Objectives: This study aimed to evaluate the predictability of the homozygous M694V genotype in paediatric FMF patients and to develop a clinical scoring system to enhance disease management strategies. Methods: This nationwide, multicentre, cross-sectional study included 3981 paediatric FMF patients with biallelic pathogenic variants in exon 10 of the Mediterranean fever gene. Patients were divided into two groups: group 1 (homozygous M694V) and group 2 (other variants). Data were collected from 37 paediatric rheumatology and/or nephrology clinics across Türkiye, covering patients followed between 2014 and 2023. Results: Group 1 had significantly earlier symptom onset (≤3 years: 49.8% vs 43.9%, P < 0.001) and diagnosis (median age: 5 years vs 5.8 years, P < 0.001) compared with group 2. A higher prevalence of family history of FMF was observed in group 1 (P < 0.001). Clinical manifestations, including arthritis (27.5%), erysipelas-like erythema (ELE) (20.3%) and protracted febrile myalgia syndrome (PFMS) (3.6%), were significantly more frequent in group 1 (P < 0.001 for all). Colchicine resistance was also higher in group 1 (18.1% vs 5.1%, P < 0.001). Logistic regression analysis showed that ≤3 years of age at symptom onset, family history, arthritis, myalgia, PFMS, ELE and splenomegaly were independent predictors of the homozygous M694V genotype. A clinical scoring system was proposed based on these findings. Conclusion: This study provides valuable insights into the clinical predictors of the homozygous M694V genotype in paediatric FMF. The proposed scoring system will support clinicians in prognosis assessment and treatment planning, contributing to improved patient outcomes.

Background: IgA vasculitis (IgAV) represents the most frequently seen form of vasculitis among children. Although it often resolves without intervention, renal involvement (IgAV nephritis) poses a risk for long-term complications. Although the lectin and alternative complement pathways are possible causes in its development, dependable serum biomarkers for the early identification of nephritis remain unavailable. Methods: In this prospective case-control study, we examined how the serum levels of a membrane attack complex (sC5b-9), complement factor H (CFH), mannose-binding lectin (MBL), and mannose-binding lectin-associated serine protease-1 (MASP-1) relate to renal involvement in IgAV. These complement proteins were measured in children diagnosed with IgAV and compared to levels in healthy controls (HCs) matched for age and sex. Results: The study cohort comprised 44 IgAV patients with a median age of 8 years and 34 HCs. The CFH levels were reduced significantly in the patient group (median: 357.31 ng/mL; IQR: 228.32) relative to the controls (median: 543.08 ng/mL; IQR: 504.05) (p < 0.001). This decrease was observed irrespective of the presence of nephritis. There were no significant differences in serum sC5b-9, MBL, or MASP-1 levels between the patients and controls. Furthermore, no correlation emerged between these complement components and renal involvement. Conclusion: The data suggest that lower CFH levels may signal systemic dysregulation of the alternative pathway in IgAV. In contrast, the serum levels of sC5b-9, MBL, and MASP-1 appear inadequate as markers for predicting renal involvement. Further research with larger cohorts that includes genetic analyses and examination of kidney tissue is needed to better define the contribution of complement activation in IgAV-related nephritis.

Background. APECED is a syndrome characterized by autoimmune polyendocrinopathy, candidiasis, and ectodermal dystrophy. The most observed clinical findings are chronic mucocutaneous candidiasis, hypoparathyroidism, and autoimmune adrenal insufficiency. Case Presentation. A three-year-old male patient was admitted with classical signs of juvenile idiopathic arthritis and treated with nonsteroidal anti-inflammatory drugs. During follow-up, signs of autoimmunity, candidiasis, nail dystrophy, and onychomycosis were observed. The parents were consanguineous, and targeted next-generation sequencing was performed. A homozygous mutation in the AIRE gene SAND domain (c.769C>T, p.Arg257Ter) was detected, and the patient was diagnosed with APECED syndrome. Conclusion. Inflammatory arthritis is rarely described in association with APECED and is often misdiagnosed as juvenile idiopathic arthritis. In APECED cases, nonclassical symptoms such as arthritis may occur before developing classical symptoms and considering the diagnosis of APECED in patients with CMC and arthritis is useful for early diagnosis before development of complications and management of disease.

Background/aim: Children with coronavirus disease 2019 (COVID-19) present milder symptoms than adults and are at lower risk of hospitalization and life-threatening complications. However, the kinetics of lymphocyte subsets and serum immunoglobulins in the peripheral blood during COVID-19 infection remains unclear. In this study, it was aimed to determine the changes in hematological and immunological parameters, especially in the lymphocyte subsets, in the peripheral blood of children with different COVID-19 disease severity. Materials and methods: The study was planned as a prospective cohort and included 68 children aged 0?18 years who were admitted to Ege University Faculty of Medicine Department of Pediatrics and diagnosed with COVID-19 infection between May 2020 and December 2021. In addition to demographic characteristics, clinical findings, and severity criteria, hematological, biochemical, and immunological laboratory (T/B lymphocyte subgroups, serum immunoglobulins) results were noted and examined if there were some correlations between disease severity and the laboratory values. Results: In the study group, while 60.6% (n = 40) of the patients received treatment in the hospital, 10.6% (n = 7) needed intensive care treatment. Lymphopenia (35.3%) was more common than neutropenia (14.7%) in the COVID-19-infected children. CD19+ B cells were low in a very high percentage of patients (26.5%), and 16.2% had low levels of NK cells. Significant correlation between disease severity and CD19+lymphocytes, CD19+CD38+IgMlow lymphocytes, CD19+CD38+CD27highIgMhigh lymphocytes, CD19+CD81+ lymphocytes (p = 0.001, p = 0.008, p = 0.014, p = 0.025, and rs = 0.394, rs = 0.326, rs = 0.303, rs = 0.280, respectively), significant inverse correlation between disease severity and absolute lymphocytes counts and CD3-CD16+CD56+ lymphocytes (p = 0.004, 0.014, and rs = ?0.353, rs = ?0.304, respectively) were observed. The percentage of hospitalized patients with low CD3 levels (15%) was significantly higher than that of the outpatients with low CD3 levels. Conclusion: As the severity of the disease increased, the CD19+, CD19+CD38+IgMlow, CD19+CD38+CD27highIgMhigh, and CD19+CD81+ lymphocytes percentages increased, while the lymphocyte count and NK cell percentage decreased. Therefore, detecting these prognostic immunobiomarkers related to the severity of the disease may contribute considerably to management of the illness.