Objectives: To analyze polymorphism of the tumor necrosis factor (TNF) gene in inflammatory bowel disease (IBD) patients from the Han Chinese ethnic group, and to investigate the role of polymorphism in the pathogenesis of IBD.
Methods: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques were used to analyze gene polymorphisms in the TNF-alpha and TNF-beta genes in 131 patients with IBD.
Results: The genotype frequency and allelic frequency of TNF-alpha-308 in patients with ulcerative colitis (UC) were 15.5% and 8.7%, respectively, significantly higher than the control population (4.1% and 2.0%, respectively; P < 0.001). There was no significant difference between patients with Crohn's disease (CD) and the normal population with regard to the genotype frequency and allelic frequency of TNF-alpha-308, and neither were there any differences with regard to TNF-beta+252 in patients with IBD (UC and CD) and the normal population. The TNF-alpha-308 polymorphism and the TNF-beta+252 loci did not correlate with age, gender, disease activity or lesion site for IBD patients.
Conclusions: The TNF-alpha-308 allele may be related to susceptibility to UC. The TNF-alpha-308 gene polymorphism is not involved in pathogenesis of CD. No correlation was found between the TNF-beta+252 polymorphism and IBD. Polymorphisms of the TNF-alpha-308 and TNF-beta+252 loci do not correlate with age, gender, disease activity or lesion site.