Molecular biology and immunology for clinicians

After tissue injury, homeostatic mechanisms attempt to repair the damage. Local changes in the vasculature allow inflammatory cells to exit to deal with pathogens and take part in healing. Cytokines produced locally can cause systemic changes: fever, leukocytosis, transfer of amino acids from muscles to the liver, and increased glucocorticoid levels. A complicated blend of cytokines, including interleukins 1 and 6 and tumor necrosis factor, modulate patterns of hepatic protein synthesis. Changes in the production of metabolism-related enzymes occur, serving to provide fuel for the body and increase protein glycosylation. Also, there is an increase in synthesis of certain proteins exported from the liver, including components of the coagulation, complement, kinin, and fibrinolytic systems, all involved in the inflammatory response. Different inflammatory conditions elicit different responses; the types of proteins and the pattern of glycosylation may vary. Serum levels of heavy metals, including iron, copper, and zinc, change during inflammation because of altered levels of relevant transport or storage proteins.It is not clear what purpose is served by some of these changes. Many of the proteins are immunomodulatory, but some "functions" may be merely in vitro artifacts. What is clear, however, is that measurement of the protein known as C-reactive protein and of the erythrocyte sedimentation rate may provide markers of inflammation and measures of the response of certain inflammatory diseases to therapy.