Contribution of major histocompatibility complex genes to susceptibility and resistance in Helicobacter pylori related diseases

Background/Aim. Although there have been numerous reports concerning the virulence factors of isolates for investigating the pathogenesis of Helicobacter pylori infection, few studies have been carried out regarding the association of HLA class II genes of the host with H. pylori related diseases. Two published studies have only analysed the HLA DQ locus alone. The aim of this study was thus to determine the association of HLA class II genes (DR, DQ and DP) with H. pylori related diseases using the DNA typing method. Methods. Fifty-eight patients with H. pylori positive gastric ulcers, 44 patients with H. pylori positive duodenal ulcers, 45 patients with H. pylori positive gastritis and 34 healthy subjects without H. pylori infection were typed for HLA class II genes by means of DNA typing with the polymerase chain reaction-sequence specific oligonucleotide probes method. Results. A negative association with DRB1*1501, DQA1*01021 and DQB1*0602 alleles was noted in all three of the patient groups studied. Compared with the healthy controls, a positive association with DPA1*0201 (P = 0.032) and DPB1*0901 (P = 0.005) in gastric ulcers, a positive association with DRB1*0405 (P = 0.022) and DQB1*0401 (P = 0.044) in duodenal ulcers, and a positive association with DPB1*0901 (P = 0.016) in gastritis were observed. A haplotype analysis showed that the association of alleles with H. pylori related disease was with the haplotype rather than with either of the alleles individually. After correction for multiple comparisons, all the significant associations obtained between H. pylori related diseases and HLA class II genes disappeared. Conclusions. The interplay between host immunogenetic factors, bacterial virulence factors and environmental conditions may thus play a more important role in the outcome of H. pylori infection than immunogenetic factors alone.