ABSTRACT
OBJECTIVE: To determine the normal range of antiagalactosyl IgG antibodies in healthy children, and to investigate the utility of determination of antiagalactosyl IgG antibodies in patients with juvenile idiopathic arthritis (JIA) and juvenile onset Sjögren's syndrome (SS). METHODS: Serum concentrations of antiagalactosyl IgG antibodies were measured in 225 healthy children, 68 patients with JIA (systemic arthritis in 21, polyarthritis in 29, oligoarthritis in 18), and 15 patients with juvenile onset SS, using a lectin-enzyme immunoassay employing prepared human agalactosyl IgG as antigen. A comparison was made between the prevalence and utility of antiagalactosyl IgG antibodies in patients and those of conventional rheumatoid factors (RF) determined by laser nephelometry. RESULTS: The average serum concentration of antiagalactosyl IgG antibodies for healthy controls was 2.41 +/- 0.93 arbitrary units (AU)/ml, and the cutoff value of the normal range was set at 4.3 AU/ml (mean + 2 SD). As a result, antiagalactosyl IgG antibodies were positive in 25 (37%) of 68 patients with JIA, and 14 (93%) of 15 patients with juvenile onset SS, in whom values were much higher than the frequencies of RF positivity. The serum concentrations of antiagalactosyl IgG antibodies in patients were closely correlated with those of RF. Thirteen patients with JIA and 6 patients with juvenile onset SS were positive for antiagalactosyl IgG antibodies despite being negative for RF. With regard to prognosis during followup periods of at least 5 years, JIA patients positive for antiagalactosyl IgG antibodies, even if negative for RF, were resistant to treatment. However, positivity for antiagalactosyl IgG antibodies had no relation to joint destruction. CONCLUSION: Our data suggest that antiagalactosyl IgG antibodies, compared with RF, show higher sensitivity to detect immunological disorders in JIA and juvenile onset SS.
Subject(s)
Arthritis, Juvenile/immunology , Autoantibodies/blood , Galactose/immunology , Immunoglobulin G/blood , Sjogren's Syndrome/immunology , Adolescent , Age of Onset , Child , Child, Preschool , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Immunoglobulin M/blood , Infant , Male , Prognosis , Rheumatoid Factor/bloodABSTRACT
BACKGROUND: We have previously reported that serum levels of hyaluronic acid (HA) objectively reflect the severity of arthritis in juvenile rheumatoid arthritis (JRA). However, clear diagnostic standards do not exist for JRA; it is difficult to evaluate arthritis in children, particularly in small children and the diagnostic criteria for JRA requires an exclusion of several diseases. Therefore, if a specific test finding associated with JRA could be established, it would enable general pediatricians to make an objective diagnosis. METHODS: We measured the serum HA levels in children with joint symptoms as a chief complaint. The total number of subjects were 197 children; of these 89 had JRA, 39 had rheumatic diseases other than JRA, and 69 had non-rheumatic diseases (including systemic 31, polyarticular 40 and pauci-articular in 17), rheumatic diseases other than JRA in 39 subjects, and non-rheumatic diseases in 69 subjects. Sandwich enzyme-linked immunosorbent assay measured HA by using the HA binding protein. RESULTS: The serum level of HA was significantly higher in systemic and polyarticular JRA patients than in patients with pauci-articular JRA, with rheumatic diseases other than JRA, and non-rheumatic patients. With a cut-off value of 100 ng/mL, a diagnostic value of HA in all JRA patients was 48.3% sensitivity and 98.1% specificity. CONCLUSIONS: In children presenting with joint symptoms, serum HA measurement is useful for diagnosing systemic and polyarticular JRA.
