High prevalence of IgA rheumatoid factor in severe polyarticular-onset juvenile rheumatoid arthritis, but not in systemic-onset or pauciarticular-onset disease

Arthritis Rheum. 1990 Feb;33(2):199-204. doi: 10.1002/art.1780330207.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Arthritis, Rheumatoid / classification
  • Arthritis, Rheumatoid / immunology*
  • Cell Separation
  • Cells, Cultured
  • Child
  • Child, Preschool
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunoglobulin A / analysis*
  • Immunoglobulin Fab Fragments / analysis
  • Immunoglobulin Fc Fragments / analysis
  • Immunoglobulin G / analysis
  • Male
  • Rheumatoid Factor / analysis*


  • Immunoglobulin A
  • Immunoglobulin Fab Fragments
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • Rheumatoid Factor