PROFILE OF CYTOKINE MESSENGER-RNA EXPRESSION IN CHRONIC ADULT PERIODONTITIS

Chronic inflammation induced by bacteria often leads to host-mediated destruction of tissues adjacent to the sites of microbial insult. The chronic inflammatory process of adult periodontitis results in the des truction of supporting osseous and connective tissues of the teeth. We hypothesized that virulence factors of periodontal pathogens such as lipopolysaccharide stimulate inflammatory cytokine expression by monon uclear cells of the host which contribute to disease development. In t his study, to elucidate the role of these cytokines in chronic adult p eriodontitis, we tested whether the prevalence of mRNA for inflammator y cytokines generally associated with mononuclear phagocytes was highe r in diseased than in healthy gingival tissue. Gingival mononuclear ce lls or whole gingival biopsies from 32 adult periodontitis patients an d five healthy individuals used as controls were evaluated for inflamm atory cytokine mRNA expression by reverse-transcription polymerase cha in-reaction (RT-PCR) procedures. The cytokines assessed included IL-1 alpha, IL-1 beta, IL-1ra, IL-6, IL-8, IL-12, IL-13, TNF-alpha, TGF-bet a and IFN-gamma. The monocyte/macrophage lipopolysaccharide (LPS) rece ptor CD14 was also assessed. Results showed that TNF-alpha mRNA was pr esent significantly more frequently in diseased than in healthy biopsi es, whereas IL-1 alpha, IL-1 beta, and IL-1ra mRNA were found in most (from 80 to 100%) healthy tissues. Message for CD14 was present in bot h healthy and diseased tissue samples (100%). This study provides evid ence for a major role of TNF-alpha in chronic adult periodontitis. Mor eover, our results suggest that the mononuclear cells derived from per iodontal tissues have the capacity to respond to components of periodo ntal pathogens and express both pro- and anti-inflammatory cytokines i n these tissues.