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OBJECTIVE: There are no validated criteria to evaluate clinical response in juvenile idiopathic arthritis (JIA). The purpose of this study was to compare 4 sets of criteria (2 from the American College of Rheumatology [ACR] and 2 from the European League Against Rheumatism [EULAR]) for clinical response evaluation in JIA patients treated with methotrexate and/or anti-tumor necrosis factor alpha drugs. METHODS: Seventy-five patients with JIA were evaluated at baseline and after 6 months of therapy with second-line drugs. Mean age at study onset was 12.8 years (range 2-32.9 years). Diagnoses were systemic JIA (n = 16), rheumatoid factor-positive JIA (n = 5), rheumatoid factor-negative JIA (n = 9), persistent oligoarticular JIA (n = 10), extended oligoarticular JIA (n = 33), and psoriatic arthritis (n = 2). Clinical response was evaluated with the ACR Pediatric 30 criteria and the ACR 20% response criteria (ACR20), and with the EULAR Disease Activity Score (DAS) and 28-joint DAS (DAS28). Patients with EULAR criteria responses of 'good' or 'moderate' were classified as responders. Responders and nonresponders according to the different criteria were then compared. RESULTS: For patients younger than 16 years, Cohen's kappa varied between 0.51 and 0.72, with a good-to-excellent reproducibility index for all comparisons, except for the DAS28/ACR20 comparison. The best agreement was obtained by comparing the DAS and the ACR Pediatric 30. For patients older than 16 years, the reproducibility index was good or excellent in only 2 cases, i.e., comparing the DAS and the ACR Pediatric 30 and comparing the DAS and the DAS28 (as expected). CONCLUSION: Our study shows a good agreement overall for the different criteria tested. The highest concordance was observed between the DAS and the ACR Pediatric 30, the lowest between the DAS28 and the ACR20. Our data suggest that the ACR Pediatric 30 criteria can be used also in adult patients affected by JIA, and that the original DAS can be an alternative to the ACR Pediatric 30 in both children and young adults with JIA. [ABSTRACT FROM AUTHOR]

ObjectiveCross-reactivity with kidney antigens is believed to be a critical determinant in the renal pathogenicity of anti-double-stranded DNA (anti-dsDNA) antibodies. Murine nephritogenic anti-dsDNA antibodies have been shown to cross-react with alpha-actinin, and anti-alpha-actinin antibodies have been found to be deposited in the kidneys of lupus mice with active nephritis. Furthermore, in humans with systemic lupus erythematosus (SLE), it has been found that a greater proportion of polyclonal IgG anti-dsDNA antibodies from patients with renal involvement bind to alpha-actinin than do those from patients without renal disease. We undertook this study to substantiate a direct link between cross-reactive anti-dsDNA/anti-alpha-actinin antibodies and the pathogenesis of lupus nephritis in humans.MethodA panel of 10 anti-dsDNA and/or anti- alpha-actinin antibodies was generated by Epstein-Barr virus transformation of lymphocytes from patients with SLE and was extensively characterized. Antibody binding was studied by enzyme-linked immunosorbent assay and Western blotting. Antibody potential for pathogenicity was assessed by measuring binding to isolated glomeruli and mesangial cells and by evaluation of histologic features of the kidney following injection in vivo.ResultsAll anti-dsDNA antibodies isolated also bound alpha-actinin. Cross-reactive antibodies bound to mesangial cells and to isolated glomeruli ex vivo. Binding to glomeruli was not inhibited by DNase treatment, but could be abrogated by alpha-actinin. Furthermore, histopathologic abnormalities seen in mice injected intraperitoneally with a cross-reactive cell line included fusion of podocyte foot processes and subepithelial and subendothelial deposition.ConclusionThese studies provide strong support for the hypothesis that alpha-actinin is a major cross-reactive target for anti-dsDNA antibodies in SLE patients. Cross-reactive anti-dsDNA/anti-alpha-actinin antibodies from SLE patients are pathogenic and may contribute to the kidney lesions in lupus nephritis. [ABSTRACT FROM AUTHOR]