Natural Killer (NK) cells are the bodyguards of our immune system and are considered our first line of defense.
Their job is to destroy invading pathogens, foreign bodies and infected cells at an early stage, thus preventing them from spreading. A decrease in the number of NK cells can lead to immune system dysfunction and increased susceptibility to disease.
Anxiety disorder and insomnia are two conditions that can disrupt the normal functioning of the immune system.
Because these disorders are quite common, researchers in Saudi Arabia have now investigated the association between anxiety, insomnia and NK cells in young female students and published their results in Frontiers in immunology.
60 female students, aged between 17 and 23, participated in the study and completed three questionnaires on sociodemographics and symptoms of anxiety and insomnia.
The symptoms of the latter two were self-reported and showed that approximately 53% of participants reported sleep disturbances indicative of insomnia, and 75% reported anxiety symptoms.
Participants also provided blood samples used to determine percentages of NK cells and their subtypes.
NK cells have two subtypes: the first type, CD16+CD56dim cells, make up the majority of NK cells in the nervous system that connects the central nervous system to the rest of the body.
Cells belonging to this subtype also exhibit cytotoxicity (cell toxicity), meaning they can damage or kill cells that enter the body.
The other subtype, CD16+CD56high cells, are less common and are involved in the production of proteins that function as chemical messengers and in immune regulation (regulation of the immune system).
The results of the study showed that students with anxiety symptoms had lower numbers of NK cells in the circulation and their subpopulations, compared to students who reported no symptoms.
Symptom severity also played a role, as students with moderate and severe anxiety symptoms had a significantly lower percentage of NK cells in the circulation compared to students without these symptoms.
In students with minimal or mild anxiety symptoms, only a statistically insignificant decrease in NK cell percentage was observed. While in students with insomnia symptoms, higher anxiety scores were negatively associated with the proportion of total peripheral NK cells.
