The Acute Phase Response: An Overview

Abstract

The acute phase response represents the substitution of new “set points” and a setting aside of many of the homeostatic processes that normally maintain stability in the face of an inconstant external environment. The acute phase response may be relatively transient, reverting to normal with recovery, or can be persistent in chronic disease. The acute phase serine proteinase inhibitors control extracellular matrix turnover, fibrinolysis, and complement activation. The process of C-reactive protein secretion, as distinct from synthesis, appears to be separately regulated during the course of the acute phase response, and may represent another cytokine-mediated phenomenon. Fever, somnolence, and anorexia are the most readily observed acute phase phenomena. Subsequent studies have revealed that a rapid erythrocyte sedimentation rate reflects elevated concentrations of several acute phase plasma proteins, particularly fibrinogen. It is probable that only a small fraction of the systemic, metabolic, humoral, nutritional, and physiologic changes that occur during the acute phase response have as yet been delineated.

Topics & Concepts