IL-8 and Tumor Necrosis Factor Alpha in Heart Valves from Patients with Infective Endocarditis

Abstract

The embedding of bacteria in the vegetation of infective endocarditis impedes the penetration of phagocytic cells. IL-8 has a stimulating effect on the immune system, particularly with respect to chemotaxis and activation of granulocytes. Tumor necrosis factor alpha (TNF-α) is 1 of the major proinflammatory cytokines. IL-8 and TNF-α were visualized by means of immunohistochemistry in paraffin-embedded heart valve biopsies from 6 patients with infective endocarditis who required cardiac surgery during the active phase of the infection. In 5/6 patients there were signs of inflammation, and in these patients IL-8- and TNF-α -containing cells were visualized in the heart valve stromas or vegetations. The largest numbers of IL-8-containing cells, and the greatest amount of inflammation, were seen in patients with short preoperative treatment courses. No such relationships were seen with respect to TNF-α -containing cells. These observations may suggest that the occurrence of IL-8-containing cells in infected heart valves could be used as a marker of disease activity.