The pathogenesis of HLA-B27 arthritis: role of HLA-B27 in bacterial defense.

The way in which a host accommodates invasive facultative intracellular bacteria must be the key to the development of reactive arthritis. Investigators have analyzed the bacterial events at several levels: invasion into host cells, intracellular survival, translocation from the sites of infection to the joints, residence in the joints, and evasion of host defense. Because HLA-B27 is present in higher incidence in patients with reactive arthritis and is an essential gene in the related ankylosing spondylitis, the role of HLA-B27 in host defense is also assumed to be important in the development of reactive arthritis. This review summarizes the various studies in this field.