IGM, IGA, AND IGG RHEUMATOID FACTORS IN EARLY RHEUMATOID-ARTHRITIS PREDICTIVE OF RADIOLOGICAL PROGRESSION

The significance of IgM, IgA and IgG rheumatoid factors (RF) for the p rediction of radiological progression, and as process variables during follow-up, was evaluated in a three-year prospective study of 149 pat ients with early rheumatoid arthritis (symptoms <1 year at study entry ). The occurrence of IgA-RF and IgG-RF at study entry without simultan eous occurrence of IgM-RF and the seroconversion from RF-negative at e ntry to RF-positive during follow-up appeared to be unusual. A signifi cant correlation was found between each of the RF-isotype levels at en try and radiological progression after three years. However, no signif icant prognostic value of IgA-RF and IgG-RF could be demonstrated if a nalysed in combination with IgM-RF initial disease activity (as measur ed by C-reactive protein level), initial radiologic score, HLA-DR4 and HLA-DR2. Although IgM-RF levels generally reflected the course of dis ease activity and did so better than IgA-RF and IgG-RF levels, their c linical significance as process variables appeared to be limited compa red to C-reactive protein.