Chapter 9: Role of kynurenine pathway in HIV/AIDS

Two of the most fundamental requirements for the host are the ability to survive periods of starvation and the capacity to mount an effective response against pathogenic invaders while tolerating mucosa-associated commensal microbes. The kynurenine (Kyn) pathway (KP) is at the crossroad of these two fundamental requirements and therefore plays an important role in HIV infection. The combination of HIV infection and tryptophan catalytic bacteria causes CD4 Th17/Th22 dysfunction in the gut mucosa leading to microbial translocation that creates a systemic KP activation cycle. This self-sustaining feedback loop has deleterious effects on disease progression and on neurocognitive impairment in HIV-infected patients while fuelling a systemic state of immune activation.