Regulation of Immunity by the Circadian Clock

Abstract

Over the last few years, molecular evidence has clearly shown a direct impact of daily rhythms on the immune system, both in steady state and under inflammatory conditions. Circadian oscillations have been demonstrated in the regulation of cytokine and chemokine levels as well as immune cell numbers in blood and tissues. A possible explanation for these rhythms is that species are more prone to be exposed to a variety of acute threats such as injuries and microbial infections at specific times during their circadian cycle. Also some chronic diseases follow a circadian rhythm, indicating that a greater understanding of the underlying molecular mechanisms will permit the development of new and improved therapeutic strategies for treating inflammatory diseases that incorporate the element of time.