Gene susceptibility in Iranian asthmatic patients: a narrative review

Association between interleukin-6-174G/C gene polymorphism and asthma severity: exploring the role of total serum IgE, blood eosinophils, and FeNO as markers of type 2 inflammation

BACKGROUND

While a connection has been established between serum interleukin-6 (IL-6) levels and the IL-6 gene (- 174G/C) polymorphism in allergic diseases such as asthma, its specific association with severe asthma remains unexplored. This study examined the relationship between the IL-6 (- 174G/C) gene polymorphism and mild and severe asthma, focusing on its influence on type 2 inflammation.

METHODS

Our study comprised 98 patients with mild asthma and 116 with severe asthma. Additionally, we recruited 121 healthy participants to serve as controls for comparative analyses. The IL-6 gene (- 174G/C) polymorphism was assessed utilizing the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

In our study, the risk of mild asthma exhibited a significant fourfold increase in individuals with the GG genotype pattern compared to healthy controls, yielding an odds ratio (OR) of 4.4 (p < 0.001). Conversely, we found no significant correlation between the IL-6 - 174G/C gene polymorphism and severe asthma when compared to the healthy control group. However, a noteworthy pattern emerged when we compared subgroups of mild and severe asthma. The risk of severe asthma increased fivefold in individuals with the GC polymorphism pattern, with an OR of 4.99 (p < 0.001), while the likelihood of mild asthma showed a similar fourfold increase with the GG polymorphism pattern, OR = 4.4 (p < 0.001). Consequently, we observed a significantly higher frequency of the C allele in patients with severe asthma, whereas the G allele was more prevalent in individuals with mild asthma (p = 0.05). Additionally, the correlation between markers of type 2 inflammation and the dominant model of the IL-6 gene -174G/C polymorphism (CC + CG vs GG) revealed a significant increase in total serum immunoglobulin E (IgE), Blood Eosinophil Counts (BEC), and Fractional Exhaled Nitric Oxide (FeNO) levels in asthmatic patients with the CC + CG gene pattern compared to those with GG, with p-values of 0.04, 0.03, and 0.04, respectively. Furthermore, after adjusting for other risk factors, the likelihood of developing severe asthma increased from fourfold to eightfold, with an OR of 8.12 (p = 0.01) with (CC + CG) gene pattern. Other predictors for severe asthma included older age and childhood-onset disease (OR = 1.13 and 19.19, p < 0.001). Allergic rhinitis (AR) and nasal polyps (NP) also demonstrated a substantial association with an increased risk of severe asthma, with odds ratios of 5 and 32.29 (p = 0.01 and < 0.001), respectively. Additionally, elevated Body Mass Index (BMI), BEC, and FeNO were linked to severe asthma, with ORs of 1.11, 1.00, and 1.04, respectively (p = 0.04, 0.05, and 0.001).

CONCLUSION

This study illuminated the intricate relationship between the IL-6 gene polymorphism, type 2 inflammation markers, and diverse risk factors in shaping asthma severity. As a significant association between the GG polymorphism of the IL-6 gene (- 174G/C) and mild asthma was found, while possessing at least one C allele, whether in a homozygous (CC) or heterozygous (CG) combination, independently predicts the likelihood of severe asthma.

Interaction of Interleukin 7 Receptor (IL7R) and IL6 Gene Polymorphisms with Smoking Associated with Susceptibility to Asthma in Chinese Han Adults

BACKGROUND

the aim of this study was to investigate the relationship between the risk of asthma and multiple single nucleotide polymorphisms (SNPs) in interleukin 7 receptor (IL7R) and IL6 genes, as well as the gene- environment interactions.

METHODS

This is a hospital- based case- control study. A total of 430 patients with asthma were continuously recruited. Four SNPs within IL7R and IL6 gene were genotyped by PCR based restriction fragment length polymorphism. The Hardy- Weinberg balance of all participants was tested by SNPstats. The best interaction combination of four SNPs in IL7R and IL6 genes and smoking was screened by generalized multifactor dimensionality reduction (GMDR). Logistic regression was used to test the association between four SNPs and asthma, and stratified analysis for rs1800795 gene-smoking interaction, synergy index (SI) was calculated.

RESULTS

The rs1494558-G and rs1800795-C were associated with an increased risk of asthma, adjusted ORs (95% CI) was 1.81 (1.29-2.42) and 1.75 (1.20-2.28), respectively. GMDR indicated that the test accuracy for two-locus model involving rs1800795 and smoking was 0.5721, and the p = .011, the results providing evidence for rs1800795 gene-smoking interaction. The asthma risk was higher in smokers with GC or CC genotype than the sum of risks in subjects with smoking or GC or CC genotype alone, compared to the never smokers with GG genotype, the OR (95%CI) was 4.97 (3.01-7.24), and the synergy index (SI) was 1.68 (1.08-2.60).

CONCLUSIONS

The rs1494558-G and rs1800795-C alleles, gene- environment interaction between rs1800795 and smoking were all associated with increased asthma risk.

Bronchial Asthma: Genetic Factors Contributing to its Pathogenesis

Researching bronchial asthma (BA)-linked gene polymorphisms can help to clarify heterogeneity of the disease and estimate its severity, which, in turn, will aid in developing an appropriate treatment corresponding to the patient’s unique asthma pathogenesis. The aim of presented review is to analyze the published data on the genetic preconditions of BA and the possible role of different genes polymorphisms in its pathogenesis. We have found that despite the fact that numerous genes are involved in the pathogenesis of BA and their polymorphisms are associated with increased risks for BA, it is important to understand that a combination of factors, both genetic and environmental, triggers BA development and determines its progression. On the other hand, the identification of BA susceptibility genes contributing to asthma pathogenesis and treatment response is the first step toward the development of personalized medicine.

Effect of ginger extract on expression of GATA3, T-bet and ROR-γt in peripheral blood mononuclear cells of patients with Allergic Asthma

INTRODUCTION AND OBJECTIVES

Allergic asthma is a chronic inflammatory disorder of the airways. Th1, Th2 and Th17 cells are the main cells involved in the pathophysiology of asthma. The function of these cells is affected by T-bet, GATA3 and RORγt transcription factors (respectively). Therefore, the aim of this study was to evaluate the effect of ginger (officinal Roscoe) extract on the expression of T-bet, GATA-3 and ROR-γ in peripheral blood mononuclear cells (PBMC) of asthmatic patients, in comparison with healthy volunteers as controls.

MATERIALS AND METHODS

In this case-control study, a total of 50 individuals including 25 patients with severe, moderate and mild allergic asthma and 25 unrelated healthy controls were involved. The PBMCs were isolated and divided into four groups: negative control, two positive controls (Budesonide and PHA) and ginger-extract treated group. After cell treatment and incubation for 48h, PBMCs were isolated and cDNA was synthesized. Gene expressions of T-bet, GATA3 and ROR-γt were evaluated by Real-time PCR.

RESULTS

According to the results of this study, hydroalcoholic extract of ginger could reduce the expression of GATA-3, ROR-γt, and T-bet in PBMCs of asthmatic patients in comparison with untreated PBMCs (P values=0.001, 0.001, and 0.002, respectively). It was also shown that the ginger extract could affect T-bet/GATA-3, T-bet/ROR-γt, and ROR-γt/GATA-3 expression ratios.

CONCLUSIONS

This study showed that the use of ginger extract could control asthma and decrease the severity of this disease by affecting the main cells involving the symptoms of asthma in the airways.

Detecting Chronic Post-Traumatic Osteomyelitis of Mouse Tibia via an IL-13Rα2 Targeted Metallofullerene Magnetic Resonance Imaging Probe

Differential diagnosis of chronic post-traumatic osteomyelitis (CPO) from aseptic inflammation remains challenging, since both pathological processes share similar clinical symptoms. Here we utilized a novel targeted metallofullerene nanoparticle based magnetic resonance imaging (MRI) probe IL-13-TAMRA-Gd₃N@C₈₀(OH)₃₀(CH₂CH₂COOH)₂₀ to detect CPO in mouse tibia via overexpressed IL-13Rα2 receptors. The functionalized metallofullerene was characterized by X-ray photoelectron spectroscopy. Upon lipopolysaccharide (LPS) stimulation, macrophage Raw 264.7 cells showed elevated IL-13Rα2 expression via immunofluorescence staining and increased MRI probe binding via built-in TAMRA fluorescence imaging. Trauma was induced in both tibia of mice and bacteria soaked suture was inserted into the right tibia to initiate infection. During the acute phase (1.5 weeks), luminol-bioluminescence imaging revealed much higher myeloperoxidase activity in the infected tibia compared to the sham. In the chronic phase (4 weeks), X-ray radiography illustrated bone deformation in the infected tibia compared to the sham. With T₁ weighted sequences, the probe clearly exhibited hyperintensity in the infection foci at both acute and chronic phases, which was not observed in the sham tibia. Histological analysis revealed severe bone structural destruction and massive inflammatory cell infiltration in the infected tibia. Immunohistochemistry confirmed abundant expression of IL-13Rα2 in the infection site. In summary, we developed a noninvasive imaging approach to detect and differentiate CPO from aseptic inflammation using a new IL-13Rα2 targeted metallofullerene MRI probe. In addition, for the first time, IL-13Rα2 was investigated as a unique biomarker in the context of osteomyelitis. Our data established a foundation for the translational application of this MRI probe in the clinical differentiation of CPO.

Interleukin-6 gene -174G/C polymorphism and bronchial asthma risk: a meta-analysis

The Interleukin-6 (IL-6) genetic polymorphism is associated with bronchial asthma, a number of studies have been conducted to investigate the association between IL-6 gene -174G/C polymorphism and bronchial asthma risk. However, the results are inconclusive. This meta-analysis aims to investigate whether -174G/C polymorphism is a potential risk factor for bronchial asthma. We searched Web of Science, PubMed, Google Scholar, China National Knowledge Infrastructure (CNKI) and Wanfang Database from inception through December 1st, 2014. Meta-analysis was performed using the STATA 12.0. Overall, a significantly reduced risk for asthma was found in IL-6 -174 CC genotype (CC vs. GG: OR = 0. 51, 95% CI = 0.27-0.96, P = 0.038). Furthermore, analysis by ethnicity indicated that there was a markedly reduced risk for asthma in IL-6 -174 CC genotype in Caucasian (CC vs. GG: OR = 0.51, 95% CI = 0.27-0.96, P = 0.038). Analysis by age indicated that there was a significantly reduced risk for asthma in IL-6 -174 CC genotype in adults (CC vs. GG: OR = 0.47, 95% CI = 0.23-0.97, P = 0.042). In conclusion, the current meta-analysis indicates that IL-6 -174 CC genotype may be a protective factor against asthma in Caucasian and adults.