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BioMed Research International
Volume 2013 (2013), Article ID 981012, 7 pages
http://dx.doi.org/10.1155/2013/981012
Research Article

Single Nucleotide Polymorphism in the Promoter of the Human Interleukin-13 Gene Is Associated with Asthma in Malaysian Adults

1Pathology Division, Faculty of Medicine and Health, International Medical University, 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
2Department of Pharmacology, Faculty of Medicine, MAHSA University, Jalan Elmu, Off Jalan University, 59100 Kuala Lumpur, Malaysia
3Department of Medicine, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia

Received 30 April 2013; Accepted 3 June 2013

Academic Editor: Tosso Leeb

Copyright © 2013 Ammu Kutty Radhakrishnan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Asthma susceptibility genes are mapped to a region on human chromosome 5q31-q33, which contains a cluster of proinflammatory cytokine genes such as interleukin-13 (IL-13), which is associated with asthma. This study investigated the allele frequencies of two single nucleotide polymorphisms (SNPs) (−1111C>T and 4257C>A) in the IL-13 gene between asthmatics and healthy volunteers as well as the relationship between these SNPs and IL-13 production. DNA extracted from buffy coat of asthmatic and control subjects was genotyped using the PCR-RFLP method. Amount of IL-13 produced by mitogen-stimulated peripheral blood leucocytes PBLs (PBLs) was determined by ELISA. The frequencies of the −1111C and 4257G wild-type alleles were 0.52 and 0.55 in asthmatics and were 0.67 and 0.56 in controls. A significant ( ) association was found between genotype and allele frequencies of SNP at position −1111C>T between asthmatic and control groups (OR, 1.810; 95% CI = 1.184 to 2.767; ). The mitogen-stimulated PBLs from asthmatics produced higher amounts of IL-13 production ( ). The 4257GA heterozygous and 4257AA homozygous mutant alleles were associated with higher IL-13 production in asthmatics ( ). Our results show that the −1111T mutant allele are associated with asthma and the 4257A mutant alleles are associated with elevated IL-13 production.