PT  - JOURNAL ARTICLE
AU  - R H Withrington
AU  - I Teitsson
AU  - H Valdimarsson
AU  - M H Seifert
TI  - Prospective study of early rheumatoid arthritis. II. Association of rheumatoid factor isotypes with fluctuations in disease activity.
AID  - 10.1136/ard.43.5.679
DP  - 1984 Oct 01
TA  - Annals of the Rheumatic Diseases
PG  - 679--685
VI  - 43
IP  - 5
4099  - http://ard.bmj.com/content/43/5/679.short
4100  - http://ard.bmj.com/content/43/5/679.full
SO  - Ann Rheum Dis1984 Oct 01; 43
AB  - Thirty-three patients with early peripheral synovitis were followed up for two to four years in order to study the relationship between fluctuations in rheumatoid factor (RF) levels and indices of clinical activity. Twenty-eight of these patients developed classical/definite rheumatoid arthritis (RA). Seventeen patients developed erosive disease of their hands and wrists and thirteen had a positive RF agglutination test. Nineteen patients had raised levels of IgM, RF, IgA, RF, or IgG RF as measured by isotype-specific ELISA techniques. The within-patient fluctuations in IgA RF levels correlated significantly with the corresponding fluctuations in grip strength (p less than 0.05), erythrocyte sedimentation rate (ESR) (p less than 0.01), and a composite index of disease activity (p less than 0.02). IgG RF levels were also associated with changes in ESR and grip strength, but IgM RF showed only a weak association with fluctuations in ESR and not with any other clinical parameters. It is suggested that serum IgA RF may be a useful marker of disease activity in rheumatoid arthritis.