title: IgA and IgM rheumatoid factors as markers of later erosive changes in rheumatoid arthritis (RA).
abstract: 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.
authors.affiliation: Department of Rheumatology Research, University College, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Winska Wiloch
authors.forename: K
authors.initials: K
authors.lastname: Thompson
authors.forename: A
authors.initials: A
authors.lastname: Young
authors.forename: M
authors.initials: M
authors.lastname: Corbett
authors.forename: M
authors.initials: M
authors.lastname: Shipley
authors.forename: F
authors.initials: F
authors.lastname: Hay
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging / Q000276:immunology; D015415:Biomarkers; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging; D005544:Forecasting; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000000981:diagnostic imaging / Q000276:immunology; D011859:Radiography; D012217:Rheumatoid Factor / Q000032:analysis*
chemical_list: D015415:Biomarkers; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D012217:Rheumatoid Factor