Narcolepsy is a disabling neurological
sleep disorder characterized by
excessive daytime sleepiness and abnormal REM sleep manifestations. Recently, the role of
cytokines and
growth hormone in the regulation of sleep and
narcolepsy has been considered, and data suggest that proinflammatory
cytokines may be involved in sleep and narcoleptic symptoms. Serum and clinical data were obtained from the Stanford Center for
Narcolepsy Research for 39 Narcoleptics (22 Females, 17 Males, age 39+/-14.9) and 40 controls (13 Females, 27 Males, age 46+/-17.9). Plasma levels of
TNF-alpha,
IL-6, and
human growth hormone (hGH) were measured by ELISA.
TNF-alpha and
IL-6 were significantly increased in narcoleptic subjects compared to controls (p=.001). Interestingly, hGH was significantly increased in narcoleptic subjects (p <.0001). There was also a significant difference in the epworth
sleepiness scale (ESS) (17.7+/-4.6 vs. 5.5+/-3.2, p <.0001). These data indicate that narcoleptics, relative to controls, had higher serum levels of
TNF-alpha,
IL-6, and hGH. These data suggest that the dysregulation of sleep observed in narcoleptics correlates with the immune and endocrine dysregulation seen in these subjects, and the observed changes may in fact contribute to the higher likelihood of disturbed sleep and/or increased incidence of
infection. Additional work is required to fully characterize connections between
cytokines and narcoleptic symptomatology.