Dust mite allergen, glutathione S-transferase, induces T cell immunoglobulin mucin domain-4 in dendritic cells to facilitate initiation of airway allergy

The HDM allergen orchestra and its cysteine protease maestro: Stimulators of kaleidoscopic innate immune responses

House dust mite (HDM) encloses an explosive cocktail of allergenic proteins sensitizing hundreds of millions of people worldwide. To date, the innate cellular and molecular mechanism(s) orchestrating the HDM-induced allergic inflammation remains partially deciphered. Understanding the kaleidoscope of HDM-induced innate immune responses is hampered by (1) the large complexity of the HDM allergome with very diverse functional bioreactivities, (2) the perpetual presence of microbial compounds (at least LPS, β-glucan, chitin) promoting as well pro-Th2 innate signaling pathways and (3) multiple cross-talks involving structural, neuronal and immune cells. The present review provides an update on the innate immune properties, identified so far, of multiple HDM allergen groups. Experimental evidence highlights the importance of HDM allergens displaying protease or lipid-binding activities on the initiation of the allergic responses. Specifically, group 1 HDM cysteine proteases are considered as the key initiators of the allergic response through their capacities to impair the epithelial barrier integrity, to stimulate the release of pro-Th2 danger-associated molecular patterns (DAMPs) in epithelial cells, to produce super-active forms of IL-33 alarmin and to mature thrombin leading to Toll-like receptor 4 (TLR4) activation. Remarkably, the recently evidenced primary sensing of cysteine protease allergens by nociceptive neurons confirms the critical role of this HDM allergen group in the early events leading to Th2 differentiation.

House dust mite exposure enhances immune responses to ovalbumin-induced intestinal allergy

House dust mites (HDM) are one of the important factors of airway allergic diseases, HDM allergens can be detected in the human gut mucosa, which induces local inflammation and increases intestinal epithelial permeability. This study tests a hypothesis that HDM contribute to the development of OVA (ovalbumin)-induced intestinal allergy. The serum levels of IgE against HDM in patients with food allergy were detected with UniCAP100 (Pharmacia, Uppsala, Sweden); a mouse model of food allergy was developed with OVA and HDM as the specific antigens. Compared to healthy controls, patients with food allergy have higher levels of serum HDM-specific IgE. Compared to food allergy alone groups, the levels of HDM-specific IgE in patients with food allergy and asthma or allergic rhinitis were significantly higher. In mouse models, we found that HDM/OVA induced allergy-like symptoms, lower body temperature, and lower body weight. The levels of IgE, IgG1, mMCP-1 (mouse mast cell protease-1), IL-4 and IL-5 in the HDM and HDM + CT (cholera toxin) groups were higher than the control groups, and the levels of IgE, IgG1, IL-4 and IL-5 in the HDM, OVA and HDM + OVA groups were higher than the control groups. The pathological changes of intestinal tissues in the HDM and HDM + CT/the HDM, OVA and HDM + OVA groups were more severe, more eosinophil infiltration than the control groups. Moreover, exposure to HDM induced intestinal barrier dysfunction, and facilitated the development of intestinal allergy in mice. In conclusion, HDM exposure enhances immune responses to OVA-induced food allergy.

Allergological Importance of Invertebrate Glutathione Transferases in Tropical Environments

Glutathione-S transferases (GSTs) are part of a ubiquitous family of dimeric proteins that participate in detoxification reactions. It has been demonstrated that various GSTs induce allergic reactions in humans: those originating from house dust mites (HDM), cockroaches, and helminths being the best characterized. Evaluation of their allergenic activity suggests that they have a clinical impact. GST allergens belong to different classes: mu (Blo t 8, Der p 8, Der f 8, and Tyr p 8), sigma (Bla g 5 and Asc s 13), or delta (Per a 5). Also, IgE-binding molecules belonging to the pi-class have been discovered in helminths, but they are not officially recognized as allergens. In this review, we describe some aspects of the biology of GST, analyze their allergenic activity, and explore the structural aspects and clinical impact of their cross-reactivity.

Specific Ag-guiding nano-vaccines attenuate neutrophil-dominant allergic asthma

Polymorphonuclear neutrophils (PMN) are one fraction of the major inflammatory cells in allergic asthma (asthma, in short); the role of PMN in the asthma pathogenesis is not fully understood yet. This study aims to investigate the effects of specific Ag-guiding exosomes on suppressing the neutrophil-dominant airway inflammation. In this study, BALB/c mice were immunized with ovalbumin plus complete Freund adjuvant to induce an asthma model featured with neutrophil-dominant lung inflammation. The Ag specific PMN (sPMN)-targeting exosomes (tExo), that were exosomes carrying a complex of specific Ag/anti-CD64 Ab and Fas ligand, were constructed to be used to alleviate neutrophilic asthma in mice. We found that sPMNs were the major cellular component in bronchoalveolar lavage fluid (BALF) in asthma mice, while less than 3% PMNs in naive control mice. The sPMNs expressed higher levels of CD64, which formed complexes with Ag-specific IgG (sIgG). The sIgG/CD64 complex-carrying PMNs could be activated upon exposing to specific Ags. Exposure to tExos induced Ag-specific PMNs apoptosis. Administration of tExos efficiently suppressed experimental asthma. We conclude that a fraction of sPMN was identified in the airway of asthma mice. The sPMNs could be activated upon exposure to specific Ags. tExos could induce sPMNs apoptosis, that show the translational potential in the treatment of asthma.

Developments in the field of allergy in 2017 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2017. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis and clinical allergy are all covered.

Survivin facilitates T-helper 2-biased inflammation in the airway

BACKGROUND

The biased T helper 2 (Th2) responses play a critical role in the pathogenesis of allergy. The underlying mechanism is not fully understood yet. Survivin can regulate multiple cellular activities. This study aims to elucidate the role of survivin in the development and maintenance of Th2 polarization.

METHODS

CD4⁺ T cells were isolated from blood samples collected from patients with allergic asthma (AS) and HS control (HS) subjects. Mice carrying CD4⁺ T cells with survivin knockout (KO mice) were employed to test the role of survivin in the development of the biased Th2 responses.

RESULTS

KO mice failed to induce airway allergy. Peripheral CD4⁺ T cells expressed survivin, which was higher in the AS group than that in the HS group. Naive CD4⁺ T cells with higher expression of survivin were prone to differentiating into Th2 cells. Survivin bound to the Il4 promoter in CD4⁺ T cells to enhance Il4 gene transcription. The expression of Fas was lower in CD4⁺ T cells of the AS group than that in the HS group. Overexpression of survivin suppressed the expression of Fas and impaired the activation-induced cell death (AICD) of CD4⁺ T cells.

CONCLUSION

Survivin facilitates the development of biased Th2 polarization through promoting expression of interleukin 4 (IL-4) and impairing the AICD machinery of CD4⁺ T cells. To modulate the expression of survivin in CD4⁺ T cells has the translational potential in the treatment of allergic diseases.

Allergic asthma: an overview of metabolomic strategies leading to the identification of biomarkers in the field

Allergic asthma is a prominent disease especially during childhood. Indoor allergens, in general, and particularly house dust mites (HDM) are the most prevalent sensitizers associated with allergic asthma. Available data show that 65-130 million people are mite-sensitized world-wide and as many as 50% of these are asthmatic. In fact, sensitization to HDM in the first years of life can produce devastating effects on pulmonary function leading to asthmatic syndromes that can be fatal. To date, there has been considerable research into the pathological pathways and structural changes associated with allergic asthma. However, limitations related to the disease heterogeneity and a lack of knowledge into its pathophysiology have impeded the generation of valuable data needed to appropriately phenotype patients and, subsequently, treat this disease. Here, we report a systematic and integral analysis of the disease, from airway remodelling to the immune response taking place throughout the disease stages. We present an overview of metabolomics, the management of complex multifactorial diseases through the analysis of all possible metabolites in a biological sample, obtaining a global interpretation of biological systems. Special interest is placed on the challenges to obtain biological samples and the methodological aspects to acquire relevant information, focusing on the identification of novel biomarkers associated with specific phenotypes of allergic asthma. We also present an overview of the metabolites cited in the literature, which have been related to inflammation and immune response in asthma and other allergy-related diseases.

Reactions of Buckwheat-Hypersensitive Patients during Oral Food Challenge Are Rare, but Often Anaphylactic

BACKGROUND

Buckwheat (BW) is a common cause of life-threatening allergy in Asia. Few have examined oral food challenges (OFCs) using BW. We here describe the OFC outcomes for the diagnosis or confirmation of tolerance acquisition and clarify risk factors for positive OFCs.

METHODS

Between July 2005 and March 2014, we retrospectively reviewed data from children who underwent OFCs using 3,072 mg of BW protein at Sagamihara National Hospital. Children were suspected of having BW allergy because of positive results for BW-specific IgE or because they had been previously diagnosed with BW allergy owing to immediate reactions to BW.

RESULTS

Of 476 such patients, we analyzed 419 aged 1-17 years (median age 6.7 years). Forty-four (10.5%) reacted to the BW OFC and 24 (54.5%) experienced anaphylaxis. Among patients with suspected BW allergies (n = 369), 30 (8.1%) reacted to OFC. However, among patients with definitive BW allergies (n = 50) who underwent OFCs a median of 7.0 years after their last immediate reaction, 14 (28.0%) reacted to OFC. Among 12 patients with past anaphylactic reactions to BW, 8 exhibited tolerance to BW. A history of immediate reaction to BW and high BW-specific IgE levels were significant risk factors for a positive OFC.

CONCLUSIONS

BW allergies are rare among children suspected of having BW allergies due to positivity for BW-specific IgE. Most children with definitive BW allergies can tolerate BW, even after anaphylactic reactions. Nevertheless, careful observation is needed when performing BW OFCs, considering the high incidence of anaphylactic reactions.