Pathogenesis of reactive arthritis.

Reactive arthritis is a member of the spondyloarthropathy. Bacteria which cause reactive arthritis infect the mucosal surfaces. Either the whole bacteria or their fragments are subsequently carried to the joints inside which are induced a TH1 lymphocyte response in which oligoclonal T lymphocytes as well peptide-specific CD8+ T lymphocytes participate. Human lymphocyte antigen (HLA)-B27 is a predisposing gene. Besides being determinants for the CD8+ T lymphocyte response it can also modify the response of other cells to the invasive bacteria. This would lead to alteration of the fate of the bacteria as well as release of arthritis-causing cytokines.