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
Human Endogenous Retrovirus-W occur when the immune system recognizes an antigen and activates the immune response cascade. The transcribed and translated products of the HERV-W Env gene come from retroviral DNA thus the human body detects these proteins as antigens triggering the immune response. Specifically, cytokine production is elevated in the MS PBMC cultures as compared to the healthy controls and mediated by the surface unit of the MSRV Env protein. This suggests that the MSRV Env protein may induce abnormal cytokine secretion, which leads to inflammation. A further explanation of how the expression of MSRV causes inflammation is found when looking at