Cytokine kinetics in nasal mucosa and sera: new insights in understanding upper-airway disease of marathon runners.

Recently, many authors have proposed that mechanisms such as inflammation and/or allergies could be partly responsible for cases of upper respiratory tract illnesses that affect athletes after exhaustive exercise. Here we studied the kinetics of cytokines in the serum and nasal mucosa of athletes after a marathon. We were able to demonstrate an increase in serum levels of all interleukins studied immediately after the marathon in athletes that present or not with upper airways symptoms followed by a return to basal levels 72 hours after the race, as described in the literature. Interleukin (IL)-10 behaviour differed in the group of asymptomatic athletes. Measurement of this cytokine in protein extract of nasal mucosal cells showed increase 72 hours after the marathon. Levels of this cytokine in sera were increased at rest in athletes that did not present symptoms. These fin- dings suggest that the maintenance of a non-inflammatory environment in the mucosal airways is an active process that requires participation of the systemic and mucosal immune systems. We propose that the understanding of the upper airway disease of the athlete involves the study of mucosal and systemic immune systems.