Single nucleotide polymorphisms of the genes encoding IL-10 and TGF-β1 in Iranian children with atopic dermatitis.

BACKGROUND: Atopic dermatitis is an inflammatory skin disease in which both genetic and environmental factors interact to determine the susceptibility and severity of the disease.

OBJECTIVE: The aim of this study was to determine the association between atopic dermatitis and IL-10 and TGF-β1 gene polymorphisms.

METHODS: The allele and genotype frequencies of genes encoding for IL-10 and TGF-β1 were investigated in 89 patients with atopic dermatitis in comparison with 138 in the control group using the PCR-SSP method.

RESULTS: A significant increase was found in the frequency of the TGF-β1 codon 10/C allele among patients (p<0.001, OR=6.77), whereas a significant decrease was observed in the frequency of the T allele at the same position (p<0.001, OR=0.14). The frequency of the TGF-β1 codon 25/G allele in the control group was significantly higher than among patients (p<0.001, OR=0.08). A significant positive correlation was seen between CC (p<0.001, OR=15.10) and CG (p<0.001) genotypes and AD at codons 10 and 25, respectively. The most frequent haplotypes among patients was TGF-β1 CG which was significantly higher than in the control subjects (50% in patients vs. 39.9% in controls, p=0.042). A significant increase was found in the frequency of TGF-β CC (36% in patients vs. 7.6% in controls, p<0.001) and TC (14% in patients vs. 0% in controls, p<0.001) haplotypes among patients compared to controls. By contrast, the TGF-β1 TG haplotype was significantly lower in patients than controls (0% in patients vs. 52.5% in controls, p<0.001). There were no significant differences in the frequency of alleles, genotypes and haplotypes of the IL-10 gene.

CONCLUSIONS: We found a strong association between the polymorphisms of the TGF-β1 gene at codon 10 and codon 25 positions and atopic dermatitis.