Sleep deprivation is known to have harmful consequences for the immune system and may increase the risk of cardiovascular disease and diabetes. Finnish researchers have studied the deeper relationship between sleep deprivation and the immune system and have identified the genes that respond most strongly. The results of the study were published in the journal PLOS One. For the study, researchers at the University of Helsinki targeted a group of young men who were restricted to four hours of sleep per night for one week. The researchers analyzed blood samples from the subjects before and after the trial and compared them to other men who slept consistently for eight hours a night. Study author Vilma Aho said sleep deprivation led to increased expression of many genes associated with the immune system. In addition, there was increased activity of B cells, which produce important antigens that contribute to the body’s defense response and also help generate antigens for asthma and allergies. Aho added, “This may explain the previously observed results related to increased asthma symptoms in sleep deprivation states.” In addition, the expression of certain interleukins that promote inflammatory responses, as well as related receptors such as Toll-like receptors, was also increased. Aho concluded that sleep deprivation can affect many aspects of the body’s immune system, and that some of these changes may persist over time, thereby increasing the risk of developing certain diseases.