MBL2 allele associated with gastric mucosal atrophy severity

MedWire News: The Mannan-binding lectin (MBL) B allele is associated with a risk for developing more severe gastric mucosal atrophy in Japanese patients infected with Helicobacter pylori, research indicates.

MBL is thought to play an essential role in systemic and mucosal immunity and deficiency, say Tomomitsu Tahara (Fujita Health University School of Medicine, Aichi, Japan) and co-workers.

Among Japanese people, only one variant of MBL2 gene, G/A at codon 54 of exon 1, has been reported. The variant allele, called “allele B” is associated with decreased MBL plasma concentrations and increased susceptibility to infectious diseases.

Tahara et al conducted MBL2 genotyping in 102 patients with gastric ulcers, 48 with duodenal ulcers, and 275 without ulcers.

They found that MBL2 genotype distributions were similar in all groups and not linked with H. pylori status.

In 311 participants, gastritis scores of noncancerous mucosa of gastric antrum were assessed according to the updated Sydney system and scored from zero (normal) to three (marked).

Among H. pylori positives, the MBL B allele was significantly associated with severity of gastric mucosal atrophy and intestinal metaplasia.

For atrophy, scores were 1.58 with G/G, 1.53 for G/A and 2.15 for A/A, while for intestinal metaplasia they were 1.05, 1.01, and 1.77, respectively.

Participants were then divided into three groups according to the severity of gastric atrophy. The frequency of A/A was significantly higher in the severe atrophic gastritis group than in others, with an odds ratio of 8.42 versus the mild atrophic gastritis group and 10.06 versus the mild atrophic and nonatrophic gastritis groups.

Reporting in the European Journal of Gastroenterology and Hepatology, the team says: “One might speculate that the B allele may increase the risk of developing gastric mucosal atrophy by altering immune defenses in the gastric mucosa against H. pylori.”