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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adolescent, Arthralgia, Arthritis, Juvenile, Arthritis, Rheumatoid, Autoantibodies, Case-Control Studies, Child, Enzyme-Linked Immunosorbent Assay, Female, Glucose-6-Phosphate Isomerase, Humans, Immunoblotting, Immunoglobulin G, Male, Osmolar Concentration, Proteins, Recombinant Proteins, Severity of Illness Index, Synovial Fluid.
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Is autoantibodies in juvenile idiopathic arthritis : glucose-6-phosphate isomerase a specific target? Context: Antibodies recognizing the ubiquitous cytosolic enzyme glucose-6-phosphate isomerase (GPI) cause arthritis in the K/BxN mouse model. Studies have shown that these antibodies are not specific for rheumatoid arthritis (RA) in humans. We evaluated GPI as a target of autoantibodies in juvenile idiopathic arthritis (JIA). We studied 324 serum and 48 synovial fluid (SF) samples from 103 patients with JIA, 36 with RA, and 8 with arthralgia and 11 controls. Anti-GPI antibodies were assessed by densitometrically evaluating immunoblots and ELISA using native and recombinant GPI. We determined the GPI activity of the soluble antigen in serum and SF. Although several samples contained anti-GPI-IgG antibodies, this was not specific for JIA or its subgroups, or for RA. Other proteins in the GPI preparation were also frequently recognized by antibodies. Additionally, we observed increased GPI activity in patients with the systemic manifestation of JIA, but not in other patients. Neither anti-GPI concentrations nor GPI activity were associated with disease activity.
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In addition to the findings in RA, our results indicate that GPI is not a general target of autoantibodies in JIA. Final Decision: no