Somnogenic activity of immune response modifiers.

Sleepiness is a presenting symptom in nearly all infectious diseases. James Krueger describes how microbial products, such as muramyl peptides, lipid A and double-stranded RNA, as well as endogenous products elicited by these substances, such as interleukin 1, modulate sleep. The altered sleep during infection seems to result from an exaggerated activation of physiological sleep mechanisms, since normal sleep is controlled by a wide range of substances including many of these immune response modifiers.