RELEVANCE OF LOCAL TH2-TYPE CYTOKINE MESSENGER-RNA EXPRESSION IN IMMUNOCOMPETENT INFILTRATES IN INFLAMED GINGIVAL TISSUE TO PERIODONTAL-DISEASES

It has been suggested that the types of inflammatory round cell infilt rates and the divergence in the cytokine production profile by macroph ages and helper T cells regulate the course of infectious or inflammat ory diseases, including periodontitis and gingivitis. We examined the expression of IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6 and tumour necrosis factor-alpha (TNF-alpha) mRNA in the inflamed gingiva by in situ hybridization. The results of single-cell analysis were used as d ata sets for statistical analyses. The density of cells expressing IL- 1 alpha, IL-4 and IL-5 mRNA was higher in periodontitis than in gingiv itis. IL-2 mRNA-expressing cells were almost absent in gingivitis spec imens. Principal component analysis disclosed three factors explaining 84.8% of the variance: one accounting for 40.5% of the variance and m ainly regulated by IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha, and two others, explaining 29.9% and 144% of the variance, describing the rela tionship between the types of cytokines derived from macrophages or Th ? type. These results suggest that the cytokines produced by inflammat ory cells infiltrating in the gingival tissue are influential on the p rogression of gingivitis, an acute and reversible inflammatory conditi on, to chronic and destructive periodontitis. Thus, periodontal diseas e progression may be regulated by the local cytokine network, and the bias in this network towards a Th2-type cytokine dominance could be an exacerbating factor.