In a multicenter cross-sectional study, low-grade duodenal eosinophilia was related to the nucleotide-binding oligomerization domain 1 (NOD1)-796 GG allele, particularly in the presence of the cagA strain. Additionally, this association was found with the allelic combination of NOD1-796 GG/interleukin-1 beta (IL-1B)-511 single T-allele, regardless of cagA strain infection, in H. pylori-related dyspepsia (HpD) patients. The objective of the study was to assess the relationship between IL-1B-511C>T and NOD1-796G>A genetic polymorphisms and low-grade duodenal eosinophilia in HpD.

Overall, 253 volunteers meeting the Rome-IV criteria were initially chosen for the study, followed by the inclusion of 98 subjects who underwent upper endoscopy without notable findings but tested positive for H. pylori in gastric biopsies. The study involved an assessment of clinical parameters, H. pylori cagA status, and duodenal histology.

Among the patients, 10% (n=10) exhibited an overlap of epigastric pain syndrome (EPS)/postprandial distress syndrome (PDS), 25% (n=24) had PDS, and 65% (n=64) experienced EPS. The different subtypes of functional dyspepsia were not found to be linked to the NOD1-796G>A and IL-1B-511C>T gene variants. However, low-grade duodenal eosinophilia was notably higher in individuals having the NOD1-796 GG genotype compared to those with a single A-allele, while there was no significant difference in individuals with a single T-allele or CC-allele at IL-1B-511.

The presence of this relationship is contingent on cagA infection, as individuals carrying the cagA strain exhibited a profound correlation with low-grade duodenal eosinophilia when possessing isolated variants NOD1-796 GG and IL-1B-511 single T-allele, but this association was not present in the absence of cagA. Furthermore, when a combined polymorphism analysis involving NOD1-796 GG/IL-1B-511 single T-allele was conducted, a synergistic impact on low-grade duodenal eosinophilia was discovered between these two genetic loci, irrespective of the presence or absence of the cagA strain in HpD.

Low-grade duodenal eosinophilia exhibited a significant connection with the NOD1-796 GG allele, especially when the cagA strain was present, and it was also linked to the allelic combination of NOD1-796 GG/IL-1B-511 single T-allele in HpD patients, regardless of cagA strain infection.