title: Single nucleotide polymorphism in the promoter of the human interleukin-13 gene is associated with asthma in Malaysian adults.
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 (P < 0.05) 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; P < 0.05). The mitogen-stimulated PBLs from asthmatics produced higher amounts of IL-13 production (P < 0.001). The 4257GA heterozygous and 4257AA homozygous mutant alleles were associated with higher IL-13 production in asthmatics (P < 0.05). Our results show that the -1111T mutant allele are associated with asthma and the 4257A mutant alleles are associated with elevated IL-13 production.
authors.affiliation: Pathology Division, Faculty of Medicine and Health, International Medical University, 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000 Kuala Lumpur, Malaysia. ammu_radhakrishnan@imu.edu.my
authors.forename: Ammu Kutty
authors.initials: AK
authors.lastname: Radhakrishnan
authors.forename: Vijaya Lechimi
authors.initials: VL
authors.lastname: Raj
authors.forename: Lee-Keng
authors.initials: LK
authors.lastname: Tan
authors.forename: Chong-Kin
authors.initials: CK
authors.lastname: Liam
mesh_terms: D000328:Adult; D001249:Asthma / Q000235:genetics*; D005787:Gene Frequency / Q000235:genetics; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D018793:Interleukin-13 / Q000096:biosynthesis / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008296:Malaysia; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic
chemical_list: C578095:IL13 protein, human; D018793:Interleukin-13