The effect of experimental chronic jet lag on the circadian rhythm of mouse and human leukocytes. Blood samples were taken from 10-week-old humanized mice without (Control) or with (Jet-lag) the induction of jet lag at different times (n = 6). The CT corresponding to light onset (6 am) was defined as CT0. The number counts of mCD45⁺ (A) and hCD45⁺ (B) cells at each time in individual mice were normalized to the initial number at time CT1. Shown are fold changes of cell number. The MFI levels of phosphorylation of p38 (C) and MK2 (D) in mCD45⁺ and hCD45⁺ cells at CT7 and CT19. (E) The MFI levels of CXCR4 in mCD45⁺ and hCD45⁺ cells at CT7 and CT19. *P < .05; **P < .01.