IL6 and insomnia: Insomnia can trigger inflammation, including the production of higher interleukin-6 and C-reactive protein levels,[40] impaired natural killer cell activity,[41] reduced T-cell cytokine levels,[42] and the inhibition of the i nterleukin-6 response.[40] Insomnia can also delay or weaken vaccine responses.[43] These mechanisms highlight the important role that sleep plays as a regulator of immunity and disease susceptibility.