Association study of a functional Toll-like receptor 4 polymorphism with susceptibility to gastric mucosa-associated lymphoid tissue lymphoma.

Toll-like receptor 4, as part of innate immune response, is the main receptor for lipopolysaccharide on marginal zone B cells. The rare allele of TLR4 Asp299Gly attenuates receptor signaling and diminishes the inflammatory response. We genotyped 87 patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, 594 Helicobacter pylori positive controls and 358 healthy blood donors to investigate an association of TLR4 Asp299Gly in the development of gastric MALT lymphoma. Heterozygote genotype was significantly less frequent in patients with gastric MALT lymphoma compared to H. pylori-infected controls (4.6% vs. 11.6%, Fischer's exact P=0.019, odds ratio=0.37, 95% confidence interval 0.13-1.03). Because 10% of caucasians are carriers of the rare allele G TLR4 Asp299Gly appears to be only one factor in the genetic susceptibility to gastric lymphoma. Further studies in larger samples are needed to confirm our findings and fully elucidate the role of TLR4 and its genetic variants in the pathophysiology of H. pylori infection and gastric lymphoma.