Association between DR antigens, rheumatoid arthritis with and without extraarticular features and systemic lupus erythematosus in northern Italy.

Seventy-two patients with rheumatoid arthritis (RA) and 18 with systemic lupus erythematosus (SLE) were typed for HLA class I and II antigens. No association was found with any of the antigens tested. However, B8 and DR3 were increased in patients with extraarticular features (EAF), while DR1 was increased in those with RA without EAF. In SLE a trend towards an increased frequency of DR7 was observed. DR5 was the negative marker in both diseases. Our results confirm the peculiar genetic characteristics in our population.