Circadian Gene Bmal1 Regulates Diurnal Oscillations of Ly6C hi Inflammatory Monocytes

Diurnal Immunology Like most organ systems in the body, several components of the immune system appear to be regulated in a diurnal manner. However, the cell populations affected, the underlying molecular mechanisms controlling these processes, and the functional consequences of such regulation are poorly understood. Now, Nguyen et al. (p. 1483 , published online 22 August; see the Perspective by Druzd and Scheiermann ) have found that trafficking of monocytes to sites of inflammation is regulated in a diurnal manner in mice. Mice harboring a myeloid cell-specific deletion in the clock protein, BMAL1, showed reduced fitness in response to both acute and chronic inflammation.