HLA-B27 AND THE SERONEGATIVE SPONDYLOARTHROPATHIES

In the 25 years since the initial reports of the association of HLA-B2 7 with ankylosing spondylitis (AS) and subsequently with Reiter's synd rome, psoriatic spondylitis, and the spondylitis of inflammatory bowel disease, the association of HLA-B27 with the seronegative spondyloart hropathies has remained one of the best examples of a disease associat ion with a hereditary marker. HLA-B27 has been recognized as represent ative of a spectrum of diseases, ranging from the majority of HLA-B27- positive individuals who have no disease at all, through those with is olated eye or skin involvement, to those with critical eye, heart, and peripheral joint compromise of full-blown AS. Yet HLA polymorphism ha s evolved in response to environmental stresses, and even the presence of HLA-B27 itself appears to confer advantages in certain infectious diseases, such as acquired immune deficiency syndrome (AIDS), This art icle mill review what is currently known about HLA-B27 and disease, es pecially in the seronegative spondyloarthropathies. The structure-func tion relationship of HLA-B27 will be presented, including differences between the B27 subtypes both in their ethnic variation and possible d isease implications. The disease spectrum conferred by the presence of HLA-B27 will also be discussed, and the theories of how HLA-B27 contr ibutes to the pathogenesis of the spondyloarthropathies will be consid ered.