Associations between IL12B polymorphisms and tuberculosis in the Hong Kong Chinese population.
BACKGROUND
Interleukin (IL)-12 plays a vital role in regulating cell-mediated immunity against tuberculosis (TB).


METHODS
To test whether IL12B genetic polymorphisms might contribute to human TB susceptibility, we examined the genotype frequencies of 5 IL12B polymorphisms (at promoter, intron 2, intron 4, exon 5, and 3' untranslated region [UTR]) in 516 patients with TB and 514 healthy control subjects from the Hong Kong Chinese population.


RESULTS
Individuals homozygous for the IL12B intron 2-repeat marker (ATT)8 had a 2.1-fold increased risk of developing TB (P < .001) (odds ratio, 2.14 [95% confidence interval, 1.45-3.19]). Estimation of the frequencies of multiple-locus haplotypes composed of IL12B promoter, intron 2, intron 4, and 3' UTR alleles revealed potential risk haplotypes (designated "A" and "K") and protective haplotypes (designated "B") for TB. Furthermore, combining the genotype data of the 4 informative IL12B loci revealed a strong association between a specific genotype pattern, termed "diplotype I" (heterozygous A and K haplotypes), and TB. In contrast, diplotype II (homozygous BB haplotypes) appeared protective against TB.


CONCLUSIONS
These findings support the association between IL12B intron 2 polymorphism and TB and between specific IL12B haplotypes and TB.
Department of Pediatrics and Adolescent Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
Hoi W
HW
Tso
Yu Lung
YL
Lau
Cheuk M
CM
Tam
Hing S
HS
Wong
Alan K S
AK
Chiang
D044466:Asian People; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006723:Hong Kong; D006801:Humans; D018664:Interleukin-12 / Q000235:genetics* / Q000378:metabolism; D053762:Interleukin-12 Subunit p40; D007438:Introns; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis; D011110:Polymorphism, Genetic; D021122:Protein Subunits / Q000378:metabolism; D014397:Tuberculosis, Pulmonary / Q000208:ethnology / Q000235:genetics*
C500879:IL12B protein, human; D053762:Interleukin-12 Subunit p40; D021122:Protein Subunits; D018664:Interleukin-12