[Treatment of ankylosing spondylitis and undifferentiated spondyloarthritis with TNF alpha-antagonists].

The spondyloarthritides (SpA) are common inflammatory rheumatic diseases with an overall prevalence of 0.6-1.9%. Ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (uSpA) are the most common subsets of SpA. Women are almost as frequently affected as men, but the total burden of disease may be similar. At least one third of AS patients are severely affected with impaired function and a poor quality of life similar to patients with rheumatoid arthritis. However, AS starts 20-30 years earlier in life. Thus, AS has a relevant socioeconomic impact on society. After decades of no progress concerning treatment options in SpA, there is now accumulating evidence that the new anti-TNF alpha agents do not only reduce signs and symptoms of AS caused by inflammation but they may also diminish structural damage. Very recent magnetic resonance imaging (MRI) data of a follow-up study support this assumption. The following paper reviews the currently available literature on anti-TNF alpha therapy in AS and uSpA. Efficacy, side effects and experiences with different doses are discussed. In expectation of the approval of infliximab and etanercept for the treatment of active AS international guidelines for initiation, monitoring and discontinuation of these agents have been recently proposed.