Inflammatory Bowel Disease: The Association of Inflammatory Cytokine Gene Polymorphisms

The frequencies of alleles and genotypes of TNF-α, TNF-β, and IL-10 genes were examined in Saudi subjects including IBD patients (UC and CD) and matched controls. Venous blood samples were collected from IBD patients and healthy control subjects, and genomic DNA was extracted using commercially available kit (Qiagen, CA, USA). In order to detect TNF-α (-308G/A), TNF-β (+252A/G), IL-10 (-1082G/A), (-819C/T), and (-592C/A) polymorphisms, the TNF-α, TNF-β, and IL-10 genes were amplified using an amplification refractory mutation systems PCR methodology. Analysis of data showed that the frequencies of alleles and genotype of TNF-α (-308G/A), TNF-β (+252A/G), and IL-10 (-1082G/A), (-819C/T), and (-592C/A) polymorphisms differ between IBD patients and control subjects. Our study clearly indicated that the TNF-α (-308G/A), TNF-β (+252A/G), and IL-10 (-1082 G/A) polymorphisms are associated significantly with the risk of IBD susceptibility while other two, IL-10-819C/T and IL-10-592C/A, polymorphisms are not associated with IBD in Saudi population. However, well-designed epidemiological as well as genetic association studies with large sample size among different ethnicities should be performed in order to have better understanding of this relationship.