Sleep deprivation lowers the percentage of natural killer cells in peripheral blood according to Dr. Zerrin Pelin, who presented her findings to participants at this year's meeting of the American Sleep Disorders Dr. Pelin reported that CD16 levels changed significantly with sleep deprivation. Dr. Pelin believes that the decrease in the proportion of natural killer cells in peripheral blood during sleep deprivation may reflect the suppression of nonspecific immune response and an increased susceptibility to viral infection.

Sleep Loss Can Also Trigger Mania

Disruption in sleep may be dangerous for people with bipolar disorder, also known as manic depression. A new study suggests that sleep disturbances may trigger an episode of mania, in which individuals lose touch with reality, need little sleep or food, have enormous amounts of energy, and are easily triggered into states of rage or paranoia. Bipolar disorder is characterized by such episodes -- periods of mania, where someone is overly optimistic and might start an ambitious, impossible-to-finish project, or invest their life savings in a risky venture -- alternating with episodes of severe depression and lethargy. About 2 million people in the U.S. suffer from bipolar disorder.