Abstract
1. INTRODUCTION: Multiple cytokines have been studied for their role in the propagation of the inflammatory process related to inflammatory bowel diseases (IBD), but the role of interleukin-4 remains controversial. The aim of this study was to evaluate the role of two IL-4 gene single nucleotide polymorphisms (SNPs) in disease susceptibility and phenotypic expression. 2. MATERIALS AND METHODS: A group of 160 patients with IBD (86CD/74UC) and 160 healthy controls were genotyped for IL-4 rs2243250/-590C/T and rs2070874/-34C/T using real-time polymerase chain reaction with TaqMan assay. 3. RESULTS: The analysis of IBD patients and controls revealed a significantly reduced frequency of the minor allele T of both SNPs in CD patients (p = 0.03, OR 0.55 and p = 0.02, OR 0.52) and for the entire IBD group (p = 0.01, OR 0.57 and p = 0.01, OR 0.55). Haplotype analysis identified the most frequent haplotype (rs2243250/rs2070874 CC) associated with a high risk for developing IBD (either UC or CD) (p = 0.003). IBD patients with extraintestinal manifestations had significantly increased frequency of the minor alleles T. We also found an association between the presence of allele C of rs2070874 and response to antiTNF treatment. 4. CONCLUSIONS: This is the first study to investigate the IL-4 gene's relation to IBD susceptibility conducted in Romania. Both SNPs were found to be associated with disease susceptibility and phenotypic features, such as extraintestinal manifestations and response to antiTNF agents.