Sleep and Immunity: Cytokine Pathways Linking Sleep and Health Outcomes

ABSTRACT— The functions of sleep are enigmatic but are beginning to be delineated. Sleep has been long thought to be important for health, and poor sleep is prospectively associated with worsened health outcomes. Yet the mechanisms accounting for this are only partially understood. In this review, we suggest that the immune system plays a role in the relationship between sleep and health and that sleep processes and immunity show bidirectional interactions, as evidenced in both animal and human studies. Immunological signaling molecules, termed cytokines, are important in coordinating brain–immune system communication, and particular cytokines such as tumor necrosis factor, interleukin-1, and interleukin-6 play a crucial role in sleep regulation. Elevated levels of these cytokines are also associated with a number of chronic diseases and may provide a pathway linking poor sleep with health outcomes.