To investigate the association between radiological severity of rheumatoid arthritis (RA) and the presence of the shared epitope.
Ninety unrelated adult Spanish patients with RA with a disease duration of at least 3 years, selected according to the American College of Rheumatology criteria, were radiologically assessed (shoulders, elbows, wrists, hands, hips, knees, and feet) and classified as having severe or nonsevere RA. DNA oligotyping was used to determine DR specificities and to detect DR4 and DR1 alleles.
Forty-one patients (45.5%) had severe RA. Sixty-six patients (73.3%) carried the shared epitope and 18 (20%) had double expression of the shared epitope. Thirty-seven (90%) of the 41 patients with severe RA expressed the shared epitope. Logistic regression analysis showed that both single and double expression of the shared epitope were strongly related to the radiological severity of RA (odds ratio = 6.3 and 9.4, respectively).
Our results show that radiological severity of RA is highly associated to the shared epitope.