A polymorphism in the promoter region of the human interleukin-16 gene is not associated with asthma or atopy in an Australian population.
BACKGROUND
IL-16 is an immunomodulatory cytokine whose expression is increased in the bronchial mucosa, bronchoalveolar lavage fluid and induced sputum of asthmatic patients. It has been suggested that IL-16 has a regulatory role in the pathophysiology of asthma. A single-nucleotide polymorphism (T(-295)C) has been described in the promoter region of the gene and it has been hypothesized that this polymorphism may be associated with altered levels of IL-16 expression, and account for the increased levels of IL-16 seen in the asthmatic airway.


OBJECTIVE
To determine the association between the T(-295)C promoter polymorphism and asthma, disease severity and atopy in a large Australian Caucasian population.


METHODS
We used PCR and restriction fragment length polymorphism analysis to establish the allele frequency of the T(-295)C promoter polymorphism in a random Australian Caucasian population (n=176) and to characterize the polymorphism in a large Australian Caucasian population of mild (n=273), moderate (n=230) and severe (n=77) asthmatic patients, and non-asthmatic controls (n=455). Genotype association analyses were performed using chi(2) tests.


RESULTS
The polymorphic C allele was present in 19% of the asthmatic population and 21% of the non-asthmatic population. There was no association between the polymorphism and asthma (P=0.153) nor with asthma severity (P=0.417) or atopy (P=0.157) in this population.


CONCLUSIONS
Although it has been hypothesized that the T(-295)C promoter polymorphism may be associated with increased IL-16 gene expression, it is not associated with asthma, disease severity or atopy in this Australian population.
Akesson
L S
LS
The Asthma and Allergy Research Institute Inc., Nedlands, WA, Australia.
Duffy
D L
DL
Phelps
S C
SC
Thompson
P J
PJ
Kedda
M-A
MA
D000328:Adult; D000368:Aged; D000483:Alleles; D001249:Asthma / Q000208:ethnology / Q000235:genetics*; D001315:Australia; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D006801:Humans; D006967:Hypersensitivity / Q000235:genetics*; D019410:Interleukin-16 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D044465:White People
D019410:Interleukin-16