Association of three sets of high-affinity IgE receptor (FcepsilonR1) polymorphisms with aspirin-intolerant asthma

Integrating Single-Cell Transcriptome and Network Analysis to Characterize the Therapeutic Response of Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a myeloproliferative disease characterized by a unique BCR-ABL fusion gene. Tyrosine kinase inhibitors (TKIs) were developed to target the BCR-ABL oncoprotein, inhibiting its abnormal kinase activity. TKI treatments have significantly improved CML patient outcomes. However, the patients can develop drug resistance and relapse after therapy discontinues largely due to intratumor heterogeneity. It is critical to understand the differences in therapeutic responses among subpopulations of cells. Single-cell RNA sequencing measures the transcriptome of individual cells, allowing us to differentiate and analyze individual cell populations. Here, we integrated a single-cell RNA sequencing profile of CML stem cells and network analysis to decipher the mechanisms of distinct TKI responses. Compared to normal hematopoietic stem cells, a set of genes that were concordantly differentially expressed in various types of stem cells of CML patients was revealed. Further transcription regulatory network analysis found that most of these genes were directly controlled by one or more transcript factors and the genes have more regulators in the cells of the patients who responded to the treatment. The molecular markers including a known drug-resistance gene and novel gene signatures for treatment response were also identified. Moreover, we combined protein-protein interaction network construction with a cancer drug database and uncovered the drugs that target the marker genes directly or indirectly via the protein interactions. The gene signatures and their interacted proteins identified by this work can be used for treatment response prediction and lead to new strategies for drug resistance monitoring and prevention. Our single-cell-based findings offered novel insights into the mechanisms underlying the therapeutic response of CML.

Fc Receptor Variants and Disease: A Crucial Factor to Consider in the Antibody Therapeutics in Clinic

The fragment crystallizable (Fc) domain of antibodies is responsible for their protective function and long-lasting serum half-life via Fc-mediated effector function, transcytosis, and recycling through its interaction with Fc receptors (FcRs) expressed on various immune leukocytes, epithelial, and endothelial cells. Therefore, the Fc-FcRs interaction is a control point of both endogenous and therapeutic antibody function. There are a number of reported genetic variants of FcRs, which include polymorphisms in (i) extracellular domain of FcRs, which change their affinities to Fc domain of antibodies; (ii) both cytoplasmic and intracellular domain, which alters the extent of signal transduction; and (iii) the promoter region of the FcRs gene, which affects the expression level of FcRs, thus being associated with the pathogenesis of disease indications. In this review, we firstly describe the correlation between the genetic variants of FcRs and immunological disorders by individual differences in the extent of FcRs-mediated regulations. Secondly, we discuss the influence of the genetic variants of FcRs on the susceptibility to infectious diseases or cancer in the perspective of FcRs-induced effector functions. Overall, we concluded that the genetic variants of FcRs are one of the key elements in the design of antibody therapeutics due to their variety of clinical outcomes among individuals.

Genetic association study of CTLA4 and FCεRIα polymorphisms in asthmatic patients in the southwestern region of Iran

Asthma is a heterogeneous chronic pulmonary disease that develops due to the interaction of genetic and environmental factors. This study aimed to investigate the polymorphisms of CTLA4(SNP-318C > T, SNP + 49A > G) and FCεRIα(SNP-344T > C) genes in asthmatic patients in Southwest Iran. The study enrolled 200 patients with asthma of Arab and Bakhtiary descent and 200 healthy controls, where asthmatic patients and healthy controls were selected based on a spirometry test. Genomic DNA from whole blood samples using the TaqMan assay was used to study the genotypes of patients and healthy controls.The results indicated no statistically significant difference between cases and controls for the SNP-344C > T of the FCεR1α gene and the SNP + 49A > G, SNP-318C > T of the CTLA4 gene. There was a significant correlation between the CTLA4-318C > T allele frequency in both the case and control groups (OR = 1.83; 95%CI, 1.14-2.94; P = 0.01). We stratified genotypes according to age, gender, ethnicity, and smoking status and discovered a significant suggestive association between the SNP + 49A > G of the CTLA4 gene and smoking. Additionally, SNP + 49A > G was found to be associated with gender and age. The results indicated that the SNP-318C > T polymorphism in the CTLA4 gene might contribute to the development of asthma in the studied population. Meanwhile, smoking can exacerbate asthma in individuals with SNP + 49A > G of the CTLA4 gene.Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2021.1964525 .

Single cell transcriptomics of mouse kidney transplants reveals a myeloid cell pathway for transplant rejection

Myeloid cells are increasingly recognized as major players in transplant rejection. Here, we used a murine kidney transplantation model and single cell transcriptomics to dissect the contribution of myeloid cell subsets and their potential signaling pathways to kidney transplant rejection. Using a variety of bioinformatic techniques, including machine learning, we demonstrate that kidney allograft–infiltrating myeloid cells followed a trajectory of differentiation from monocytes to proinflammatory macrophages, and they exhibited distinct interactions with kidney allograft parenchymal cells. While this process correlated with a unique pattern of myeloid cell transcripts, a top gene identified was Axl, a member of the receptor tyrosine kinase family Tyro3/Axl/Mertk (TAM). Using kidney transplant recipients with Axl gene deficiency, we further demonstrate that Axl augmented intragraft differentiation of proinflammatory macrophages, likely via its effect on the transcription factor Cebpb. This, in turn, promoted intragraft recruitment, differentiation, and proliferation of donor-specific T cells, and it enhanced early allograft inflammation evidenced by histology. We conclude that myeloid cell Axl expression identified by single cell transcriptomics of kidney allografts in our study plays a major role in promoting intragraft myeloid cell and T cell differentiation, and it presents a potentially novel therapeutic target for controlling kidney allograft rejection and improving kidney allograft survival.

In a murine model of allogeneic kidney transplantation, single-cell transcriptomics identifies that myeloid cell Axl expression promotes allograft rejection by inducing inflammatory macrophage differentiation.

Identification of Novel Biomarkers for Drug Hypersensitivity After Sequencing of the Promoter Area in 16 Genes of the Vitamin D Pathway and the High-Affinity IgE Receptor

The prevalence of allergic diseases and drug hypersensitivity reactions (DHRs) during recent years is increasing. Both, allergic diseases and DHRs seem to be related to an interplay between environmental factors and genetic susceptibility. In recent years, a large effort in the elucidation of the genetic mechanisms involved in these disorders has been made, mostly based on case-control studies, and typically focusing on isolated SNPs. These studies provide a limited amount of information, which now can be greatly expanded by the complete coverage that Next Generation Sequencing techniques offer. In this study, we analyzed the promoters of sixteen genes related to the Vitamin D pathway and the high-affinity IgE receptor, including FCER1A, MS4A2, FCER1G, VDR, GC, CYP2R1, CYP27A1, CYP27B1, CYP24A1, RXRA, RXRB, RXRG, IL4, IL4R, IL13, and IL13RA1. The study group was composed of patients with allergic rhinitis plus asthma (AR+A), patients with hypersensitivity to beta-lactams (BLs), to NSAIDs including selective hypersensitivity (SH) and cross-reactivity (CR), and healthy controls without antecedents of atopy or adverse drug reactions. We identified 148 gene variations, 43 of which were novel. Multinomial analyses revealed that three SNPs corresponding to the genes FCER1G (rs36233990 and rs2070901), and GC (rs3733359), displayed significant associations and, therefore, were selected for a combined dataset study in a cohort of 2,476 individuals. The strongest association was found with the promoter FCER1G rs36233990 SNP that alters a transcription factor binding site. This SNP was over-represented among AR+A patients and among patients with IgE-mediated diseases, as compared with control individuals or with the rest of patients in this study. Classification models based on the above-mentioned SNPs were able to predict correct clinical group allocations in patients with DHRs, and patients with IgE-mediated DHRs. Our findings reveal gene promoter SNPs that are significant predictors of drug hypersensitivity, thus reinforcing the hypothesis of a genetic predisposition for these diseases.

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: an update on pharmacogenetics studies

Nonsteroidal anti-inflammatory drugs are the medications most frequently involved in hypersensitivity reactions to drugs. These can be induced by specific immunological and nonimmunological mechanisms, being the latter the most frequent. The nonimmunological mechanism is related to an imbalance of inflammatory mediators, which is aggravated by the cyclooxygenase inhibition. Genetic studies suggest that multiples genes and additional mechanisms might be involved. The proposals of this review is summarize the contribution of variations in genes involved in the arachidonic acid, inflammatory and immune pathways as well as the recent genome-wide association studies findings related to cross-intolerant nonsteroidal anti-inflammatory drugs hypersensitivity reactions. In addition, using integration of different genetic studies, we propose new target genes. This will help to understand the underlying mechanism of these reactions.

Aspirin-exacerbated respiratory disease: an update

PURPOSE OF REVIEW

The pathophysiology of aspirin-exacerbated respiratory disease (AERD) is not fully understood and diagnostic methods and so far, treatments for AERD have not been standardized. We summarize recent research into the pathological mechanisms of AERD, diagnostic methods, and treatments for AERD patients.

RECENT FINDINGS

In AERD pathophysiology, not only the reduced expression of E prostanoid 2 but also the dysfunction of its pathway could be involved. Moreover, eosinophils of AERD patients could be directly activated by aspirin to produce prostaglandin D2. Platelet activations are well known to be involved in AERD; however, plasma markers do not change during aspirin challenge tests. Additionally, novel genetic polymorphisms, such as P2RY12 and dipeptidyl peptidase 10 gene, and epigenetic predispositions of AERD were found. In AERD diagnosis, bronchial and nasal aspirin challenges have been applied in addition to oral challenge. Serum periostin has been suggested as a potential biomarker for AERD. Apart from standard pharmacological treatment and aspirin desensitization, biologics, including omalizumab and mepolizumab, as well as CRTH2 antagonists have been suggested as promising therapies for AERD treatment.

SUMMARY

AERD is usually associated with severe asthma phenotypes. AERD pathophysiology mainly involves the dysregulation of eicosanoid metabolisms, activations of effector cells, which could be influenced by genetic/epigenetic factors. Understanding the pathophysiology of AERD is key to improve the diagnostic methods and proper management of AERD patients.

Aspirin exacerbated respiratory disease: Current topics and trends

Aspirin-exacerbated respiratory disease is a chronic and treatment-resistant disease, characterized by the presence of eosinophilic rhinosinusitis, nasal polyposis, bronchial asthma, and nonsteroidal anti-inflammatory drugs hypersensitivity. Alterations in arachidonic acid metabolism may induce an imbalance between pro-inflammatory and anti-inflammatory substances, expressed as an overproduction of cysteinyl leukotrienes and an underproduction of prostaglandin E2. Although eosinophils play a key role, recent studies have shown the importance of other cells and molecules in the development of the disease like mast cells, basophils, lymphocytes, platelets, neutrophils, macrophages, epithelial respiratory cells, IL-33 and thymic stromal lymphopoietin, making each of them promissory diagnostic and treatment targets. In this review, we summarize the most important clinical aspects of the disease, including the current topics about diagnosis and treatment, like provocation challenges and aspirin desensitization. We also discuss recent findings in the pathogenesis of the disease, as well as future trends in diagnosis and treatment, including monoclonal antibodies and a low salicylate diet as a treatment option.

Association analysis of ILVBL gene polymorphisms with aspirin-exacerbated respiratory disease in asthma

Background

We previously reported that the ILVBL gene on chromosome 19p13.1 was associated with the risk for aspirin-exacerbated respiratory disease (AERD) and the percent decline of forced expired volume in one second (FEV1) after an oral aspirin challenge test. In this study, we confirmed the association between polymorphisms and haplotypes of the ILVBL gene and the risk for AERD and its phenotype.

Methods

We recruited 141 AERD and 995 aspirin-tolerant asthmatic (ATA) subjects. All study subjects underwent an oral aspirin challenge (OAC). Nine single nucleotide polymorphisms (SNPs) with minor allele frequencies above 0.05, which were present in the region from 2 kb upstream to 0.5 kb downstream of ILVBL in Asian populations, were selected and genotyped.

Results

In an allelic association analysis, seven of nine SNPs were significantly associated with the risk for AERD after correction for multiple comparisons. In a codominant model, the five SNPs making up block2 (rs2240299, rs7507755, rs1468198, rs2074261, and rs13301) showed significant associations with the risk for AERD (corrected P = 0.001–0.004, OR = 0.59–0.64). Rs1468198 was also significantly associated with the percent decline in FEV1 in OAC tests after correction for multiple comparisons in the codominant model (corrected P = 0.033), but the other four SNPs in hapblock2 were not.

Conclusion

To the best of our knowledge, this is the first report of an association between SNPs on ILVBL and AERD. SNPs on ILVBL could be promising genetic markers of this condition.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0556-6) contains supplementary material, which is available to authorized users.

Potential Biomarkers for NSAID-Exacerbated Respiratory Disease

Asthma is a common chronic disease with several variant phenotypes and endotypes. NSAID-exacerbated respiratory disease (NERD) is one such endotype characterized by asthma, chronic rhinosinusitis (CRS) with nasal polyps, and hypersensitivity to aspirin/cyclooxygenase-1 inhibitors. NERD is more associated with severe asthma than other asthma phenotypes. Regarding diagnosis, aspirin challenge tests via the oral or bronchial route are a standard diagnostic method; reliable in vitro diagnostic tests are not available. Recent studies have reported various biomarkers of phenotype, diagnosis, and prognosis. In this review, we summarized the known potential biomarkers of NERD that are distinct from those of aspirin-tolerant asthma. We also provided an overview of the different NERD subgroups.

FCERI and Histamine Metabolism Gene Variability in Selective Responders to NSAIDS

The high-affinity IgE receptor (Fcε RI) is a heterotetramer of three subunits: Fcε RIα, Fcε RIβ, and Fcε RIγ (αβγ2) encoded by three genes designated as FCER1A, FCER1B (MS4A2), and FCER1G, respectively. Recent evidence points to FCERI gene variability as a relevant factor in the risk of developing allergic diseases. Because Fcε RI plays a key role in the events downstream of the triggering factors in immunological response, we hypothesized that FCERI gene variants might be related with the risk of, or with the clinical response to, selective (IgE mediated) non-steroidal anti-inflammatory (NSAID) hypersensitivity. From a cohort of 314 patients suffering from selective hypersensitivity to metamizole, ibuprofen, diclofenac, paracetamol, acetylsalicylic acid (ASA), propifenazone, naproxen, ketoprofen, dexketoprofen, etofenamate, aceclofenac, etoricoxib, dexibuprofen, indomethacin, oxyphenylbutazone, or piroxicam, and 585 unrelated healthy controls that tolerated these NSAIDs, we analyzed the putative effects of the FCERI SNPs FCER1A rs2494262, rs2427837, and rs2251746; FCER1B rs1441586, rs569108, and rs512555; FCER1G rs11587213, rs2070901, and rs11421. Furthermore, in order to identify additional genetic markers which might be associated with the risk of developing selective NSAID hypersensitivity, or which may modify the putative association of FCERI gene variations with risk, we analyzed polymorphisms known to affect histamine synthesis or metabolism, such as rs17740607, rs2073440, rs1801105, rs2052129, rs10156191, rs1049742, and rs1049793 in the HDC, HNMT, and DAO genes. No major genetic associations with risk or with clinical presentation, and no gene-gene interactions, or gene-phenotype interactions (including age, gender, IgE concentration, antecedents of atopy, culprit drug, or clinical presentation) were identified in patients. However, logistic regression analyses indicated that the presence of antecedents of atopy and the DAO SNP rs2052129 (GG) were strongly related (P < 0.001 and P = 0.005, respectively) with selective hypersensitivity to ibuprofen. With regard to patients with selective hypersensitivity to ASA, men were more prone to develop such a reaction than women (P = 0.011), and the detrimental DAO SNP rs10156191 in homozygosity increased the risk of developing such hypersensitivity (P = 0.039).

What we know about nonsteroidal anti-inflammatory drug hypersensitivity

Nonsteroidal anti-inf lammatory drugs (NSAIDs) are widely prescribed for the treatment of inflammatory diseases, but their use is frequently related to hypersensitivity reactions. This review outlines our current knowledge of NSAID hypersensitivity (NHS) with regard to its pathogenic, molecular, and genetic mechanisms, as well as diagnosis and treatment. The presentation of NHS varies from a local (skin and/or airways) reaction to systemic reactions, including anaphylaxis. At the molecular level, NHS reactions can be classified as cross-reactive (mediated by cyclooxygenase inhibition) or selective (specific activation of immunoglobulin E antibodies or T cells). Genetic polymorphisms and epigenetic factors have been shown to be closely associated with NHS, and may be useful as predictive markers. To diagnose NHS, inhalation or oral challenge tests are applied, with the exclusion of any cross-reactive NSAIDs. For patients diagnosed with NHS, absolute avoidance of NSAIDs/aspirin is essential, and pharmacological treatment, including biologics, is often used to control their respiratory and cutaneous symptoms. Finally, desensitization is recommended only for selected patients with NHS. However, further research is required to develop new diagnostic methods and more effective treatments against NHS.

Genetic basis of hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

PURPOSE OF REVIEW

NSAIDs are the main triggers of hypersensitivity reactions to drugs. However, the full genetic and molecular basis of these reactions has yet to be uncovered. In this article, we have summarized research from recent years into the effects of genetic variants on the different clinical entities induced by NSAID hypersensitivity, focusing on prostaglandin and leukotriene-related genes as well as others beyond the arachidonic acid pathway.

RECENT FINDINGS

We introduce recent contributions of high-throughput approaches including genome-wide association studies as well as available information from epigenetics and next-generation sequencing. Finally, we give our thoughts on future directions in this field, including the scope for bioinformatics and systems biology and the need for clear patient phenotyping.

SUMMARY

The full genetic and molecular basis of clinical entities induced by NSAIDs hypersensitivity has yet to be uncovered, and despite commendable efforts over recent years, no clinically proven genetic markers currently exist for these disorders. It is clear that we will continue to find more about these reactions in the coming years, concurrently with improvements in technology and experimental techniques, and a precise definition of different phenotypes.

Epidemiology of chronic rhinosinusitis, selected risk factors, comorbidities, and economic burden

Chronic rhinosinusitis (CRS) is a relevant and prevalent medical condition in Germany, Europe and the world. If analysed in detail, the prevalence of CRS shows regional and temporary variety. In this review, currently available data regarding the prevalence of CRS is therefore sorted by country and/or region, time point of data collection and the CRS-definition employed. Risk factors like smoking and gastroesophageal reflux are discussed regarding their influence on CRS prevalence. Moreover, comorbidities of CRS, like asthma, conditions of the cardiovascular system and depression are listed and their influence on CRS is discussed. Furthermore, data on CRS prevalence in special cohorts, like immunocompromised patients, are presented. To estimate the economic burden of CRS, current data e.g. from Germany and the USA are included in this review.

The role of aspirin desensitization in patients with aspirin-exacerbated respiratory disease (AERD)

Introduction

Aspirin-exacerbated respiratory disease (AERD) consists of a classic tetrad: moderate/severe asthma, chronic rhinosinusitis, nasal polyps, and intolerance to aspirin or other nonsteroidal anti-inflammatory drugs. Clinical control with drugs, surgery, and desensitization are treatment options.

Objective

To evaluate the efficacy and tolerability of aspirin desensitization in patients with AERD.

Methods

Periodic symptom assessment and endoscopy in patients with AERD undergoing surgery who were desensitized.

Results

Seventeen patients were desensitized. Eight patients completed the desensitization and were followed for a minimum of a one-year period (mean 3.1 years). These patients showed improvement in all symptoms. Moreover, surgical reassessment was not indicated in any of these patients and there was a decrease in costs with medication and procedures. Eight patients did not complete desensitization, mainly due to procedure intolerance and uncontrolled asthma, whereas another patient was lost to follow-up.

Conclusion

Aspirin desensitization, when tolerated, was effective in patients with AERD and with poor clinical/surgical response.

Genetic variants in arachidonic acid pathway genes associated with NSAID-exacerbated respiratory disease

AIM

NSAIDs are the most frequent cause of hypersensitivity drug reactions. We have examined the association between NSAID-exacerbated respiratory disease (NERD) and genetic variants in arachidonic acid metabolism genes.

PATIENTS & METHODS

We included 250 NERD patients, 260 NSAID-tolerant asthmatic (NTA) subjects and 315 healthy controls.

RESULTS

Significant associations with NERD were identified for: ALOX15 rs3892408 C/C homozygous genotype (NERD vs NTA; p = 0.0001, pc = 0.0011; NERD vs controls; p = 0.0001, pc = 0.0011), PTGS-1 rs5789 A/A homozygous genotype (NERD vs NTA; p = 0.0001, pc = 0.0011; NERD vs controls; p = 0.0001, pc = 0.0011), PTGS-1 rs10306135 A/A homozygous genotype (NERD vs NTA; p = 0.0009, pc = 0.0091; NERD vs controls; p = 0.0064, pc = 0.045). Differences in ALOX5 copy number variations were also found (NERD vs NTA; p = 0.010; NERD vs controls; p = 0.0001).

CONCLUSION

These results improve our understanding of the underlying mechanisms of NERD and may help develop a predictive test for this pathology. Original submitted 3 November 2014; Revision submitted 2 April 2015.

An Exploratory Pilot Study of Genetic Marker for IgE-Mediated Allergic Diseases with Expressions of FcεR1α and Cε

The high affinity immunoglobulin E (IgE) receptor-FcεR1 is mainly expressed on the surface of effector cells. Cross-linking of IgE Abs bound to FcεR1 by multi-valent antigens can induce the activation of these cells and the secretion of inflammatory mediators. Since FcεR1 plays a central role in the induction and maintenance of allergic responses, this study aimed to investigate the association of FcεR1 with the allergic phenotype of Cε expression and cytokine and histamine release from peripheral leukocytes. Peripheral leukocytes from 67 allergic and 50 non-allergic subjects were used for genotyping analysis. Peripheral mononuclear cells (PBMCs) were used for Cε expression and ELISpot analysis, while polymorphonuclear cells (PMNs) were used for histamine release. The association between genotype polymorphism of the FcεR1α promoter region (rs2427827 and rs2251746) and allergic features of Cε expression and histamine were analyzed, and their effects on leukocytes function were compared with wild type. The genotype polymorphisms of FcεR1α promoter region with CT and TT in rs2427827 and TC in rs2251746 were significantly higher in allergic patients than in non-allergic controls. Patients with single nucleotide polymorphism (SNP) of FcεR1α promoter region had high levels of total IgE, mite-specific Der p 2 (Group 2 allergen of Dermatophagoides pteronyssinus)-specific IgE and IgE secretion B cells. The mRNA expression of FcεR1α was significantly increased after Der p2 stimulation in PBMCs with SNPs of the FcεR1α promoter region. Despite the increased Cε mRNA expression in PBMCs and histamine release from PMNs and the up-regulated mRNA expression of interleukin (IL)-6 and IL-8 secretions after Der p2 stimulation, there was no statistically significant difference between SNPs of the FcεR1α promoter region and the wild type. SNPs of FcεR1α promoter region were associated with IgE expression, IgE producing B cells, and increased Der p2-induced FcεR1α mRNA expression. These SNPs may be used as a disease marker for IgE-mediated allergic inflammation caused by Dermatophagoides pteronyssinus.

Unravelling adverse reactions to NSAIDs using systems biology

We introduce the reader to systems biology, using adverse drug reactions (ADRs), specifically hypersensitivity reactions to multiple non-steroidal anti-inflammatory drugs (NSAIDs), as a model. To disentangle the different processes that contribute to these reactions - from drug intake to the appearance of symptoms - it will be necessary to create high-throughput datasets. Just as crucial will be the use of systems biology to integrate and make sense of them. We review previous work using systems biology to study related pathologies such as asthma/allergy, and NSAID metabolism. We show examples of their application to NSAIDs-hypersensitivity using current datasets. We describe breakthroughs in high-throughput technology and speculate on their use to improve our understanding of this and other drug-induced pathologies.

Exonic variants associated with development of aspirin exacerbated respiratory diseases

Aspirin-exacerbated respiratory disease (AERD) is one phenotype of asthma, often occurring in the form of a severe and sudden attack. Due to the time-consuming nature and difficulty of oral aspirin challenge (OAC) for AERD diagnosis, non-invasive biomarkers have been sought. The aim of this study was to identify AERD-associated exonic SNPs and examine the diagnostic potential of a combination of these candidate SNPs to predict AERD. DNA from 165 AERD patients, 397 subjects with aspirin-tolerant asthma (ATA), and 398 normal controls were subjected to an Exome BeadChip assay containing 240K SNPs. 1,023 models (2¹⁰-1) were generated from combinations of the top 10 SNPs, selected by the p-values in association with AERD. The area under the curve (AUC) of the receiver operating characteristic (ROC) curves was calculated for each model. SNP Function Portal and PolyPhen-2 were used to validate the functional significance of candidate SNPs. An exonic SNP, exm537513 in HLA-DPB1, showed the lowest p-value (p = 3.40×10⁻⁸) in its association with AERD risk. From the top 10 SNPs, a combination model of 7 SNPs (exm537513, exm83523, exm1884673, exm538564, exm2264237, exm396794, and exm791954) showed the best AUC of 0.75 (asymptotic p-value of 7.94×10⁻²¹), with 34% sensitivity and 93% specificity to discriminate AERD from ATA. Amino acid changes due to exm83523 in CHIA were predicted to be “probably damaging” to the structure and function of the protein, with a high score of ‘1’. A combination model of seven SNPs may provide a useful, non-invasive genetic marker combination for predicting AERD.

A whole genome analyses of genetic variants in two Kelantan Malay individuals

Background

The sequencing of two members of the Royal Kelantan Malay family genomes will provide insights on the Kelantan Malay whole genome sequences. The two Kelantan Malay genomes were analyzed for the SNP markers associated with thalassemia and Helicobacter pylori infection. Helicobacter pylori infection was reported to be low prevalence in the north-east as compared to the west coast of the Peninsular Malaysia and beta-thalassemia was known to be one of the most common inherited and genetic disorder in Malaysia.

Result

By combining SNP information from literatures, GWAS study and NCBI ClinVar, 18 unique SNPs were selected for further analysis. From these 18 SNPs, 10 SNPs came from previous study of Helicobacter pylori infection among Malay patients, 6 SNPs were from NCBI ClinVar and 2 SNPs from GWAS studies. The analysis reveals that both Royal Kelantan Malay genomes shared all the 10 SNPs identified by Maran (Single Nucleotide Polymorphims (SNPs) genotypic profiling of Malay patients with and without Helicobacter pylori infection in Kelantan, 2011) and one SNP from GWAS study. In addition, the analysis also reveals that both Royal Kelantan Malay genomes shared 3 SNP markers; HBG1 (rs1061234), HBB (rs1609812) and BCL11A (rs766432) where all three markers were associated with beta-thalassemia.

Conclusions

Our findings suggest that the Royal Kelantan Malays carry the SNPs which are associated with protection to Helicobacter pylori infection. In addition they also carry SNPs which are associated with beta-thalassemia. These findings are in line with the findings by other researchers who conducted studies on thalassemia and Helicobacter pylori infection in the non-royal Malay population.

Mast cells, their subtypes, and relation to asthma phenotypes

Mast cells (MCs) are among the first cell types associated with allergies and asthma. Studies in human asthma have identified their presence in the lung submucosa and smooth muscle and also in the airway epithelium. As our understanding of the distribution and location of these MCs in the human airway has increased, it is clear that much remains to be understood regarding the presence and subtype of these MCs in relationship to asthma phenotypes, defined both clinically and on the basis of immunologic pathways. Human MCs have traditionally been divided into two major subtypes based on the protease granule content, with tryptase representing total MCs. There is emerging evidence that in the epithelium, MCs of an altered subtype (with tryptase, chymase, and/or carboxypeptidase A3) may play a role in the pathophysiology of poorly controlled, severe, Th2-associated asthma.

Unraveling the genetic basis of aspirin hypersensitivity in asthma beyond arachidonate pathways

Although aspirin-exacerbated respiratory disease (AERD) has attracted a great deal of attention because of its association with severe asthma, it remains widely under-diagnosed in the asthmatic population. Oral aspirin challenge is the best method of diagnosing AERD, but this is a time-consuming procedure with serious complications in some cases. Thus, development of non-invasive methods for easy diagnosis is necessary to prevent unexpected complications of aspirin use in susceptible patients. For the past decade, many studies have attempted to elucidate the genetic variants responsible for risk of AERD. Several approaches have been applied in these genetic studies. To date, a limited number of biologically plausible candidate genes in the arachidonate and immune and inflammatory pathways have been studied. Recently, a genome-wide association study was performed. In this review, the results of these studies are summarized, and their limitations discussed. In addition to the genetic variants, changes in methylation patterns on CpG sites have recently been identified in a target tissue of aspirin hypersensitivity. Finally, perspectives on application of new genomic technologies are introduced; these will aid our understanding of the genetic pathogenesis of aspirin hypersensitivity in asthma.

Biochemical pathogenesis of aspirin exacerbated respiratory disease (AERD)

Aspirin exacerbated respiratory disease (AERD) is a distinct clinical entity characterized by eosinophilic rhinosinusitis, asthma and often nasal polyposis. Exposure to aspirin or other nonsteroid anti-inflammatory drugs (NSAIDs) exacerbates bronchospasms with asthma and rhinitis. Disease progression suggests a skewing towards TH2 type cellular response along with moderate to severe eosinophil and mast cell infiltration. Alterations in upper and lower airway cellular milieu with abnormalities in eicosanoid metabolism and altered eicosanoid receptor expression are the key features underlying AERD pathogenesis. Dysregulation of arachidonic acid (AA) metabolism, notably reduced prostaglandin E2 (PGE2) synthesis compared to their aspirin tolerant counterpart and relatively increased PGD2 production, a TH2/eosinophil chemoattractant are reported in AERD. Underproduced PGE2 is metabolized by overexpression of 15 prostaglandin dehydrogenase (15-PGDH) to inactive products further reducing PGE2 at real time. This relives the inhibitory effect of PGE2 on 5-lipoxygenase (5-LOX) resulting in overproduction of cysteinyl leukotrienes (CysLTs). Diminished formation of CysLT antagonists called lipoxins (LXs) also augments CysLTs responsiveness. Occasional intake of NSAIDs favors even more 5-LOX product formation, further narrowing the bronchoconstrictive bottle neck, resulting in acute asthmatic exacerbations along with increased mucus production. This review focuses on abnormalities in biochemical and molecular mechanisms in eicosanoid biosynthesis, eicosanoid receptor dysregulation and associated polymorphisms with special reference to arachidonic acid metabolism in AERD.

IL-5 Promoter Polymorphism Enhances IgE Responses to Staphylococcal Superantigens in Adult Asthmatics

Interleukin 5 (IL-5) is a key cytokine involved in the induction of T-helper type 2 (Th2) responses in the asthmatic airway. We investigated IL-5 genetic polymorphisms associated with asthma phenotypes, including IgE responses to staphylococcal enterotoxins A and B (SEA and SEB, respectively), in asthmatics. Adult asthmatics (n=310) and normal controls (n=160) were enrolled in the present study. Serum total and specific IgE to SEA and SEB were measured. Two IL-5 polymorphisms, -746A>G and +4499T>G, were genotyped using the primer-extension method. There were no significant differences in genotype or haplotype frequencies of these polymorphisms between the two groups. Asthmatics carrying the AG/GG genotype at -746A>G had a significantly higher prevalence of serum specific IgE to SEA (P=0.008), higher total IgE levels (P=0.014), and lower PC20 methacholine levels (P=0.002) compared to those with the AA genotype. These findings suggest that the IL-5 promoter polymorphism at -746A>G enhances serum total and specific IgE responses to SEA, which may augment airway hyperresponsiveness in adult asthmatics.

[Physiopathology of aspirin intolerant asthma]

Aspirin-exacerbated respiratory disease (AERD) refers to the development of bronchoconstriction in individuals with asthma following the ingestion of aspirin. AERD affects up to 20 % of adults with asthma. At present, no reliable in vitro test is available to confirm the diagnosis. The confirmation of the diagnosis of AERD therefore depends on the response to challenge testing with aspirin. The pathogenesis of AERD is linked to abnormalities in arachidonic acid metabolism. Prior to exposure to aspirin, respiratory mucosal inflammation is the result of a cell infiltration, an overproduction of leukotrienes, prostaglandins D2, 5-oxo-eicosatetraenoic acid and an underproduction of lipoxins. After aspirin ingestion, patients with AERD synthesize excessive amounts of cysteinyl leukotrienes and prostaglandin metabolites involved in bronchoconstriction. New hypotheses concerning AERD pathogenesis have been added to the initial cyclooxygenase theory. These propose that AERD may be linked to the complement system, adenosine metabolism or angiotensin converting enzyme gene and IgE receptor gene polymorphisms.

FCεRI gene promoter polymorphisms and total IgE levels in susceptibility to atopic dermatitis in Korea

IgE-dependent activation of mast cells and basophils through the high-affinity IgE receptor (FcεRI) is involved in the pathogenesis of allergen-induced immune responsiveness in atopic diseases like atopic dermatitis (AD). We sought to determine FcεRI gene polymorphisms are associated with AD in Korean patients, and analyzed the relevance of FcεRI gene polymorphisms and serum IgE levels. We conducted a case-control association analysis (175 patients and 56 controls) of Korean subjects. Genotyping was performed using the TaqMan fluorogenic 5' nuclease assay, and serum levels of IgE were measured using a fluorescence enzyme immunoassay. We found that there were no significant relationships between FcεRI and AD, although there were trends towards an association between the 66T>C (rs2251746) polymorphism and total serum IgE levels in the Korean AD patients. In conclusion, while the 66T>C (rs2251746) of the FcεRIα polymorphism may be linked to AD and higher serum IgE levels, polymorphisms in the FcεRIβ gene did not confer susceptibility to AD in our patient sample.

Over-expression of the LTC4 synthase gene in mice reproduces human aspirin-induced asthma

BACKGROUND

The pathogenesis of aspirin-induced asthma (AIA) is presumed to involve the aspirin/non-steroidal anti-inflammatory drug (NSAID)-induced abnormal metabolism of arachidonic acid, resulting in an increase in 5-lipoxygenase (5-LO) metabolites, particularly leukotriene C(4) (LTC(4) ). However, the role of LTC(4) in the development of AIA has yet to be conclusively demonstrated.

OBJECTIVE

The aim of this study was to evaluate the contribution of the lipid product LTC(4) secreted by the 5-LO pathway to the pathogenesis of AIA.

METHODS

To evaluate antigen-induced airway inflammation, the concentrations of T-helper type 2 cytokine in bronchoalveolar lavage fluid (BALF) obtained from LTC(4) synthase-transgenic (Tg) and wild-type (WT) mice after challenge with ovalbumin were measured. Subsequently, the ex vivo and in vivo effects of the NSAID sulpyrine were investigated in these Tg and WT mice by measuring the secretion of LTC(4) from sulpyrine-treated BAL cells and the levels of LTC(4) in BALF following challenge with sulpyrine. Finally, the sulpyrine-induced airway response by the administration of pranlukast, an antagonist of the cysteinyl (cs)-LT1 receptor, was analysed.

RESULTS

The concentrations of IL-4, -5, and -13 in BALF from Tg mice were significantly higher than those in WT mice. In addition, sulpyrine augmented the secretion of LTC(4) in BALF and by BAL cells in Tg mice, but not in WT mice. Additionally, the increased airway resistance induced by sulpyrine could be reduced by treatment with pranlukast. Furthermore, the secretion of LTC(4) from mast cells, eosinophils, and macrophages was increased in the allergen-stimulated LTC(4) synthase gene Tg mice, even in the absence of sulpyrine, as well as in BAL cells after sulpyrine.

CONCLUSION AND CLINICAL RELEVANCE

The over-expression of the LTC(4) synthase in a mouse asthma model also replicates the key features of AIA. And our study supports that cys-LTs play a major role in the pathogenesis of AIA in patients with chronic asthma.

Positive association between aspirin-intolerant asthma and genetic polymorphisms of FSIP1: a case-case study

BACKGROUND

Aspirin-intolerant asthma (AIA), which is caused by non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, causes lung inflammation and reversal bronchi reduction, leading to difficulty in breathing. Aspirin is known to affect various parts inside human body, ranging from lung to spermatogenesis. FSIP1, also known as HDS10, is a recently discovered gene that encodes fibrous sheath interacting protein 1, and is regulated by amyloid beta precursor protein (APP). Recently, it has been reported that a peptide derived from APP is cleaved by alpha disintegrin and metalloproteinase 33 (ADAM33), which is an asthma susceptibility gene. It has also been known that the FSIP1 gene is expressed in airway epithelium.

OBJECTIVES

Aim of this study is to find out whether FSIP1 polymorphisms affect the onset of AIA in Korean population, since it is known that AIA is genetically affected by various genes.

METHODS

We conducted association study between 66 single nucleotide polymorphisms (SNPs) of the FSIP1 gene and AIA in total of 592 Korean subjects including 163 AIA and 429 aspirin-tolerant asthma (ATA) patients. Associations between polymorphisms of FSIP1 and AIA were analyzed with sex, smoking status, atopy, and body mass index (BMI) as covariates.

RESULTS

Initially, 18 SNPs and 4 haplotypes showed associations with AIA. However, after correcting the data for multiple testing, only one SNP showed an association with AIA (corrected P-value = 0.03, OR = 1.63, 95% CI = 1.23-2.16), showing increased susceptibility to AIA compared with that of ATA cases. Our findings suggest that FSIP1 gene might be a susceptibility gene for aspirin intolerance in asthmatics.

CONCLUSION

Although our findings did not suggest that SNPs of FSIP1 had an effect on the reversibility of lung function abnormalities in AIA patients, they did show significant evidence of association between the variants in FSIP1 and AIA occurrence among asthmatics in a Korean population.

Genetic variability of the high-affinity IgE receptor alpha-subunit (FcepsilonRIalpha)

Our knowledge on the variability of FCER1A gene encoding for alpha-subunit of the high-affinity immunoglobulin E receptor (FcepsilonRI) that plays a central role in the pathogenesis of allergy and related disorders, has been recently much extended. Last findings from FCER1A mutational screening and genetic association studies, followed by functional analyses of the polymorphisms, are briefly summarized in this mini-review. The association between FCER1A gene variants and total serum IgE levels seems especially interesting and, supported by functional analyses of polymorphisms, may provide a rationale for pharmacogenetic studies on anti-IgE therapy that indirectly suppresses FcepsilonRI expression.

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.

Association of the histamine N-methyltransferase C314T (Thr105Ile) polymorphism with atopic dermatitis in Caucasian children

STUDY OBJECTIVE

To investigate potential associations between the histamine N-methyltransferase (HNMT) gene, HNMT, C314T (Thr105Ile) polymorphism and atopic dermatitis in a cohort of Caucasian children.

DESIGN

Prospective, multicenter, genotype-association study.

SETTING

Four academic, tertiary care medical centers within the Pediatric Pharmacology Research Unit network.

PARTICIPANTS

Two hundred forty-nine Caucasian children aged 6 months-5 years with atopic dermatitis (127 patients) or without (122 control subjects).

INTERVENTION

Buccal swabs (one swab/cheek) were performed to obtain epithelial cells for extraction of genomic DNA.

MEASUREMENTS AND MAIN RESULTS

Data were collected on severity of atopic dermatitis, oral antihistamine treatment, and treatment response through parental report. The HNMT genotypes were successfully obtained in 116 control subjects and 122 patients with atopic dermatitis. Frequencies of the T314 variant allele (0.12 vs 0.06, p=0.04) and combined CT/TT genotype (0.24 vs 0.12, p=0.02) were significantly higher in children with atopic dermatitis compared with control subjects. Children with genotypes conferring reduced HNMT activity were 2 times more likely to have atopic dermatitis than those who were homozygous for the C314 reference allele.

CONCLUSION

Increased histamine levels in patients with atopic dermatitis may result, at least in part, from reduced enzymatic inactivation via HNMT. Genetically associated reduction in histamine biotransformation may therefore contribute to the pathogenesis, persistence, and progression of atopic dermatitis. If confirmed, these data indicate that HNMT genotype might represent a common risk factor for development of atopic dermatitis, asthma, and allergic rhinitis and may be useful in identifying individuals who are candidates for early preventive pharmacotherapeutic intervention. Additional longitudinal studies will be required to assess the relationship between genotype, disease severity, and antihistamine response.

What do we know about the genetics of aspirin intolerance?

Although acetylsalicylic acid is prescribed for a broad range of diseases, it can induce a wide array of clinically recognized hypersensitivity reactions, including aspirin-intolerant asthma (AIA) with rhinitis and aspirin-intolerant urticaria (AIU) with anaphylaxis. Altered eicosanoid metabolism is the generally accepted mechanism of aspirin intolerance; the overproduction of cysteinyl leucotrienes has been suggested to play a causative role in both AIA and AIU. Genetic markers suggested for AIA include HLA-DPBI*0301, leucotriene C4 synthase (LTC4S), ALOX5, CYSLT, PGE2, TBXA2R and TBX21. Similarly, HLA-DB1*0609, ALOX5, FCER1A and HNMT have been identified as possible genetic markers for AIU. An additional low-risk genetic marker for AIA is MS4A2, which encodes the beta-chain of FCER1. Other single and sets of two or more interacting genetic markers are currently being investigated. Analyses of the genetic backgrounds of patients with AIA and AIU will promote the development of early diagnostic and therapeutic interventions, which may reduce the incidence of AIA and AIU.