Autoantibodies against interleukin 1alpha in rheumatoid arthritis: association with long term radiographic outcome.

OBJECTIVES: To investigate the possible association of interleukin 1alpha autoantibodies (IL1alpha aAb) with the long term course of joint erosion in patients with rheumatoid arthritis (RA). METHODS: Serum samples from 176 patients with RA included in a prospective study over 30 years were analysed for IL1alpha aAb by binding to human [(125)I]IL1alpha. Erosions of 19 diarthrodial joints were radiographically scored by the Larsen method. RESULTS: The relative risk (RR) of early IL1alpha aAb positive patients developing at least 30% of maximum radiographic joint destruction was significantly lower than for IL1alpha aAb negative patients, RR=0.29 (p=0.04). In rheumatoid factor positive patients RR was only 0.18 (p=0.02). Patients who seroconverted more than two years after the onset of RA showed the most aggressive development of joint erosion, with a relative risk of at least 40% of maximum radiographic joint destruction of 2.56 (p=0.048) CONCLUSIONS: The progression of radiographic joint destruction in patients with RA is associated with, and perhaps modified by, circulating IL1alpha aAb, suggesting that IL1alpha or IL1alpha aAb, or both, have a role in the erosive processes. IL1alpha aAb appear to be of prognostic significance in RA.