Association of a lymphotoxin-alpha gene polymorphism and atopic asthma in Taiwanese children

A Meta-Analysis of the Influence of Tumor Necrosis Factor-α-308 Gene Polymorphism on Liver Cirrhosis

Cirrhosis is an active hepatic inflammation process of the liver considered as the serious phase of different liver injuries. Epidemiological studies have evaluated the possible association between TNF-α-308G/A gene polymorphism and liver cirrhosis. In this study, we have furthered the study to assess the exact association of TNF-α-308G/A gene polymorphism with liver cirrhosis susceptibility by integrating all available data. Eligible case-control studies were carried out from the establishment of the project to September 2021. Published literature from multiple databases was retrieved, collected, and analyzed by two investigators independently. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for every study. Review Manager 5.2 and Stata 15.0 software were used for meta-analysis and stability was assessed by both subgroup analysis and sensitivity analysis. Begg's funnel plot and Egger's regression across the studies were also explored. We examined 22 case-control studies with 2683 cirrhosis patients and 2905 normal controls in four genetic models (GA vs. GG: OR = 0.95, 95%CI: (0.70, 1.30); AA vs. GG: OR = 1.11, 95% CI: (0.66, 1.85), GA + AA vs. GG: OR = 1.00, 95% CI: (0.73, 1.37); AA vs. GA + GG: OR = 1.07, 95%CI: (0.70,1.63)). TNF-α-308G/A gene polymorphism was relatively independent, and the results did not show a significant difference between the two groups. In the subgroup analysis by etiological classification of liver cirrhosis, cirrhosis after HCV infection was positively associated with the risk of TNF-α-308G/A polymorphism (AA vs. GG: OR = 3.02, 95% CI: (1.15, 7.88), AA vs. GA + GG: OR = 2.68, 95% CI: (1.04, 6.95)). The meta-analysis showed TNF-α-308G/A gene polymorphism might not have affected susceptibility for liver cirrhosis. Nevertheless, further and well-designed studies were needed to confirm the findings.

Cytokine Gene Polymorphisms in Saudi Patients With Atopic Dermatitis: A Case-Control Study

The cause of atopic dermatitis (AD) is multifactorial and a number of genes including cytokines have been involved. We genotyped 315 subjects for polymorphisms in TNF-α and TNF-β and IL-10 genes. Patients had significantly higher frequency of GA genotype of TNF-α (−308 G/A) than healthy controls. Patients with AD and controls had similar distribution of A and G alleles. Genotype AA was found in 7.11% of controls while completely absent in cases. The frequencies of genotypes GG and AA of TNF-β (+252 A/G) polymorphism were higher whereas the frequency of genotype GA was significantly lower in patients than the controls. The frequencies of genotypes GG and AA of IL-10 (1082 G/A) polymorphism were significantly increased whereas genotype GA was decreased in patients than the controls. It is concluded that TNF-α (−308 G/A), TNF-β (+252 A/G), and IL-10 (−1082 G/A) polymorphisms are linked with the susceptibility of AD in Saudis and can be a risk factor.

Environment Changes Genetic Effects on Respiratory Conditions and Allergic Phenotypes

The prevalence of asthma and allergic diseases is disproportionately distributed among different populations, with an increasing trend observed in Western countries. Here we investigated how the environment affected genotype-phenotype association in a genetically homogeneous, but geographically separated population. We evaluated 18 single nucleotide polymorphisms (SNPs) corresponding to 8 genes (ADAM33, ALOX5, LT-α, LTC4S, NOS1, ORMDL3, TBXA2R and TNF-α), the lung function and five respiratory/allergic conditions (ever asthma, bronchitis, rhinitis, dermatitis and atopy) in two populations of Inuit residing either in the westernized environment of Denmark or in the rural area of Greenland. Our results showed that lung function was associated with genetic variants in ORMDL3, with polymorphisms having a significant interaction with place of residence. LT-α SNP rs909253 and rs1041981 were significantly associated with bronchitis risk. LT-α SNP rs2844484 was related to dermatitis susceptibility and was significantly influenced by the place of residence. The observed gene-phenotype relationships were exclusively present in one population and absent in the other population. We conclude that the genotype-phenotype associations relating to bronchitis and allergy susceptibility are dependent on the environment and that environmental factors/lifestyles modify genetic predisposition and change the genetic effects on diseases.

The +252A/G polymorphism in the lymphotoxin-α gene increases the risk of asthma: a meta-analysis

BACKGROUND AND OBJECTIVE

A number of studies have shown that the +252A/G polymorphism (rs909253) in the lymphotoxin-α (LT-α) gene is implicated in susceptibility to asthma. However, the findings have been inconclusive. The aim of this study was to investigate the association between the +252A/G polymorphism in the LT-α gene and the risk of asthma by performing a meta-analysis.

METHODS

The Pubmed and Embase databases were searched for all studies relating to this polymorphism and the risk of asthma. Statistical analyses were performed using the Revman4.2 and STATA 10.0 software.

RESULTS

Thirteen case-control studies that included a total of 2220 cases and 6428 controls were included in the meta-analysis. There was no significant association between this polymorphism and the risk of asthma in the all-combined analysis (odds ratio (OR) 1.14, 95% confidence interval (CI): 0.89-1.45 for GG+GA vs AA). In a subgroup analysis by ethnicity, no significant association with asthma risk was identified in Asians (OR 1.31, 95% CI: 0.97-1.77) or Europeans (OR 1.08, 95% CI: 0.77-1.53). In a subgroup analysis by age, a significantly increased risk was identified among adults (OR 1.25, 95% CI: 1.03-1.50) but not children (OR 1.04, 95% CI: 0.28-3.89). In a subgroup analysis by atopic status, a significantly elevated risk was identified among atopic (OR 1.55, 95% CI: 1.28-1.87) but not non-atopic individuals (OR 0.94, 95% CI: 0.53-1.68).

CONCLUSIONS

This meta-analysis suggested that the +252A/G polymorphism in the LT-α gene is a risk factor for asthma in adults and atopic populations.

Asthma susceptible genes in Chinese population: a meta-analysis

BACKGROUND

Published data regarding the associations between genetic variants and asthma risk in Chinese population were inconclusive. The aim of this study was to investigate asthma susceptible genes in Chinese population.

METHODS

The authors conducted 18 meta-analyzes for 18 polymorphisms in 13 genes from eighty-two publications.

RESULTS

Seven polymorphisms were found being associated with risk of asthma, namely: A Disintegrin and Metalloprotease 33 (ADAM33) T1-C/T (odds ratio [OR] = 6.07, 95% confidence interval [CI]: 2.69-13.73), Angiotensin-Converting Enzyme (ACE) D/I (OR = 3.85, 95%CI: 2.49-5.94), High-affinity IgE receptor β chain (FcεRIβ) -6843G/A (OR = 1.49, 95%CI: 1.01-2.22), Interleukin 13(IL-13) -1923C/T (OR = 2.99, 95%CI: 2.12-4.24), IL-13 -2044A/G (OR = 1.49, 95%CI: 1.07-2.08), Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES) -28C/G (OR = 1.64, 95%CI: 1.09-2.46), Tumor Necrosis Factor-α (TNF-α) -308G/A(OR = 1.42, 95%CI: 1.09, 1.85). After subgroup analysis by age, the ACE D/I, β2-Adrenergic Receptor (β2-AR) -79G/C, TNF-α -308G/A, Interleukin 4 receptor(IL-4R) -1902G/A and IL-13 -1923C/T polymorphisms were found significantly associated with asthma risk in Chinese children. In addition, the ACE D/I, FcεRIβ -6843G/A, TNF-α -308G/A, IL-13 -1923C/T and IL-13 -2044A/G polymorphisms were associated with asthma risk in Chinese adults.

CONCLUSION

ADAM33, FcεRIβ, RANTES, TNF-α, ACE, β2-AR, IL-4R and IL-13 genes could be proposed as asthma susceptible genes in Chinese population. Given the limited number of studies, more data are required to validate these associations.

Importance of cytokines in murine allergic airway disease and human asthma

Asthma is a common, disabling inflammatory respiratory disease that has increased in frequency and severity in developed nations. We review studies of murine allergic airway disease (MAAD) and human asthma that evaluate the importance of Th2 cytokines, Th2 response-promoting cytokines, IL-17, and proinflammatory and anti-inflammatory cytokines in MAAD and human asthma. We discuss murine studies that directly stimulate airways with specific cytokines or delete, inactivate, neutralize, or block specific cytokines or their receptors, as well as controversial issues including the roles of IL-5, IL-17, and IL-13Ralpha2 in MAAD and IL-4Ralpha expression by specific cell types. Studies of human asthmatic cytokine gene and protein expression, linkage of cytokine polymorphisms to asthma, cytokine responses to allergen stimulation, and clinical responses to cytokine antagonists are discussed as well. Results of these analyses establish the importance of specific cytokines in MAAD and human asthma and have therapeutic implications.