Low Levels of Cytokines and Growth Factors in Serum of Allergic and Non-Allergic Top Atletes

RATIONALE: Several changes of the immune cells and of the cytokine profile have been reported after an acute exercise challenge. However, in spite of the high prevalence of allergic diseases and upper respiratory tract infections reported in athletes, the immune response to an intense and prolonged training has been for less investigated.METHODS: In the framework of an International study of Olympic athletes (www.ga2len.net) sera from 92 athletes of the Italian delegation in the Beijing Olympic Games and from 49 healthy non-allergic sedentary controls were tested for a broad cytokine and growth factor array. On the basis of data available through clinical history, an allergy specific questionnaire for athletes (AQUA), skin-tests, pulmonary function tests and serum total IgE determination, athletes were classified as allergic (n=41) or non-allergic (n=51). A Cytokine bead luminometric assay was used to measure the following cytokines and growth factors: IL-1ra, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, Il-17, IFNg, TNFa, RANTES, IP-10, MCP-1, MIP-1a, MIP-1b, Eotaxin, G-CSF, PDGF and VEGF.RESULTS: For all cytokines and growth factors measured, apart from IL-13, TNFa and MIP-1a, serum levels in athletes were significantly lower (p<0.05) than in controls. This was particularly evident for IL-1ra, IL-8, IL-12, MCP-1, IFNg, PDGF and VEGF (p<0.0001). No difference was observed between allergic and non-allergic athletes except for G-CSF which was significantly lower (p=0.01) in allergic athletes.CONCLUSIONS: The increased prevalence of allergic diseases and URTI reported in top athletes after a long-term intensive physical training is associated with a general down-regulation of the cytokine and growth factor profile.