Genotyping of IL-4 -590 (C>T) Gene in Iraqi Asthma Patients

Interleukin-4 (C590T) Gene Polymorphism in Association with Asthma Severity

Background

A significant link between T allele of the IL-4 (C590T) gene and developing asthma in some populations was reported. However, no study discussed the link between IL-4 (C590T) gene polymorphism and asthma severity groups (mild and severe). This study investigated the link between IL-4 gene variation and asthma severity.

Methods

The study included 215 asthmatic patients, of which 102 had mild asthma, and 126 participants were healthy controls. A previously published polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to identify various IL-4 (C590T) gene polymorphism genotypes.

Results

The T allele frequency was higher in mild asthma (p=0.002) but not in severe asthma (p=0.12) compared to controls. In mild asthma, the CT genotype and (CT+TT versus CC) increased the likelihood of asthma threefold (p<0.001, 0.001). However, no significant association with severe asthma was found in either genetic model. Stratification analysis showed that the C allele and CC genotype increased the risk of severe asthma (p=0.01). The recessive genetic model indicated a decrease in the risk of severe asthma (OR=0.5, p=0.01) in the non-adjusted regression analysis. Adjusting for age, sex, and other risk factors revealed that the IL-4 gene polymorphism did not influence the risk of severe asthma (OR=0.92, p=0.80); however, being an elderly female with a history of childhood-onset disease and associated nasal polyp (NP) increased the likelihood of severe asthma, OR=1.08, 2.01, 2.36, 8.42; p<0.001, 0.05, 0.05, <0.001, respectively.

Conclusion

The T allele and CT genotype in the co-dominant genetic model and the (CT+TT) genotype in the recessive model were found to have a higher likelihood of developing mild asthma but not severe asthma; severe asthma was found to be higher in elderly females with a history of childhood-onset disease and associated nasal polyps.

Association between Interleukin-4-590C>T Polymorphism and the Susceptibility to Asthma: A Meta-Analysis of Case-Control Study

This study was aimed to investigate the relationship between the interleukin-4-590C > T gene polymorphism and the susceptibility to asthma by meta-analysis. To explore the underlying relationship between the polymorphism of IL-4-590C > T and the susceptibility to asthma, this study systematically retrieved the literature including cohort studies and case-control studies published before June 2019 in PubMed, Embase, and Cochrane Library. Data on the odds ratio (OR) and 95% confidence interval (CI) of the literature were included in the relative studies. Subsequently, the included data were weighted by an inverse variance and then analyzed by the fixed or random effects model. Overall, 818 asthma patients and 831 healthy individuals participated in the 8 independent case-control studies in the current meta-analysis. There was no correlation between IL-4-590C > T TT genotype and the increased susceptibility to asthma (dominant model: OR = 1.31, 95% CI = 0.68-2.53). Subgroup analysis by ethnicity showed no significant results in the Asians (OR = 1.28, 95% CI = 0.24-6.80); however, IL-4-590C > T TT genotype significantly elevated the susceptibility to asthma in the Caucasians (OR = 1.43, 95%CI = 1.03-1.98). Meanwhile, subgroup analysis was performed by source of control. A statistically significant result was found in the population-based control group (OR = 1.33, 95% CI = 1.01-1.76), but not in the hospital-based control group (OR = 1.22, 95% CI = 0.27-5.46). The results demonstrated that IL-4-590C > T TT genotype could significantly enhance the susceptibility to asthma in Caucasians without increasing that in Asian populations. However, it still required a large sample of high-quality studies in multicentral hospital to further confirm its reliability.

Finding a molecular genetic marker for the incidence of recurrent episodes of acute obstructive bronchitis in children

Over the last ten years, the incidence of the pathology of the bronchus-pulmonary system in children has increased 3.6 times, mainly due to acute and recurrent inflammatory diseases of the upper and lower respiratory tract. Thus, the problem of identifying children with recurrent episodes of acute obstructive bronchitis and an increased risk of developing asthma is relevant and promising. The goal of this study was to find molecular genetic markers associated with increased susceptibility of children to repeated episodes of acute obstructive bronchitis. The molecular genetic testing of the IL4 gene of a single nucleotide polymorphism C-33T was performed in 35 children with recurrent episodes of acute obstructive bronchitis and 35 children with acute bronchitis. The results were statistically processed on a personal computer with the calculation of values the arithmetic mean (M), of the errors arithmetic mean (m), Student criterion (t), the degree of probability (p), Pearson criterion (χ2), and the odds ratio (OR). Statistically significant differences were figured at p<0.01 and p<0.05. It has been proved that the presence of a child's genotype 33CT IL4 increases the risk of recurrent acute obstructive bronchitis four times.

Polymorphisms in the interleukin 4 promoter -589C/T gene and the risk of asthma: a systematic review and meta-analysis

BACKGROUND

To identify the association between polymorphisms in the interleukin 4 (IL-4) promoter -589C/T gene and the risk of asthma.

METHODS

The databases of PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, Chongqing VIP (CQVIP), and Chinese Biomedical Literature (CBM) were searched and appropriate journal articles on the association between polymorphisms in the IL-4 promoter -589C/T gene and the risk of asthma were retrieved from establishment of the database to April 2021. All relevant randomized controlled trials (RCTs) were included, to the exclusion of duplicate publications, studies with no whole composition, imperfect information or inability to extract data, animal experiments and reviews, and systematic reviews. The software Review manager 5.3 was used to analyze the data.

RESULTS

Literature search led to retrieving of 16 publications containing 3181 cases and 3786 controls. The results show that CT, CC, and T gene polymorphisms were risk factors for asthma [odds ratio (OR) =1.05, 95% confidence interval (CI): 0.89-1.24; OR =1.04, 95% CI: 0.85-1.27; OR =1.98, 95% CI: 1.54-2.53]. Ethnic subgroup analysis showed that genotype CT was associated with the risk of asthma in the Asian population (OR =1.75, 95% CI: 1.01-3.05).

DISCUSSION

Through the study of IL-4 (C-590T) gene polymorphism, it was found that CT, TT, and T gene polymorphism were risk factors for asthma, and the results suggested that this locus polymorphism was related to the risk of asthma. The results of subgroup analysis showed that CC and T gene polymorphisms were risk factors for asthma. Thus, IL-4(C-590T) may be the susceptibility gene of asthma.

Macrophage-derived cytokines in pneumonia: Linking cellular immunology and genetics

Macrophages represent the first line of anti-pathogen defense - they encounter invading pathogens to perform the phagocytic activity, to deliver the plethora of pro- and anti-inflammatory cytokines, and to shape the tissue microenvironment. Throughout pneumonia course, alveolar macrophages and infiltrated blood monocytes produce increasing cytokine amounts, which activates the antiviral/antibacterial immunity but can also provoke the risk of the so-called cytokine "storm" and normal tissue damage. Subsequently, the question of how the cytokine spectrum is shaped and balanced in the pneumonia context remains a hot topic in medical immunology, particularly in the COVID19 pandemic era. The diversity in cytokine profiles, involved in pneumonia pathogenesis, is determined by the variations in cytokine-receptor interactions, which may lead to severe cytokine storm and functional decline of particular tissues and organs, for example, cardiovascular and respiratory systems. Cytokines and their receptors form unique profiles in individual patients, depending on the (a) microenvironmental context (comorbidities and associated treatment), (b) lung monocyte heterogeneity, and (c) genetic variations. These multidisciplinary strategies can be proactively considered beforehand and during the pneumonia course and potentially allow the new age of personalized immunotherapy.

Interleukin 4 gene polymorphism (-589C/T) and the risk of asthma: a meta-analysis and met-regression based on 55 studies

BACKGROUND

Numerous investigations have previously evaluated the association of interleukin (IL) 4 gene polymorphisms and the risk of asthma, conferring inconsistent results. To resolve the incongruent outcomes yielded from different single studies, we conducted the most up-to-date meta-analysis of IL4 gene -589C/T (rs2243250) polymorphism and susceptibility to asthma.

METHODS

A systematic literature search was performed in ISI web of science, Scopus, Medline/PubMed databases prior to September 2020, and the pooled odds ratio (OR) and their corresponding 95% CI were calculated to determine the association strength.

RESULTS

Literature search led to retrieving of 49 publications (55 case-control studies) containing 9572 cases and 9881 controls. It was revealed that IL4 gene -589C/T polymorphism increased the risk of asthma across all genetic models, including dominant model (OR = 1.22), recessive model (OR = 1.17), allelic model (OR = 1.21), and TT vs. CC model (OR = 1.34), but not the CT vs. TT model. The subgroup analysis by age indicated that IL4 gene -589C/T polymorphism was significantly associated with asthma risk in both pediatrics and adults. Additionally, the subgroup analysis by ethnicity revealed significant association in Asian, American, and Europeans. Finally, subgroup analysis by East Asian and non-East Asian populations indicated significant associations.

CONCLUSIONS

The current meta-analysis revealed that IL4 gene -589C/T polymorphism was a susceptibility risk in both pediatrics and adults in the whole and different ethnic groups.

Association of genetic variants with level of asthma control in the Arab population

Background

Rates of asthma in Jordan have been doubled in the past decade, but this increased prevalence was not met with improved asthma control protocols. The aim of the present study was to assess whether there was any significant association between the level of asthma control and certain single-nucleotide polymorphisms (SNPs) in five genes: (ADRB2; rs1042713 and rs1042714), (CRHR1; rs1876828, rs242939, and rs242941), (STIP1; rs2236647), (ADH5, rs1154400), and (ARG1; rs2781659). These SNPs were selected based on their involvement in enzymes and receptors that are related to asthma pathways and subsequent response to medication and based on a high degree of linkage disequilibrium.

Patients and methods

A cross-sectional genetic association study was conducted from June 2016 to June 2017 in the two major hospitals in Jordan. The present study involved sampling from adult asthmatic patients of Arab descent who were selected from two phenotypic groups, ie, controlled and uncontrolled asthma. The blood samples and medical data were collected from the participants. DNA samples were extracted, quantified, and genotyped according to standard operating procedure. Allelic and haplotypic analyses were performed using the Haploview^®.

Results

A total of 245 Arab asthmatic patients were enrolled in this study. Genotyping analysis revealed that the two SNPs (rs1042713 and rs1042714) in ADRB2 gene, along with their related haplotypes, were nominally significantly associated with asthma control in the Jordanian population. The A-allele of rs1042713 and the C-allele of rs1042714 were more common in the uncontrolled asthma group than in the controlled asthma group (P=0.048 and P=0.017, respectively).

Conclusion

This was the first study that identified the nominal significant association between the level of asthma control and genetic variants in ADRB2 gene in Arab population. Further studies in other Arab region with larger sample size are recommended to confirm the relationship.