Systemic inflammation

neurodegenerative disorders,^[1] and coronary heart disease.^[2]

acute inflammation and an individual's exposome. Age-related systemic chronic inflammation is associated with several cytokines including CXCL9, TRAIL, interferon gamma, CCL11, and CXCL1, and a proposed measurement of chronic systemic inflammation based on these cytokines (iAge) correlates with immunosenescence and predicts risk for cardiovascular disease, frailty syndrome, and multimorbidity.^[5]Damaged proteins and other cellular debris can provoke chronic inflammation in the innate immune system

COVID-19 morbidity.^[9][10] In severe cases, COVID-19 causes a cytokine storm which contributes to excessive and uncontrolled inflammation of organs, particularly respiratory tissues.^[11][12] If untreated, this increased inflammation can result in reduced immune response, pneumonia, lymphoid tissue damage, and death.^[11] Individuals with abnormal cytokine production, such as those with obesity or systemic chronic inflammation, have poorer health outcomes from COVID-19.^[9][10] Elevated cytokine production alters the innate immune response which leads to abnormal T-cell and B-Cell function that decreases control of viral replication and host defense.^[9] Anti-viral therapeutic drugs which also reduce inflammation seem to be the most effective treatment, but research is still ongoing.^[12] Reactive oxygen species are upregulated during inflammation as part of the immune response to defend against pathogens.^[13] However, excessive inflammation causes dangerous levels of reactive oxygen species which cause oxidative stress to tissues.^[13] The immune system naturally produces antioxidant compounds to regulate and detoxify reactive oxygen species.^[13] Anti-oxidative therapy with supplements such as vitamin C, vitamin E, curcumin, or baicalin is speculated to reduce infection severity in COVID-19,^[14][12] but previous research has not found antioxidants supplementation to be effective in the prevention of other diseases.^[15] Shifting from the typical western diet to a Mediterranean diet or plant-based diet may improve COVID-19 health outcomes by reducing prevalence of comorbidities (i.e. obesity or hypertension), decreasing intake of pro-inflammatory foods, and increasing consumption of anti-inflammatory and antioxidant nutrients.^[12][16][17]

T-regulatory cells (Treg) is possibly the primary risk factor for the development of SI. In functioning immune responses, T-helper and T-cytotoxic cells are activated by presentation of antigens by antigen-presenting cells (APCs). Chief among these are dendritic cells (DCs). When a DC presents an antigen to a Treg cell, a signal is then sent to the nucleus of the DC, resulting in the production of indoleamine 2,3-dioxygenase (IDO). IDO inhibits T cell responses by depleting tryptophan and producing kynurenine