Immune tolerance the resulting effect is similar. Immune tolerance is important for normal physiology. Central tolerance is the main way the immune system learns to discriminate self from non-self. Peripheral tolerance is key to preventing over-reactivity of the immune system to various environmental entities (allergens, gut microbes, etc.). Deficits in central or peripheral tolerance also cause autoimmune disease, resulting in syndromes such as systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, autoimmune polyendocrine syndrome type 1 (APS-1), and immunodysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX), and potentially contribute to asthma, allergy, and inflammatory bowel disease. And immune tolerance in pregnancy is what allows
Behavioral immune system disease transmission. For instance, when the potential threat of disease is made salient, people tend to be less extraverted or sociable. Evidence suggests that the behavioral immune system also incorporates mechanisms designed to search out and process (heuristic) signs of disease at the level of basic visual attention. The behavioral immune system also has consequences at a cultural level of analysis. Under ecological circumstances in which diseases are more prevalent, people also tend to display more reticent and socially restricted forms of behavior, and human cultures are defined by more conservative norms and value systems. Some research suggests that the