Abstract:
Single nucleotide polymorphisms present on the promoter sequence of the TNF-a gene may affect
production ofTNF-a, a pro-inflammatory cytokine, duringimmune responses. The presence of TNF-a
polymorphisms is also reportedly associated with more severe manifestations of Helicobacter pylori
infection. However, the frequency of TNF-a polymorphisms and the associated disease severity vary
between different patient groups. In this study, gastric biopsies and blood specimens were collected
from 138 patients with dyspepsia undergoing routine upper gastrointestinal endoscopy. Our
institution's Ethics Review Committee approved the study and written informed consent was obtained
from all participants. The presence of H. pylori was confirmed histologically in all patients. The
frequency of TNF-a polymorphisms in the study cohort was investigated using PCR–restriction
fragment length polymorphism and expression of serumTNF-aquantitated using a commercial ELISA
assay.The proportions of selectedTNF-a polymorphisms (TNF-a-238, -308 and -863) were similar in H.
pylori-positive and -negative patients. Homozygous mutations of TNF-a polymorphisms were rarely
detected in the study group. There was a significant difference in TNF-a concentrations between
patients with mild chronic gastritis and TNF-a -308 GG genotype and patients with moderate to severe
chronic gastritis (P¼0.008). It was not possible to identify an association between these genotypes and
disease severity because of the low frequency of heterozygous and homozygous mutated genes in Sri
Lankan patients with dyspepsia.
