Interleukin 10 and transforming growth factor beta 1 gene polymorphisms in juvenile idiopathic arthritis.

OBJECTIVES: The aim of this study is to identify the associations between interleukin 10 (IL-10) and transforming growth factor beta 1 (TGF-β1) gene polymorphisms and individual susceptibility to juvenile idiopathic arthritis (JIA) in a group of Iranian patients.

BACKGROUND: Cytokine genes, including IL-10 and TGF-β1, are known to play important roles in the pathogenesis of JIA.

METHODS: Using polymerase chain reaction with sequence-specific primers method, the frequency of alleles, genotypes and haplotypes of IL-10 (positions -1082, -819, -592) and TGF-β1 (codon 10, codon 25) single-nucleotide polymorphisms (SNPs) were investigated in 55 patients with JIA as a case group and compared with 140 healthy unrelated controls.

RESULTS: The G allele was significantly less frequent at TGF-β1 codon 25 in patients with JIA than in the controls (p < 0.01). The frequency of CT genotype at TGF-β1 codon 10 was found to be higher in healthy individuals in comparison with that in patients group (p = 0.04). We observed no differences in the frequency of alleles, genotypes and haplotypes of IL-10 gene between the groups of patients and controls.

CONCLUSIONS: Considering the low frequency of existence of TGF-β1 G allele at codon 25 as well as TGF-β1 CT genotype at codon 10 in patients with JIA, it seems that these cytokine gene polymorphisms could play role as the protective factors against JIA.