Influence of IL-1 gene cluster polymorphisms on the development of H. pylori associated gastric ulcer

A possible role of IL-1RN gene polymorphism in the outcome of gastrointestinal diseases associated with H. pylori infection

Objective

To verify whether the variable number of tandem repeat (VNTR) polymorphism in the IL-1RN gene that encodes the interleukin (IL)-1 receptor antagonist (IL-1Ra) plays a role in the outcome of gastrointestinal diseases associated with Helicobacter pylori (H. pylori) infection.

Methods

Patients with normal endoscopy (n = 71), inflammation of the upper gastrointestinal tract only (n = 196), gastric ulcer (n = 28), duodenal ulcer (n = 76), and gastric cancer (n = 19) were studied. H. pylori infection was diagnosed by the urease test, histological examination, and polymerase chain reaction. The IL-1 receptor antagonist gene (IL-1RN intron 2 VNTR) was analyzed by polymerase chain reaction. Gastritis was scored according to the updated Sydney system of classification.

Results

H. pylori infection was an independent risk factor for mild (odds ratio [OR] = 5.53 [95% confidence interval [CI] = 2.63–11.64; P < 0.05]), moderate (OR = 83.93 [95% CI = 29.7–237.18; P < 0.05]) and marked (OR = 47.47 [95% CI = 5.39–418.05; P < 0.05]) gastritis. The carriage of IL-1RN*2/*2 had a significant protective effect of H. pylori infection (OR = 0.31 [95% CI = 0.17–0.57; P < 0.05]). H. pylori infection was identified as an independent risk of inflammation, duodenal ulcer, and gastric ulcer. The carriage of IL-1RN*2/*2 was an independent risk factor for gastric cancer (OR = 5.81 [95% CI = 1.06–31.98; P < 0.05]); nonetheless, the carriage of allele 2 (IL-1RN*2/*2 plus IL-1RN*L/*2) had an independent protective effect on duodenal ulcer (OR = 0.45 [95% CI = 0.22–0.91; P < 0.05]).

Conclusions

Allele 2 of the VNTR IL-1RN polymorphism had a protective effect against duodenal ulcer and H. pylori infection; however, it increased the risk of gastric cancer.

A frequent Toll-like receptor 1 gene polymorphism affects NK- and T-cell IFN-γ production and is associated with Helicobacter pylori-induced gastric disease

BACKGROUND

Helicobacter pylori infects approximately 50% of the world population. Among the infected individuals, only 10-20% develop peptic ulcers and <3% progress to gastric cancer (GC). Th1-predominant immune responses have been suggested to underlie H. pylori-induced gastric diseases. However, the reason for a strong inter-individual variation of susceptibility and course of the disease is currently far from being understood. It has been shown that H. pylori stimulates the host's Toll-like receptor (TLR) 2/1 complex. Furthermore, the single nucleotide polymorphism (SNP) I602S of TLR1 alters the inflammatory cytokine response of monocytes. Therefore, we hypothesized an association of this TLR1 SNP with H. pylori-mediated gastric pathologies.

MATERIALS AND METHODS

Subjects with different TLR1 genotypes were analyzed for their IFN-γ response of NK- and T-cells. We further genotyped 548 patients with gastric diseases for this SNP and compared patients with gastritis with those having ulcer, and patients with high-risk gastritis versus patients with GC.

RESULTS

Homozygous 602S allele carriers exhibited impaired in vitro IFN-γ responses to the TLR2/1 agonist Pam(3) CSK(4). The TLR1 I602S SNP is significantly associated with GC (p = .002) and gastric ulcer (p = .051). Odds ratios showed significantly reduced risk regarding GC and peptic ulcer for the homozygous mutated genotype. The odds ratios were 0.4 (95% CI, 0.22-0.72) and 0.588 (95% CI, 0.35-1.00), respectively.

CONCLUSION

In conclusion, our results suggest that the nonfunctional TLR1 602S/S genotype is associated with a reduced risk of H. pylori-induced gastric diseases, probably via diminished Th1 responses.

Urease and Helicobacter spp. antigens in pulmonary granuloma

Pulmonary sarcoidosis, a human disease of unknown cause, has no animal model. Sarcoidosis patients have serum antibodies specific for Helicobacter pylori and its surface enzyme urease. H. pylori do not survive in the high-oxygen pulmonary atmosphere, but urease may access the lung by oesophageal reflux. A model was established in rats to study gastro-oesophageal reflux of urease into the airways. Pathology in tissues from human sarcoidosis patients was compared with that in the rat model. Changes observed in the rat model included prominent peribronchial lymphocytic infiltration, which is seen occasionally in human sarcoidosis. Granulomas, pathognomonic for human sarcoidosis, occurred occasionally in the lungs of rats given urease protein intratracheally, but were widespread when urease was coupled to microbeads and administered intravenously. Biomarkers associated with human sarcoidosis (interleukin1-β and platelet-activating factor) were up-regulated acutely in the rat model. Further investigations with this model may provide significant insights into the origin and pathogenesis of pulmonary diseases in man and other species that carry gastric Helicobacter spp. and its associated enzyme.

A novel exonic variant (221delT) in the LGALS13 gene encoding placental protein 13 (PP13) is associated with preterm labour in a low risk population

Predicting adverse pregnancy outcome in low risk patients in a community with poor socio-economic circumstances is difficult, yet about 5% of these pregnancies will result in preterm labour or severe pre-eclampsia. In this study we aimed to identify markers in pro- and anti-inflammatory genes that may contribute to disease and possibly disease prediction in a low risk community setting. A prospective study was undertaken on 450 consecutive low risk primigravid patients. Blood obtained at first booking was screened for known immunological gene variants (IL4 -590, IL1B +3953, IL1RN, IL10 -1082; -819; -592 and TNFA -308; -238; +488) as well as for novel variants in the LGALS13 gene coding for placental protein 13 (PP13). The incidence of preterm labour and pre-eclampsia was 7.1% and 6.8% respectively. A novel exonic variant (221delT) in the LGALS13 gene increased the risk for preterm labour in the total study group (relative risk RR 2.27). Maternal carriage of the interleukin-1 RN*2 allele was associated with an increased risk of hypertension in pregnancy in the Coloured subgroup of the study cohort (RR 2.53). There was an increased risk for preterm labour in the same subgroup with carriage of the TNFA -308 A-allele (TNF2) (RR 2.53). No significance was found for the other variants examined. We conclude that single nucleotide polymorphisms (SNPs) in certain genes regulating implantation and inflammation may contribute to the complex etiology of pre-eclampsia and preterm labour. The association between the 221delT deletion and adverse pregnancy outcome needs to be confirmed in different populations.

An interleukin-1beta (IL-1beta) single-nucleotide polymorphism at position 3954 and red complex periodontopathogens independently and additively modulate the levels of IL-1beta in diseased periodontal tissues

Inflammatory cytokines such as interleukin-1beta (IL-1beta) are involved in the pathogenesis of periodontal diseases. A high individual variation in the levels of IL-1beta mRNA has been verified, which is possibly determined by genetic polymorphisms and/or by the presence of periodontopathogens such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans. In this study, we investigated the role of an IL-1beta promoter single-nucleotide polymorphism at position 3954 [IL-1beta(3954) SNP] and the presence of the periodontopathogens in the determination of the IL-1beta levels in the periodontal tissues of nonsmoking chronic periodontitis (CP) patients (n = 117) and control (C) subjects (n = 175) and the possible correlations with the clinical parameters of the disease. IL-1beta(3954) SNP was investigated by restriction fragment length polymorphism, while the IL-1beta levels and the presence of the periodontopathogens were determined by real-time PCR. Similar frequencies of IL-1beta(3954) SNP were found in the C and CP groups, in spite of a trend toward a higher incidence of T alleles in the CP group. The IL-1beta(3954) SNP CT and TT genotypes, as well as P. gingivalis, T. forsythia, and T. denticola, were associated with higher IL-1beta levels and with higher values of the clinical parameters of disease severity. Concomitant analyses demonstrate that IL-1beta(3954) and the red complex periodontopathogens were found to independently and additively modulate the levels of IL-1beta in periodontal tissues. Similarly, the concurrent presence of both factors was associated with increased scores of disease severity. IL-1beta(3954) genotypes and red complex periodontopathogens, individually and additively, modulate the levels of IL-1beta in the diseased tissues of nonsmoking CP patients and, consequently, are potentially involved in the determination of the disease outcome.

Association of interleukin-1 gene polymorphisms with gastric cancer: a meta-analysis

Previous studies on the association between interleukin-1 (IL-1) genetic polymorphisms and the risk of gastric cancer have produced conflicting results. The purpose of this study was to examine the association between IL-1 genotype and gastric cancer by systematically reviewing the risk of the original studies. Thirty-nine studies, which included 6,863 gastric cancer cases and 8,434 controls, met the inclusion criteria and were included in the meta-analysis. By pooling all the studies identified, the summary odds ratio (OR) of gastric cancer risk associated with IL-1B-511T, -31C, +3954T and IL-1RN*2 was 1.26 (95% confidence interval (CI): 1.03-1.55), 1.00 (95% CI: 0.82-1.22), 1.37 (95% CI: 0.94-2.00) and 1.20 (95% CI: 1.01-1.41), respectively. A stratified analysis showed that IL-1B-511T was associated with an increased risk of gastric cancer (intestinal type) (OR = 1.76, 95% CI: 1.12-2.57). Moreover, IL-1RN*2 was also associated with an increased risk of gastric cancer among Caucasians (OR = 1.30, 95% CI: 1.09-1.54). In conclusion, IL-1B-511 and IL-1RN genetic polymorphisms are associated with an increased risk of developing gastric cancer.

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