title: High prevalence of IgA rheumatoid factor in severe polyarticular-onset juvenile rheumatoid arthritis, but not in systemic-onset or pauciarticular-onset disease.
abstract: The presence of IgA rheumatoid factor (IgA-RF) has been correlated with severe joint disease in adult rheumatoid arthritis (RA), but IgA-RF has not been reported in juvenile rheumatoid arthritis (JRA). In the present study, IgA-RF was assayed by an enzyme-linked immunosorbent assay and was found in the sera of 14 of 24 children (58%) with active polyarticular JRA. The presence of IgA-RF correlated with the degree of functional disability. In contrast, IgA-RF was not found in the sera of systemic-onset disease patients, regardless of the degree of dysfunction. IgA-RF was detected in only 1 patient with pauciarticular disease, despite the fact that several patients in this group had severe disease. The presence of IgA-RF in polyarticular JRA did not correlate with serum IgA levels, but did correlate with the presence and the level of serum IgM-RF. Thus, the presence of IgA-RF appears to be specific for polyarticular JRA, and shows a correlation with severe disease in this group.
authors.affiliation: Department of Pediatrics, Childrens Hospital of Los Angeles, University of Southern California 90027.
authors.forename: S M
authors.initials: SM
authors.lastname: Walker
authors.forename: D K
authors.initials: DK
authors.lastname: McCurdy
authors.forename: B
authors.initials: B
authors.lastname: Shaham
authors.forename: R
authors.initials: R
authors.lastname: Brik
authors.forename: H
authors.initials: H
authors.lastname: Wietting
authors.forename: Y
authors.initials: Y
authors.lastname: Arora
authors.forename: T J
authors.initials: TJ
authors.lastname: Lehman
authors.forename: V
authors.initials: V
authors.lastname: Hanson
authors.forename: B
authors.initials: B
authors.lastname: Bernstein
mesh_terms: D000293:Adolescent; D000328:Adult; D001172:Arthritis, Rheumatoid / Q000145:classification / Q000276:immunology*; D002469:Cell Separation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007140:Immunoglobulin Fab Fragments / Q000032:analysis; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D012217:Rheumatoid Factor / Q000032:analysis*
chemical_list: D007070:Immunoglobulin A; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D012217:Rheumatoid Factor