Studies have shown sleep loss could affect the immune system - it can weaken some aspects of it that fight pathogens, and possibly strengthen another part that may attack our own tissues. A study was published in the July edition of the Sleep Journal by Dr. Ackermann and others about sleep loss and the immune system. They studies healthy, young males in the sleep lab for 3 days straight. The first night was an adjustment night, the second night was an 8 hour sleep opportunity, and the participants were kept awake for the entire time during the third night. Blood was drawn every three hours during the study.
The results showed that there was an overall increase in circulating granulocytes (a type of immune cell involved in fighting bacteria) in the blood after the acute sleep deprivation night. The study authors suggest that the increase in circulating granulocytes is a response to the stress of acute sleep deprivation. The health consequence of this are not yet known. However, there is evidence that increased granulocytes are associated with cardiovascular disease. This could provide the missing link between studies showing an association between sleep deprivation and cardiovascular disease. It's not known whether the granulocyte concentration would remain elevated or even be elevated with chronic partial sleep deprivation, versus a night of total sleep deprivation as in this study. It is possible that over the long term, the immune system compensates for chronic partial sleep loss. Apparently this compensatory effect has been demonstrated in long term shift workers.