Interleukin 12B mRNA level and rs3212227 genotyping in peripheral blood mononuclear cells of inflammatory bowel disease patients

Background/aim: Inflammatory bowel disease (IBD) is a multifactorial disorder. Single nucleotide polymorphisms (SNPs) in the IL-12 gene, which are the main factors to regulate the immune reaction, play an important role in the production of IL-12 molecules. The aim of this study was to evaluate the correlation between the SNP on position +1188 of the 3 ' UTR region of the IL-12 p40 subunit gene and expression of the IL-12 p40 gene. Materials and methods: This case-control study was performed with 102 patients with IBD and 107 healthy people. PCR-RFLP and comparative real-time PCR were performed to assess the association between genotype and IL-12 gene expression. Results: The frequency of AA, CA, and CC genotypes of this gene at position +1188 was calculated to be 58.8%, 32.4%, and 8.8% in patients and 61.7%, 26.2%, and 12.1% in the control group, respectively, with no significant difference between the two groups (IL- 12B rs3212227: AA (Reference 1), CA (P = 0.407); OR (95% CI) 0.771 (0.418­1.424), CC (P = 0.561); OR (95% CI) 1.313 (0.524­3.292)). Also, the IL-12B mRNA expression level was compared between IBD patients and healthy controls and demonstrated a significant association (R 2 0.136, 95% CI 1.892­3.872, P < 0.0001). Conclusion: Our results show that IL-12B expression in IBD may be associated with altered immune and inflammatory responses.