Association of Helicobacter pylori infection and virulence factors with selected Human Leukocyte Antigen-DQAl and -DQB1 alleles among dyspeptic patients

Abstract

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Aims: This study aimed to assess association of selected HLA (Human Leukocyte antigen) alleles; HLA-DQA1*0102, HLA-DQA1*0103, HLA-DQB1*0301 with H. pylori infection among a Sri Lankan dyspeptic patient population. M ethods: Gastric biopsy specimens from 100 patients who underwent upper gastrointestinal endoscopy at a tertiary care hospital were investigated in this study. Presence o f H. pylori was confirmed using histology and PCR. Histological interpretation w as done using M odified ‘Sydney system’. The presence of HLA alleles and selected virulence genes of H. pylori; cagA, vacA and babA2, were determined using Polym erase Chain Reaction (PCR). Results: MQd to moderate inflam m ation was observed in 96 biopsy specimens. A lleles, HLA-DQA1*0102, HLA-DQA1*0103, HLA-DQB1*0301 was seen 39%, 31% and 20% respectively in the 100 dyspeptic patients. Out of 25 H. pylori confirm ed patients (by PCR or histology), 56% (14/25), 36% (9/25) and 12% (3/25) were positive for HLA-DQA1*0102, HLA-DQA1*0103 and HLADQB1*0301 alleles respectively. Out of 22 H . pylori PCR positive biopsies, one w as positive for cagA w ith vacA s2/m l strain type, 7 were positive for babA2 and histological examination revealed m ild to moderate inflammation. H. pylori infection showed significant association w ith HLA-DQA1*0102 (p=0.044) and inflam m ation (p=0.030). HLA-DQA1*0103 and HLA-DQB1*0301 showed no significant association with either H. pylori infection, inflammation or the presence of virulence genes. Conclusion: HLA-DQA1*0102 allele has a significant association with H. pylori infection w hile HLA-DQA1*0103 and HLA-DQB1*0301 shows no significant association in a Sri Lankan dyspeptic patient population. Keywords - Dyspepsia, Human Leukocyte Antigen, HLA-DQ, Helicobacter pylori, virulence genes.