IL-1b and TNF-a-driven sleep alterations: Neuroimmune mechanisms and behavioral implications

Sleep is a fundamental physiological state essential for immune function, metabolic regulation, and recovery from illness. During infection, sleep patterns are altered in a stereotyped fashion-characterized by increased non-rapid eye movement (NREM) sleep and reduced rapid eye movement (REM) sleep. These sleep changes are not incidental consequences of illness but reflect an evolutionarily conserved neuroimmune adaptation driven by proinflammatory cytokines. In particular, interleukin 1b (IL-1b) and tumor necrosis factor-a (TNFa) modulate sleep by acting directly on central nervous system circuits, including the serotonergic system and homeostatic sleep regulation. In this review, we synthesize current knowledge on how IL-1b and TNFa interact with sleep-regulating networks to alter behavioral state transitions during immune challenge. We also explore the broader clinical relevance of cytokine-driven sleep changes across infectious, psychiatric, and neurodegenerative disorders, and highlight emerging therapeutic opportunities targeting neuroimmune pathways to restore sleep homeostasis. Understanding these interactions is essential for advancing mechanistic insight into sleep regulation and for improving clinical management of inflammation-related sleep disturbances.