Inflammation and acute phase response.

ABSTRACT

Inflammation caused by infection takes place by the cooperative cascade of cytokines and leukocytes. Tumor necrosis factor, interlukin-1, and interlukin-6 play important roles as proinflammatory cytokines to mediate local inflammation and activate other inflammatory cells e.g. neutrophils, monocytes, and macrophages. At least 15 different low molecular weight cytokine are secreted by activated leukocytes and are responsible for triggering acute phase response in the form of fever, leukocytosis, increased secretion of adreno corticotropic hormones, and production of acute phase proteins. Acute phase proteins are produced in liver under the influence of cytokines, which through blood stream passes to the site of inflammation and kill the pathogens by opsonization and activating complement pathways. The changes in the concentrations of positive acute-phase proteins and negative acute-phase proteins are due to the changes in their production by liver. Three of the best known acute phase proteins are C-reactive protein, serum anyloid A, and haptoglobin. Some disease states are casually related to acute phase proteins. C-reactive protein mediated compliment activation has a key role in some forms of tissue alteration such as cardiac infarction. Elevated S amyloid A levels are seen in chronic arthritis and tuberculosis. Other acute phase proteins show more moderate rise, usually less than fivefold.