Lack of an association between a newly identified promoter polymorphism (-1702G > A) of the leukotriene C4 synthase gene and aspirin-intolerant asthma in a Korean population

Correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma: A meta-analysis and trial sequential analysis

Background

This study aims to uncover the potential correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma.

Methods

Literatures reporting the correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma published before 1st June, 2019 were searched in PubMed, Embase, Cochrane, Wanfang and CNKI. Eligible literatures were enrolled and their data were extracted. OR and its 95% CI were calculated for assessing the correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma. The included data were weighted by an inverse variance and then analyzed by a fixed or random effects model. Heterogeneity test and sensitivity analysis were performed on the enrolled reports. STATA12.1 and TSA (trial sequential analysis) were utilized for analyses.

Aspirin-Induced Delayed Urticaria in Children with Kawasaki Disease: A Retrospective Case-Control Study

Background

Aspirin remains a key component of the standard therapy for Kawasaki disease (KD) in children. Although it is well known that aspirin can cause hypersensitivity such as aspirin-induced urticaria (AIU), AIU in children with KD has not been described.

Methods

A retrospective case-control study was conducted to investigate AIU clinical features, biochemical parameters, treatment and outcomes in children with KD. Furthermore, biomarkers for predicting AIU were explored using the receiver operating characteristic (ROC) curve analysis.

Results

We identified 46 AIU cases with 22 boys and 24 girls during April 2015–May 2019. Eighty-nine age-matched KD patients without AIU were randomly chosen as controls. The proportions of children with allergy history and aspirin doses administered in the 2 groups were found not to be significantly different. AIU group had substantially higher baseline C-reactive protein and NT-proBNP levels, and increased neutrophil percent. AIU appeared 6.0 (4.0, 8.0) days after aspirin treatment. Aspirin withdrawal and anti-allergic treatment were applied for AIU, and AIU disappeared in 1–3 days. Baseline NT-proBNP predicted AIU with an AUC of 0.70 (95% CI [0.60 to 0.79]) for sensitivity and specificity of 72.1% and 62.5%, respectively, for a cut-off value of 612.9 mg/L. The length of hospital stay for AIU patients was significantly greater compared with controls.

Conclusion

AIU in KD children is not related to gender or aspirin dose, and those with AIU have more severe inflammation at admission. Aspirin should be withdrawn for AIU management. Baseline NT-proBNP may serve as a valuable biomarker to predict AIU.

Gene Polymorphism of Aspirin-Induced Urticaria in Children With Kawasaki Disease

Objective: To investigate the distribution of the single nucleotide polymorphism (SNP) of LTC4S A-444C in children with Kawasaki disease in northern China and determine whether LTC4S A-444C SNP is associated with aspirin-induced urticaria (AIU). Methods: The clinical data of children with Kawasaki disease hospitalized in our center from April 2015 to November 2017 were collected, and fluorescence in situ hybridization was used to detect the LTC4S A-444C. According to the genotype, the subjects were divided into three groups: AA genotypes, AC genotypes, and CC genotypes. The incidence of AIU in the three groups was calculated and the relationship between LTC4S A-444C SNP and AIU was analyzed. Results: (1) A total of 574 children with Kawasaki disease were enrolled in the study. The allele frequencies for A, C were 980 (85.4%), 168 (14.6%). (2) Twenty-five cases of AIU in AA genotypes, with a positive rate of 6%, 11 cases of AIU in AC genotypes, with a positive rate of 7.5%, 2 cases of AIU in CC genotypes, with a positive rate of 18.2%. CC genotypes had higher incidence of AIU than that of AA and AC genotypes. However, there was no significant difference among the three groups (P > 0.05). Conclusion: The proportion of CC genotypes of LTC4S A-444C in children with Kawasaki disease in northern China is lower than that of AA genotypes and AC genotypes, and the incidence of AIU of CC genotypes is higher than that of AC genotypes and AA genotypes.

The -444A/C polymorphism in the LTC4S gene and the risk of asthma: a meta-analysis

BACKGROUND AND AIMS

The -444A/C polymorphism in the leukotriene C4 synthase (LTC4S) gene has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study was to investigate the association between the -444A/C polymorphism in the LTC4S gene and asthma risk using meta-analysis.

METHODS

We searched Pubmed, Embase, CNKI and Wanfang databases. Statistical analysis was performed using the software Revman4.2 and STATA10.0.

RESULTS

A total of 3042 cases and 1902 controls in 13 case-control studies were included in the meta-analysis. The results indicated that the variant C allele carriers (CC + AC) did not have increased/decreased risk of asthma when compared with the homozygote AA (CC + AC vs. AA: OR = 1.13, 95% CI = 1.00-1.28, p = 0.06). In the subgroup analysis by age, ethnicity and aspirin sensitivity, significantly elevated risks were found only in Caucasians (OR = 1.21, 95% CI = 1.02-1.44, p = 0.03) and aspirin-tolerant populations (OR = 1.36, 95% CI = 1.12-1.65, p = 0.002) but not in other subgroups.

CONCLUSIONS

This meta-analysis suggested that the -444A/C polymorphism in the LTC4S gene would be a risk factor for asthma in Caucasians and aspirin-tolerant populations. Future studies are needed to validate our results.

Genetic mechanisms in aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) refers to the development of bronchoconstriction in asthmatics following the exposure to aspirin or other nonsteroidal anti-inflammatory drugs. The key pathogenic mechanisms associated with AERD are the overproduction of cysteinyl leukotrienes (CysLTs) and increased CysLTR1 expression in the airway mucosa and decreased lipoxin and PGE2 synthesis. Genetic studies have suggested a role for variability of genes in disease susceptibility and the response to medication. Potential genetic biomarkers contributing to the AERD phenotype include HLA-DPB1, LTC4S, ALOX5, CYSLT, PGE2, TBXA2R, TBX21, MS4A2, IL10, ACE, IL13, KIF3A, SLC22A2, CEP68, PTGER, and CRTH2 and a four-locus SNP set composed of B2ADR, CCR3, CysLTR1, and FCER1B. Future areas of investigation need to focus on comprehensive approaches to identifying biomarkers for early diagnosis.

Update on recent advances in the management of aspirin exacerbated respiratory disease

Aspirin intolerant asthma (AIA) is frequently characterized as an aspirin (ASA)-exacerbated respiratory disease (AERD). It is a clinical syndrome associated with chronic severe inflammation in the upper and lower airways resulting in chronic rhinitis, sinusitis, recurrent polyposis, and asthma. AERD generally develops secondary to abnormalities in inflammatory mediators and arachidonic acid biosynthesis expression. Upper and lower airway eosinophil infiltration is a key feature of AERD; however, the exact mechanisms of such chronic eosinophilic inflammation are not fully understood. Cysteinyl leukotriene over-production may be a key factor in the induction of eosinophilic activation. Genetic studies have suggested a role for variability of genes in disease susceptibility and response to medication. Potential genetic biomarkers contributing to the AERD phenotype include HLA-DPB1*301, LTC4S, ALOX5, CYSLT, PGE2, TBXA2R, TBX21, MS4A2, IL10 -1082A > G, ACE -262A > T, and CRTH2 -466T > C; the four-locus SNP set was composed of B2ADR 46A > G, CCR3 -520T > G, CysLTR1 -634C > T, and FCER1B -109T > C. Management of AERD is an important issue. Aspirin ingestion may result in significant morbidity and mortality, and patients must be advised regarding aspirin risk. Leukotriene receptor antagonists (LTRA) that inhibit leukotriene pathways have an established role in long-term AERD management and rhinosinusitis. Aspirin desensitization may be required for the relief of upper and lower airway symptoms in AERD patients. Future research should focus on identification of biomarkers for a comprehensive diagnostic approach.

Recommendations for using standardised phenotypes in genetic association studies

Genetic association studies of complex traits often rely on standardised quantitative phenotypes, such as percentage of predicted forced expiratory volume and body mass index to measure an underlying trait of interest (eg lung function, obesity). These phenotypes are appealing because they provide an easy mechanism for comparing subjects, although such standardisations may not be the best way to control for confounders and other covariates. We recommend adjusting raw or standardised phenotypes within the study population via regression. We illustrate through simulation that optimal power in both population- and family-based association tests is attained by using the residuals from within-study adjustment as the complex trait phenotype. An application of family-based association analysis of forced expiratory volume in one second, and obesity in the Childhood Asthma Management Program data, illustrates that power is maintained or increased when adjusted phenotype residuals are used instead of typical standardised quantitative phenotypes.

Leukotriene pathway genetics and pharmacogenetics in allergy

Leukotrienes (LT) are biologically active lipid mediators known to be involved in allergic inflammation. Leukotrienes have been shown to mediate diverse features of allergic conditions including inflammatory cell chemotaxis/activation and smooth muscle contraction. Cysteinyl leukotrienes (LTC(4), LTD(4) and, LTE(4)) and the dihydroxy leukotriene LTB(4) are generated by a series of enzymes/proteins constituting the LT synthetic pathway or 5-lipoxygenase (5-LO) pathway. Their function is mediated by interacting with multiple receptors. Leukotriene receptor antagonists (LTRA) and LT synthesis inhibitors (LTSI) have shown clinical efficacy in asthma and more recently in allergic rhinitis. Despite growing knowledge of leukotriene biology, the molecular regulation of these inflammatory mediators remains to be fully understood. Genes encoding enzymes of the 5-LO pathway (i.e. ALOX5, LTC4S and LTA4H) and encoding for LT receptors (CYSLTR1/2 and LTB4R1/2) provide excellent candidates for disease susceptibility and severity; however, their role remains unclear. Preliminary data also suggest that 5-LO pathway/receptor gene polymorphism can predict patient responses to LTSI and LTRA; however, the exact mechanisms require elucidation. The aim of this review was to summarize the recent advances in the knowledge of these important mediators, focusing on genetic and pharmacogenetic aspects in the context of allergic phenotypes.

Nonsteroidal anti-inflammatory drug hypersensitivity in preschool children

: Although extensively studied in adults, nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity in children, especially in young children, remains poorly defined. Pediatricians, prescribing antipyretics for children, rarely encounter significant problems, but the few epidemiologic studies performed show conflicting results. Although it is clear that some patients with acetylsalicylic acid (ASA)-sensitive asthma have their clinical onset of disease in childhood and bronchoconstriction after ASA challenge is seen in 0 to 22% of asthmatic children so challenged, ibuprofen at antipyretic doses may cause acute respiratory problems only in a very small number of mild to moderate asthmatics. The recently elucidated mechanism of action of acetaminophen may explain some occurrences of adverse reactions in patients with cross-reactive NSAID hypersensitivity on the basis of its inhibitory activity on the newly described enzyme, cyclooxygenase (COX)-3. This nonspecific sensitivity to inhibition of COX is most likely genetically determined and shows a remarkable association with atopic disease even in the very young age group and possibly an increased predilection in specific ethnic groups. This review summarizes state-of-the-art published data on NSAID hypersensitivity in preschool children.

Pathogenesis, diagnosis, and treatment of aspirin intolerance

OBJECTIVES

To provide an overview of aspirin intolerance (AI), to summarize the latest genetic and pathophysiologic findings, and to discuss the current therapeutic recommendations, including aspirin desensitization.

DATA SOURCES

Using the PubMed database, a systematic search of articles published between 1968 and 2006 was performed to evaluate the current literature on AI. The bibliographies of selected articles served as a source of additional literature.

STUDY SELECTION

Included articles were selected for their relevance to the pathogenesis, diagnosis, and management of AI.

RESULTS

The prevalence of AI is approximately 0.3% to 0.9%, but AI is often overlooked. It can display a wide range of clinical pictures, such as acute asthma attacks, urticaria, angioedema, chronic rhinitis, myocardial ischemia, and anaphylactic shock. Regarding the pathogenesis of AI, modifications of eicosanoid metabolism are supposed to underlie AI, including aspirin-induced asthma and aspirin-induced urticaria. However, the pathogenesis of AI has not yet been clearly elucidated. Associations of several HLA alleles with subtypes of AI, such as aspirin-induced urticaria and aspirin-induced asthma, and single nucleotide polymorphisms in genes encoding enzymes involved in arachidonic acid metabolism have been shown.

CONCLUSIONS

Because aspirin therapy should be avoided in AI patients, the use of alternative drugs is recommended. Patients intolerant of alternative drugs and those with therapy-resistant asthma or sinusitis benefit from aspirin desensitization.

Differential contribution of the CysLTR1 gene in patients with aspirin hypersensitivity

In this study, we compared the roles of CysLT receptor type 1 (CysLTR1) and leukotriene C4 synthase (LTC4S) gene polymorphisms in two major aspirin-related allergic diseases, aspirin-intolerant asthma (AIA) and aspirin-induced chronic urticaria/angioedema (AICU). CysLTR1-634C>T and LTC4S-444A>C polymorphisms were genotyped and its functional effect on the promoter activity was compared. As in vivo functional study, changes of peripheral mRNA level of CysLTR1 were measured by real-time PCR before and after aspirin challenge. A significant association was found for the CysLTR1 promoter polymorphism and the AIA phenotype compared to AICU (P = 0.015). In U937 cells, the variant genotype reporter construct showed significantly higher promoter activity than the common genotype (P < 0.05). The CysLTR1 mRNA levels increased significantly after aspirin challenge in AIA patients (P = 0.013). In conclusion, the CysLTR1 polymorphism may contribute to develop to the AIA phenotype and be used as a genetic marker for differentiating two major aspirin hypersensitivity phenotypes.

Hypersensitivity to paracetamol in Asian children with early onset of nonsteroidal anti-inflammatory drug allergy

BACKGROUND

The published incidence of paracetamol cross-reactivity in adults and adolescents with nonsteroidal anti-inflammatory drug (NSAID) reactions is low and all data on such reactions in young children is sparse. The study aim was to characterize the clinical presentation and cross-reactivity with paracetamol in patients with a reported onset of NSAID hypersensitivity before 6 years of age.

METHODS

A retrospective case review was done of patients with cross-reactive hypersensitivity reactions to antipyretic/analgesic medications from the pediatric allergy clinic of the Kendang Kerbau Hospital, Singapore. Included patients reported the onset of such reactions before 6 years of age. Hypersensitivity was established through a detailed history of recurrent reactions to NSAIDs or an oral provocation test.

RESULTS

Eighteen patients fulfilled the diagnostic criteria within the study period. Eighty-three percent had cross-reactive reactions with paracetamol. When compared to the group of children with later onset of NSAID hypersensitivity, children with onset before 6 years of age had a significantly increased likelihood of reacting to paracetamol (odds ratio 9.6, 95% confidence interval 1.6-58.0, p < 0.05).

CONCLUSION

Paracetamol seems to be a major eliciting drug in this group of children.