title: IgM, IgA, and IgG rheumatoid factors in early rheumatoid arthritis predictive of radiological progression?
abstract: The significance of IgM, IgA and IgG rheumatoid factors (RF) for the prediction of radiological progression, and as process variables during follow-up, was evaluated in a three-year prospective study of 149 patients with early rheumatoid arthritis (symptoms < 1 year at study entry). The occurrence of IgA-RF and IgG-RF at study entry without simultaneous occurrence of IgM-RF, and the seroconversion from RF-negative at entry to RF-positive during follow-up appeared to be unusual. A significant correlation was found between each of the RF-isotype levels at entry and radiological progression after three years. However, no significant prognostic value of IgA-RF and IgG-RF could be demonstrated if analysed in combination with IgM-RF, initial disease activity (as measured by C-reactive protein level), initial radiologic score, HLA-DR4 and HLA-DR2. Although IgM-RF levels generally reflected the course of disease activity and did so better than IgA-RF and IgG-RF levels, their clinical significance as process variables appeared to be limited compared to C-reactive protein.
authors.affiliation: Dept. Rheumatology, University Hospital Groningen, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: van Leeuwen
authors.forename: J
authors.initials: J
authors.lastname: Westra
authors.forename: P L
authors.initials: PL
authors.lastname: van Riel
authors.forename: P C
authors.initials: PC
authors.lastname: Limburg
authors.forename: M H
authors.initials: MH
authors.lastname: van Rijswijk
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D012044:Regression Analysis; D012217:Rheumatoid Factor / Q000097:blood*
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor