PARTIAL SLEEP-DEPRIVATION REDUCES NATURAL-KILLER-CELL ACTIVITY IN HUMANS

Sleep disturbance, measured by either subjective report or electroence phalographic (EEG) assessment of sleep, correlates with a reduction of natural killer (NK) cell activity in major depression. To test whethe r sleep loss independent of mood disturbance alters daytime values of cellular immune function, the effect of late-night partial sleep depri vation on NK cell activity was studied in 23 medically and psychiatric ally healthy male volunteers. After a night of sleep deprivation betwe en 3 and 7 AM, NK cell activity was reduced in 18 of the 23 subjects w ith average lytic activity reduced significantly (p < .01) to a level 72% of the mean of three separate baseline values. After a night of re sumed nocturnal sleep, NK cell activity had returned to baseline level s. These data implicate sleep in the modulation of natural immunity an d demonstrate that even modest disturbances of sleep produce a reducti on of NK cell activity.