Association between HLA-Ⅱgene polymorphism and Helicobacter pylori infection in Asian and European population: A meta-analysis

Investigating Associations between HLA-DR Genotype, H. pylori Infection, and Anti-CagA IgA Seropositivity in a Turkish Gastritis Cohort

Helicobacter pylori (H. pylori) is associated with gastric inflammation and mucosal antibodies against its cytotoxin-associated gene A (CagA) are protective. Vaccine-elicited immunity against H. pylori requires MHC class II expression, indicating that CD4+ T cells are protective. We hypothesized that the HLA-DR genotypes in human populations include protective alleles that more effectively bind immunogenic CagA peptide fragments and susceptible alleles with an impaired capacity to present CagA peptides. We recruited patients (n = 170) admitted for gastroendoscopy procedures and performed high-resolution HLA-DRB1 typing. Serum anti-CagA IgA levels were analyzed by ELISA (23.2% positive) and H. pylori classified as positive or negative in gastric mucosal tissue slides (72.9% positive). Pearson Chi-square analysis revealed that H. pylori infection was significantly increased in DRB1*11:04-positive individuals (p = 0.027). Anti-CagA IgA was significantly decreased in DRB1*11:04 positive individuals (p = 0.041). In contrast, anti-CagA IgA was significantly increased in DRB1*03:01 positive individuals (p = 0.030). For these HLA-DRB1 alleles of interest, we utilized two in silico prediction methods to compare their capacity to present CagA peptides. Both methods predicted increased numbers of peptides for DRB1*03:01 than DRB1*11:04. In addition, both alleles preferred distinctively different CagA 15mer peptide sequences for high affinity binding. These observations suggest that DRB1*11:04 is a susceptible genotype with impaired CagA immunity, whereas DRB1*03:01 is a protective genotype that promotes enhanced CagA immunity.

Association of human leukocyte antigen DQ-rs3920AG genotype with Helicobacter pylori recurrence in Kafrelsheikh, Egypt

AIMS

The aim was to evaluate the role of HLA-DP/DQ single-nucleotide polymorphisms (SNPs) in Helicobacter pylori infection in Kafrelsheikh governorate, Egypt.

METHODS AND RESULTS

The study enrolled 120 persons; 48 naïve H. pylori-infected patients, 42 relapsers and 30 H. pylori-free controls. Gastroscopy, H. pylori stool antigen, anti-CagA and anti-VacA antibodies were determined. Genotyping of HLA-DPA1rs3077 (A/G) SNP and HLA-DQ-rs3920(A/G) SNP was done using real-time PCR. The antibody profile against H. pylori showed that 85.7% of patients with recurrent infection have IgG against CagA (p = 0.001*). There was a significant association between the occurrence of H. pylori infection and both HLA-DPA1rs3077AA and HLA-DQ-rs3920AG genotypes. Concerning H. pylori relapse, the HLA-DQ-rs3920AG genotype was detected in 78.6% of patients with recurrent infection (p = 0.002*). Patients carrying this genotype tend to be relapsers 9.8 times more than patients carrying other genotypes.

CONCLUSIONS

HLA-DPA1rs3077AA and/or HLA-DQ-rs3920AG genotypes could be risk factors for the occurrence of H. pylori infection. HLA-DQ-rs3920AG genotype is markedly linked to recurrent H. pylori infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

Host factors as HLA gene polymorphism could be a predisposing factor for susceptibility, recurrence or chronicity of H. pylori and should be studied in different ethnic groups.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Association between human leukocyte antigen gene polymorphisms and multiple EPIYA-C repeats in gastrointestinal disorders

BACKGROUND

Polymorphisms of human leukocyte antigen (HLA) genes are suggested to increase the risk of gastric cancer (GC).

AIM

To investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+ multiple (≥ 2) EPIYA-C repeats.

METHODS

The patient group comprised 94 patients [44 GC and 50 duodenal ulcer (DU) patients], and the control group comprised 86 individuals [(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori (H. pylori)]. Polymerase chain reaction was performed for the amplification of the H. pylori cagA gene and typing of EPIYA motifs. HLA sequence-specific oligonucleotide (SSO) typing was performed using Lifecodes SSO typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1, and HLA-DQA1-B1 kits).

RESULTS

The comparison of GC cases in terms of CagA+ multiple (≥ 2) EPIYA-C repeats showed that only the HLA-DQB1*06 allele [odds ratio (OR): 0.37, P = 0.036] was significantly lower, but significance was lost after correction (Pc = 0.1845). The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats, but this was not significant in the univariate analysis. We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion, and none of the HLA alleles were significantly associated with GC or DU. Also, none of the alleles were detected as independent risk factors after the multivariate analysis. On the other hand, in a multivariate logistic regression with no discriminative criterion, HLA-DQA1*01 (OR = 1.848), HLA-DQB1*06 (OR = 1.821) and HLA-A*02 (OR = 1.579) alleles were detected as independent risk factors for GC and DU.

CONCLUSION

None of the HLA alleles were detected as independent risk factors in terms of CagA+ multiple EPIYA-C repeats. However, HLA-DQA1*01, HLA-DQB1*0601, and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis. We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.

Association between polymorphisms in HLA-A, HLA-B, HLA-DR, and DQ genes from gastric cancer and duodenal ulcer patients and cagL among cagA-positive Helicobacter pylori strains: The first study in a Turkish population

Colonization of the human gastric mucosa by H. pylori may cause peptic and duodenal ulcers (DUs), gastric lymphomas, and gastric cancers. The cagL gene is a component of cag T4SS and is involved in cagA translocation into host. An association between the risk of gastric cancer and the type of HLA class II (DR and/or DQ) was suggested in different populations. The aim of this study was to investigate, the clinical association of the cagL gene with host HLA alleles in H. pylori strains that were isolated from patients with gastric cancer, DU, and non-ulcer dyspepsia (NUD) and to determine the HLA allele that confers susceptibility or resistance for the risk of gastric cancer and DU development in Turkish patients. A total of 94 patients (44 gastric cancer and 50 DU patients; 58 male, 36 female; mean age, 49.6 years), and 86 individuals (50 NUD patients and 36 persons with normal gastrointestinal system [NGIS]; 30 male, 56 female; mean age, 47.3 years) were included as the patient and the control groups, respectively. CagA and cagL were determined by PCR method. DNA from peripheral blood samples was obtained by EZ-DNA extraction kit. For HLA SSO typing, LIFECODES SSO Typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1 and HLA-DQA1/B1 kits) were used. The CagL/CagA positivity distribution in the groups were as follows: 42 (95.4%) gastric cancer, 46 (92%) DU and, 34 (68%) NUD and no NGIS cases. The HLA-DQA1*01 (OR: 3.82) allele was significantly different, suggesting that these individuals with H. pylori strains harbouring the CagL/CagA positivity are susceptible to the risk of gastric cancer and DU, and the HLA-DQA1*05 (OR, 0.318) allele was suggested as a protective allele for the risk of gastric cancer and DU using univariate analyses. HLA-DQA1*01 (OR, 2.21), HLA-DQB1*06 (OR, 2.67), sex (male, OR, 2.27), and CagL/CagA/(<2) EPIYA C repeats (OR, 5.72) were detected independent risk factors that increased the risk of gastric cancer and DU using multivariate analyses. However, the HLA-DRB1*04 (OR, 0.28) allele was shown to be a protective allele, which decreased the risk of gastric cancer and DU. Gastric pathologies result from an interaction between bacterial virulence factors, host epigenetic and environmental factors, and H. pylori strain heterogeneity, such as genotypic variation among strains and variations in H. pylori populations within an individual host.

EVALUATION OF HUMAN LEUKOCYTE ANTIGEN CLASS I AND II ANTIGENS IN HELICOBACTER PYLORI-POSITIVE PEDIATRIC PATIENTS WITH ACTIVE GASTRITIS AND DUODENAL ULCER

BACKGROUND

As being the first bacteria determined to be carcinogenic, Helicobacter pylori (H. pylori) is a pathogen localized in the stomach in more than half of the world population. Some earlier studies have found a relation between tissue histocompatibility antigens and gastric cancers depending on the regions.

OBJECTIVE

The present study aimed to determine the distribution of human leukocyte antigen (HLA) class I and class II antigens in H. pylori-positive pediatric patients with active gastritis and duodenal ulcer, excluding cancer cases, in our center.

METHODS

The study included 40 patients diagnosed with H. pylori-positive active gastritis and duodenal ulcer and 100 controls consisting of healthy donor candidates. The HLA class I and class II antigens were studied in the isolated DNA samples using the polymerase chain reaction sequence-specific oligonucleotide probes.

RESULTS

The frequency of HLA-B*51 antigen was significantly higher in the patient group than in the control group (40% vs 17%; P=0.003). There was no difference between the two groups in terms of the frequencies of HLA-A, HLA-C, HLA-DR, and HLA-DQ antigens.

CONCLUSION

It was determined that HLA-B*51 plays a critical role in H. pylori infection.

Associations between cytokine gene polymorphisms and susceptibility to Helicobacter pylori infection and Helicobacter pylori related gastric cancer, peptic ulcer disease: A meta-analysis

Objectives

The aim of this study is to clarify the associations between IL-1B31C/T, IL-1B-511C/T, IL-8-251T/A gene polymorphisms and the risk of Helicobacter pylori (H. pylori) infection together with H. pylori-related gastric cancer (GC), peptic ulcer disease (PUD).

Methods

All eligible literature published up to July 2016 were identified by searching Pubmed, Embase, Web of Science and CNKI. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated using a fixed or random effects model.

Results

29 case-control studies were eligible, and each of them may focus on more than one gene polymorphism. Ultimately, there were 21 studies (3159 cases and 2816 controls) for IL-1B-31C/T, 16 studies (2486 cases and 1989 controls) for IL-1B-511C/T polymorphisms, 9 studies (1963 cases and 1205 controls) for IL-8-251T/A polymorphisms. Overall, an increased risk of H. pylori infection was found for IL-1B-31C/T polymorphisms in total population [OR = 1.134, 95%CI = 1.008–1.275 for recessive model; OR = 1.145, 95%CI = 1.007–1.301 for TT vs CC model]. While, for IL-1B-511C/T and IL8-251T/A polymorphisms, no evidence indicated that they were associated with the risk of H. pylori infection in all genetic models. Furthermore, we found an increased risk of H. pylori-related GC with IL-1B-511C/T polymorphisms [OR = 1.784, 95%CI = 1.289–2.469 for recessive model; OR = 1.772, 95%CI = 1.210–2.594 for TT vs CC model] and IL8-251A/T polymorphisms [OR = 1.810, 95%CI = 1.229–2.667 for recessive model; OR = 1.717, 95%CI = 1.143–2.580 for TT vs AA model], an increased risk of H. pylori-related PUD with IL8-251T/A polymorphisms [OR = 1.364, 95%CI = 1.010–1.843 for recessive model; OR = 1.427, 95%CI = 1.039–1.959 for AA vs TT model].

Conclusions

IL-1B-31C/T gene polymorphisms might increase H. pylori infection risk. IL-1B-511-C/T and IL-8-251T/A gene polymorphisms might act as a risk factor to H. pylori-related diseases including GC or PUD

Virulence factors and pathogenic mechanism of Helicobacter pylori

Helicobacter pylori (H. pylori) is closely related with some diseases such as chronic gastritis, peptic ulcer, gastric mucosa associated lymphoid tissue lymphoma, and gastric cancer. The pathogenicity of H. pylori mainly relies on its flagellum, spiral structure, lipopolysaccharide, cytotoxin associated protein A, and vacuolating cytotoxin A. Through complex pathogenic mechanisms, H. pylori causes various kinds of diseases. In this paper, we discuss the latest research progress in the understanding of the virulence factors and pathogenic mechanism of H. pylori.

Association between the IL1B -31C > T polymorphism and Helicobacter pylori infection in Asian and Latin American population: A meta-analysis

BACKGROUND

Host genetic factors that control the production of cytokines, including interleukin-1β (IL-1β), possibly affect susceptibility to many Helicobacter pylori-related diseases. There is a complex interplay between H. pylori infection, the subsequent production of certain cytokines, and H. pylori-related diseases. We conducted a meta-analysis to clarify the association between the IL1B -31C > T polymorphism and H. pylori infection, and possible subsequent pathogenic mechanisms.

METHODS

Published literature contained within PubMed, Embase, and the Cochrane Library was used in our meta-analysis. Data were analyzed with the STATA 13.1 software package using pooled odds ratios (ORs) with 95% confidence intervals (95% CI). Egger's regression test, Begg's rank correlation test, and Begg's funnel plot were used to test publication bias.

RESULTS

A total of 12 case-control studies comprising 5827 subjects (3335 cases and 2492 controls) were available for our meta-analysis. The IL1B -31C > T polymorphism was associated with an increased risk of H. pylori infection in Asian and Latin American population (TT + CT vs. CC, OR = 1.29, 95% CI = 1.14-1.46; TT vs. CT + CC, OR = 1.23, 95% CI = 1.09-1.39; TT vs. CC, OR = 1.43, 95% CI = 1.22-1.67; T allele vs. C allele, OR = 1.19, 95% CI = 1.10-1.29). A significant association was also found for all genetic models in various subgroups (cancer and no-cancer, hospital- and population-based).

CONCLUSION

Our meta-analysis demonstrated that IL1B -31C > T polymorphism might increase H. pylori infection risk in Asian and Latin American population. Further studies with different ethnicities and larger sample size are required to validate this result.