Clinical manifestations in HLA-B27-positive patients

The clinical manifestations of rheumatic diseases have been studied in a population of 440 HLA-B27-positive patients. Fifty-eight per cent had peripheral joint involvement. After statistical analysis and clustering of characteristics, three patterns of peripheral joint involvement were found. They were referred to as the X, Y and Z type for mnemotechnical reasons. The X type includes male patients with sacroiliitis, spondylitis, uveitis and uni- or bilateral arthritis of hip and/or shoulder. Y type patients present sacroiliitis, pauci-articular asymmetrical joint involvement and tendinitis. Z type patients are characterized by sacroiliitis, polyarticular symmetrical joint involvement and a positive IgM rheumatoid factor. This classification enables a new approach to the pathology, diagnosis and therapy of the seronegative spondyloarthropathies.