Immunologic influences on allergy and the TH1/TH2 balance

Oat β-(1 → 3, 1 → 4)-d-glucan alleviates food allergy-induced colonic injury in mice by increasing Lachnospiraceae abundance and butyrate production

Oat β-(1 → 3, 1 → 4)-d-glucan (OBG), a linear polysaccharide primarily found in oat bran, has been demonstrated to possess immunomodulatory properties and regulate gut microbiota. This study aimed to investigate the impact of low molecular weight (Mw) OBG (155.2 kDa) on colonic injury and allergic symptoms induced by food allergy (FA), and to explore its potential mechanism. In Experiment 1, results indicated that oral OBG improved colonic inflammation and epithelial barrier, and significantly relieved allergy symptoms. Importantly, the OBG supplement altered the gut microbiota composition, particularly increasing the abundance of Lachnospiraceae and its genera, and promoted the production of short-chain fatty acids, especially butyrate. However, in Experiment 2, the gut microbial depletion eliminated these protective effects of OBG on the colon in allergic mice. Further, in Experiment 3, fecal microbiota transplantation and sterile fecal filtrate transfer directly validated the role of OBG-mediated gut microbiota and its metabolites in relieving FA and its induced colonic injury. Our findings suggest that low Mw OBG can alleviate FA-induced colonic damage by increasing Lachnospiraceae abundance and butyrate production, and provide novel insights into the health benefits and mechanisms of dietary polysaccharide intervention for FA.

Impact of antigen loading in tolerogenic nanoparticles to mitigate Th2-mediated allergic lung inflammation

Allergic disease is a major global health concern that imposes significant life-altering and economic burdens on affected individuals. However, there is still no cure. Polymer-based nanoparticles (NP) have shown the potential to induce antigen (Ag)-specific immune tolerance in various Th1/17 and Th2-mediated immune disorders including autoimmunity and allergy. Common methods by which Ags are associated with NPs are through surface conjugation or encapsulation. However, these Ag delivery strategies can be associated with several caveats that dampen their effectiveness such as uncontrolled Ag loading, a high Ag burst release, and an increased immune recognition profile. We previously developed Ag-polymer conjugate NPs (acNPs) to overcome those noted limitations, while allowing for controlled delivery of precise quantities of Ag to innate immune cells for Ag-specific CD4 T cell modulation. Here, we utilized ovalbumin (OVA) protein-poly(lactic-co-glycolic acid) (PLGA) conjugate NPs (acNP-OVA) to elucidate the impact of Ag loading on the induction of Th2 tolerance using a prophylactic and therapeutic OVA/ALUM-induced mouse model of allergic lung inflammation (ALI) in comparison to Ag-encapsulated PLGA NPs (NP(Ag)). We demonstrate that acNP-OVA formulations reduced OVA-specific IgE and inhibited Th2 cytokine secretions in an Ag loading-dependent manner when administered prophylactically. Administration of acNP-OVA to pre-sensitized mice did not affect OVA-specific IgE and Th2 cytokines tended to be reduced, however, there was no clear Ag loading dependency. acNP-OVA with medium-to-low Ag loadings were well tolerated, while formulations with high Ag loadings, including NP(Ag) resulted in anaphylaxis. Overall, our results clarify the relationship between Ag loading and Ag-specific IgE and Th2 cytokine responses in a murine model of ALI, which provides insight useful for future design of tolerogenic NP-based immunotherapies.

The Skin Histopathology of Pro- and Parabiotics in a Mouse Model of Atopic Dermatitis

As it has been revealed that the activation of human immune cells through the activity of intestinal microorganisms such as pro- and prebiotics plays a vital role, controlling the proliferation of beneficial bacteria and suppressing harmful bacteria in the intestine has become essential. The importance of probiotics, especially for skin health and the immune system, has led to the emergence of products in various forms, including probiotics, prebiotics, and parabiotics. In particular, atopic dermatitis (AD) produces hypersensitive immunosuppressive substances by promoting the differentiation and activity of immune regulatory T cells. As a result, it has been in the Th1 and Th2 immune balance through a mechanism that suppresses skin inflammation or allergic immune responses caused by bacteria. Furthermore, an immune mechanism has recently emerged that simultaneously controls the expression of IL-17 produced by Th17. Therefore, the anti-atopic effect was investigated by administering doses of anti-atopic candidate substances (Lactobacilus sakei CVL-001, Lactobacilus casei MCL, and Lactobacilus sakei CVL-001 Lactobacilus casei MCL mixed at a ratio of 4:3) in an atopy model using 2,4-dinitrochlorobenzene and observing symptom changes for 2 weeks to confirm the effect of pro-, para-, and mixed biotics on AD. First, the body weight and feed intake of the experimental animals were investigated, and total IgG and IgM were confirmed through blood biochemical tests. Afterward, histopathological staining was performed using H&E staining, Toluidine blue staining, Filaggrin staining, and CD8 antibody staining. In the treatment group, the hyperproliferation of the epidermal layer, the inflammatory cell infiltration of the dermal layer, the expression of CD8, the expression of filaggrin, and the secretion of mast cells were confirmed to be significantly reduced. Lastly, small intestine villi were observed through a scanning microscope, and scoring evaluation was performed through skin damage. Through these results, it was confirmed that AD was reduced when treated with pro-, para-, and mixed biotics containing probiotics and parabiotics.

Augmented type 2 inflammatory response in allergic rhinitis patients experiencing systemic reactions to house dust mite subcutaneous immunotherapy

BACKGROUND

Subcutaneous immunotherapy (SCIT) can induce systemic reactions (SRs) in certain patients, but the underlying mechanisms remain to be fully elucidated.

METHODS

AR patients who were undergoing standardized HDM SCIT (Alutard, ALK) between 2018 and 2022 were screened. Those who experienced two consecutive SRs were included in the study group. A control group was established, matched 1:1 by gender, age, and disease duration with the study group, who did not experience SRs during SCIT. Clinical and immunological parameters were recorded and analyzed both before SCIT and after 1 year of treatment.

RESULTS

A total of 161 patients were included, with 79 (49.07%) in the study group. The study group had a higher proportion of AR combined asthma (26.8% vs. 51.8%, p < 0.001) and higher levels of sIgE to HDM and HDM components (all p < .001). Serum IL-4 and IL-13 levels in the study group were higher than those in the control group (p < .05). The study group received a lower maintenance dosage of HDM extracts injections than control group due to SRs (50000SQ vs. 100000SQ, p < .05). After 1 year of SCIT, the VAS score, the lung function parameters of asthmatic patients over 14 years old significantly improved in both groups (all p < .05). After a 7-day exposure to 20 μg/mL HDM extracts, the percentages of Th1, Th17, Tfh10, and Th17.1 in PBMCs decreased, while the Tfh13 cells significantly increased in the study group (p < .05).

CONCLUSION

The type 2 inflammatory response is augmented in HDM-induced AR patients who experienced SRs during SCIT. Despite this, SCIT remains effective in these patients when administered with low-dosage allergen extracts.

AllergoOncology: Biomarkers and refined classification for research in the allergy and glioma nexus-A joint EAACI-EANO position paper

Epidemiological studies have explored the relationship between allergic diseases and cancer risk or prognosis in AllergoOncology. Some studies suggest an inverse association, but uncertainties remain, including in IgE-mediated diseases and glioma. Allergic disease stems from a Th2-biased immune response to allergens in predisposed atopic individuals. Allergic disorders vary in phenotype, genotype and endotype, affecting their pathophysiology. Beyond clinical manifestation and commonly used clinical markers, there is ongoing research to identify novel biomarkers for allergy diagnosis, monitoring, severity assessment and treatment. Gliomas, the most common and diverse brain tumours, have in parallel undergone changes in classification over time, with specific molecular biomarkers defining glioma subtypes. Gliomas exhibit a complex tumour-immune interphase and distinct immune microenvironment features. Immunotherapy and targeted therapy hold promise for primary brain tumour treatment, but require more specific and effective approaches. Animal studies indicate allergic airway inflammation may delay glioma progression. This collaborative European Academy of Allergy and Clinical Immunology (EAACI) and European Association of Neuro-Oncology (EANO) Position Paper summarizes recent advances and emerging biomarkers for refined allergy and adult-type diffuse glioma classification to inform future epidemiological and clinical studies. Future research is needed to enhance our understanding of immune-glioma interactions to ultimately improve patient prognosis and survival.

The role of immune cells and inflammation in pulmonary hypertension: mechanisms and implications

Pulmonary hypertension (PH) is a malignant disease with progressive increase of pulmonary vascular pressure, which eventually leads to right heart failure. More and more evidences show that immune cells and inflammation play an important role in the occurrence and development of PH. In the context of pulmonary vascular diseases, immune cells migrate into the walls of the pulmonary vascular system. This leads to an increase in the levels of cytokines and chemokines in both the bloodstream and the surrounding tissues of the pulmonary vessels. As a result, new approaches such as immunotherapy and anti-inflammatory treatments are being considered as potential strategies to halt or potentially reverse the progression of PH. We reviewed the potential mechanisms of immune cells, cytokines and chemokines in PH development. The potential relationship of vascular cells or bone morphogenetic protein receptor 2 (BMPR2) in immune regulation was also expounded. The clinical application and future prospect of immunotherapy were further discussed.

Sea Buckthorn Flavonoid Extracted by High Hydrostatic Pressure Inhibited IgE-Stimulated Mast Cell Activation through the Mitogen-Activated Protein Kinase Signaling Pathway

Sea buckthorn (Hippophaë rhamnoides L.), as one of the Elaeagnaceae family, has the significant function of anti-tumor, anti-inflammation, anti-oxidation, and other physiological activities. High hydrostatic pressure (HHP) extraction has the advantages of being easy and efficient, while maintaining biological activity. In this study, sea buckthorn flavonoid (SBF) was extracted with HHP and purified sea buckthorn flavonoid (PSBF) was isolated by AB-8 macroporous resin column. HPLC analysis was used to quantified them. In addition, the effect of anti-allergy in RBL-2H3 cells by SBF, PSBF, and their flavonoid compounds was evaluated. The results demonstrate the conditions for obtaining the maximum flavonoid amount of SBF: 415 MPa for 10 min, 72% ethanol concentration, and a liquid to solid ratio of 40 mL/g, which increased the purity from 1.46% to 13.26%. Both SBF and PSBF included rutin, quercitrin, quercetin, isorhamnetin, and kaempferol. In addition, quercitrin, kaempferol, and SBF could regulate Th1/Th2 cytokine balance. Moreover, extracellular Ca2+ influx was reduced by quercitrin and PSBF. Furthermore, rutin, quercetin, iso-rhamnetin, and SBF could also inhibit P-p38 and P-JNK expression, thereby suppressing the phosphorylation of the MAPK signaling pathways. Overall, SBF is effective for relieving food allergy and might be a promising anti-allergic therapeutic agent.

Sustained silencing peanut allergy by xanthopurpurin is associated with suppression of peripheral and bone marrow IgE-producing B cell

Introduction

Peanut allergy is an immunoglobulin E (IgE) mediated food allergy. Rubia cordifolia L. (R. cordifolia), a Chinese herbal medicine, protects against peanut-induced anaphylaxis by suppressing IgE production in vivo. This study aims to identify IgE-inhibitory compounds from the water extract of R. cordifolia and investigate the underlying mechanisms using in vitro and in vivo models.

Methods

Compounds were isolated from R. cordifolia water extract and their bioactivity on IgE production was assessed using a human myeloma U266 cell line. The purified active compound, xanthopurpurin (XPP), was identified by LC-MS and NMR. Peanut-allergic C3H/HeJ mice were orally administered with or without XPP at 200µg or 400µg per mouse per day for 4 weeks. Serum peanut-specific IgE levels, symptom scores, body temperatures, and plasma histamine levels were measured at challenge. Cytokines in splenocyte cultures were determined by ELISA, and IgE + B cells were analyzed by flow cytometry. Acute and sub-chronic toxicity were evaluated. IL-4 promoter DNA methylation, RNA-Seq, and qPCR analysis were performed to determine the regulatory mechanisms of XPP.

Results

XPP significantly and dose-dependently suppressed the IgE production in U266 cells. XPP significantly reduced peanut-specific IgE (>80%, p <0.01), and plasma histamine levels and protected the mice against peanut-allergic reactions in both early and late treatment experiments (p < 0.05, n=9). XPP showed a strong protective effect even 5 weeks after discontinuing the treatment. XPP significantly reduced the IL-4 level without affecting IgG or IgA and IFN-γ production. Flow cytometry data showed that XPP reduced peripheral and bone marrow IgE + B cells compared to the untreated group. XPP increased IL-4 promoter methylation. RNA-Seq and RT-PCR experiments revealed that XPP regulated the gene expression of CCND1, DUSP4, SDC1, ETS1, PTPRC, and IL6R, which are related to plasma cell IgE production. All safety testing results were in the normal range.

Conclusions

XPP successfully protected peanut-allergic mice against peanut anaphylaxis by suppressing IgE production. XPP suppresses murine IgE-producing B cell numbers and inhibits IgE production and associated genes in human plasma cells. XPP may be a potential therapy for IgE-mediated food allergy.

Mixed connective tissue disease-myositis overlap syndrome presenting as an allergic disease process to the emergency department: A case report

BACKGROUND

The "allergy epidemic" of the Western World, has led to an overwhelming number of emergency department presentations with allergic rhinitis, allergic conjunctivitis, atopic eczema, and asthma. Careful consideration should be given to screening for the typical signs and symptoms of Mixed connective tissue disease (MCTD) in patients presenting to the ED with what appears to be a simple allergic process. MCTD is a rare systemic rheumatic disease characterized by high levels of anti-U1RNP antibodies and various clinical signs and symptoms. The pathophysiology of MCTD is poorly understood. An association between allergen-mediated processes and MCTD has been reported in recent literature. Our case report involves a 40 year old African American female with initial outpatient presentation suggestive of atopic disease, with progressive worsening of symptoms while receiving allergen immunotherapy. The patient presented to the emergency department with bilateral leg cramping. The patient was found to have a CPK of 7000 unresponsive to fluids. The patient was evaluated by the Allergy and Rheumatology services. The patient was ultimately diagnosed with MCTD-Myositis Overlap Syndrome and started on steroids and IVIG with improvement in symptoms. While MCTD is not a diagnosis readily made in the ED, early identification and treatment of the disease is critical for prevention of long term complications.

Impact of chemical mixtures from wastewater treatment plant effluents on human immune cell activation: An effect-based analysis

BACKGROUND

Humans are exposed to many different chemicals on a daily basis, mostly as chemical mixtures, usually from food, consumer products and the environment. Wastewater treatment plant effluent contains mixtures of chemicals that have been discarded or excreted by humans and not removed by water treatment. These effluents contribute directly to water pollution, they are used in agriculture and may affect human health. The possible effect of such chemical mixtures on the immune system has not been characterized.

OBJECTIVE

The aim of this study was to investigate the effect of extracts obtained from four European wastewater treatment plant effluents on human primary immune cell activation.

METHODS

Immune cells were exposed to the effluent extracts and modulation of cell activation was performed by multi-parameter flow cytometry. Messenger-RNA (mRNA) expression of genes related to immune system and hormone receptors was measured by RT-PCR.

RESULTS

The exposure of immune cells to these extracts, containing 339 detected chemicals, significantly reduced the activation of human lymphocytes, mainly affecting T helper and mucosal-associated invariant T cells. In addition, basophil activation was also altered upon mixture exposure. Concerning mRNA expression, we observed that 12 transcripts were down-regulated by at least one extract while 11 were up-regulated. Correlation analyses between the analyzed immune parameters and the concentration of chemicals in the WWTP extracts, highlighted the most immunomodulatory chemicals.

DISCUSSION

Our results suggest that the mixture of chemicals present in the effluents of wastewater treatment plants could be considered as immunosuppressive, due to their ability to interfere with the activation of immune cells, a process of utmost importance for the functionality of the immune system. The combined approach of immune effect-based analysis and chemical content analysis used in our study provides a useful tool for investigating the effect of environmental mixtures on the human immune response.

T-cell subset changes during the first year of pre-seasonal allergoid allergen-specific immunotherapy

Allergen-specific immunotherapy (AIT) is the only treatment for type I allergy, which achieves long-lasting effects. Repeated subcutaneous applications of allergen extracts cause a protective antibody response and an immune deviation of T cells. In AIT with allergoids, chemically modified allergen extracts are injected. During a so-called special pre-seasonal application scheme, after the initial phase of applying increased doses of allergoids is followed by natural allergen exposure as a maintenance phase. The effectiveness of allergoid vaccines has been described regarding the improvement of clinical symptoms and the development of protective humoral responses. In this longitudinal observational study, we sought to investigate changes at the T cell level in pre-seasonal AIT with allergoid. Different subsets within CD4+ and CD8+ T cells were monitored by flow cytometry in PBMC of patients known to possess protective antibody responses. Compared to before treatment, a small early boost among allergenic Th cells was observed after 4 months of AIT. In line, a slight Th2 bias was observed after 4 months within circulating T follicular T cells, Tfh and Tfc, representing pre-existing memory Th2 cells. Furthermore, it was demonstrated that responsiveness of CD8+ T cells to allergen stimulation decreased during the course of treatment. Apart from that, we found an influence of the meteorological season on the activation profile of Tfh and Tfc over the course of the treatment. Together, this is the first study investigating changes of different T cell subsets over the course of an allergoid AIT against airborne allergens. Our findings match previous reports on conventional AIT, especially the initial increase of Th2 responses. However, the observed changes were less pronounced which may be either due to the modification of allergens or to the reduced maintenance dose provided by natural allergen exposure compared to a perennial protocol.

Modulation of soy protein immunoreactivity by different matrix structures of lactic acid bacterium-induced soy protein gels: Epitope destruction during in vitro gastroduodenal digestion and absorption

Soy allergy is a common health problem. Food structure may change the gastroduodenal digestion and absorption of soy proteins, thus leading to the modulation of the immunoreactivity of soy proteins. In this study, lactic acid bacterium (LAB)-fermented soy protein isolates (FSPIs) were prepared at four concentrations (0.2 %-5.0 %, w/v) to present various matrix structures (nongel, NG; weak gel, WG; medium gel, MG; and firm gel, FG) and subjected to in vitro dynamic gastroduodenal digestion model. The results of sandwich enzyme-linked immunosorbent and human serum IgE binding capacity assays demonstrated that FSPI gels, especially the FSPI-MG/WG digestates obtained at the early and medium stages of duodenal digestion (D-5 and D-30), possessed greater potency in immunoreactivity reduction than FSPI-NG and reduced to 1.9 %-68.3 %. The transepithelial transport study revealed that the immunoreactivity of FSPI-MG/WG D-5 and D-30 digestates decreased through the stimulation of interferon-γ production and the induction of dominant Th1/Th2 differentiation. Peptidomics and bioinformatics analyses illustrated that compared with FSPI-NG, the FSPI-gel structure promoted the epitope degradation of the major allergens glycinin G2/G5, β-conglycinin α/β subunit, P34, lectin, trypsin inhibitor, and basic 7S globulin. Spatial structure analysis showed that FSPI-gel elicited an overall promotion in the degradation of allergen epitopes located in interior and exterior regions and was dominated by α-helix and β-sheet secondary structures, whereas FSPI-MG/WG promoted the degradation of epitopes located in the interior region of glycinin/β-conglycinin and exterior region of P34/basic 7S globulin. This study suggested that the FSPI-gel structure is a promising food matrix for decreasing the allergenic potential of allergenic epitopes during gastroduodenal digestion and provided basic information on the production of hypoallergenic soy products.

Genetic Predisposition to SARS-CoV-2 Infection: Cytokine Polymorphism and Disease Transmission within Households

We addressed the question of the influence of the molecular polymorphism of cytokines from different T helper subsets on the susceptibility to SARS-CoV-2 infection. From a cohort of 527 samples (collected from 26 May 2020 to 31 March 2022), we focused on individuals living in the same household (n = 58) with the SARS-CoV-2-infected person. We divided them into households with all individuals SARS-CoV-2 PCR positive (n = 29, households, 61 individuals), households with mixed PCR pattern (n = 24, 62) and negative households (n = 5, 15), respectively. TGF-β1 and IL-6 were the only cytokines tested with a significant difference between the cohorts. We observed a shift toward Th2 and the regulatory Th17 and Treg subset regulation for households with all members infected compared to those without infection. These data indicate that the genetically determined balance between the cytokines acting on different T helper cell subsets may play a pivotal role in transmission of and susceptibility to SARS-CoV-2 infection. Contacts infected by their index persons were more likely to highly express TGF-β1, indicating a reduced inflammatory response. Those not infected after contact had a polymorphism leading to a higher IL-6 expression. IL-6 acts in innate immunity, allergy and on the T helper cell differentiation, explaining the reduced susceptibility to SARS-CoV-2.

The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between Polish infants with the food allergy and/or atopic dermatitis and without the disease

Objectives

Epigenetic dynamics has been indicated to play a role in allergy development. The environmental stimuli have been shown to influence the methylation processes. This study investigated the differences in CpGs methylation rate of immune-attached genes between healthy and allergic infants. The research was aimed at finding evidence for the impact of environmental factors on methylation-based regulation of immunological processes in early childhood.

Methods

The analysis of methylation level of CpGs in the IL4, IL5, IL10, IFNG and FOXP3 genes was performed using high resolution melt real time PCR technology. DNA was isolated from whole blood of Polish healthy and allergic infants, with food allergy and/or atopic dermatitis, aged under six months.

Results

The significantly lower methylation level of FOXP3 among allergic infants compared to healthy ones was reported. Additional differences in methylation rates were found, when combining with environmental factors. In different studied groups, negative correlations between age and the IL10 and FOXP3 methylation were detected, and positive - in the case of IL4. Among infants with different allergy symptoms, the decrease in methylation level of IFNG, IL10, IL4 and FOXP3 associated with passive smoke exposure was observed. Complications during pregnancy were linked to different pattern of the IFNG, IL5, IL4 and IL10 methylation depending on allergy status. The IFNG and IL5 methylation rates were higher among exclusively breastfed infants with atopic dermatitis compared to the non-breastfed. A decrease in the IFNG methylation was noted among allergic patients fed exclusively with milk formula. In different study groups, a negative correlation between IFNG, IL5 methylation and maternal BMI or IL5 methylation and weight was noted. Some positive correlations between methylation rate of IL10 and child's weight were found. A higher methylation of IL4 was positively correlated with the number of family members with allergy.

Conclusion

The FOXP3 methylation in allergic infants was lower than in the healthy ones. The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between the studied groups. The results offer insights into epigenetic regulation of immunological response in early childhood.

Evaluation of the Impact of BaP Exposure on the Gut Microbiota and Allergic Responses in an OVA-Sensitized Mouse Model

BACKGROUND

Exposure to environmental pollutants, including benzo[a]pyrene (BaP), has been implicated in allergic diseases and intestinal microbiota homeostasis, but the environment-microbiota-immunity triangular relationship and to what extent BaP-induced remodeling of the gut microbiota contributes to intestinal allergic inflammation remain to be established.

OBJECTIVES

We investigated the impact of BaP on intestinal allergic inflammation and examined the relationship between this effect and gut microbiota dysbiosis. We explored the potential ability of intestinal bacteria to degrade BaP and alleviate cytotoxicity as a detoxification strategy to counteract the effects of BaP exposure.

METHODS

We combined microbiome shotgun metagenomics with animal histological and intestinal allergic inflammatory responses to assess the effects of BaP (50μg/mouse per day) in a 23-d toxicity test in antigen-induced allergic female mice. In addition, genome annotation, quantitative analysis of BaP, and in vitro cytotoxicity-tests using CaCo-2 cells were conducted to infer the role of intestinal bacteria in BaP detoxification.

RESULTS

BaP exposure impacted the taxonomic composition and the functional potential of the gut microbiota and aggravated antigen-induced intestinal allergic inflammatory responses. The level of inflammatory cytokines correlated with the abundance of specific bacterial taxa, including Lachnospiraceae bacterium 28-4 and Alistipes inops. We identified 614 bacteria harboring genes implicated in the degradation of BaP, and 4 of these bacterial strains were shown to significantly reduce the cytotoxicity of BaP to CaCo-2 cells in vitro.

DISCUSSION

Using allergic female mice as a model, we investigated the relationship between BaP, microbiota, and host immune reactions, highlighting the role of gut bacteria in BaP-aggravated allergic reactions. Our findings offer novel insight toward establishing the causal relationship between BaP exposure and the occurrence of allergic disorders. Identifying gut bacteria that degrade BaP may provide new strategies for ameliorating BaP cytotoxicity. https://doi.org/10.1289/EHP11874.

Mast cell ontogeny: From fetal development to life-long health and disease

Mast cells (MCs) are evolutionarily ancient innate immune cells with important roles in protective immunity against bacteria, parasites, and venomous animals. They can be found in most organs of the body, where they also contribute to normal tissue functioning, for example by engaging in crosstalk with nerves. Despite this, they are most widely known for their detrimental roles in allergy, anaphylaxis, and atopic disease. Just like macrophages, mast cells were conventionally thought to originate from the bone marrow. However, they are already present in fetal tissues before the onset of bone marrow hematopoiesis, questioning this dogma. In recent years, our view of myeloid cell ontogeny has been revised. We now know that the first mast cells originate from progenitors made in the extra-embryonic yolk sac, and later get supplemented with mast cells produced from subsequent waves of hematopoiesis. In most connective tissues, sizeable populations of fetal-derived mast cells persist into adulthood, where they self-maintain largely independently from the bone marrow. These developmental origins are highly reminiscent of macrophages, which are known to have critical functions in development. Mast cells too may thus support healthy development. Their fetal origins and longevity also make mast cells susceptible to genetic and environmental perturbations, which may render them pathological. Here, we review our current understanding of mast cell biology from a developmental perspective. We first summarize how mast cell populations are established from distinct hematopoietic progenitor waves, and how they are subsequently maintained throughout life. We then discuss what functions mast cells may normally have at early life stages, and how they may be co-opted to cause, worsen, or increase susceptibility to disease.

What Have Mechanistic Studies Taught Us About Childhood Asthma?

Childhood asthma is a chronic heterogeneous syndrome consisting of different disease entities or phenotypes. The immunologic and cellular processes that occur during asthma development are still not fully understood but represent distinct endotypes. Mechanistic studies have examined the role of gene expression, protein levels, and cell types in early life development and the manifestation of asthma, many under the influence of environmental stimuli, which can be both protective and risk factors for asthma. Genetic variants can regulate gene expression, controlled partly by different epigenetic mechanisms. In addition, environmental factors, such as living space, nutrition, and smoking, can contribute to these mechanisms. All of these factors produce modifications in gene expression that can alter the development and function of immune and epithelial cells and subsequently different trajectories of childhood asthma. These early changes in a partially immature immune system can have dramatic effects (e.g., causing dysregulation), which in turn contribute to different disease endotypes and may help to explain differential responsiveness to asthma treatment. In this review, we summarize published studies that have aimed to uncover distinct mechanisms in childhood asthma, considering genetics, epigenetics, and environment. Moreover, a discussion of new, powerful tools for single-cell immunologic assays for phenotypic and functional analysis is included, which promise new mechanistic insights into childhood asthma development and therapeutic and preventive strategies.

Avenanthramide Improves Colonic Damage Induced by Food Allergies in Mice through Altering Gut Microbiota and Regulating Hsp70-NF-κB Signaling

Food allergies can cause intestinal damage that can exacerbate allergic symptoms, and gut microbiota have been shown to influence allergic development. This study was intended to investigate the effects of Avenanthramide (AVA) on colonic damage induced by food allergy and its mechanism. In Exp. 1, AVA administrations alleviated colonic inflammation in mice challenged with ovalbumin, as shown by decreased concentrations of TNF-α, IL-25 and IL-33. Additionally, the AVA supplementations improved intestinal barrier damage by elevating occludin, ZO-1 and claudin-1 levels. Moreover, AVA inhibited NF-κB phosphorylation and enhanced heat shock protein 70 (Hsp70) expression in the colon. In Exp. 2, apoptozole as a Hsp70 inhibitor was used to explore the Hsp70-NF-κB signaling contribution to AVA function. The AVA additions increased the productions of acetate and butyrate, but decreased propionate. Notably, AVA reduced the colonic abundance of propionate-producing microbes such as Muribaculaceae, but elevated butyrate-producing microbes including Roseburia, Blautia, and Lachnospiraceae_NK4A136_group. Microbial alteration could be responsible for the increased butyrate, and thus the up-regulated Hsp70. However, apoptozole treatment eliminated the effects of AVA. Our study revealed that AVA improved colonic injury and inflammation induced by food allergies, and this mechanism may be mediated by the increased microbial-derived butyrate and involved in the Hsp70-NF-κB signaling.

Relationship between serum Th1/Th2 imbalance and depression in elderly patients with COPD and its clinical implications

BACKGROUND

Chronic obstructive pulmonary disease (COPD) causes organic damage as well as anxiety, depression, fear, and other psychological disorders, which seriously affect the quality of life and prognosis of patients and cause a huge economic burden to the family and society.

OBJECTIVE

The aim of this study was to investigate the correlation between an imbalance of serum Th1/Th2 indicators and psychiatric depression in elderly patients with COPD and analyze its implications for clinical management.

METHODS

From January 2018 to May 2022, 120 elderly patients with COPD treated at our hospital were categorized into two groups based on the self-rating depression scale (SDS): COPD with depression (SDS score ⩾ 50) and COPD alone (SDS score < 50). Blood gas analysis, pulmonary function, and serum Th1/Th2 index were determined. Receiver operating characteristic (ROC) curves were analyzed to explore the diagnostic value of serum Th1/Th2 ratios for COPD complicated by depression.

RESULTS

Compared with the group without depression, the partial pressure of carbon dioxide and COPD assessment test scores were significantly higher, and the oxygenation index, forced expiratory volume in one second (FEV1), and percent predicted FEV1 were significantly lower in the COPD with depression group (P< 0.05). Interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, and tumor necrosis factor-α (TNF-α) were significantly higher in the COPD with depression group than in the group without depression (P< 0.05). Logistic regression analysis indicated that the imbalance of serum IL-1β, IL-2, IL-6, IL-8, IL-10, and TNF-α was a risk factor for mental depression in elderly patients with COPD. When comparing prognostic indices, the interval before the first onset of clinically noticeable deterioration (CID-C) in the COPD with depression group was noticeably shorter than that in the COPD without depression group; the incidence of CID-C within 6 months was noticeably higher in the COPD with depression group than in the group without depression.

CONCLUSION

Elderly patients with COPD and depression had reduced pulmonary function and higher serum Th1/Th2 levels, and an imbalance in serum Th1/Th2 indicators was a potential risk factor for depression. Moreover, elderly patients with COPD and depression were at a higher risk of disease progression and had a worse prognosis. Thus, an imbalance in serum Th1/Th2 indicators is a potential prognostic factor for evaluating depression in patients with COPD.

Immunomodulatory effects of two recombinant arginine kinases in Sarcoptes Scabiei on host peripheral blood mononuclear cells

Background

As an important zoonotic parasitic disease with global distribution, scabies causes serious public health and economic problems. Arginine kinase (AK) is involved in cell signal transduction, inflammation, and apoptosis. Two AKs were identified in Sarcoptes scabiei, but their functions in the host immune response remain unclear.

Methods

rSsAK-1 and rSsAK-2 were expressed, purified, and immunolocalized. The effects of rSsAK-1 and rSsAK-2 on rabbit PBMC proliferation, apoptosis, and migration; Bcl-2, Bcl-xl, Fas, Bax, and NF-κB transcription levels; and IL-2, IFN-γ, IL-4, IL-10, TGF-β1, and IL-17 secretion were detected.

Results

rSsAK-1 and rSsAK-2 were cloned and expressed successfully. Both enzymes were ~57 kDa and contained 17-kDa tagged proteins, and had good catalytic activity and immunoreactivity. The proteins were located in the S. scabiei exoskeleton, chewing mouthparts, legs, stomach, and intestine. SsAK-1 and SsAK-2 were secreted in the pool and epidermis of the skin lesions, which may be involved in S. scabiei–host interaction. rSsAK-1 and rSsAK-2 significantly promoted cell proliferation, induced cell migration, inhibited apoptosis, and increased Bcl-2, Bcl-xl and NF-κB (p65) transcription levels concentration-dependently, and inhibited IL-2, IFN-γ, and IL-10 secretion and promoted IL-4 and IL-17 secretion.

Conclusion

rSsAK-1 and rSsAK-2 might increase Bcl-2 and Bcl-xl expression by activating the NF-κB signaling pathway to promote cell proliferation and inhibit apoptosis, which induced PBMC survival. By inducing PBMC migration to the infection site, rSsAK-1 and rSsAK-2 shifted the Th1/Th2 balance toward Th2 and changed the Th17/Treg balance, which indicated their immune role in S. scabiei allergic inflammation.

Treating allergies via skin - Recent advances in cutaneous allergen immunotherapy

Subcutaneous allergen immunotherapy has been practiced clinically for decades to treat airborne allergies. Recently, the cutaneous route, which exploits the immunocompetence of the skin has received attention, which is evident from attempts to use it to treat peanut allergy. Delivery of allergens into the skin is inherently impeded by the barrier imposed by stratum corneum, the top layer of the skin. While the stratum corneum barrier must be overcome for efficient allergen delivery, excessive disruption of this layer can predispose to development of allergic inflammation. Thus, the most desirable allergen delivery approach must provide a balance between the level of skin disruption and the amount of allergen delivered. Such an approach should aim to achieve high allergen delivery efficiency across various skin types independent of age and ethnicity, and optimize variables such as safety profile, allergen dosage, treatment frequency, application time and patient compliance. The ability to precisely quantify the amount of allergen being delivered into the skin is crucial since it can allow for allergen dose optimization and can promote consistency and reproducibility in treatment response. In this work we review prominent cutaneous delivery approaches, and offer a perspective on further improvisation in cutaneous allergen-specific immunotherapy.

Allergic Inflammation: Effect of Propolis and Its Flavonoids

The incidence of allergic diseases and their complications are increasing worldwide. Today, people increasingly use natural products, which has been termed a "return to nature". Natural products with healing properties, especially those obtained from plants and bees, have been used in the prevention and treatment of numerous chronic diseases, including allergy and/or inflammation. Propolis is a multi-component resin rich in flavonoids, collected and transformed by honeybees from buds and plant wounds for the construction and adaptation of their nests. This article describes the current views regarding the possible mechanisms and multiple benefits of flavonoids in combating allergy and allergy-related complications. These benefits arise from flavonoid anti-allergic, anti-inflammatory, antioxidative, and wound healing activities and their effects on microbe-immune system interactions in developing host responses to different allergens. Finally, this article presents various aspects of allergy pathobiology and possible molecular approaches in their treatment. Possible mechanisms regarding the antiallergic action of propolis on the microbiota of the digestive and respiratory tracts and skin diseases as a method to selectively remove allergenic molecules by the process of bacterial biotransformation are also reported.

Therapeutic potency of curcumin for allergic diseases: A focus on immunomodulatory actions

In light of increasing research evidence on the molecular mechanisms of allergic diseases, the crucial roles of innate and acquired immunity in the disease's pathogenesis have been well highlighted. In this respect, much attention has been paid to the modulation of unregulated and unabated inflammatory responses aiming to suppress pathologic immune responses in treating allergic diseases. One of the most important natural compounds with a high potency of immune modulation is curcumin, an active polyphenol compound derived from turmeric, Curcuma longa L. Curcumin's immunomodulatory action mainly arises from its interactions with an extensive collection of immune cells such as mast cells, eosinophils, epithelial cells, basophils, neutrophils, and lymphocytes. Up to now, there has been no detailed investigation of curcumin's immunomodulatory actions in allergic diseases. So, the present review study aims to prepare an overview of the immunomodulatory effects of curcumin on the pathologic innate immune responses and dysregulated functions of T helper (T_H) subtypes, including T_H1, T_H2, T_H17, and regulator T cells (Tregs) by gathering evidence from several studies of In-vitro and In-vivo. As the second aim of the present review, we also discuss some novel strategies to overcome the limitation of curcumin in clinical use. Finally, this review also assesses the therapeutic potential of curcumin regarding its immunomodulatory actions in allergic diseases.

Anti-allergic function of the cell wall (DeinoWall) from Deinococcus radiodurans

Deinococcus radiodurans is an extremophile, well known to be extremely resistant to external stresses due to its unique physiological system and structure of cellular components. Although the proportion of D. radiodurans has been reported to be negatively correlated with atopic dermatitis, the exact function of D. radiodurans in allergic diseases and its precise mechanisms have not been studied. In the present study, we hypothesize that D. radiodurans or its cellular constituents play a critical role in the skin to prevent allergic inflammatory responses by modulating immunity. Heat-killed D. radiodurans inhibited the production of Th2 cytokines, such as IL-4 and IL-5, induced by ovalbumin (OVA) stimulation in splenocytes from OVA-sensitized mice. Among the cellular constituents of D. radiodurans, such as cell wall (DeinoWall), cell membrane (DeinoMem), and exopolysaccharide (DeinoPol), only DeinoWall inhibited the production of Th2 cytokines and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD), a Th2-predominant allergic disease in mice. Moreover, serum IgE levels and infiltration of mast cells into skin lesions, the markers of Th2 response induced by DNCB application, were significantly inhibited by treatment with DeinoWall. Remarkably, DeinoWall induced the maturation of bone marrow-derived dendritic cells (BMDCs) that promote Th1-biased immunity, which might balance Th1/Th2 and regulate allergic inflammatory responses. Collectively, these results suggest that DeinoWall acts as a major cellular constituent in the negative regulation of allergic inflammatory responses by D. radiodurans and might be a viable candidate for the treatment of allergic diseases.

Ameliorating the efficacy of galacto-oligosaccharides on ovalumin-induced allergic dermatitis symptoms in Balb/c mice by regulating Th2 immune response and the ecosystem of gut microbiota

In this study, we evaluated the effect of oral administration of galacto-oligosaccharide (GOS), famous biological molecules that are comprised of galactose and lactose, on ovalbumin (OVA)-induced allergic dermatitis. OVA-induced mice were divided into the OVA-administered group (OVA-C), promethazine hydrochloride-administered group (PC), and 100 and 200 mg kg^-1 GOS-administered groups (GL and GH, respectively). GOS administration significantly improved epidermal thickness and decreased CD4⁺ cell numbers. The concentrations of IgE, OVA-specific IgE, and inflammatory cytokines (IL-4, IL-5, and INF-γ) in GH group mice were significantly lower than those in OVA-C group mice. Firmicutes and Bacteroidetes were identified as the major phyla in the intestinal microbiota in mice, and the relative abundance of Deferribacteres was significantly lower in the GH group than in the OVA-C group. Deferribacteraceae and Mucispirillum species were significantly lower in the GH group than in the OVA-C group. The relative abundance of Muribaculum species was significantly lower, but those of Lachnospira and Lactococcus species were significantly higher in the GH group than in the OVA-C group. Our results suggest that the alleviation effect of GOS on allergic dermatitis induced by OVA sensitization was achieved by regulating hypersensitive immune responses by improving the intestinal microbial ecosystem.

Role of Respiratory Epithelial Cells in Allergic Diseases

The airway epithelium provides the first line of defense to the surrounding environment. However, dysfunctions of this physical barrier are frequently observed in allergic diseases, which are tightly connected with pro- or anti-inflammatory processes. When the epithelial cells are confronted with allergens or pathogens, specific response mechanisms are set in motion, which in homeostasis, lead to the elimination of the invaders and leave permanent traces on the respiratory epithelium. However, allergens can also cause damage in the sensitized organism, which can be ascribed to the excessive immune reactions. The tight interaction of epithelial cells of the upper and lower airways with local and systemic immune cells can leave an imprint that may mirror the pathophysiology. The interaction with effector T cells, along with the macrophages, play an important role in this response, as reflected in the gene expression profiles (transcriptomes) of the epithelial cells, as well as in the secretory pattern (secretomes). Further, the storage of information from past exposures as memories within discrete cell types may allow a tissue to inform and fundamentally alter its future responses. Recently, several lines of evidence have highlighted the contributions from myeloid cells, lymphoid cells, stromal cells, mast cells, and epithelial cells to the emerging concepts of inflammatory memory and trained immunity.

T Cell Metabolism in Infection

T lymphocytes (T cells) are divided into two functionally different subgroups the CD4+ T helper cells (Th) and the CD8+ cytotoxic T lymphocytes (CTL). Adequate CD4 and CD8 T cell activation to proliferation, clonal expansion and effector function is crucial for efficient clearance of infection by pathogens. Failure to do so may lead to T cell exhaustion. Upon activation by antigen presenting cells, T cells undergo metabolic reprograming that support effector functions. In this review we will discuss how metabolic reprograming dictates functionality during viral infections using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human immunodeficiency virus (HIV) as examples. Moreover, we will briefly discuss T cell metabolic programs during bacterial infections exemplified by Mycobacterium tuberculosis (MT) infection.

The inhibition of pectin oligosaccharides on degranulation of RBL-2H3 cells from apple pectin with high hydrostatic pressure assisted enzyme treatment

The conditions for the preparation of pectic oligosaccharides (POS) by high hydrostatic pressure-assisted enzymatic (E-HHP) method were explored. The optimal conditions consisted of the pressure of 350 MPa for 20 min, and enzymolysis for 60 min with 0.011 U/mL enzyme. The products were isolated by ion exchange chromatography, galacturonic acid, di- and tri-galacturonides (Tri-GalA) with high purity were obtained. Additionally, the effects of POS on activation and degranulation of RBL-2H3 mast cells were investigated. It was found that Tri-GalA and POS could attenuate the release of β-hexosaminidase and histamine, reduce the production of IL-4 and inhibit the extracellular Ca²⁺ influx of RBL-2H3 cells. Notably, 150 μg/mL POS significantly alleviated the IgE-mediated allergic reaction of RBL-2H3 cells. These results indicate that POS could be used as an inhibitor in regulating mast cell-mediated allergic inflammatory responses.

Maternal Influences and Intervention Strategies on the Development of Food Allergy in Offspring

Food allergies and other immune-mediated diseases have become serious health concerns amongst infants and children in developed and developing countries. The absence of available cures limits disease management to allergen avoidance and symptomatic treatments. Research has suggested that the presence of maternal food allergies may expose the offspring to genetic predisposition, making them more susceptible to allergen sensitization. The following review has focused on epidemiologic studies regarding maternal influences of proneness to develop food allergy in offspring. The search strategy was "food allergy OR maternal effects OR offspring OR prevention". A systematically search from PubMed/MEDLINE, Science Direct and Google Scholar was conducted. Specifically, it discussed the effects of maternal immunity, microbiota, breastfeeding, genotype and allergy exposure on the development of food allergy in offspring. In addition, several commonly utilized prenatal and postpartum strategies to reduce food allergy proneness were presented, including early diagnosis of high-risk infants and various dietary interventions.

Features of B Cell Responses Relevant to Allergic Disease

This Brief Review delves into B cell responses in the context of allergy. The primary contribution of B cells to allergy is the production of IgE, the Ab isotype that triggers immediate hypersensitivity reactions through the release of mediators from mast cells and basophils. B cells may also have protective roles in allergy, such as through the production of IgG or as regulatory B cells. In this review, I focus on the basic principles of B cell differentiation and discuss features relevant to allergic immune responses. In particular, I discuss: (1) class-switch recombination; (2) plasma cell differentiation; (3) germinal centers and affinity maturation; and (4) memory B cells and recall responses, with an emphasis on IgE, IgG1, and IgG4. I also consider how B cells may contribute to allergic responses independent of Ab production-for example, by serving as APCs.

Protective effects on ovalbumin-induced mouse asthma models and qualitative and quantitative analysis of multiple compounds in Gerberae Piloselloidis Herba

Gerberae Piloselloidis Herba is widely used to treat cough and asthma in China. However, its effects on allergic asthma as related to its chemical compositions have not been fully elucidated, and there is a scarcity of methods to determine multi-component contents for quality control. In this study, protective effects of Gerberae Piloselloidis Herba on ovalbumin-induced asthma models were investigated, while qualitative and quantitative analyses of multiple constituents in Gerberae Piloselloidis Herba were conducted by using an ultrahigh-performance liquid chromatography -Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry and an ultrahigh-performance liquid chromatography -photodiode array detection. The results showed that Gerberae Piloselloidis Herba could significantly mitigate asthma symptoms, reduce eosinophils counts in the bronchoalveolar lavage fluid, as well as decrease IgE, IL-5 and IL-13 concentration, and inflammatory cellular infiltration in lung tissues. A total of 51 compounds were tentatively identified, in which the content of 10 representative compounds was determined in 24 batches of Gerberae Piloselloidis Herba by using an ultrahigh-performance liquid chromatography method with good linearity, precision, repeatability, accuracy and stability. This research presents a comprehensive strategy combining biological activity evaluation with chemical profiling, providing a useful and comprehensive reference for further application and quality control of Gerberae Piloselloidis Herba. This article is protected by copyright. All rights reserved.

Barrier Impairment and Type 2 Inflammation in Allergic Diseases: The Pediatric Perspective

Allergic diseases represent a global burden. Although the patho-physiological mechanisms are still poorly understood, epithelial barrier dysfunction and Th2 inflammatory response play a pivotal role. Barrier dysfunction, characterized by a loss of differentiation, reduced junctional integrity, and altered innate defence, underpins the pathogenesis of allergic diseases. Epithelial barrier impairment may be a potential therapeutic target for new treatment strategies Up now, monoclonal antibodies and new molecules targeting specific pathways of the immune response have been developed, and others are under investigation, both for adult and paediatric populations, which are affected by atopic dermatitis (AD), asthma, allergic rhinitis (AR), chronic rhinosinusitis with nasal polyps (CRSwNP), or eosinophilic esophagitis (EoE). In children affected by severe asthma biologics targeting IgE, IL-5 and against IL-4 and IL-13 receptors are already available, and they have also been applied in CRSwNP. In severe AD Dupilumab, a biologic which inhibits both IL-4 and IL-13, the most important cytokines involved in inflammation response, has been approved for treatment of patients over 12 years. While a biological approach has already shown great efficacy on the treatment of severe atopic conditions, early intervention to restore epithelial barrier integrity, and function may prevent the inflammatory response and the development of the atopic march.

Study on alleviation effect of stachyose on food allergy through TLR2/NF-κB signal pathway in a mouse model

AIMS

To explore the effect on food allergy of stachyose.

MAIN METHODS

The egg allergen ovalbumin (OVA) was used to induce a food allergy model of BALB/c mice, and different doses of stachyose were given in process. Using enzyme-linked immunosorbent assay (ELISA) methods to detect the levels of IgE, IgG₁, histamine and cytokines. And flow cytometry was used to analyze T_H1/T_H2 balance further. Besides, Hematoxylin-eosin (HE) staining was used to observe changes of intestinal morphology. Lastly, Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) and western Blot was conducted to explore the possible mechanism.

KEY FINDINGS

Compared with OVA group, serum IgE and IgG₁ levels in the low-dose (1mg/mouse) group and high-dose (5mg/mouse) group of stachyose were significantly reduced (P < 0.05); the level of plasma histamine was also decreased significantly (P < 0.05) and the body temperature were decreased. In all, allergic symptoms were alleviated after stachyose treatment. Furthermore, T_H1/T_H2 balance was improved after stachyose treatment. Lastly, the expression of TLR2 and NF-κB were increased significantly (P < 0.05) in both mRNA and protein levels after stachyose treatment.

SIGNIFICANCE

Food allergy was alleviated through improving T_H1/T_H2 balance by activating TLR2/NF-κB signal by stachyose.

Caspase-11 regulates lung inflammation in response to house dust mites

Asthma is an inflammatory lung disorder characterized by mucus hypersecretion, cellular infiltration, and bronchial hyper-responsiveness. House dust mites (HDM) are the most prevalent cause of allergic sensitization. Canonical and noncanonical inflammasomes are multiprotein complexes that assemble in response to pathogen or danger-associated molecular patterns (PAMPs or DAMPs). Murine caspase-11 engages the noncanonical inflammasome. We addressed the role of caspase-11 in mediating host responses to HDM and subsequent allergic inflammation using caspase-11-/- mice, which lack caspase-11 while express caspase-1. We found that HDM induce caspase-11 expression in vitro. The presence of IL-4 and IL-13 promote caspase-11 expression. Additionally, caspase-11-/- macrophages show reduced release of IL-6, IL-12, and KC, and express lower levels of costimulatory molecules (e.g., CD40, CD86 and MHCII) in response to HDM stimulation. Notably, HDM sensitization of caspase-11-/- mice resulted in similar levels of IgE responses and hypothermia in response to nasal HDM challenge compared to WT. However, analysis of cell numbers and cytokines in bronchiolar alveolar lavage fluid (BALF) and histopathology of representative lung segments demonstrate altered inflammatory responses and reduced neutrophilia in the airways of the caspase-11-/- mice. These findings indicate that caspase-11 regulates airway inflammation in response to HDM exposure.

Heterogeneity of magnitude, allergen immunodominance, and cytokine polarization of cockroach allergen-specific T cell responses in allergic sensitized children

BACKGROUND

Characterization of allergic responses to cockroach (CR), a common aeroallergen associated with asthma, has focused mainly on IgE reactivity, but little is known about T cell responses, particularly in children. We conducted a functional evaluation of CR allergen-specific T cell reactivity in a cohort of CR allergic children with asthma.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from 71 children, with mild-to-moderate asthma who were enrolled in a CR immunotherapy (IT) clinical trial, prior to treatment initiation. PBMC were stimulated with peptide pools derived from 11 CR allergens, and CD4+ T cell responses assessed by intracellular cytokine staining.

RESULTS

Highly heterogeneous responses in T cell reactivity were observed among participants, both in terms of the magnitude of cytokine response and allergen immunodominance. Reactivity against Bla g 9 and Bla g 5 was most frequent. The phenotype of the T cell response was dominated by IL-4 production and a Th2 polarized profile in 54.9% of participants, but IFNγ production and Th1 polarization was observed in 25.3% of the participants. The numbers of regulatory CD4+ T cells were also highly variable and the magnitude of effector responses and Th2 polarization were positively correlated with serum IgE levels specific to a clinical CR extract.

CONCLUSIONS

Our results demonstrate that in children with mild-to-moderate asthma, CR-specific T cell responses display a wide range of magnitude, allergen dominance, and polarization. These results will enable examination of whether any of the variables measured are affected by IT and/or are predictive of clinical outcomes.

Miquelianin Inhibits Allergic Responses in Mice by Suppressing CD4+ T Cell Proliferation

Allergic diseases, including atopic dermatitis (AD), induce type 2 helper T (Th2) cell-dominant immune responses. Miquelianin (quercetin 3-O-glucuronide, MQL) is an active compound in Rosae multiflorae fructus extract with anti-allergic properties. Here, we investigate the anti-allergic effects of MQL in an ovalbumin (OVA)-induced Th2-dominant mouse model and the associated mechanisms. Oral MQL suppressed cytokine and IL-2 production and proliferation of Th2 cells and upregulated heme oxygenase-1 (HO-1) in splenocytes. Ex vivo MQL suppressed Th1- and Th2-related immune responses by inhibiting CD4⁺ T cell proliferation, and upregulated HO-1 in CD4⁺ T cells by activating C-Raf-ERK1/2-Nrf2 pathway via induction of reactive oxygen species generation. In a trimellitic anhydride-induced AD-like mouse model, both topical and oral MQL ameliorated AD symptoms by suppressing Th2 immune responses. Our results suggest that MQL is a potential therapeutic agent for CD4⁺ T cell-mediated diseases, including allergic diseases.

Interleukin-32 in Pathogenesis of Atopic Diseases: Proinflammatory or Anti-Inflammatory Role?

Atopic diseases, such as atopic dermatitis (AD), allergic asthma (AA), and allergic rhinitis (AR), are increasingly becoming a worldwide issue. This atopic triad originates at an early age and on a multifactorial basis, causing significant discomfort to susceptible individuals. The global case number is now reaching new highs, so exploring immune system regulation and its components is becoming critical. One cytokine, interleukin-32 (IL-32), is involved in inflammation and regulation of the immune system. It has nine isoforms that show varying degrees of expression, both intracellularly and extracellularly. IL-32 is secreted by immune cells, such as monocytes, macrophages, natural killer cells, and T cells, and by nonimmune cells, including fibroblasts, keratinocytes, and endothelial cells. Its production is regulated and augmented by microorganisms, mitogens, and other cytokines. Early studies demonstrated that IL-32 was an immune regulator that functioned to protect against inflammatory diseases, including AD, AA, and AR, and proposed a proinflammatory role for IL-32 in immune regulation and symptom exacerbation. However, several later reports suggested that IL-32 is downregulated in inflammatory diseases and exerts an anti-inflammatory effect. This review article focuses on recent findings regarding the detrimental and protective roles of IL-32 in development and management of inflammatory diseases. The exact role of IL-32 in AD, AA, and AR still remains to be elucidated. Future research should explore new avenues of IL-32 functionality in human inflammatory diseases.

OVA-Experienced CD4+ T Cell Transfer and Chicken Protein Challenge Affect the Immune Response to OVA in a Murine Model

Chicken meat is often a major component of a modern diet. Allergy to chicken meat is relatively rare and occurs independently or in subjects allergic to ovalbumin (OVA). We examined the effect of adoptive transfer of OVA-CD4⁺ T cells on the immune response to OVA in mice fed chicken meat. Donor mice were injected intraperitoneally with 100 µg of OVA with Freund’s adjuvant two times over a week, and CD4⁺ T cells were isolated from them and transferred to naïve mice (CD4⁺/OVA/ChM group), which were then provoked with OVA with FA and fed freeze-dried chicken meat for 14 days. The mice injected with OVA and fed chicken meat (OVA/ChM group), and sensitized (OVA group) and healthy (PBS group) mice served as controls. Humoral and cellular response to OVA was monitored over the study. The CD4⁺/OVA/ChM group had lowered levels of anti-OVA IgG and IgA, and total IgE. There were significant differences in CD4⁺, CD4⁺CD25⁺, and CD4⁺CD25⁺Foxp3⁺ T cells between groups. OVA stimulation decreased the splenocyte proliferation index and IFN-γ secretion in the CD4⁺/OVA/ChM group compared to the OVA group. IL-4 was increased in the OVA/ChM mice, which confirms allergenic potential of the egg–meat protein combination. Transfer of OVA-experienced CD4⁺ T cells ameliorated the negative immune response to OVA.

Allergen Immunotherapy in Pediatric Respiratory Allergy

Purpose of Review

Atopic diseases such as asthma and allergic rhinitis are highly prevalent in children. Common triggers include tree and grass pollens, house dust mites, molds, and animal dander. These diseases are most often treated symptomatically; however, many patients show partial or poor response and require long-term medication use. Allergen immunotherapy (AIT) stands as the only treatment modality that can alter the underlying disease process and potentially offer a cure. In this review article, we discuss the merits of AIT with particular emphasis on its efficacy and safety in pediatric patients. We also discuss the challenges for AIT implementation and present an overview of current research that aims at improving its applicability for the treatment of allergic diseases.

Recent Findings

Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are both safe and efficacious treatment options in children with allergic rhinitis and allergic asthma. Additionally, AIT has efficacy in preventing the development of asthma in children. Although there are clear advantages with AIT, there are challenges to overcome to optimize treatment. Solutions include improved diagnostics with pre-treatment biomarkers and molecular multiplex assays, biomarkers for prediction of response (e.g., basophil activation markers), improved allergen immunogenicity with the use of recombinant AIT, adjuvants, and allergoids, and lastly improved safety with the concurrent use of omalizumab.

Summary

AIT has shown safety and efficacy in major clinical trials for the treatment of allergic rhinitis and allergic asthma in children. AIT provides a curative treatment option for atopic disorders and should be considered in children with allergic rhinitis and allergic asthma. There are many continued advances being made in the field of allergy to further improve the safety and efficacy profile and shorten the duration of AIT treatment.

A Review of Acquired Autoimmune Blistering Diseases in Inherited Epidermolysis Bullosa: Implications for the Future of Gene Therapy

Gene therapy serves as a promising therapy in the pipeline for treatment of epidermolysis bullosa (EB). However, with great promise, the risk of autoimmunity must be considered. While EB is a group of inherited blistering disorders caused by mutations in various skin proteins, autoimmune blistering diseases (AIBD) have a similar clinical phenotype and are caused by autoantibodies targeting skin antigens. Often, AIBD and EB have the same protein targeted through antibody or mutation, respectively. Moreover, EB patients are also reported to carry anti-skin antibodies of questionable pathogenicity. It has been speculated that activation of autoimmunity is both a consequence and cause of further skin deterioration in EB due to a state of chronic inflammation. Herein, we review the factors that facilitate the initiation of autoimmune and inflammatory responses to help understand the pathogenesis and therapeutic implications of the overlap between EB and AIBD. These may also help explain whether corrections of highly immunogenic portions of protein through gene therapy confers a greater risk towards developing AIBD.

Anaphylaxis: Focus on Transcription Factor Activity

Anaphylaxis is a severe allergic reaction, rapid in onset, and can lead to fatal consequences if not promptly treated. The incidence of anaphylaxis has risen at an alarming rate in past decades and continues to rise. Therefore, there is a general interest in understanding the molecular mechanism that leads to an exacerbated response. The main effector cells are mast cells, commonly triggered by stimuli that involve the IgE-dependent or IgE-independent pathway. These signaling pathways converge in the release of proinflammatory mediators, such as histamine, tryptases, prostaglandins, etc., in minutes. The action and cell targets of these proinflammatory mediators are linked to the pathophysiologic consequences observed in this severe allergic reaction. While many molecules are involved in cellular regulation, the expression and regulation of transcription factors involved in the synthesis of proinflammatory mediators and secretory granule homeostasis are of special interest, due to their ability to control gene expression and change phenotype, and they may be key in the severity of the entire reaction. In this review, we will describe our current understanding of the pathophysiology of human anaphylaxis, focusing on the transcription factors' contributions to this systemic hypersensitivity reaction. Host mutation in transcription factor expression, or deregulation of their activity in an anaphylaxis context, will be updated. So far, the risk of anaphylaxis is unpredictable thus, increasing our knowledge of the molecular mechanism that leads and regulates mast cell activity will enable us to improve our understanding of how anaphylaxis can be prevented or treated.

Pharmacological Benefits of Triphala: A Perspective for Allergic Rhinitis

Allergic rhinitis (AR) is considered a major nasal condition impacting a large number of people around the world, and it is now becoming a global health problem. Because the underlying mechanisms of AR are complex, the development of single-drug treatment might not be enough to treat a wide spectrum of the disease. Although the standard guidelines classify and provide suitable diagnosis and treatment, the vast majority of people with AR are still without any means of controlling it. Moreover, the benefits of AR drugs are sometimes accompanied by undesirable side effects. Thus, it is becoming a significant challenge to find effective therapies with limited undesirable side effects for a majority of patients suffering from uncontrolled AR. Aller-7/NR-A2, a polyherbal formulation, has revealed promising results in patients by reducing nasal symptoms and eosinophil counts without serious adverse effects. Interestingly, three out of seven of the herbals in the Aller-7/NR-A2 formulation are also found in an Ayurvedic polyherbal formulation known as “Triphala,” which is a potential candidate for the treatment of AR. However, there are no current studies that have examined the effects of Triphala on the disease. This review aims to describe the complexity of AR pathophysiology, currently available treatments, and the effects of Triphala on AR in order to help develop it as a promising alternative treatment in the future.

Poria cocos Modulates Th1/Th2 Response and Attenuates Airway Inflammation in an Ovalbumin-Sensitized Mouse Allergic Asthma Model

Poria cocos, called fuling, is a famous tonic in traditional Chinese medicine that reportedly possesses various pharmacological properties, including anti-inflammation and immunomodulation. However, few studies have investigated the effects of P. cocos on allergic diseases, such as allergic asthma. Allergic asthma is caused primarily by Th2 immune response and characterized by airway inflammation. This study first demonstrated the anti-allergic and anti-asthmatic effects of P. cocos extract (Lipucan^®). P. cocos extract distinctly exhibited reduced inflammatory cell infiltration in the peribronchial and peribronchiolar regions compared to the asthma group in the histological analysis of pulmonary tissue sections. Prolonged P. cocos extract administration significantly reduced eosinophil infiltration, PGE2 levels, total IgE, and OVA-specific IgE. Moreover, P. cocos extract markedly suppressed Th2 cytokines, IL-4, IL-5, and IL-10. On the other hand, P. cocos extract significantly elevated IL-2 secretion by Th1 immune response. In addition, P. cocos extract elevated the IFN-γ level at a lower dose. We also observed that P. cocos extract increased the activity of NK cells. Our results suggest that P. cocos extract remodels the intrinsic Th1/Th2 response to prevent or alleviate allergy-induced asthma or symptoms.

Epicutaneous immunotherapy protects cashew-sensitized mice from anaphylaxis

Background

The prevalence of tree nut allergy has increased worldwide, and cashew has become one of the most common food allergens. More critically, cashew allergy is frequently associated with severe anaphylaxis. Despite the high medical need, no approved treatment is available and strict avoidance and preparedness for prompt treatment of allergic reactions are considered dual standard of care. In the meantime, Phase III study results suggest investigational epicutaneous immunotherapy (EPIT) may be a relevant and safe treatment for peanut allergy and may improve the quality of life for many peanut allergic children.

Objective

We aimed to evaluate the capacity of EPIT to provide protection against cashew‐induced anaphylaxis in a relevant mouse model.

Methods

The efficacy of EPIT was evaluated by applying patches containing cashew allergens to cashew‐sensitized mice. As negative control, sham mice received patches containing excipient. Following treatment, mice were challenged orally to cashew and anaphylactic symptoms, as well as plasmatic levels of mast‐cell proteases (mMCP)‐1/7, were quantified.

Results

Of 16 weeks of EPIT significantly protects against anaphylaxis by promoting a faster recovery of challenged mice. This protection was characterized by a significant reduction of temperature drop and clinical symptoms, 60 minutes after challenge. This was associated with a decrease in mast‐cell reactivity as attested by the reduction of mMCP‐1/7 in plasma, suggesting that EPIT specifically decrease IgE‐mediated anaphylaxis.

Conclusion

We demonstrate that EPIT markedly reduced IgE‐mediated allergic reactions in a mouse model of cashew allergy, which suggests that EPIT may be a relevant approach to treating cashew allergy.

Effects of mineral complex material treatment on 2,4- dinitrochlorobenzene-induced atopic dermatitis like-skin lesions in mice model

Background

Atopic dermatitis (AD) is a chronic allergic inflammatory skin disease characterized by complex pathogenesis including skin barrier dysfunction, immune-redox disturbances, and pruritus. Prolonged topical treatment with medications such as corticosteroids, calcineurin inhibitors, and T-cell inhibitors may have some potential side-effects. To this end, many researchers have explored numerous alternative therapies using natural products and mineral compounds with antioxidant or immunomodulatory effects to minimize toxicity and adverse-effects. In the current study, we investigated the effects of mineral complex material (MCM) treatment on 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in SKH-1 hairless mice.

Methods

Animals were divided into four groups; normal control (NC), negative control treated with DNCB only (DNCB only), positive control treated with DNCB and tacrolimus ointment (PC) and experimental group treated with DNCB and MCM patch (MCM). Skin inflammation and lesion severity were investigated through analyses of skin parameters (barrier score and strength, moisture and trans-epidermal water loss level), histopathology, immunoglobulin E, and cytokines. In addition, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT) levels were measured in both serum and skin lysate.

Results

Our results demonstrates that MCM patch improved the progression of AD-like skin lesions by significantly increasing skin barrier strength and decreasing trans-epidermal water loss. Additionally, dermal administration of MCM patch significantly reduced epidermal thickness, ROS, and NO levels in skin lysate. Furthermore, we found that MCM suppressed the levels of AD-involved (Th₁ and Th₂) cytokines such as IL-2, IFN-γ, and IL-4 in blood. In addition, the levels of other Th_1, and Th₂ and inflammatory cytokines such as IL-1β, TNF-α, IL-6, IL-12(p70) and IL-10 were found lowest in the MCM group than in the DNCB only and PC groups. Moreover, we found total serum IgE level significantly increased after DNCB treatment, but decreased in the PC and MCM groups.

Conclusion

Taken together, our findings suggest that MCM application may have beneficial effects either systemic or regional on DNCB-induced AD lesional skin via regulation of the skin barrier function and immune-redox response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03259-5.

Fecal short chain fatty acids in children living on farms and a link between valeric acid and protection from eczema

Children growing up on farms have low rates of allergy, but the mechanism for this protective effect has not been fully elucidated. Short chain fatty acids (SCFAs) produced by the gut microbiota may play a role in protection from allergy. We measured fecal SCFA levels in samples collected from 28 farming and 37 control children over the first 3 years of life using gas chromatography. Data on diet and other host factors were recorded and allergy was diagnosed at 8 years of age. Among all children, median propionic and butyric acid concentration increased over the first 3 years, and longer SCFAs typically appeared by 1 year of age. Farm children had higher levels of iso-butyric, iso-valeric and valeric acid at 3 years of age than rural controls. In addition, children with elder siblings had higher levels of valeric acid at 3 years of age, and dietary factors also affected SCFA pattern. High levels of valeric acid at 3 years of age were associated with low rate of eczema at 8 years of age. The fecal SCFA pattern in farm children suggests a more rapid maturation of the gut microbiota. Valeric acid or associated microbes may have protective potential against eczema.

IL-21 is a broad negative regulator of IgE class switch recombination in mouse and human B cells

IgE antibodies may elicit potent allergic reactions, and their production is tightly controlled. The tendency to generate IgE has been thought to reflect the balance between type 1 and type 2 cytokines, with the latter promoting IgE. Here, we reevaluated this paradigm by a direct cellular analysis, demonstrating that IgE production was not limited to type 2 immune responses yet was generally constrained in vivo. IL-21 was a critical negative regulator of IgE responses, whereas IFN-γ, IL-6, and IL-10 were dispensable. Follicular helper T cells were the primary source of IL-21 that inhibited IgE responses by directly engaging the IL-21 receptor on B cells and triggering STAT3-dependent signaling. We reconciled previous discordant results between mouse and human B cells and revealed that the inhibition of IgE class switch recombination by IL-21 was attenuated by CD40 signaling, whereas IgG1 class switch recombination was potentiated by IL-21 in the context of limited IL-4. These findings establish key features of the extrinsic regulation of IgE production by cytokines.

Diagnostic and Therapeutic Value of Hsa_circ_0002594 for T Helper 2-Mediated Allergic Asthma

INTRODUCTION

Circular RNAs (circRNAs) are an endogenous mircoRNA sponge that could act as potential biomarkers for the diagnosis and treatment of diseases. However, the role of circRNAs in asthma is far from clear.

OBJECTIVE

The aim of this study is to assess the diagnostic and therapeutic value of hsa_circ_0002594 for T helper (Th) 2-mediated allergic asthma.

METHODS

The expression profiles of hsa_circ_0002594 in CD4+ T cells were revealed by circRNA microarray. Hsa_circ_0002594 expression was confirmed via quantitative real-time PCR (qRT-PCR) in asthmatic patients and healthy subjects. Hsa_circ_0002594 levels were compared between subgroups. The clinical diagnostic abilities and therapeutic response of hsa_circ_0002594 were evaluated. The analyses utilized included a student's t test, nonparametric tests, Spearman's rank-order correlation, Fisher's exact test, and the generation of receiver operating characteristic (ROC) curves.

RESULTS

Hsa_circ_0002594 was upregulated and positively correlated with fraction of exhaled nitric oxide while negatively correlated with methacholine dose producing a decrease of 20% from baseline in forced expiratory volume in the first second (PD20) in CD4+ T cells of asthma. Furthermore, hsa_circ_0002594 expression was higher in subgroups with a family history, skin pricking test (SPT)-positive, or Th2-high. The hsa_circ_0002594-high subgroup was more frequently associated with Th2-high biomarker profiles and positive SPT. Hsa_circ_0002594 was decreased after inhaled corticosteroids (ICS) treatment. ROC curve analyses of hsa_circ_0002594 showed high area under the curve values in the presence of ICS or not.

CONCLUSIONS

Our data suggested that hsa_circ_0002594 was upregulated in CD4+ T cells and might have potential value in the diagnosis and treatment of Th2-mediated allergic asthma.