The human immune system is an early riser

The migration of dendritic cells from the skin into lymphatic vessels depends on the time of day. Mouse dendritic cells ( green ) migrating into the lymphatic vessels ( red ). The blood vessels are in blue. UNIGE - Christoph Scheiermann - Swiss and German scientists show that activation of the immune system oscillates throughout the day, with a peak just before the start of the day. Circadian clocks, which regulate most of the physiological processes of living beings over a rhythm of about 24 hours, are one of the most fundamental biological mechanisms. By deciphering the cell migration mechanisms underlying the immune response, scientists from the University of Geneva , in Switzerland, and the Ludwigs-Maximilians University (LMU), in Germany, have shown that the activation of the immune system is modulated according to the time of day. Indeed, the migration of immune cells from the skin to the lymph nodes oscillates over a 24-hours period.