“Hypoxia and immunity are highly interdependent. Hypoxia affects molecular and cellular inflammatory processes. Hypoxia activates distinct hypoxia-signaling pathways, including a group of transcription factors known as hypoxia-inducible factors and adenosine signaling. In vitro and animal studies have shown that these pathways are involved in modulation of inflammatory responses. Inflammatory conditions are frequently characterized by tissue hypoxia due to enhanced metabolic demand as well as decreased metabolic substrates resulting from edema, microthrombi, and atelectasis, in turn causing “inflammatory hypoxia.”
 Immunologic Consequences of Hypoxia during Critical Illness. Harmke D. Kiers, M.D.; Gert-Jan Scheffer, M.D., Ph.D.; Johannes G. van der Hoeven, M.D., Ph.D.; Holger K. Eltzschig, M.D., Ph.D.; Peter Pickkers, M.D., Ph.D.