Why is there a link between sleep and the immune system?

[star apple]

When you don't sleep.. your immune system gets weak.. but even if you stay still or rest without sleeping.. your body should theoretically be in a restful state.. so the immune system being products of cells, Brownian motion and thermodynamics, etc. should not be related to sleep..

Yet it is.. why? What is the connection of sleep to the immune system?

 

[rootone]

You need to provide a reference regarding the idea that lack of sleep weakens the immune system.
Sure, lack of sleep can cause mood disorders in humans, but then the immune system works by itself regardless of it's owners mood.

 

[Tom.G]

Here is one reference:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256323/
Google finds 1 040 000 more.