Ankylosing Spondylitis (AS) is an inflammatory rheumatic disease that mainly affects the axial skeleton, and results in characteristic lower back pain and stiffness, impaired physical and structural function and fatigue. AS patients have an increased serum level of CRP and SR, and a higher blood concentration of TNF-alpha, IL-6, IL-17 and IL-23 compared to the general population.
Physical activity is the cornerstone in treatment of AS, with evidence of positive effects on clinical symptoms. However, it is less known how physical activity affects the inflammatory markers in patients with a systemic inflammation.
In patients with AS there is four cytokines of particular interest: TNF-alpha, IL-6, IL-17, and IL-23. IL-6 is increased in patients with AS, and the concentration correspond to the laboratory and clinical parameters of inflammation. TNF-alpha is overexpressed in the ileosacral joints, and there is shown effective therapeutic results with TNF-inhibitors. TNF-alpha together with IL-23 is known to give signal effects to IL-17 that is associated with both inflammation and autoimmunity. Also, there are indications that IL-17 and IL-23 are involved in the pathogenesis of AS. In healthy individuals IL-6 is significantly increased after an acute exercise and leucocytosis is observed immediately after an acute physical exertion. It is to be expected that patients with AS respond differently to the exposure of an exhaustion test, because they already have an underlying inflammation present.
Research suggests that there is created an anti-inflammatory environment with each bout of exercise. The purpose of this experimental study was to examine how patients with AS respond to an acute physical exertion by measuring inflammatory markers in resting state and immediately after a maximal exhaustion test on a treadmill. This may explain the health benefit we see in physical active patients.
In this experiment we measured increased values of TNF-alpha and IL-23. However, there were no significant changes in IL-6 and IL-17.
Conclusion: There was a significant increase in two proinflammatory cytokines, which is a contradiction to what we would expect because of the clinical benefit we observe in physical active patients. The study showed no significant increase in IL-6, as seen in healthy individuals. This might indicate that the increase in cytokines seen in an inflammatory process is probably distinct from the increase seen after an intense bout of exercise. Nevertheless, this finding may provide useful information to the ongoing research on the use of exercise as a form of treatment for patients with Ankylosing Spondylitis.