Positive Relationship Between a Polymorphism in Helicobacter pylori Neutrophil-Activating Protein A Gene and Iron-Deficiency Anemia

Background Numerous studies have suggested a link between iron-deficiency anemia (IDA) and Helicobacter pylori infection. Previously, we found that strains isolated from IDA patients showed higher levels of Fe ion uptake and Fe-ion-dependent rapid proliferation than those of strains derived from patients without IDA. Materials and Methods Twenty-four H.pylori strains from IDA patients (IDA strains) and 25 strains from patients who had H.pylori gastritis without anemia (non-IDA strains) were examined. Their nucleotide sequences of napA, fur, and feoB, which contribute to Fe ion uptake, were determined. Results Numerous polymorphisms of the three genes were found in both strains. Frequency of neutrophil-activating protein A (NapA), which encoded by napA, with threonine at amino acid residue No. 70 (Thr70-type NapA) was significantly higher in IDA strains than in non-IDA strains. Strains with Thr70-type NapA showed significantly higher levels of Fe3+ and Fe2+ uptake than did strains with other types, Ser70-type of NapA, which is found in standard strains. Other significantly different occurrences of polymorphisms between IDA and non-IDA groups were not observed in these genes. Conclusion The results suggest that H.pylori strains with Thr70-type NapA have enhanced Fe ion uptake ability and are associated with the pathogenesis of IDA.