Change in sickness behavior assessed with the Sickness Questionnaire after endotoxin challenge is associated with the degree of change in inflammatory cytokines

• Published in: BRAIN BEHAVIOR AND IMMUNITY Vol. 66; p. e33
• Main Authors: Andreasson, A., Lasselin, J., Karshikoff, B., Olsson, M.J., Axelsson, J., Lekander, M.
• Format: Journal Article Publication
• Language: English
• Published: Elsevier Inc 01.11.2017
• ISSN: 0889-1591; 1090-2139
• DOI: 10.1016/j.bbi.2017.07.123

The Sickness Questionnaire is a newly developed questionnaire for self-reported sickness behavior in humans. Here, we determined the time-course of sickness behavior and the association with changes in cytokine levels in an experimental study where 22 subjects received 2.0ng/kg endotoxin or placebo in a crossover design, with a minimum of 20days between injections. The Sickness questionnaire (from 0 to 30) and cytokines interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha were assessed at five time points: baseline, 1.5h, 3h, 5h and 7h post injection. Sickness behavior after endotoxin injection peaked at 1.5 and 3h (Sickness Questionnaire score 18.9 and 19.8, respectively, vs baseline 5.8, p’s<0.001). Although a significant recovery was seen at 5 and 7h (scores 11.8 and 10.4, respectively, p’s<0.001), levels had still not returned to baseline (p’s<0.001). The changes in all cytokines from baseline to 1.5h, 1.5 to 3h, 3 to 5h and 5 to 7h were significantly associated with change in sickness behavior (p’s<0.01). In conclusion, change in sickness behavior assessed with the Sickness Questionnaire after endotoxin challenge is associated with the degree of change in inflammatory cytokines and can last for 7h, further supporting the validity of Sickness Questionnaire as a measure of cytokine induced sickness behavior.