Polymorphism at position -174 of IL-6 gene is associated with susceptibility to chronic periodontitis in a Caucasian Brazilian population.
BACKGROUND
Interleukin-6 (IL-6) is a multifunctional cytokine that mediates inflammatory tissue destruction. A G to C substitution at position -174 in the promoter of IL-6 gene reduces in vitro transcription of IL-6. This polymorphism has been associated with inflammatory diseases like chronic arthritis.


OBJECTIVE
The aim of this study was to investigate the association between the IL-6-174 polymorphism and susceptibility to chronic periodontitis in Brazilians.


METHODS
Eighty-four nonsmoking subjects over 25 years (mean age 42.4) were divided according to the severity level of periodontal disease: 36 healthy individuals (control group), 24 subjects with moderate and 24 with severe periodontitis. Genomic DNA was obtained from epithelial cells through a mouthwash with 3% glucose and scraping of oral mucosa. The samples were analyzed for IL-6-174 polymorphism using PCR-RFLP. The significance of the differences in the frequencies of the polymorphism in the control and groups with periodontitis was assessed by chi2 test (p<0.05).


RESULTS
Differences were found between control and groups with periodontitis in the genotype (p=0.0036, OR=3.0) and in the allele (p=0.0838, OR=1.9) frequencies.


CONCLUSIONS
We concluded that the IL-6-174 polymorphism is associated with susceptibility to chronic periodontitis in the population studied.
Trevilatto
P C
PC
Department of Morphology, Dental School of Piracicaba, State University of Campinas, SP, Brazil.
Scarel-Caminaga
R M
RM
de Brito
R B
RB
de Souza
A P
AP
Line
S R P
SR
D000328:Adult; D000483:Alleles; D001483:Base Sequence; D001938:Brazil; D016009:Chi-Square Distribution; D002908:Chronic Disease; D003596:Cytosine; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006147:Guanine; D006801:Humans; D018836:Inflammation Mediators / Q000276:immunology; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D010518:Periodontitis / Q000145:classification / Q000235:genetics* / Q000276:immunology; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D044465:White People / Q000235:genetics*
D018836:Inflammation Mediators; D015850:Interleukin-6; D006147:Guanine; D003596:Cytosine