title: Haplotypes of susceptibility to chronic periodontitis in the Interleukin 8 gene do not influence protein level in the gingival crevicular fluid.
abstract: OBJECTIVE
  Previously, we identified that the ATC/TTC haplotype formed by polymorphisms in the Interleukin-(IL)8 gene conferred susceptibility to chronic periodontitis (CP). The aim of the study was to investigate whether the IL8 haplotype ATC/TTC was associated with the volume of gingival crevicular fluid (GCF), the concentration of interleukin IL-8 in the GCF, as well as periodontal conditions in patients with CP in comparison to controls without CP.
  
  
  METHODS
  Seventy-nine individuals (CP: n=41, controls: n=38) were grouped according to the presence (susceptible for CP) or absence (not susceptible for CP) of the IL8 ATC/TTC haplotype. After periodontal clinical evaluation, they were subdivided by the presence or absence of CP. GCF was collected from each patient and the IL-8 levels were determined by ELISA. The GCF volume of each subject was measured by means of a calibrated electronic device. Comparisons of means between carriers and non-carriers of the ATC/TTC haplotype were evaluated using the Mann-Whitney test. Linear regression and stepwise linear regression analysis were used to analyse the association of the GCF volume with potential covariates and their contribution for the phenotype.
  
  
  RESULTS
  We did not find significant differences of both periodontal conditions and IL-8 concentration in the GCF of patients with the presence or absence of the IL8 ATC/TTC haplotype. However, the GCF volume was significantly higher amongst the patients affected by CP that are absent for the IL8 ATC/TTC haplotype. In addition, linear regression analysis showed a statistically significant association between GCF volume and CP, IL8 haplotype ATC/TTC and IL-8 concentration.
  
  
  CONCLUSIONS
  The IL8 haplotype of susceptibility to CP was neither associated with IL-8 cytokine levels nor with clinical periodontal parameters. Also, CP, IL8 haplotype and IL-8 concentration showed a positive association with the GCF volume levels in the studied patients.
authors.affiliation: Department of Oral Diagnosis and Surgery, School of Dentistry at Araraquara, UNESP-São Paulo State University, Araraquara, SP, Brazil.
authors.forename: Sâmia C T
authors.initials: SC
authors.lastname: Corbi
authors.forename: Giovana
authors.initials: G
authors.lastname: Anovazzi
authors.forename: Lívia S
authors.initials: LS
authors.lastname: Finoti
authors.forename: Yeon J
authors.initials: YJ
authors.lastname: Kim
authors.forename: Marisa V
authors.initials: MV
authors.lastname: Capela
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Secolin
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Marcaccini
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Gerlach
authors.forename: Silvana R P
authors.initials: SR
authors.lastname: Orrico
authors.forename: Joni A
authors.initials: JA
authors.lastname: Cirelli
authors.forename: Raquel M
authors.initials: RM
authors.lastname: Scarel-Caminaga
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D055113:Chronic Periodontitis / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D020022:Genetic Predisposition to Disease; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D006239:Haplotypes; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011506:Proteins / Q000737:chemistry*; D018709:Statistics, Nonparametric
chemical_list: D016209:Interleukin-8; D011506:Proteins