Early exposure to sunlight and allergic morbidity: The PARIS birth cohort.

The relationship between sunlight and allergies in children has received limited attention from researchers. We sought to explore how early exposure to solar radiation is associated with allergic morbidity within the PARIS birth cohort study. Our research dealt with children who attended at least one of two health checkups: at 18 months (n = 2012) and at 8-9 years (n = 1080). Early exposure to solar radiation was assessed using meteorological data (e.g., solar radiation, temperature, and relative humidity). Children with similar meteorological exposure trajectories were grouped by a longitudinal and multidimensional cluster analysis. The association between solar radiation exposure and allergic morbidity (i.e., allergic sensitization at 18 months and 8-9 years; current asthma, rhinitis, and eczema at 8-9 years) was quantified by multivariable logistic regression models adjusted for potential confounders. The effect modification of maternal vitamin D supplementation during pregnancy was tested. Four meteorological exposure trajectories were found. The trajectory with the highest exposure to early solar radiation had a reduced risk of sensitization at 8-9 years compared to the trajectory with the lowest exposure (p = 0.06). The association was statistically significant in the vitamin D supplementation group. Solar radiation during prenatal and postnatal periods was significantly associated with a lower risk of sensitization at 8-9 years (for one interquartile range (IQR) increase, adjusted odds ratio (aOR): 0.47; 95 % confidence interval (CI): 0.25-0.87 and 0.84; 0.7-1.00, respectively). Increased prenatal exposure to solar radiation was significantly associated with a lower risk of asthma at 8-9 years (for one IQR increase, aOR: 0.32; 95 % CI: 0.1-0.96). Early sunlight exposure may reduce the risk of sensitization and asthma in school-aged children, especially in those prenatally exposed to vitamin D. These findings highlight the importance of vitamin D in preventing allergic diseases in children, either through supplementation or sunlight exposure.

Maternal fish oil and/or probiotics intervention: Allergic diseases in children up to two years old.

BACKGROUND: As n-3 long-chain polyunsaturated fatty acids and probiotics possess immunomodulatory properties, theoretically they could lower the risk of allergic diseases. But their effects remain controversial. We aimed to study the effects of fish oil and probiotics separately or in combination from early pregnancy onwards to lower the risk of allergic diseases in the infants. METHODS: In this double-blind trial, women (n = 439) in early pregnancies were randomized into four intervention groups: fish oil + placebo, probiotics + placebo, fish oil + probiotics, and placebo + placebo. Fish oil (1.9 g docosahexaenoic acid and 0.22 g eicosapentaenoic acid) and probiotic (Lacticaseibacillus rhamnosus HN001 and Bifidobacterium animalis ssp. lactis 420, 1010 colony-forming units each) supplements were provided for daily consumption from randomization up to 6 months postpartum. All analyses were adjusted with pet ownership. RESULTS: No difference between the infants in the four intervention groups were found regarding physician-diagnosed food allergy, atopic eczema, or atopy at the age of 12 or 24 months (all p > .05). The probiotic intervention was associated with lower odds of recurrent wheezing at 24 months (OR 0.39, 95% CI 0.18-0.84, p = .017), but not at 12 months. CONCLUSIONS: The use of fish oil and/or probiotics from early pregnancy onwards did not lower the odds of childhood allergic diseases or atopy, with the exception of the probiotic intervention which decreased the risk of recurrent wheezing when the infants were two years old. This suggests that the incidence of asthma could also decrease later in childhood and thus these outcomes need to be clarified in further investigations.

Rastreamento da hipersensibilidade metálica pelos profissionais e estudantes de saúde na prática clínico-cirúrgica / Seguimiento de la hipersensibilidad metálica por profesionales y estudiantes de salud en la práctica clínico-quirúrgica / Screening of metallic hypersensitivity by health professionals and students in clinical-surgical practice

Objetivo: investigar o rastreamento da hipersensibilidade metálica realizada pelos profissionais e estudantes de saúde durante a prática clínico-cirúrgico. Método: estudo exploratório-descritivo realizado com 228 profissionais e estudantes da área da saúde, por meio de questionário eletrônico semiestruturado, aplicado durante abril e maio de 2021, analisado por meio da estatística descritiva e da frequência de palavras. Resultados: 11,0% dos participantes realizaram a investigação sobre a hipersensibilidade metálica. 67,1% declararam que muito provavelmente poderiam incluir essa temática durante a triagem em seus atendimentos. Falta de conhecimento sobre alergia a metais e causas multifatoriais durante a prática clínico-cirúrgica foram citadas como barreiras para a implementação do rastreamento da hipersensibilidade metálica. Conclusão: pouco se evidencia o rastreamento da hipersensibilidade metálica em pacientes durante a prática clínico-cirúrgica dos profissionais e estudantes de saúde.

Objetivo: investigar el rastreo de la hipersensibilidad metálica realizada por los profesionales y estudiantes de salud durante la práctica clínico-quirúrgica. Método: estudio exploratorio-descriptivo realizado con 228 profesionales y estudiantes del área de la salud, por medio de cuestionario electrónico semiestructurado, aplicado durante abril y mayo de 2021, analizado por medio de la estadística descriptiva y de la frecuencia de palabras. Resultados: 11,0% de los participantes realizaron la investigación sobre la hipersensibilidad metálica. El 67,1% declaró que muy probablemente podrían incluir esa temática durante la selección en sus atenciones. La falta de conocimientos sobre la alergia a los metales y las causas multifactoriales durante la práctica clínico-quirúrgica se citaron como barreras para la implementación del seguimiento de la hipersensibilidad metálica. Conclusión: poco se evidencia el rastreo de la hipersensibilidad metálica en pacientes durante la práctica clínico-quirúrgica de los profesionales y estudiantes de salud.

Objective to investigate the screening of metallic hypersensitivity performed by health professionals and students during clinical-surgical practice. Method: an exploratory-descriptive study conducted with 228 health professionals and students, through a semi-structured electronic questionnaire, applied during April and May 2021, analyzed through descriptive statistics and the frequency of words. Results: 11.0% of participants conducted research on metallic hypersensitivity. 67.1% stated that they could very likely include this theme during screening in their care. Lack of knowledge about metal allergy and multifactorial causes during clinical-surgical practice were cited as barriers to the implementation of metallic hypersensitivity screening. Conclusion: there is little evidence of metallic hypersensitivity screening in patients during the clinical-surgical practice of health professionals and students.

Anti-inflammatory and anti-allergic potential of dietary flavonoids: A review.

Chronic inflammation plays an imperative role in the onset and progression of chronic diseases including diabetes, hypertension, cancer, allergies, and asthma. Diet can modulate different stages of inflammation since it is a rich source of antioxidants and bioactive compounds. Flavonoids are bioactive compounds abundantly found in various food groups such as vegetables, fruits, nuts, cereals, and beverages. Recent work on flavonoids has unveiled their potential to regulate or inhibit inflammation. This is attributed to their anti-inflammatory, anti-oxidative, and immune-modulatory properties, making flavonoids an invaluable component in nutraceutical, pharmaceutical, and medicinal applications. However, information related to their anti-inflammatory mechanism is still not well understood. The current review is an attempt to elaborate chemical structure, dietary sources, and anti-inflammatory properties of flavonoids against allergic diseases.

Semaphorin 3A: A potential target for prevention and treatment of nickel allergy.

Metal allergy is one of the typical immune disorders encountered during the application of dental/medical materials and has a highly complex pathogenic mechanism. Semaphorin 3A (Sema3A), a member of the semaphorin family, is reported to be involved in various immune disorders. However, its role in metal allergy has not been clarified yet. Herein, we show that Sema3A expression was upregulated in nickel (Ni) allergy-induced mouse ear tissue and in NiCl2-stimulated mouse keratinocytes. Moreover, Sema3A regulated tumor necrosis factor-alpha production and mitogen-activated protein kinase activation in keratinocytes. The specific deletion of Sema3A in keratinocytes did not affect immune cell infiltration but reduced edema and ear swelling; it also impeded Th1 responses to cause a slight alleviation in Ni allergy in mice. Our results demonstrate that Sema3A promotes the development of metal allergy and should be explored as a potential target for the prevention and treatment of metal allergy.

Effective Ways to Prevent Allergic Diseases: Where Do We Stand?

Since allergic diseases are of great public health relevance, effective primary prevention strategies are urgently needed. This chapter gives an overview of existing primary prevention programs on environmental exposures and dietary strategies based on epidemiological studies which have defined risk- and protective factors for the development of allergic diseases.The allergy protective effect mediated by growing up on a traditional farm environment is well studied. But the exact underlying mechanisms have still not been fully clarified and have not yet led to concrete prevention strategies. The beneficial effect of avoiding cigarette smoke exposure, indoor moisture and molds in pregnancy and childhood on the development of asthma is well documented. Whereas the avoidance of house dust mite exposure is not recommended to prevent eczema or allergy. Dietary supplementation with vitamins, pre- and probiotics in pregnant woman and their offspring is not harmful but evidence for the prevention of allergic diseases is still lacking. Fish oil consumption was shown to be asthma protective. The early introduction of peanuts and egg protein to prevent peanut and egg allergy in children with atopic dermatitis is promising. Further studies are needed to increase the overall evidence in allergy prevention. Most studies lack methodological standards such as randomization and blinding. More evidence is in demand on the potential beneficial impact of multifaceted interventional studies. The future of allergy prevention strategies might be based on individual risk assessment. Therefore, research in the immunological and molecular basis of allergic diseases needs to be promoted.

A Component-Resolved Therapeutic Vaccine for Cockroach Allergy Made of Per a 9 and Transforming Growth Factor-ß Homologue, an Immunosuppressive Protein of Brugia malayi.

Allergen-specific-immunotherapy (ASIT) can cause long-term resolution of allergic diseases, reduces drug use and chances of new allergen sensitization. Nevertheless, therapeutic vaccine and data on ASIT efficacy for cockroach (CR) allergy are relatively scarce. In this study, efficacy and mechanism of a novel intranasal vaccine consisting of liposome (L)-entrapped mixture of American CR (Periplaneta americana) major allergen (Per a 9) and immunosuppressive protein of Brugia malayi nematode named transforming growth factor-beta homologue (TGH) in treatment of CR allergy were investigated along with two other vaccines (L-Per a 9 alone and L-TGH alone). All three vaccines could reduce pathogenic type 2 response and lung immunopathology in the vaccines-treated CR-allergic mice, but by different mechanisms. L-Per a 9 caused a deviation of the pathogenic type 2 to type 1 response (IFN-γ-upregulation), whereas the L-(TGH + Per a 9) and L-TGH generated regulatory immune responses including up-expression of immunosuppressive cytokine genes and increment of serum adenosine and lung indoleamine-2,3-dioxygenase-1 which are signatures of regulatory T cells (Tregs) and tolerogenic dendritic cells, respectively. The L-(TGH + Per a 9) should be further evaluated towards clinical application, as this vaccine has a propensity to induce broadly effective therapeutic effects for inhalant allergies.

Decrease in CD38+ TH2A cell frequencies following immunotherapy with house dust mite tablet correlates with humoral responses.

BACKGROUND: In line with evidence for a role of pathogenic TH2A in seasonal allergies, we previously showed that individuals suffering from food allergy exhibited a decrease in circulating TH2A cells following multi-food immunotherapy. Herein, we aim to confirm the decline of TH2A cells in individuals undergoing house dust mite immunotherapy (HDM-AIT) and extend our observation to a new subset of CD38 expressing activated TH2A cells. METHODS: The frequencies of TH2A and CD38+ TH2A cells were analysed by flow cytometry in blood cells from 182 Japanese HDM-allergic individuals included in a 1-year clinical trial assessing the efficacy of HDM tablets. Interrelationship between these cellular responses and humoral mite-specific IgE and IgG4 levels was further explored. RESULTS: A decrease in TH2A cells was observed in both active and placebo groups. Interestingly, CD38+ TH2A cell frequencies significantly decreased only in active groups. In younger individuals (16-30 years), both TH2A and CD38+ TH2A cells were significantly reduced in active groups but not in the placebo group. Significant inverse correlations were observed in the course of HDM-AIT between changes in TH2A or CD38+ TH2A frequencies and IgG4 antibody levels. CONCLUSIONS: We confirm the value of monitoring TH2A cell frequencies in allergic individuals and extend this observation to perennial allergy to HDM. We highlight the interest of CD38 to better identify the subset of TH2A cell down-regulated by AIT. Finally, correlated cellular and humoral responses observed in immunoreactive individuals stress that coordinated pathways occur in the adaptive responses during AIT.

Insights into allergic risk factors from birth cohort studies.

OBJECTIVE: To present an update of birth cohort study designs and their contributions to allergic risk. DATA SOURCES: The PubMed database was used to search for relevant articles. STUDY SELECTIONS: Peer-reviewed prospective and retrospective studies involving the assessment of allergy using human birth cohorts between 2014 and 2021 were evaluated. RESULTS: Parental history of allergic diseases, especially in cases involving both parents, is associated with increased risk of allergy. Exposure to prenatal and postnatal smoking and limited diet diversity were associated with increased allergic burden. The impact of early-life infections and antibiotics on disease development may be associated with the onset of asthma, though this remains debated. Cohort studies also revealed that the mode of delivery and breastfeeding duration affect the odds ratio of asthma and eczema development. Household exposures, including pets, house dust mites, and scented aeroallergens may confer protective effects, whereas high air pollution exposure and low socioeconomic status may be risk enhancing. Exposure to antibiotics during early life may be associated with increased asthma risk, whereas viral infections may lead to disease protection, though the impact of the coronavirus disease 2019 pandemic on allergic risk is yet to be understood. CONCLUSION: Although evaluating the risk of allergic disease development is complex, clinicians can apply these insights on the multifactorial nature of atopy to better understand and potentially mitigate disease development.

[COVID-19 vaccines: vaccine targets, immunogenicity and allergic reactions]. / Vaccins contre le Covid-19 : cibles vaccinales, immunogénicité et réactions allergiques.

Many vaccine strategies have been developed to control the COVID-19 pandemic. This article presents the mechanisms of action and the efficacy of different vaccines including mRNA- and adenovirus-based vaccines. We will discuss the different vaccine targets, immune responses and allergic reactions which have been reported during the vaccination campaigns. Finally, the latest recommendations for the prevention and management of severe allergic reactions will be summarized.

De nombreuses stratégies vaccinales ont été développées pour tenter de contrôler la pandémie de Covid-19. Cet article présente le fonctionnement et l'efficacité de différents vaccins, en particulier ceux à ARN messager et adénovecteurs. Nous discutons des cibles vaccinales, des véhicules vaccinaux ainsi que de l'immunité qu'ils induisent. Nous nous penchons également sur la question des allergies aux vaccins qui a rapidement été soulevée après le début des campagnes de vaccination à large échelle. Les allergènes potentiellement en cause et les mécanismes impliqués sont discutés. Enfin, nous proposons des recommandations pour la prévention et la prise en charge des réactions allergiques sévères.

Histopathological evaluation of cutaneous reactions to tattoos: Study at a tertiary care center.

BACKGROUND: Tattooing has been around for many years and is becoming an increasingly common fashion trend. As there are often few regulatory laws regarding the practice, an increase in the incidence of cutaneous reactions to tattoo inks is noted. These include allergic reactions, granulomatous dermatitis, infections, lichenoid dermatoses, and sometimes malignancy. The present study examines the histopathological changes seen in patients with cutaneous reactions to tattoo ink. METHOD: A prospective observational study was conducted over 18 months in the dermatology clinic of a tertiary care center in western India. The study population included 22 patients with cutaneous reactions over the tattoos. Punch biopsy specimens were sent to study the pattern of histopathological response. RESULTS: All 22 patients studied were between the ages of 17 and 35 years. The mean duration of development of reaction was 8.1 months. Most of the reactions were seen in black ink tattoos performed by amateurs. Perivascular and spongiotic dermatitis suggestive of allergic response was the most common feature on histopathology. Granulomatous response and lichenoid response were seen in five and three biopsies, respectively. CONCLUSION: Legalization is needed for this practice to prevent tattoo reactions. Histopathological evaluation is important as tattoo reactions may be associated with skin infections and malignancies.

Attenuating Effect of Peruvian Cocoa Populations on the Acute Asthmatic Response in Brown Norway Rats.

Cocoa contains bioactive components, which vary according to genetic and environmental factors. The present study aimed to ascertain the anti-allergic properties of native Peruvian cocoa populations ("Blanco de Piura" or BPC, "Amazonas Peru" or APC, "Criollo de Montaña" or CMC, "Chuncho" or CCC, and an ordinary cocoa or OC). To do so, after an initial in vitro approach, an in vivo study focused on the induction of an anaphylactic response associated with allergic asthma in Brown Norway rats was carried out. Based on their polyphenol content, antioxidant activity and in vitro effects, the APC and CMC were selected to be included in the in vivo study. Cocoa diets were tested in a model of allergic asthma in which anaphylactic response was assessed by changes in body temperature, motor activity and body weight. The concentration of specific immunoglobulin E (IgE), mast cell protease and leukotrienes was also quantified in serum and/or bronchoalveolar lavage fluid. CMC and OC populations exhibited a protective effect on the allergic asthma rat model as evidenced by means of a partial protection against anaphylactic response and, above all, in the synthesis of IgE and the release of mast cell protease.

Preventive Allergen-Specific Vaccination Against Allergy: Mission Possible?

Vaccines for infectious diseases have improved the life of the human species in a tremendous manner. The principle of vaccination is to establish de novo adaptive immune response consisting of antibody and T cell responses against pathogens which should defend the vaccinated person against future challenge with the culprit pathogen. The situation is completely different for immunoglobulin E (IgE)-associated allergy, an immunologically-mediated hypersensitivity which is already characterized by increased IgE antibody levels and T cell responses against per se innocuous antigens (i.e., allergens). Thus, allergic patients suffer from a deviated hyper-immunity against allergens leading to inflammation upon allergen contact. Paradoxically, vaccination with allergens, termed allergen-specific immunotherapy (AIT), induces a counter immune response based on the production of high levels of allergen-specific IgG antibodies and alterations of the adaptive cellular response, which reduce allergen-induced symptoms of allergic inflammation. AIT was even shown to prevent the progression of mild to severe forms of allergy. Consequently, AIT can be considered as a form of therapeutic vaccination. In this article we describe a strategy and possible road map for the use of an AIT approach for prophylactic vaccination against allergy which is based on new molecular allergy vaccines. This road map includes the use of AIT for secondary preventive vaccination to stop the progression of clinically silent allergic sensitization toward symptomatic allergy and ultimately the prevention of allergic sensitization by maternal vaccination and/or early primary preventive vaccination of children. Prophylactic allergy vaccination with molecular allergy vaccines may allow halting the allergy epidemics affecting almost 30% of the population as it has been achieved for vaccination against infectious diseases.

Specific Polyunsaturated Fatty Acids Can Modulate in vitro Human moDC2s and Subsequent Th2 Cytokine Release.

Allergy is becoming a rapidly increasing problem worldwide, and in vitro models are frequently used to study the mechanisms behind the different types of allergic response. The dendritic cell (DC)-T-cell model can be used to study sensitization. However, lipopolysaccharide (LPS) is often used to maturate the DCs, but it gives rise to a DC1 phenotype, whereas Th2-driven inflammatory diseases such as allergy are characterized by the involvement of the DC2 phenotype. Our aim was to create a DC2-T-cell human model (human moDC2s) to study in vitro sensitization and validate the model using polyunsaturated fatty acids (PUFAs) that were previously shown to have immunomodulatory properties. We found that the generated DC2s expressed OX40L and drove naive T-cells into IL-13 production of CD4+ effector T-cells. In line with in vivo findings, n-3 long-chain (LC)PUFA docosahexaenoic acid (DHA) effectively decreased the DC2's surface expression of OX40L, as well as the IL-12p40 and IL-23 cytokine production by DC2s and subsequently lowered IL-13 production by DC2-induced effector T-cells. Similar cytokine production effects were found with eicosapentaenoic acid (EPA) and arachidonic acid (AA), whereas linoleic acid (LA) increased OX40L surface expression and subsequent T-cell-derived IL-13/IFNγ ratios, suggesting an increased risk of allergy development. Altogether, these data show that human moDC2s are able to induce Th2-type IL-13 secretion by T-cell differentiated in the presence of these DC2s and that this model can be differentially modulated by PUFAs. These results are in line with previous in vivo studies using PUFAs, indicating that this model may be of use to predict in vivo outcomes.

Anisakiasis: The Importance of Prevention and the Role of Diet Therapy in Allergic Patients.

INTRODUCTION: Anisakiasis is a zoonosis of parasitic origin whose diffusion seems to be continuously increasing. OBJECTIVE: The aim of this study was to evaluate the benefits of a fish-free diet in patients allergic to Anisakis simplex as well as underlining the importance of awareness and prevention. Furthermore, we aimed to investigate the critical issues related to the spread of anisakiasis in relation to eating habits. METHODS: Patients were assessed by means of skin prick tests (SPTs) and targeted laboratory testing, with an 18-month-long fish-free diet being recommended in cases of severe sensitization. The degree of awareness about anisakiasis was evaluated from interviews. Patients were subjected to follow-up visits after 18 months. RESULTS: A total of 70 cases of sensitization to A. simplex were evaluated. The Interview answers highlighted a general state of misinformation among patients and healthy subjects along with a remarkable underestimation of anisakiasis-related risks. An overall lack of care regarding eating habits and diet plans also emerged. In 21 patients affected by severe sensitization, clinical and laboratory evaluations were repeated after 18 months of the subjects being on a fish-free diet. There was a remarkable improvement in serum IgE levels and clinical symptoms. CONCLUSION: Data analysis proved the need to implement new and more effective awareness-raising and prevention campaigns in order to reduce the incidence of anisakiasis. It is crucial to establish an adequate diet therapy for sensitized patients. Evaluation of cytokine patterns suggests how a polyphenol-rich regime can activate regulatory T cell function and possibly reduce the allergic and inflammatory components of the disease.

Immunomodulatory Components of Human Colostrum and Milk.

Human milk is a unique and complex secretion differing from lacteal secretions of other species. Besides nutrition, it provides protection during the newborn's adaption to the extrauterine environment and reduces the morbidity and mortality caused by both infectious and noninfectious diseases. Its components act directly against infectious agents, but they also accelerate the newborn's immune system development, increasing its capacity for defense and reducing the risk of allergy and other immune-related diseases. Cytokines show the most refined immunomodulatory effects, but oligosaccharides, hormones, and other components affect the newborn's immunity as well. Furthermore, milk components substantially affect the microbial colonization of infant mucosa, which substantially influences the development of all parts of the immune system. All these components act primarily locally, on the mucosal membranes, preventing the penetration of microbes and other antigenic components into the circulation thus ensuring effective defense without the damaging inflammation. Human lacteal secretions contain a number of live cells. Although there are no major differences in the cytokine production between allergic and healthy mothers, they are able to respond to multiple stimuli. By increasing happiness, boosting protective immunity, and decreasing the risk of breast cancer, breastfeeding may have multiple benefits for the mother as well.

Successful prevention of severe allergic transfusion reactions with omalizumab.

BACKGROUND: Allergic transfusion reactions (ATRs) are a common adverse reaction to transfusion therapy and can be potentially fatal. Washing blood products is the most effective strategy for preventing ATRs; however, washed products, especially platelets, are not available at many blood centers. STUDY DESIGN AND METHODS: A 29-year-old female patient with an advanced myelodysplastic/myeloproliferative neoplasm, unclassifiable, developed severe ATRs after four platelet transfusions in a week. She showed no response to premedication with histamines and steroids and still had severe ATRs with the next three platelet transfusions. A laboratory workup revealed that her IgA level was slightly decreased, while her haptoglobin level was normal. Anti-IgA testing was not available. The patient decided to undergo allogeneic peripheral blood stem cell (PBSC) transplantation. As the onset of symptoms ATR, which were similar to Type 1 hypersensitivity reactions mediated by IgE antibodies, occurred immediately after transfusion and omalizumab is a humanized monoclonal anti-IgE, we elected to offer off-label use of omalizumab before administering the conditioning regimen. RESULTS: Omalizumab was injected subcutaneously at a dose of 150 mg. Surprisingly, transfusion reactions fully resolved within 24 hours. No serious side effects were noticed. Another 150 mg of omalizumab was administered 1 day before PBSC infusion. The patient remained asymptomatic without any signs of ATRs throughout the whole period of transplantation. Seven months after transplantation, the patient was in complete remission without overt complications. CONCLUSION: This case suggests that omalizumab is a promising new alternative treatment for the prevention of severe ATRs.

Inhibitory effects of orientin in mast cell-mediated allergic inflammation.

BACKGROUND: Mast cells are immune effector cells mediating allergic inflammation by the secretion of inflammatory mediators such as histamine and pro-inflammatory cytokines. Orientin is a naturally occurring bioactive flavonoid that possesses diverse biological properties, including anti-inflammation, anti-oxidative, anti-tumor, and cardio protection. The objective of this study was to rule out the effectiveness of orientin in mast cell-mediated allergic inflammation. METHODS: In this study, in vitro effects of orientin were evaluated in RBL-2H3, mouse bone marrow-derived mast cells, rat peritoneal mast cells, and in vivo effects were evaluated by inducing passive cutaneous anaphylaxis (PCA) in Imprinting Control Region (ICR) mice. RESULTS: Findings show that orientin suppressed the immunoglobulin E (IgE)-mediated mast cell degranulation by reducing intracellular calcium level in a concentration-dependent manner. Orientin suppressed the secretion of pro-inflammatory cytokines in mast cells. This inhibitory effects of orientin was through inhibition of FcεRI-mediated signaling proteins. In addition, oral administration of orientin suppressed the IgE-mediated PCA reactions in a dose-dependent manner, which was evidenced by reduced Evan's blue pigmentation and ear swelling. CONCLUSIONS: Based on these findings, we suggest that orientin might have potential to alleviate allergic reaction and mast cell-mediated allergic disease.