Psoriatic arthritis.

Psoriatic arthritis and its associated enthesopathy appear to be another immune-mediated manifestation of the genetic predisposition to develop psoriasis. The occurrence of psoriatic arthritis in the setting of the selective immune deficiency of advanced HIV infection, especially in the association with HLA-B27, points to a role of the CD8 T cell in disease pathogenesis. The relationship of Reiter's syndrome to psoriatic arthritis is emphasized.