In vivo endotoxin synchronizes and suppresses clock gene expression in human peripheral blood leukocytes.

Objectives The intravenous administration of a bolus dose of endotoxin to healthy human subjects triggers acute systemic inflammatory responses that include cytokine production and dynamic changes in gene expression in peripheral blood leukocytes (PBL). This study sought to determine the state of clock gene expression in human PBL, and leukocytes subpopulations, challenged with in vivo endotoxin at two circadian/diurnal phases of the clock.