TNF involvement and anti-TNF therapy of reactive and unclassified arthritis.

A growing body of evidence shows that tumor necrosis factor (TNF) alpha, a pro-inflammatory cytokine involved in the pathogenesis of rheumatoid arthritis (RA), is also involved in the pathogenesis of reactive and unclassified arthritis. Elevated levels of TNF-alpha and other pro-inflammatory cytokines are seen in these inflammatory arthropathies. The clinical effect on a potential underlying infection is not known, but several studies have suggested at least short-term effectiveness and safety of anti-TNF-alpha therapy in reactive and unclassified arthritis.