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Nature 454, 428-435 (24 July 2008) | doi:10.1038/nature07201; Published online 23 July 2008

Origin and physiological roles of inflammation

Ruslan Medzhitov1

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Inflammation underlies a wide variety of physiological and pathological processes. Although the pathological aspects of many types of inflammation are well appreciated, their physiological functions are mostly unknown. The classic instigators of inflammation — infection and tissue injury — are at one end of a large range of adverse conditions that induce inflammation, and they trigger the recruitment of leukocytes and plasma proteins to the affected tissue site. Tissue stress or malfunction similarly induces an adaptive response, which is referred to here as para-inflammation. This response relies mainly on tissue-resident macrophages and is intermediate between the basal homeostatic state and a classic inflammatory response. Para-inflammation is probably responsible for the chronic inflammatory conditions that are associated with modern human diseases.

  1. Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, TAC S-669, 300 Cedar Street, New Haven, Connecticut 06510, USA.