Research paperExercise-induced cytokine changes in antigen stimulated whole-blood cultures compared to serum

•Intraindividually, exercise-induced systemic cytokine changes are different from sWBC.•The cytokine output in a sWBC is a measure of leukocyte function.•A sWBC offers a more sensitive insight into the cytokine response to exercise.•Serum measurements reflect net changes with respect to both production and clearance.•It is proposed to use both approaches synergistically.

Strenuous exercise is followed by an elevation of many cytokines with inflammation regulating properties. Since most cytokines act at pico- or nanomolar concentrations many investigations failed to detect their concentrations in vivo. Hence, the aim of this study was to evaluate the significance of cytokine measurements (IL-1β, TNF-α, IL-1ra, IL-6, CCL2 and CXCL8) in a stimulated whole-blood culture (sWBC) compared to serum with respect to their exercise-induced kinetics and detection rates. 40 male volunteers (age: 25,5 ± 4,3 years, BMI: 24,00 ± 2,24, VO2peak: 46,9 ± 4,1 mL/kg × min) performed 60 min of intensive bicycle exercise (80% VO2peak). Blood samples were taken before and for up to 24 h after exercise. All cytokines were determined by a multiplex ELISA. There were weak to moderate correlations between cytokines in sWBC and serum. While exercise did not affect pro-inflammatory cytokines in serum, in sWBC only IL-1β was increased 1.2-fold at 3 h (p < 0,05). All other cytokines increased both in sWBC and serum. The detection rate was superior in sWBC vs serum for most cytokines. Exercise-induced cytokine kinetics in sWBC do not reflect systemic changes. Both approaches provide a synergistic insight into inflammatory processes on the cytokine level.