Impact of cytokines genes polymorphisms and their serum levels on childhood asthma in Egyptian population

Role of the TGF-β cytokine and its gene polymorphisms in asthma etiopathogenesis

Transforming growth factor beta (TGF-β) is a pluripotent cytokine expressed by all cells of the human body which plays important roles in maintaining homeostasis and allowing for proper individual development. Disturbances in TGF-β signaling contribute to the development of many diseases and disorders, including cancer and organ fibrosis. One of the diseases with the best-characterized correlation between TGF-β action and etiopathogenesis is asthma. Asthma is the most common chronic inflammatory disease of the lower and upper respiratory tract, characterized by bronchial hyperresponsiveness to a number of environmental factors, leading to bronchospasm and reversible limitation of expiratory flow. TGF-β, in particular TGF-β1, is a key factor in the etiopathogenesis of asthma. TGF-β1 concentration in bronchoalveolar lavage fluid samples is elevated in atopic asthma, and TGF-β expression is increased in asthmatic bronchial samples. The expression of all TGF-β isoforms is affected by a number of single nucleotide polymorphisms found in the genes encoding these cytokines. Some of the SNPs that alter the level of TGF-β expression may be associated with the occurrence and severity of symptoms of asthma and other diseases. The TGF-β gene polymorphisms, which are the subject of this paper, are potential diagnostic factors. If properly used, these polymorphisms can facilitate the early and precise diagnosis of asthma, allowing for the introduction of appropriate therapy and reduction of asthma exacerbation frequency.

Impact of Interleukin-17 Receptor A Gene Variants on Asthma Susceptibility and Clinical Manifestations in Children and Adolescents

Several single nucleotide polymorphisms (SNPs) in multiple interleukin receptor genes could be associated with asthma risk and/or phenotype. Interleukin-17 (IL-17) has been implicated in tissue inflammation and autoimmune diseases. As no previous studies have uncovered the potential role of IL17 receptor A (RA) gene variants in asthma risk, we aimed to explore the association of four IL17RA SNPs (i.e., rs4819554A/G, rs879577C/T, rs41323645G/A, and rs4819555C/T) with asthma susceptibility/phenotype in our region. TaqMan allelic discrimination analysis was used to genotype 192 individuals. We found that the rs4819554 G/G genotype significantly reduced disease risk in the codominant (OR = 0.15, 95%CI = 0.05-0.45, p < 0.001), dominant (OR = 0.49, 95%CI = 0.26-0.93, p = 0.028), and recessive (OR = 0.18, 95%CI = 0.07-0.52, p < 0.001) models. Similarly, rs879577 showed reduced disease risk associated with the T allele across all genetic models. However, the A allele of rs41323645 was associated with increased disease risk in all models. The G/A and A/A genotypes have higher ORs of 2.47 (95%CI = 1.19-5.14) and 3.86 (95%CI = 1.62-9.18), respectively. Similar trends are observed in the dominant 2.89 (95%CI = 1.47-5.68, p = 0.002) and recessive 2.34 (95%CI = 1.10-4.98, p = 0.025) models. For the rs4819555 variant, although there was no significant association identified under any models, carriers of the rs4819554*A demonstrated an association with a positive family history of asthma (71.4% in carriers vs. 27% in non-carriers; p = 0.025) and the use of relievers for >2 weeks (52.2% of carriers vs. 28.8% of non-carriers; p = 0.047). Meanwhile, the rs4819555*C carriers displayed a significant divergence in the asthma phenotype, specifically atopic asthma (83.3% vs. 61.1%; p = 0.007), showed a higher prevalence of chest tightness (88.9% vs. 61.5%; p = 0.029), and were more likely to report comorbidities (57.7% vs. 16.7%, p = 0.003). The most frequent haplotype in the asthma group was ACAC, with a frequency of 22.87% vs. 1.36% in the controls (p < 0.001). In conclusion, the studied IL17RA variants could be essential in asthma susceptibility and phenotype in children and adolescents.

Self-Reported Insufficient Sleep Is Associated With Clinical and Inflammatory Features of Asthma: A Prospective Cohort Study

BACKGROUND

A few studies have explored the association between short sleep duration and worse asthma outcomes in patients with self-reported asthma; however, all of them were cross-sectional.

OBJECTIVES

To investigate the association between self-reported sleep duration and asthma-related clinical and inflammatory characteristics and whether sleep duration is associated with asthma exacerbations (AEs) in the following year.

METHODS

A prospective cohort study consecutively recruited participants with asthma, who were classified into short (n = 58), normal (n = 380), and long (n = 84) sleep duration groups. We investigated the clinical and inflammatory characteristics and exacerbations within a 1-year follow-up.

RESULTS

Patients with short sleep duration were older and had significantly lower total IgE and FeNO levels and higher airway inflammation, characterized by increased levels of IL-6 and TNF-α in sputum than those of patients with normal sleep duration. Furthermore, they had a significantly increased risk for poorly controlled asthma (adjusted odds ratio = 2.741; 95% CI, 1.379-5.447; P = .004) and moderate to severe AEs (adjusted incidence rate ratio = 1.798; 95% CI, 1.098-2.942; P = .020).

CONCLUSIONS

Short sleep duration was associated with non-type 2 inflammation and is an independent risk factor for future AEs. Therefore, as a potentially treatable trait, sleep duration may have clinical implications for asthma management.

Associations between interleukin 17A and 17F polymorphisms and asthma susceptibility: A meta-analysis

Owing to their role in inflammatory reactions and immunological responses as well as their chromosomal location, interleukin (IL) 17A and 17F are regarded as candidate causal genes associated with asthma. The aim of this study was to determine whether IL17 polymorphisms are associated with susceptibility to asthma. We used the PubMed/Medline and Embase databases to search for studies reporting IL17 polymorphisms in patients with asthma and healthy controls. Meta-analyses were conducted to determine the associations between IL17A rs8193036 (-737C/T), rs2275913 (-197G/A), rs3819024 (A/G), rs3748067 (C/T), and rs4711998 (A/G) and IL17F rs763780 (7488A/G), rs2397084 (T/C), rs1889570 (C/T), rs11465553 (G/A), and rs1266828 (T/C) polymorphisms and asthma susceptibility. A total of 20 studies were included in this meta-analysis. Our results revealed the IL17A rs8193036 CC genotype was associated with asthma susceptibility (odds ratio [OR] = 1.490, 95% confidence interval [CI] = 1.027-2.161, p = .036). However, stratification by ethnicity indicated no association between this polymorphism and asthma in European and Asian subjects. Furthermore, no association was found between this polymorphism and asthma using the allele contrast, dominant or homozygous contrast models. No evidence of an association was found between any of the other IL17A and IL17F polymorphisms and asthma susceptibility in this meta-analysis. This meta-analysis showed that, among the studied polymorphisms, only the CC genotype of IL17A rs8193036 is associated with asthma susceptibility.