Localization of interleukin-8 in human gingival tissues.

Periodontitis and gingivitis are chronic inflammatory diseases of the periodontium and adjacent tissues. This site-specific inflammation is characterized by a local infiltration of polymorphonuclear leukocytes and T lymphocytes. Interleukin-8 is a low molecular-weight cytokine that is thought to be responsible for the induction and maintenance of localized inflammation. We hypothesized that locally produced interleukin-8 plays a central role in chronic inflammation of periodontitis by regulating the recruitment and activation of leukocytes in the gingival tissues. To test this hypothesis, we determined whether the interleukin-8 antigen is present locally and is cell-associated. Inflamed and control tissues were analyzed: 1) for the interleukin-8 antigen; 2) by molecular weight; 3) for location; and 4) for the messenger RNA (mRNA) of interleukin-8. The conclusions from these data were that: 1) interleukin-8 antigen and mRNA was elevated in chronically inflamed gingiva; and 2) the major interleukin-8 antigen was detected only in the epithelial cell layer. These results support that interleukin-8 may play a crucial role in the recruitment and activation of neutrophils and T lymphocytes in periodontitis.