IgA and IgM rheumatoid factors as markers of later erosive changes in rheumatoid arthritis (RA)

Scand J Rheumatol Suppl. 1988;75:238-43. doi: 10.3109/03009748809096770.


Stored samples from within the first year of disease of 119 patients with rheumatoid arthritis (RA) enrolled in a long-running prospective study have been studied for the presence of IgM and IgA rheumatoid factors (RF), using agglutination of rabbit IgG-coated red blood cells to detect IgMRF and an ELISA technique using rabbit IgG coated on the microtitre plates and labelled F(aB)2 fragment of goat anti-IgA. Outcome measures at a mean follow-up of 10.1 years (range 3-20) included the Steinbrocker functional grade and grading of erosive changes on hand and feet Xrays using a modification of Lawrence's method. Both IgA and IgG levels at presentation correlated significantly with outcome measured by erosive changes and functional grade at a mean of 10 years and with the time of first appearance of erosions. In patients who are IgMRF negative early in the disease, IgARF positivity indicates a greater chance of developing both erosions and impaired function than when both tests are negative. IgARF positivity seems to precede IgMRF.

MeSH terms

  • Adult
  • Aged
  • Arthritis, Rheumatoid / blood*
  • Arthritis, Rheumatoid / diagnostic imaging
  • Arthritis, Rheumatoid / immunology
  • Biomarkers
  • Female
  • Foot / diagnostic imaging
  • Forecasting
  • Hand / diagnostic imaging
  • Humans
  • Immunoglobulin A / immunology*
  • Immunoglobulin M / immunology*
  • Male
  • Middle Aged
  • Osteoarthritis / blood
  • Osteoarthritis / diagnostic imaging
  • Osteoarthritis / immunology
  • Radiography
  • Rheumatoid Factor / analysis*


  • Biomarkers
  • Immunoglobulin A
  • Immunoglobulin M
  • Rheumatoid Factor