Allergen Immunotherapy: Current and Future Trends.

Allergen immunotherapy (AIT) is the sole disease-modifying treatment for allergic rhinitis; it prevents rhinitis from progressing to asthma and lowers medication use. AIT against mites, insect venom, and certain kinds of pollen is effective. The mechanism of action of AIT is based on inducing immunological tolerance characterized by increased IL-10, TGF-ß, and IgG4 levels and Treg cell counts. However, AIT requires prolonged schemes of administration and is sometimes associated with adverse reactions. Over the last decade, novel forms of AIT have been developed, focused on better allergen identification, structural modifications to preserve epitopes for B or T cells, post-traductional alteration through chemical processes, and the addition of adjuvants. These modified allergens induce clinical-immunological effects similar to those mentioned above, increasing the tolerance to other related allergens but with fewer side effects. Clinical studies have shown that molecular AIT is efficient in treating grass and birch allergies. This article reviews the possibility of a new AIT to improve the treatment of allergic illness.

Neuroimmune Pathophysiology in Asthma.

Asthma is a chronic inflammation of lower airway disease, characterized by bronchial hyperresponsiveness. Type I hypersensitivity underlies all atopic diseases including allergic asthma. However, the role of neurotransmitters (NT) and neuropeptides (NP) in this disease has been less explored in comparison with inflammatory mechanisms. Indeed, the airway epithelium contains pulmonary neuroendocrine cells filled with neurotransmitters (serotonin and GABA) and neuropeptides (substance P[SP], neurokinin A [NKA], vasoactive intestinal peptide [VIP], Calcitonin-gene related peptide [CGRP], and orphanins-[N/OFQ]), which are released after allergen exposure. Likewise, the autonomic airway fibers produce acetylcholine (ACh) and the neuropeptide Y(NPY). These NT/NP differ in their effects; SP, NKA, and serotonin exert pro-inflammatory effects, whereas VIP, N/OFQ, and GABA show anti-inflammatory activity. However, CGPR and ACh have dual effects. For example, the ACh-M3 axis induces goblet cell metaplasia, extracellular matrix deposition, and bronchoconstriction; the CGRP-RAMP1 axis enhances Th2 and Th9 responses; and the SP-NK1R axis promotes the synthesis of chemokines in eosinophils, mast cells, and neutrophils. In contrast, the ACh-α7nAChR axis in ILC2 diminishes the synthesis of TNF-α, IL-1, and IL-6, attenuating lung inflammation whereas, VIP-VPAC1, N/OFQ-NOP axes cause bronchodilation and anti-inflammatory effects. Some NT/NP as 5-HT and NKA could be used as biomarkers to monitor asthma patients. In fact, the asthma treatment based on inhaled corticosteroids and anticholinergics blocks M3 and TRPV1 receptors. Moreover, the administration of experimental agents such as NK1R/NK2R antagonists and exogenous VIP decrease inflammatory mediators, suggesting that regulating the effects of NT/NP represents a potential novel approach for the treatment of asthma.

Subcutaneous Allergen-Specific Immunotherapy Is Safe in Pediatric Patients with Allergic Rhinitis.

INTRODUCTION: Subcutaneous allergen-specific immunotherapy (SCIT) is one of the main cornerstones in the treatment of allergic rhinitis in pediatric patients. It has demonstrated symptoms and quality of life improvement, but it is not exempt from adverse reactions (ADVrs). Nevertheless, there are a few reports that have evaluated their safety. Our objective was to evaluate the ADVr to SCIT in pediatric patients. METHODS: We reviewed 786 clinical records with SCIT from 2005 to 2018, comparing the clinical characteristics of patients with ADVrs with SCIT versus a group of a similar number of patients who completed SCIT (control group, CG). The analysis of ADVrs was according to the World Allergy Organization (WAO) 2010 grading system by frequency analysis, survival curve, and log rank. RESULTS: Of 786 patients, 106 (13.4%) presented ADVrs, and the patients with ADVr had sensitivity and immunotherapy with at least 2 allergens versus CG p < 0.001, containing a combination of standardized and nonstandardized allergens (p = 0.003). The ADVrs were in the buildup phase (p < 0.001). The survival curve showed that 50% had some reaction at 12 weeks of SCIT. The most frequent ADVr was grade 1 in 73/106 patients (68.8%) and grade 2 in 33/106 (31.1%). The log-rank analysis between the grades of the WAO grading system showed a statistically significant difference (p = 0.02). CONCLUSIONS: The SCIT is safe in pediatric patients. The ADVrs are infrequent, grade 1 being the most reported; however, at >12 weeks, the risk of ADVrs that involve 2 organs systems increases.

Effect of LTRA in L-ASA Challenge for Aspirin-Exacerbated Respiratory Disease Diagnosis.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) consists of asthma, chronic rhinosinusitis with polyps, and hypersensitivity to aspirin and/or nonsteroidal anti-inflammatory drugs (NSAIDs). Nasal Lysine Aspirin Challenge is an effective tool for the diagnosis of hypersensitivity to aspirin and/or NSAIDs in patients with AERD. However, there is no unified international consensus version to perform nasal provocation tests (NPTs). OBJECTIVE: To investigate the effect of a leukotriene receptor antagonist (LTRA), montelukast, on the lysine-acetylsalicylate (L-ASA) nasal challenge. METHODS: We included 86 patients divided into 3 samples: group A (AERD without LTRA), group B (AERD with LTRA), and the control group (NSAID-tolerant asthmatics). NPT with L-ASA was performed with 25 mg of L-ASA every 30 minutes 4 times followed by rhinomanometry and spirometric measurements and evaluation of symptoms using a novel clinical scale. RESULTS: In group A, 94.5% of patients (35 of 37) developed a positive response to NPT (drop >40% in total nasal flow), whereas only 46% of group B subjects (13 of 28) showed a positive response to the nasal challenge (P < .001). Control subjects did not show any response to the L-ASA challenge. A novel clinical score demonstrated accuracy in classifying the hypersensitivity to aspirin and/or NSAIDs when patients avoid LTRA (33 of 37). CONCLUSION: Patients with AERD without LTRA showed a greater positive response to the L-ASA challenge than those taking this drug; therefore, LTRA treatment should be discontinued before the challenge for optimal diagnostic accuracy.

Proteomic identification of allergenic proteins in red oak (Quercus rubra) pollen.

BACKGROUND: Red oak pollen is an important cause of allergic respiratory disease and it is widely distributed in North America and central Europe. To date, however, red oak pollen allergens have not been identified. Here, we describe the allergenic protein profile from red oak pollen. METHODS: Total proteins were extracted from red oak pollen using a modified phenolic extraction method, and, subsequently, proteins were separated by two-dimensional gel electrophoresis (2DE) for both total protein stain (Coomassie Blue) and immunoblotting. A pool of 8 sera from red oak sensitive patients was used to analyze blotted proteins. Protein spots were analyzed by Mass Spectrometry. RESULTS: Electrophoretic pattern of total soluble proteins showed higher intensity bands in the regions of 26-40 and 47-52 kDa. Two dimensional immunoblots using pool sera from patients revealed four allergenic proteins spots with molecular masses in the range from 50 to 55 kDa. Mass spectrometry analysis identified 8 proteins including Enolase 1 and Enolase 1 chloroplastic, Xylose isomerase (X1 isoform), mitochondrial Aldehyde dehydrogenase, UTP-Glusose-1-phosphate uridylyltransferase, Betaxylosidase/alpha-l-arabinofuranosidase and alpha- and beta subunits of ATP synthase. CONCLUSIONS: This study has identified for first time 8 IgE binding proteins from red oak pollen. These findings will pave the way towards the development of new diagnostic and therapeutic modalities for red oak allergy.

MS4A2-rs573790 Is Associated With Aspirin-Exacerbated Respiratory Disease: Replicative Study Using a Candidate Gene Strategy.

Aspirin exacerbated respiratory disease (AERD) is a set of diseases of the unified airway, and its physiopathology is related to disruption of the metabolism of arachidonic acid (AA). Genetic association studies in AERD had explored single nucleotide polymorphism (SNPs) in several genes related to many mechanisms (AA metabolism, inflammation, drug metabolism, etc.) but most lack validation stages in second populations. Our aim is to evaluated whether contribution to susceptibility of SNPs reported in other populations are associated with AERD in Mexican Mestizo patients. We developed a replicative study in two stages. In the first, 381 SNPs selected by fine mapping of associated genes, (previously reported in the literature), were integrated into a microarray and tested in three groups (AERD, asthma and healthy controls -HC-) using the GoldenGate array. Results associated to risk based on genetic models [comparing: AERD vs. HC (comparison 1, C1), AERD vs. asthma (C2), and asthma vs. HC (C3)] were validated in the second stage in other population groups using qPCR. In the first stage, we identified 11 SNPs associated with risk in C1.The top SNPs were ACE-rs4309C (p = 0.0001) and MS4A2-rs573790C (p = 0.0002). In C2, we detected 14 SNPs, including ACE-rs4309C (p = 0.0001). In C3, we found MS4A2-rs573790C (p = 0.001). Using genetic models, C1 MS4A2-rs57370 CC (p = 0.001), and ACE-rs4309 CC (p = 0.002) had associations. In C2 ACE-rs4309 CC (p = 0.0001) and C3 MS4A2-rs573790 CC (p = 0.001) were also associate with risk. In the second stage, only MS4A2-rs573790 CC had significance in C1 and C3 (p = 0.008 and p = 0.03). We concluded that rs573790 in the MS4A2 gene is the only SNP that supports an association with AERD in Mexican Mestizo patients in both stages of the study.

Single nucleotide polymorphisms in TNF are associated with susceptibility to aspirin-exacerbated respiratory disease but not to cytokine levels: a study in Mexican mestizo population.

AIM: To evaluate the association of three single nucleotide polymorphisms in TNF and one in LTA in Mexican patients with aspirin-exacerbated respiratory disease (AERD) and the correlation of those single nucleotide polymorphisms with serum levels of TNF-α. PATIENTS & METHODS: Case-control study including 133 patients with AERD, 135 patients with asthma (aspirin-tolerant asthmatics) and 182 healthy subjects. RESULTS: GA genotype of rs1800629 in TNF was found to be associated with the risk of developing AERD (p < 0.05; odds ratio = 2.36) and by dominant model (p < 0.05; odds ratio = 2.51). Furthermore, there was a difference in the serum levels between the aspirin-tolerant asthmatics group and the other groups (p < 0.001). CONCLUSION: The GA genotype of rs1800629 is associated with genetic susceptibility to AERD, but it does not correlate to protein serum levels.

Physiopathology and genetics in aspirin-exacerbated respiratory disease.

INTRODUCTION: Aspirin-exacerbated respiratory disease (AERD) is a clinical entity characterized by hypersensitivity to aspirin leading to asthma and chronic rhinosinusitis with nasosinusal polyposis. The pathophysiology of the disease involves disruption at the level of arachidonic acid metabolism. Therefore, genetic association studies have been focused on the genes coding this pathway. As other mechanisms involved in the genesis of the disease were elucidated, the corresponding genes were also explored. AIM: To describe the association reported in the literature between gene polymorphisms involved in the pathophysiology or therapeutic processes of AERD. RESULTS: There is a genetic association between polymorphisms of genes involved in the synthesis of proteins related to arachidonic acid metabolism (LTC4S, ALOX5), antigen presentation (HLA), inflammation (IL5, IL17), and aspirin metabolism (CYP2C19). CONCLUSIONS: Genetic association research in AERD has evaluated studies of SNPs in metabolic pathways related to arachidonic acid. Recently, whole genome analysis strategies have allowed the detection of new genetic variants that were previously not considered. Furthermore, these studies have identified SNPs that are associated with inflammatory processes, which could serve as diagnostic markers or predictors of the therapeutic response.

The IL1B-511 Polymorphism (rs16944 AA Genotype) Is Increased in Aspirin-Exacerbated Respiratory Disease in Mexican Population.

Aspirin exacerbated respiratory disease (AERD) is characterized by chronic hyperplastic rhinosinusitis, nasal polyposis, asthma, and aspirin sensitivity. The mechanisms which produce these manifestations of intolerance are not fully defined, current research focuses on cyclooxygenase 1 (COX-1) inhibition, metabolism of arachidonic acid, and the COX pathway to the lipoxygenase (LO) route, inducing increased synthesis of leukotrienes (LT). The biological plausibility of this model has led to the search for polymorphisms in genes responsible for proinflammatory cytokines synthesis, such as IL1B and IL8. We performed a genetic association study between IL8-251 (rs4073) and IL1B-511 (rs16944) polymorphisms in AERD, aspirin-tolerant asthma (ATA), and healthy control subjects. Using allelic discrimination by real-time PCR, we found statistically nonsignificant associations between AERD, ATA, and healthy control subjects for the GG and GA genotypes of IL1B (rs16944). Interestingly, the AA genotype showed an increased frequency in the AERD patients versus the ATA group (GF = 0.19 versus 0.07, p = 0.018, OR 2.98, and 95% CI 1.17-7.82). This is the first observation that IL1B polymorphisms are involved in AERD. Thus, future studies must investigate whether interleukin-1ß is released in the airways of AERD patients and whether it relates to genetic polymorphisms in the IL1B gene.