Association analysis between interleukin-1 family polymorphisms and generalized aggressive periodontitis in a Chinese population.
BACKGROUND
It has been suggested that aggressive periodontitis (AgP) has a genetic basis, but this theory has not been confirmed. The intent of this investigation was to study whether specific interleukin (IL)-1 genotypes and/or alleles could be used to predict susceptibility to generalized AgP (GAgP) in Chinese.


METHODS
The GAgP group consisted of 122 patients, and the control group included 95 healthy subjects. Single nucleotide polymorphisms at IL-1A (+4845) and IL-1B (-511, +3954) were analyzed by standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The polymorphism of a variable number tandem repeat (VNTR) in intron 2 of IL-1RN was detected by PCR amplification and fragment size analysis.


RESULTS
There was no significant association of IL-1 polymorphisms with GAgP in the unstratified subjects. However, when cases were stratified by gender, the frequencies of A2+ genotype and allele 2 at IL-1A +4845 were significantly increased in male patients compared to male controls (genotype: odds ratio [OR] 5.58, 95% confidence interval [CI]: 1.09 to 28.68, P = 0.039; allele: OR 4.97, 95% CI: 1.01 to 24.50, P = 0.049; adjusted for age and smoking status). The frequency of IL-1B -511 A1/A2 heterozygote was significantly increased in male GAgP group compared to male controls (adjusted OR 3.16, 95% CI: 1.01 to 9.89, P = 0.048). In females, no significant differences were found between patients and controls in corresponding analyses at all polymorphic loci. A possible combined effect of IL-1B -511 polymorphism and smoking on the elevated risk to GAgP was observed. The OR of GAgP for combined A2+ genotype and smoking was 12.45 (95% CI: 1.43 to 108.06, P = 0.022), and for combined allele 2 and smoking was 18.25 (95% CI: 2.32 to 143.86, P = 0.006).


CONCLUSIONS
The polymorphisms of IL-1A +4845 and IL-1B -511 may play an important role in determining GAgP susceptibility in Chinese males. Furthermore, a possible combined effect of the polymorphism of IL-1B -511 and smoking on GAgP susceptibility was suggested.
Li
Qi Yan
QY
Department of Periodontology, School of Stomatology, Peking University, Beijing, China.
Zhao
Hong Shan
HS
Meng
Huan Xin
HX
Zhang
Li
L
Xu
Li
L
Chen
Zhi Bin
ZB
Shi
Dong
D
Feng
Xiang Hui
XH
Zhu
Xiao Ling
XL
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000483:Alleles; D019943:Amino Acid Substitution; D044466:Asian People / Q000235:genetics*; D002681:China; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats; D016017:Odds Ratio; D010518:Periodontitis / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D012737:Sex Factors; D012907:Smoking
D007375:Interleukin-1