Objective:To analyze the clinical characteristics and treatment outcomes of children with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibody-mediated necrotizing myopathy, and to explore early identification and management strategies to provide reference for clinical diagnosis and treatment.Methods:A retrospective analysis was conducted on the clinical data and treatment outcomes of 10 pediatric patients with anti-HMGCR antibody-mediated necrotizing myopathy admitted to the Department of Rheumatology, Children′s Hospital of Fudan University from December 2020 to December 2024. Statistical description was performed using SPSS 22.0.Results:Among the 10 patients, the male-to-female ratio was 1:4, the age of onset was (7.2±4.0) years, and the disease duration at diagnosis was (22.2±19.6) months. None had a history of statin exposure. Six patients presented with muscle weakness, and4 were diagnosed due to asymptomatic elevation of creatine kinase (CK); 4 had dermatomyositis-like rashes. All patients showed significantly elevated CK levels [median 3 291(1 969, 8 776)U/L] and underwent muscle biopsy. Histopathological findings revealed myofiber degeneration, necrosis, and regeneration in all cases, with inflammatory infiltration in 9 cases, MHC-Ⅰ positivity in all, and C5b-9 positivity in 9 cases. The median follow-up duration was (15.7±6.3) months. At the last follow-up, muscle strength was normal or nearly normal, and the CK median value had decreased to 977.5 (211.0, 3 536.0) U/L.Conclusion:For patients with suspected idiopathic inflammatory myopathy and significantly elevated CK, muscle-specific antibody testing-including anti-HMGCR-and muscle biopsy should be performed promptly regardless of the presence of skin rash, to ensure accurate diagnosis and guide treatment, thereby avoiding misdiagnosis or missed diagnosis.

Objective:To investigate the clinical characteristics and independent risk factors of severe disease in patients with anti-nuclear matrix protein (NXP) 2 antibody-positive juvenile dermatomyositis (JDM).Methods:A retrospective cohort study was conducted, including 219 anti-NXP2 antibody-positive JDM patients admitted to 23 children′s hospitals across China from July 2011 to July 2023. Patients were classified into severe and non-severe groups based on classification criteria for severe dermatomyositis. Demographic characteristics, clinical manifestations, and laboratory parameters were compared between the 2 groups using independent sample t-test, Mann-Whitney U test, or χ2 test. Univariate and multivariate Logistic regression analyses were performed to identify risk factors for severe disease. The receiver operating characteristic curve was employed to calculate optimal cut-off values. Results:Among the 219 patients, 108 were male and 111 were female, with an age at onset of 6.3 (3.5, 9.4) years. The severe group comprised 69 patients, and the non-severe group 150 patients. The severe group had significantly higher rates of fever, heliotrope rash, subcutaneous edema, periorbital edema, anti-Ro52 antibody positivity, as well as elevated levels of ferritin-to-albumin ratio (FAR), creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) (all P<0.05). Multivariate analysis identified anti-Ro52 antibody positivity ( OR=13.26, 95% CI 1.37-128.29) and elevated FAR ( OR=1.90, 95% CI 1.09-2.31) as independent risk factors for severe anti-NXP2 antibody-positive JDM (both P<0.05). Receiver operating characteristic curve analysis revealed that a FAR cutoff value of 6.82 predicted severe disease with an area under the curve of 0.87 (95% CI 0.81-0.94, P<0.001), sensitivity of 0.85, and specificity of 0.70. All patients received glucocorticoid therapy, and the severe group received higher proportions of steroid pulse therapy, cyclophosphamide, mycophenolate mofetil, intravenous immunoglobulin, biologics, and adjuvant treatments compared to the non-severe group (all P<0.05). In terms of outcomes, 2 patients (2.9%) in the severe group died (due to neurological involvement and intestinal perforation, respectively), while the remaining patients achieved complete clinical response or remission. All patients in the non-severe group achieved remission. Conclusions:The primary clinical features of anti-NXP2 antibody-positive JDM included fever, heliotrope rash, subcutaneous edema, periorbital edema, anti-Ro52 antibody positivity, and elevated levels of CK, AST, LDH, and FAR. Furthermore, anti-Ro52 antibody positivity and a FAR>6.82 were identified as independent risk factors.

Objective:To investigate the clinical characteristics and independent risk factors of severe disease in patients with anti-nuclear matrix protein (NXP) 2 antibody-positive juvenile dermatomyositis (JDM).Methods:A retrospective cohort study was conducted, including 219 anti-NXP2 antibody-positive JDM patients admitted to 23 children′s hospitals across China from July 2011 to July 2023. Patients were classified into severe and non-severe groups based on classification criteria for severe dermatomyositis. Demographic characteristics, clinical manifestations, and laboratory parameters were compared between the 2 groups using independent sample t-test, Mann-Whitney U test, or χ2 test. Univariate and multivariate Logistic regression analyses were performed to identify risk factors for severe disease. The receiver operating characteristic curve was employed to calculate optimal cut-off values. Results:Among the 219 patients, 108 were male and 111 were female, with an age at onset of 6.3 (3.5, 9.4) years. The severe group comprised 69 patients, and the non-severe group 150 patients. The severe group had significantly higher rates of fever, heliotrope rash, subcutaneous edema, periorbital edema, anti-Ro52 antibody positivity, as well as elevated levels of ferritin-to-albumin ratio (FAR), creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) (all P<0.05). Multivariate analysis identified anti-Ro52 antibody positivity ( OR=13.26, 95% CI 1.37-128.29) and elevated FAR ( OR=1.90, 95% CI 1.09-2.31) as independent risk factors for severe anti-NXP2 antibody-positive JDM (both P<0.05). Receiver operating characteristic curve analysis revealed that a FAR cutoff value of 6.82 predicted severe disease with an area under the curve of 0.87 (95% CI 0.81-0.94, P<0.001), sensitivity of 0.85, and specificity of 0.70. All patients received glucocorticoid therapy, and the severe group received higher proportions of steroid pulse therapy, cyclophosphamide, mycophenolate mofetil, intravenous immunoglobulin, biologics, and adjuvant treatments compared to the non-severe group (all P<0.05). In terms of outcomes, 2 patients (2.9%) in the severe group died (due to neurological involvement and intestinal perforation, respectively), while the remaining patients achieved complete clinical response or remission. All patients in the non-severe group achieved remission. Conclusions:The primary clinical features of anti-NXP2 antibody-positive JDM included fever, heliotrope rash, subcutaneous edema, periorbital edema, anti-Ro52 antibody positivity, and elevated levels of CK, AST, LDH, and FAR. Furthermore, anti-Ro52 antibody positivity and a FAR>6.82 were identified as independent risk factors.

Objective:To analyze the clinical characteristics and treatment outcomes of children with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibody-mediated necrotizing myopathy, and to explore early identification and management strategies to provide reference for clinical diagnosis and treatment.Methods:A retrospective analysis was conducted on the clinical data and treatment outcomes of 10 pediatric patients with anti-HMGCR antibody-mediated necrotizing myopathy admitted to the Department of Rheumatology, Children′s Hospital of Fudan University from December 2020 to December 2024. Statistical description was performed using SPSS 22.0.Results:Among the 10 patients, the male-to-female ratio was 1:4, the age of onset was (7.2±4.0) years, and the disease duration at diagnosis was (22.2±19.6) months. None had a history of statin exposure. Six patients presented with muscle weakness, and4 were diagnosed due to asymptomatic elevation of creatine kinase (CK); 4 had dermatomyositis-like rashes. All patients showed significantly elevated CK levels [median 3 291(1 969, 8 776)U/L] and underwent muscle biopsy. Histopathological findings revealed myofiber degeneration, necrosis, and regeneration in all cases, with inflammatory infiltration in 9 cases, MHC-Ⅰ positivity in all, and C5b-9 positivity in 9 cases. The median follow-up duration was (15.7±6.3) months. At the last follow-up, muscle strength was normal or nearly normal, and the CK median value had decreased to 977.5 (211.0, 3 536.0) U/L.Conclusion:For patients with suspected idiopathic inflammatory myopathy and significantly elevated CK, muscle-specific antibody testing-including anti-HMGCR-and muscle biopsy should be performed promptly regardless of the presence of skin rash, to ensure accurate diagnosis and guide treatment, thereby avoiding misdiagnosis or missed diagnosis.

Objective:To gain insight into the constitution of juvenile rheumatic diseases, treatment outcome and trends of rheumatic inpatients in past 12 years, and to improve awareness of juvenile rheumatic diseases.Methods:The clinical data of 5 950 patients in rheumatology department of the affiliated pediatric hospital of Fudan University (from 2005 to 2016) were analyzed retrospectively, and the chi-square test was used to compare and analyze the incidence.Results:Disease changes: ① The top three rheumatic diseases were Kawasaki disease (KD) (44.3%), Henoch-schoniein purpura (HSP) (35.4%), juvenile idiopathic arthritis (JIA)(9.6%). ② The number of all constitution of juvenile rheumatic diseases in hospital increased other than HSP. ③ The rheumatic diseases were increased from 17 to 37 kinds in the past 6 years. ④ The number of systemic lupus erythematosus (SLE) increased year by year (112/2 348 vs 197/3 602, χ2=1.41, P=0.235), as well as the severe SLE (35/112 vs 55/197, χ2=0.38, P=0.536). ⑤ The rate of rheumatic diseases complicated with macrophage activation (MAS) was 7.2‰(43/5 950). 12.9%(26/201) of systemic juvenile idiopathic arthritis(sJIA) were complicated with MAS, which was accounted for 60.5%(26/43) of total number of MAS in rheumatic diseases. In the last 6 years, there was a significant increase in the number of patients with MAS in patients with rheumatic diseases ( χ2=14.1, P<0.01) and sJIA( χ2=11.2, P<0.01). ⑥ 1.1%(64/5 950) of rheumatic diseases patients had lung lesions, juvenile dermatomyositis (JDM) accounted for 24.4%(20/82). In the last 6 years, the number of patients with lung lesions associated with rheumatic diseases increased significantly ( χ2=5.66, P=0.017). ⑦ The mortality rate of juvenile rheumatic diseases was only 3.7‰(22/5 950), and 45.5% occurred in SLE (10/22). The mortality rate of SLE decreased in last 6 years (5/112 vs 5/197, χ2=0.34, P=0.558). Conclusion:The constitution of juvenile rheumatic diseases in our center is decreasing for systemic vasculitis (KD, HSP), JIA, SLE, JDM in last 6 years. The annual total number of patients is relatively stable. But rare, difficult and critically illed cases increase year by year. Although SLE is still the primary cause of death in juvenile rheumatic diseases in recent 6 years, the mortality rate has decreased year by year.