Objective.: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. The American College of Rheumatology (ACR) 1997, Systemic Lupus International Collaborating Clinics (SLICC) 2012, and European League Against Rheumatism (EULAR)/ACR 2019 SLE classification criteria are formed based on data mainly from adult patients. We aimed to test the performances of the SLE classification criteria among pediatric patients with SLE.Methods.: Pediatric patients with SLE (n = 262; 80.9% female) were included from 3 different centers in Turkey. As controls, 174 children (60.9% female) with other diseases who had ANA (antinuclear antibody) test results were included. The gold standard for SLE diagnosis was expert opinion.Results.: The sensitivities of the ACR 1997, SLICC 2012, and EULAR/ACR 2019 criteria were 68.7%, 95.4%, and 91.6%, respectively. The specificities of the ACR 1997, SLICC 2012, and EULAR/ACR 2019 criteria were 94.8%, 89.7%, and 88.5%, respectively. Eighteen patients with SLE met the SLICC 2012 but not the EULAR/ACR 2019 criteria. Among these, hematologic involvement was prominent (n = 13; 72.2%). Eight patients with SLE fulfilled the EULAR/ACR 2019 but not the SLICC 2012 criteria. Among these, joint involvement was prominent (n = 6; 75%).Conclusion.: To our knowledge, this is the largest cohort study of pediatric SLE to test the performances of all 3 classification criteria. The SLICC 2012 criteria yielded the best sensitivity, whereas the ACR 1997 criteria had the best specificity. SLICC 2012 criteria performed better than EULAR/ACR 2019 criteria. Separation of different hematological manifestations in the SLICC 2012 criteria might have contributed to the higher performance of this criteria set.

Objectives: This study aims to discuss the clinical, laboratory and genetic findings, and treatment options for six patients who were diagnosed with Blau syndrome (BS)/early-onset sarcoidosis (EOS). Patients and methods: The study included four patients (2 males,2 females; mean age 7 years; range 4 to 10 years) with EOS and two siblings (1 male, 1 female; mean age 10 years; range, 9 to 11 years) with BS. Age, age of initial symptoms, age of diagnosis; articular involvement, presence of uveitis, dermatitis, or fever, other organ involvement, laboratory findings, results of metabolic tests for mucopolysaccharidosis and mucolipidosis, results of genetic, pathologic, and immunologic tests, radiologic findings to evaluate skeletal dysplasia, and treatment options were collected. Results: The median age at diagnosis of all patients was 6 years (range, 1 to 10 years). Five patients had camptodactyly and bilateral boggy synovitis in the wrists and ankles, one had granulomatous inflammatory changes in the liver and kidney biopsy, and one had attacks of fever and granulomatous dermatitis. None had uveitis. The detected mutations in nucleotide-binding oligomerization domain containing 2 (NOD2) were P268S (rs2066842), M513T (rs104895473), R702W (rs2066844), V955I (rs5743291), H343Y (rs199858111), and M491L (16:50745293). The treatments of patients included corticosteroids, non-steroid anti-inflammatory drugs, methotrexate, infliximab, adalimumab, anakinra, and canacinumab. Conclusion: Camptodactyly and boggy synovitis are important signs of BS/EOS. Methotrexate and tumor necrosis factor blockers are more effective in patients with predominantly articular symptoms. In patients 5 and 6 and their mother, we determined a novel M491L mutation in the NOD2 gene. Currently, this work is in progress towards identifying the pathogenesis and treatment options for this disease.