Abstract

Fifty patients with ankylosing spondylitis (AS) confined to the spine and sacroiliac joints were compared with 50 cases of AS complicated by various patterns of non-axial joint involvement. Radiological and clinical features were evaluated and HLA-DR4 typing was carried out. This antigen was found in 16% of 200 normal individuals in 18% of patients suffering from exclusively axial AS, and in 54% of patients with additional purely peripheral joint involvement (wrist, finger, ankle, toe). The possibility that HLA-DR4 represents a non-specific marker for peripheral arthritis in patients with ankylosing spondylitis is discussed.