Polymorphisms in IL4 and iLARA confer susceptibility to asthma.
BACKGROUND
Asthma is a complex disease that is caused by genetic and environmental factors. The production of interleukin (IL)-4, which can influence mast cell responsiveness to immunoglobulin (Ig) E--mediated signaling, could be modified by genetic variants in the IL-4 promoter.


OBJECTIVE
To investigate the association between the IL-4 and IL-4RA promoter polymorphisms and asthma in a sample of Iranian patients.


METHODS
We used polymerase chain reaction with sequence-specific primers to investigate the allele and genotype frequencies of 2 polymorphic genes coding for IL-4 and IL-4RA in 59 Iranian patients with asthma and 139 healthy controls.


RESULTS
The most frequent genotypes in the patient group were IL-4TC (-590), IL-4TC (-33), IL-4 GT (-1098), and IL-4RA GA (+1902). In contrast, the frequencies of IL-4 CC (-590), IL-4 CC (-33), IL-4TT (-1098), and IL-4RAAA (+1902) were significantly lower in the patient group than in the control group. The most frequent haplotypes in our patients were IL-4 TCT and GTC at positions -1098,-590,-33. The mean total serum IgE level in patients with the TTT/GCC genotype was 258.8 IU/mL, which was significantly higher than the 95.4 IU/mL observed for other genotypes.


CONCLUSIONS
We showed a strong association between the polymorphisms of the IL-4 gene promoter at positions -590, -33 and -1098 and bronchial asthma. We also demonstrated an association between their haplotypes and serum total IgE.
Amirzargar
A A
AA
Immunogenetic Laboratory, Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Movahedi
M
M
Rezaei
N
N
Moradi
B
B
Dorkhosh
S
S
Mahloji
M
M
Mahdaviani
S A
SA
D001249:Asthma / Q000097:blood / Q000175:diagnosis / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology; D004252:DNA Mutational Analysis; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D015847:Interleukin-4 / Q000235:genetics* / Q000276:immunology; D053662:Interleukin-4 Receptor alpha Subunit / Q000235:genetics* / Q000276:immunology; D007492:Iran; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012882:Skin Tests; D018418:Th2 Cells / Q000276:immunology
C508598:IL4 protein, human; D053662:Interleukin-4 Receptor alpha Subunit; D015847:Interleukin-4; D007073:Immunoglobulin E