Interleukin-1 Receptor Antagonist and Interleukin-4 Genes Variable Number Tandem Repeats Are Associated with Adiposity in Malaysian Subjects

Interleukin-1 receptor antagonist (IL1RA) intron 2 86 bp repeat and interleukin-4 (IL4) intron 3 70 bp repeat are variable number tandem repeats (VNTRs) that have been associated with various diseases, but their role in obesity is elusive. The objective of this study was to investigate the association of IL1RA and IL4 VNTRs with obesity and adiposity in 315 Malaysian subjects (128 M/187 F; 23 Malays/251 ethnic Chinese/41 ethnic Indians). The allelic distributions of IL1RA and IL4 were significantly different among ethnicities, and the alleles were associated with total body fat (TBF) classes. Individuals with IL1RA I/II genotype or allele II had greater risk of having higher overall adiposity, relative to those having the I/I genotype or I allele, respectively, even after controlling for ethnicity [Odds Ratio (OR) of I/II genotype = 12.21 (CI = 2.54, 58.79; p = 0.002); II allele = 5.78 (CI = 1.73, 19.29; p = 0.004)]. However, IL4 VNTR B2 allele was only significantly associated with overall adiposity status before adjusting for ethnicity [OR = 1.53 (CI = 1.04, 2.23; p = 0.03)]. Individuals with IL1RA II allele had significantly higher TBF than those with I allele (31.79 ± 2.52 versus 23.51 ± 0.40; p = 0.005). Taken together, IL1RA intron 2 VNTR seems to be a genetic marker for overall adiposity status in Malaysian subjects.

IL-1 polymorphisms in children with peptic symptoms in South China

BACKGROUND

Polymorphisms of IL-1 gene cluster are reported to be associated with histological changes and IL-1β expression in the gastric mucosa in adults, especially in Helicobacter pylori-infected subjects. As H. pylori infecting adults and children own different virulence genotypes, the aim of this study was to investigate whether IL-1 polymorphisms are risk factors in young children in South China.

MATERIALS AND METHODS

A total of 128 children with peptic symptoms were enrolled in this study. Polymorphisms of IL-1B-511 and IL-1B-31 were identified by dual fluorescence PCR. Variable number of tandem repeat region in IL-1RN was detected by conventional PCR and IL-1β mRNA expression by real-time PCR ddCT assay.

RESULTS

IL-1B-31T and IL-1B-511C were completely linked in this study. Significant differences of IL-1B-511/-31 genotypes were observed among different clinical outcomes (p = .001). The IL-1B-511TT/-31CC was mostly found in the moderate gastritis and the above (severe gastritis or gastric ulcer) groups, with percentage of 60.7%. While no association was observed between IL-1RN genotypes and the gastric mucosal histological changes (p = .128). Also no relationships were found between IL-1 polymorphisms and H. pylori infection or gastric mucosal IL-1β mRNA expression level.

CONCLUSION

Children with IL-1B-511TT/-31CC may have a risk to develop relatively severe gastric mucosal histological changes in South China.

VNTR polymorphism of human IL1RN in Chinese Han and She ethnic populations

Interleukin 1 receptor antagonist (IL-1Ra) is an important anti-inflammatory molecule encoded by the IL1RN gene. The polymorphism of IL1RN characterized by variable numbers of an 86 bp tandem repeat (VNTR) sequence in intron 2 has been described. Moreover, frequencies of the IL1RN alleles vary among different ethnics. In the present study, we analysed the IL1RN polymorphism in intron 2 in 256 Chinese Han and 252 Chinese She individuals. Four alleles including IL1RN*1, *2, *3 and IL1RN*4 were identified in this study. Data revealed that the distribution of the IL-1RN genotypes and allele was significantly different between the two Chinese populations (P < 0.001). Among them, 66.8% (171/256) and 86.5% (218/252) were homozygous for the allele IL-1RN*1 in Chinese Han and She individuals respectively. Homozygosity for allele IL-1RN*2 was only observed in Chinese Han with the percentage of 0.8% (2/256). Heterozygosity for IL-1RN*1/2, IL1RN*1/3 and IL1RN*1/4 was 30.9% (79/256), 0.4% (1/256) and 1.2% (3/256) in Chinese Han, whereas only heterozygosity for IL-1RN*1/2 was found in Chinese She (13.5%, 34/252). Frequencies of the most common allele IL-1RN*1 and IL-1RN*2 were 83.0% and 16.2% for Chinese Han and 93.3% and 6.7% for Chinese She respectively. The rare allele IL-1RN*3 and IL-1RN*4 was only observed in the Chinese Han population with the frequency of 0.2% and 0.6% respectively. Our findings suggested that the ethnic background plays an important role in IL-1Ra gene variation in different populations.