Positive relationship between a polymorphism in Helicobacter pylori neutrophil-activating protein a gene and
Shin-Ichi Yokota1, Nariaki Toita, Soh Yamamoto
1Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan.
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 Fe(3+) and Fe(2+) 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.
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