL-6 inhibitors have become available for the treatment of sJIA and AOSD. While these biologics were originally largely reserved for patients in whom non-steroidal anti-inflammatory drugs, corticosteroids and conventional synthetic disease-modifying anti-rheumatic drugs had failed, they are increasingly used earlier in the treatment paradigm. Among IL-1 inhibitors, canakinumab is the only biologic approved in the US for the treatment of both sJIA and AOSD.

Population Pharmacokinetics of the Anti-Interferon-Gamma Monoclonal Antibody Emapalumab: An Updated Analysis.

INTRODUCTION: Emapalumab is a fully human monoclonal antibody that targets free and receptor-bound interferon-gamma (IFNγ), neutralizing its biological activity. IFNγ levels differ by orders of magnitude between patients with primary hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS; a form of secondary HLH) in systemic juvenile idiopathic arthritis (sJIA). Therefore, this study aimed to develop a population pharmacokinetic model for emapalumab across a patient population with a wide range of total (free and emapalumab-bound) IFNγ levels using observations from patients with primary HLH or MAS in sJIA in clinical trials. METHODS: Pharmacokinetic data were pooled (n = 58; 2709 observations) from studies enrolling patients administered emapalumab for primary HLH or MAS in sJIA. Patients with primary HLH were administered emapalumab 1 mg/kg (potentially increasing to 3, 6, and up to 10 mg/kg based on clinical response) every 3 days. Patients with MAS in sJIA were administered emapalumab 6 mg/kg, followed by 3 mg/kg every 3 days until day 15 and twice weekly until day 28. An earlier population PK model was re-parameterized using this data. RESULTS: The final model for emapalumab comprised a 2-compartment model with first-order elimination. Emapalumab clearance remains constant when the total IFNγ concentration (free and emapalumab-bound) is < ~ 10,000 pg/ml but increases proportionally to total IFNγ concentration above this threshold. Emapalumab clearance was estimated to be 0.00218, 0.00308, 0.00623 and 0.01718 l/h at total serum IFNγ concentrations of 103, 104, 105 and 106 pg/ml, respectively, with corresponding terminal half-lives of 19.2, 13.8, 7.18 and 3.12 days for a 1-year-old patient weighing 10 kg with primary HLH. The median terminal half-life for emapalumab in patients with MAS in sJIA was estimated to be 24.0 (range, 6.13-32.4) days, which is similar to observations in healthy volunteers. CONCLUSIONS: Emapalumab pharmacokinetics in patients with primary HLH and MAS in sJIA were described by a two-compartment model with fixed allometric exponents and an age-related effect. Differences in total IFNγ levels between patients with primary HLH and MAS may affect emapalumab pharmacokinetics, suggesting that each indication may require different dosing to rapidly control hyperinflammation. TRIAL REGISTRATION: Clinicaltrials.gov identifiers: NCT01818492, NCT03311854 and NCT02069899.

Patients with a rare condition called hemophagocytic lymphohistiocytosis (HLH) produce excessive amounts of a molecule called interferon-gamma. Excessive interferon-gamma causes extreme (or hyper) inflammation, which can be fatal. A drug called emapalumab can be used to block the action of interferon-gamma. However, we need to understand how the concentration of emapalumab in the blood changes over time to ensure that the correct dose is administered when attempting to control interferon-gamma-driven hyperinflammation in patients with HLH. Because HLH is a rare condition, data from a small number of patients were used to create a mathematical model that predicts emapalumab concentrations in the blood at various times after it is administered. Importantly, the amount of interferon-gamma observed in patients with different types of HLH is highly variable, which can alter how quickly emapalumab is removed from the blood. The higher interferon-gamma levels go above a certain threshold, the faster emapalumab is removed. In particular, interferon-gamma levels generally only exceed this threshold in patients with a familial or genetic form of HLH (primary HLH). Interferon-gamma levels in patients with a type of HLH called macrophage activation syndrome, which can occur in patients with systemic juvenile idiopathic arthritis (sJIA), do not usually cross the threshold associated with faster removal of emapalumab. This means that higher dosing may be required for patients with primary HLH compared with patients who have macrophage activation syndrome in sJIA to expedite control of hyperinflammation because of differences in the rate at which emapalumab is removed from the blood.

Predictors of disease course in systemic juvenile idiopathic arthritis.

PURPOSE: To identify potential predictors of the disease course of systemic juvenile idiopathic arthritis (sJIA) at the time of diagnosis. METHODS: This retrospective observational study was conducted in patients diagnosed with sJIA in our hospital between April 2009 and October 2023. The relationship between the disease course of sJIA patients and demographic, clinical, laboratory findings and complications were analyzed. RESULTS: Of the 51 patients diagnosed with sJIA, 26 (51%) patients had monocyclic, 7 (13.7%) polycyclic and 18 (35.2%) persistent disease course. 3 (5.8%) patients had a persistent disease course with persistent arthritis developed flares with systemic manifestations during follow-up. The presence of arthritis, polyarticular involvement, and hip involvement at the time of diagnosis were associated with persistent disease course (p=0.009, p=0.003, p=0.003). Serositis and higher white blood cell and neutrophil counts at the time of diagnosis were associated with a monocyclic disease course (p=0.034, p=0.002, p=0.008). However, no significant correlation was found between macrophage activation syndrome (MAS) and disease course (p=1). CONCLUSIONS: Systemic JIA patients with polyarthritis and hip involvement at disease onset may develop a persistent course. Although MAS is an important complication of sJIA, its effect on the course of the disease was not found in this study.

Efficacy and safety of canakinumab in systemic juvenile idiopathic arthritis, the first Chinese experience.

BACKGROUND: Systemic juvenile idiopathic arthritis (sJIA) is a severe form of juvenile arthritis that is characterized by chronic joint inflammation and systemic symptoms such as fever, rash, and organ involvement. Anti-IL-6 receptor monoclonal antibody tocilizumab is an effective treatment. However, some patients still experience persisting or recurrent symptoms and the real-world effectiveness of canakinumab in Chinese patients with sJIA has never been reported. Therefore, this study aimed to assess the efficacy and safety of canakinumab in Chinese patients with sJIA using real-world data. METHODS: We conducted a retrospective study on children with active sJIA. Clinical features, laboratory data, corticosteroid dosage, and adverse events (AEs) were collected at baseline and at 4, 8, 12, and 24 weeks after initiating canakinumab treatment. RESULTS: Seven female and four male patients were included in the study. All patients had previously been treated with tocilizumab and were administered canakinumab for 12.4 ± 3.4 months. Notably, significant improvements were observed in both clinical signs and symptoms as well as laboratory indicators. Four children under corticosteroid treatment were able to successfully discontinue their corticosteroid therapy: one at week 4, two at week 12, and one at week 24. Notably, there was a significant reduction in the number of tender and swollen joints (P = 0.0059) as well as the systemic juvenile arthritis disease activity score (P < 0.0001). The most common AE was infection, but no patients experienced serious AEs. No cases of macrophage activation syndrome or death were reported during the follow-up period. CONCLUSIONS: Canakinumab was found to be potentially efficacious and safe in Chinese patients with sJIA. No new AEs were observed with canakinumab treatment.

Canakinumab in the treatment of systemic juvenile idiopathic arthritis: a retrospective single center study in China.

Objective: Systemic juvenile idiopathic arthritis (sJIA) is characterized by excessive production of proinflammatory cytokines. As an anti-IL-1 agent, canakinumab has been approved in the USA and Europe for the treatment of sJIA patients aged ≥2 years. However, the use of canakinumab has never been reported in China. In this study, we aimed to assess the efficacy and safety of canakinumab in Chinese patients with sJIA. Methods: A total of 11 patients with sJIA who were treated with canakinumab were included in this study. Clinical data were collected retrospectively from medical records. Efficacy was evaluated by the systemic juvenile arthritis disease activity score (sJADAS). The follow-up was performed at canakinumab initiation, at months 1, 3, 6, 9 and 12, or at the last follow-up. Results: Of the 11 patients enrolled, 91.0% (10/11) had previously received treatment with tocilizumab. The mean duration of canakinumab was 9 (3-18) months. 45.5% (5/11) of patients showed complete response, 45.5% (5/11) showed partial response, and 9.0% (1/11) showed no response. 18.2% (2/11) experienced disease flare during the treatment with canakinumab. 81.8% (9/11) of patients successfully reduced the dose of corticosteroids, with six discontinuing corticosteroids. 45.6% (5/11) of patients experienced infection. No serious adverse events occurred during the treatment with canakinumab. Conclusions: Canakinumab may be effective and tolerable for Chinese sJIA patients, helping to reduce the dosage of corticosteroids. However, additional researches on large samples are required to evaluate its efficacy and safety.