Systemic inflammation

Chronic systemic inflammation (SI) is the result of release of pro-inflammatory cytokines from immune-related cells and the chronic activation of the innate immune system. Chronic systemic inflammation (SI) is the result of release of pro-inflammatory cytokines from immune-related cells and the chronic activation of the innate immune system. It can contribute to the development or progression of certain conditions. Release of pro-inflammatory cytokines and activation of the innate immune system may be the result of either external (biological or chemical agents) or internal (genetic mutations/variations) factors. While SI may be induced by multiple external factors, research suggests that a lack of control by tolerogenic dendritic cells and 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, which is toxic to the cell.