HLA-B27 AS A RELATIVE RISK FACTOR IN ANKYLOSING ENTHESOPATHY IN TRANSGENIC MICE

HLA-B27 is a risk factor for several human diseases through a mechanis m that is not yet understood. This article describes a naturally occur ring joint disease in laboratory mice, ANKENT. ANKENT begins with mild inflammation and culminates in irreversible stiffening of the ankle a nd/or tarsal joints in one or both hind paws. The macroscopic and hist ologic features of ANKENT, its relationship to age, gender, and enviro nment, and some immunologic aspects are considered. With respect to ge netics, it is demonstrated that an HLA-B27 transgene is a relative ris k factor for ANKENT. Its impact depends on the H-2 haplotype, reaching a relative risk value of 9.4 for C57Bl/10, H-2(b) males (P < 0.025). Several features of ANKENT are reminiscent of human AS: joint patholog y, age and gender distribution, the presence of non-MHC as well as MHC risk factors (in eluding HLA-B27), and the suspicion that environment al factors are involved.