The COVID-19 Burden or Tryptophan Syndrome: Autoimmunity, Immunoparalysis and Tolerance in a Tumorigenic Environment

Long covid is due to changes in the metabolism of tryptophan and the lack of niacin (NAD/NADH+). Tryptophan has its metabolism altered by the lack of intestinal absorption due to internalization of ACE-2 and hypoxemia and inflammation, diverting its products to the formation of toxic Kynurenine metabolites. The longer time under hypoxemia, the less niacin and the more tryptophan will deviate to Kynurenine in an inflamed environment