title: Increased interleukin-18 in gingival crevicular fluid from periodontitis patients.
abstract: BACKGROUND
  This study aimed to measure the levels of interleukin-18 (IL-18) in inflamed shallow sites and inflamed deep sites in patients with periodontitis and to compare the data with results from inflamed shallow sites in patients with gingivitis. A secondary aim was to examine the composition of the subgingival microbiota in the sampled sites.
  
  
  METHODS
  Gingival crevicular fluid was collected from five gingivitis sites and five periodontitis sites from 18 patients with chronic periodontitis, and from five gingivitis sites from 15 patients with gingivitis. Samples from each site category were pooled and IL-18 levels were measured using an enzyme-linked immunosorbent assay. The subgingival microbiota was analyzed by checkerboard DNA-DNA hybridization.
  
  
  RESULTS
  All clinical parameters and gingival crevicular fluid volumes were higher in periodontitis sites compared with gingivitis sites from patients with periodontitis and gingivitis. The total amount of IL-18 was higher in periodontitis sites than gingivitis sites in both periodontitis (P = 0.018) and gingivitis (P = 0.002) patients and was higher in gingivitis sites from periodontitis patients than in those from gingivitis patients (P = 0.015). There were higher levels of Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola (red complex species) in periodontitis sites compared with gingivitis sites in both the periodontitis and gingivitis patients (P < 0.001).
  
  
  CONCLUSIONS
  Levels of IL-18 were higher in patients with chronic periodontitis compared with patients with gingivitis, even at sites with similar pocket depths. The presence of similar levels of red complex species in gingivitis sites from periodontitis patients and from gingivitis patients suggested that the higher levels of IL-18 were not associated with a different microbial challenge.
authors.affiliation: Department of Periodontology, Rio de Janeiro State University - UERJ, Rio de Janeiro, Brazil. cmfigueredo@hotmail.com
authors.forename: C M
authors.initials: CM
authors.lastname: Figueredo
authors.forename: B
authors.initials: B
authors.lastname: Rescala
authors.forename: R P
authors.initials: RP
authors.lastname: Teles
authors.forename: F P
authors.initials: FP
authors.lastname: Teles
authors.forename: R G
authors.initials: RG
authors.lastname: Fischer
authors.forename: A D
authors.initials: AD
authors.lastname: Haffajee
authors.forename: S S
authors.initials: SS
authors.lastname: Socransky
authors.forename: A
authors.initials: A
authors.lastname: Gustafsson
mesh_terms: D001439:Bacteroides / Q000302:isolation & purification; D016022:Case-Control Studies; D002908:Chronic Disease; D004269:DNA, Bacterial / Q000032:analysis; D003773:Dental Plaque / Q000737:chemistry; D005883:Gingival Crevicular Fluid / Q000737:chemistry* / Q000382:microbiology; D005891:Gingivitis / Q000378:metabolism / Q000382:microbiology; D006801:Humans; D020382:Interleukin-18 / Q000032:analysis / Q000378:metabolism*; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D010518:Periodontitis / Q000378:metabolism* / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D018709:Statistics, Nonparametric; D048373:Treponema denticola / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D020382:Interleukin-18