Autoantibodies such as rheumatoid factor (RF), antikeratin antibodies (AKA), antiperinuclear factor (APF), and anti-RA 33 antibodies are considered of value for the diagnosis of RA. The purpose of this study was to evaluate these autoantibodies as predictors of severe radiographic damage in rheumatoid arthritis (RA).
Eighty six patients with RA (70 women, 16 men) fulfilling 1987 ACR criteria were selected from a cohort of 469 patients followed up since the first year of RA onset because they could be divided in two groups according to the severity of the radiographic damage. These 86 patients had a mean (SD) disease duration of eight (four) years: 43 patients had severe radiographic damage (Larsen score > or = 2) and 43 had limited radiographic damage (Larsen score < 2). The two groups were matched by disease duration and sex. The following autoantibodies were looked for: RF, ANA, AKA, APF, and anti-RA 33 antibodies. In addition, HLA class II DR beta alleles and standard inflammatory parameters (erythrocyte sedimentation rate, C reactive protein) were determined.
Patients with severe radiographic damage differed from those with limited radiographic damage in that they had higher RF (p = 0.01), APF (p < 0.02), and AKA (p = 0.001) titres. Stepwise regression analysis was done to calculate the odds ratios (OR) for each clinical and laboratory variable; only presence of cutaneous nodules (OR: 14.9; 95% CI: 7, 128), HLA DRB1*04 or DRB1*01 (OR: 7.53; 95% CI: 1.32, 42.9), AKA (OR: 3.11; 95%, CI: 0.58, 16.8), a high erythrocyte sedimentation rate (OR: 2.66; 95% CI: 0.60, 11.9), and a high C reactive protein value (OR: 7.4; 95% CI: 1.43, 38.1) were predictive of severe radiographic damage.
These data suggest that the risk of severe radiographic damage in RA patients is higher when cutaneous nodules, HLA DRB1*04 or DRB1*01, and/or AKA are present. The other autoantibodies of diagnostic significance are of little help for predicting joint destruction.