The Immune System Is an Early Riser, Research Shows

Medscape Staff

October 19, 2021

The migration of dendritic cells to the lymphatic system oscillates according to the time of day, suggesting certain times are associated with higher immune system activity.

What to know:

  • The activity of the immune system rises and falls over the course of a day, according to new research published in Nature Immunology.

  • The migration of dendritic cells to the lymph nodes changes over a period of 24 hours in response to circadian rhythms.

  • Researchers from the University of Geneva and Ludwig-Maximilian University identified several molecules, such as chemokines, that are involved in this migratory process. The expression of these molecules is regulated by circadian clocks.

  • In mice, which are nocturnal, peaks in the migratory process were seen during the mice's resting phase in the afternoon, just before activity resumed.

  • Researchers then evaluated human skin cells taken from patients at different times of the day and found that the migratory process peaked in the early morning.

  • The results suggest that time of day may be a point of consideration in the future for administering vaccines or delivering immunotherapies.

This is a summary of the article "The Human Immune System Is an Early Riser," published by the University of Geneva on October 18. The full article can be found on

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