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.
Immunogenetic Laboratory, Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
A A
AA
Amirzargar
M
M
Movahedi
N
N
Rezaei
B
B
Moradi
S
S
Dorkhosh
M
M
Mahloji
S A
SA
Mahdaviani
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