Human subjects without peanut allergy demonstrate T cell-dependent, TH2-biased, peanut-specific cytokine and chemokine responses independent of TH1 expression

A novel iridoid glycoside leonuride (ajugol) attenuates airway inflammation and remodeling through inhibiting type-2 high cytokine/chemokine activity in OVA-induced asthmatic mice

BACKGROUND

Asthma is a chronic airway disorder with a hallmark feature of airflow obstruction that associated with the remodeling and inflammation in the airway wall. Effective therapy for controlling both remodeling and inflammation is still urgently needed. Leonuride is the main pharmacological component identified from Bu-Shen-Yi-Qi-Tang (BSYQT) which has been traditionally used in treatment of lung diseases. However, no pharmacological effects of leonuride in asthma were reported.

PURPOSE

Here we aimed to investigated whether leonuride provided a therapeutic efficacy in reversing asthma airway remodeling and inflammation and uncover the underlying mechanisms.

STUDY DESIGN AND METHODS

Mouse models of chronic asthma were developed with ovalbumin (OVA) exposure for 8 weeks. Respiratory mechanics, lung histopathology and asthma-related cytokines were examined. Lung tissues were analyzed using RNA sequencing to reveal the transcriptional profiling changes.

RESULTS

After oral administration with leonuride (15 mg/kg or 30 mg/kg), mice exhibited a lower airway hyperresponsiveness in comparison to asthmatic mice. Leonuride suppressed airway inflammation evidenced by the significant reductions in accumulation of inflammatory cells around bronchi and vessels, leukocyte population counts and the abundance of type 2 inflammatory mediators (OVA specific IgE, IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF). On the other hand, leonuride slowed down the process of active remodeling as demonstrated by weaker goblet cell metaplasia and subepithelial fibrosis in lung histopathology and lower transforming growth factor (TGF)-β1 levels in serum and BALF in comparison to mice treated with OVA only. Furthermore, we uncovered transcriptional profiling alternations in lung tissue of mice after OVA exposure and leonuride treatment. Gene sets belonging to type-2 cytokine/chemokine activity stood out in leonuride target transcripts. Those upregulated (Bmp10, Ccl12, Ccl22, Ccl8, Ccl9, Cxcl15, Il13, Il33, Tnfrsf9, Il31ra, Il5ra, Il13ra2 and Ccl24) or downregulated (Acvr1c and Il18) genes in asthmatic mice, were all reversely regulated by leonuride treatment.

CONCLUSIONS

Our results revealed the therapeutic efficacy of leonuride in experimental chronic asthma for the first time, and implied that its anti-inflammatory and antifibrotic properties might be mediated by regulation of type-2 high cytokine/chemokines responses.

IgE-Mediated food allergy: Current diagnostic modalities and novel biomarkers with robust potential

Food allergy (FA) is a serious public health issue afflicting millions of people globally, with an estimated prevalence ranging from 1-10%. Management of FA is challenging due to overly restrictive diets and the lack of diagnostic approaches with high accuracy and prediction. Although measurement of serum-specific antibodies combined with patient medical history and skin prick test is a useful diagnostic tool, it is still an imprecise predictor of clinical reactivity with a high false-positive rate. The double-blind placebo-controlled food challenge represents the gold standard for FA diagnosis; however, it requires large healthcare and involves the risk of acute onset of allergic reactions. Improvement in our understanding of the molecular mechanism underlying allergic disease pathology, development of omics-based methods, and advances in bioinformatics have boosted the generation of a number of robust diagnostic biomarkers of FA. In this review, we discuss how traditional diagnostic modalities guide appropriate diagnosis and management of FA in clinical practice, as well as uncover the potential of the latest biomarkers for the diagnosis, monitoring, and prediction of FA. We also raise perspectives for precise and targeted medical intervention to fill the gap in the diagnosis of FA.

Quantifying Human Innate Cytokine and Chemokine Responses Ex Vivo via Pattern Recognition Receptor Stimulation

Linkages between human innate immune capacity, the environment in which we live, and the development of clinical tolerance versus a spectrum of disease phenotypes are a major focus of inflammatory disease research. While extensive epidemiologic evidence indicates key roles for the microbiome and other environmental factors, the underlying mechanisms that explain how these stimuli lead to a given clinical phenotype remain speculative. Here we review strategies for characterizing human cytokine production ex vivo in response to innate immune receptor stimulation with defined ligands. Human cytokine and chemokine biomarker data provides a tool to test hypotheses on the relationship between innate immune capacity in vivo and expression of current or future clinical phenotypes. The most important limitations of experimental strategies that have been used to date are reviewed. Detailed experimental protocols are provided for characterization of pattern recognition receptor (PRR)-driven stimulation with a panel of bacterial (TLR4, TLR5) and viral (TLR3, TLR7/8, RIG-I/MDA5) ligands to assess the role played by human pro-inflammatory, anti-inflammatory, Th1-like, and Th2-like responses. The importance of characterizing human innate immune phenotypes extends beyond discovery-based research to development of improved strategies for prevention or inhibition of chronic inflammatory diseases, improved design of immunization programs, and more effective cancer immunotherapy.

Naturally occurring tolerance acquisition to foods in previously allergic children is characterized by antigen specificity and associated with increased subsets of regulatory T cells

BACKGROUND

Food allergy affects approximately 6-8% of children, and increasing in prevalence. Some children naturally outgrow their food allergy without intervention, but the mechanisms by which this occurs remain poorly understood. We sought to investigate the role of regulatory T cells in the development of naturally acquired tolerance.

METHODS

Fifty-eight children (1-18 years) with either egg or peanut allergy, recent acquisition of natural tolerance to egg or peanut, or no food allergy were studied. Peripheral blood mononuclear cells (PBMC) from these groups were stimulated with relevant antigen for 48 h and flow cytometry performed to characterize both surface (CD3, CD4, CD25, CD14, CD19, and CD127) and intracellular markers (IL-10, Foxp3, and IL-5).

RESULTS

Resting PBMC from naturally tolerant patients had significantly increased CD3+CD4+CD25+CD127loFoxp3+ cells, when compared to allergic or control patients (mean 6.36 vs. 2.37 vs. 2.62%, respectively, P < 0.05). Upon stimulation with relevant antigen, naturally tolerant patients also had increased IL-10-expressing CD25+CD127lo cells (6.33 vs. 1.65 vs. 0.7, P < 0.01), Foxp3+ cells (mean 12.6 vs. 5.42 vs. 3%, P < 0.01), and CD4+ cells (mean 4.48 vs. 1.59 vs. 0.87%, P < 0.01); the increase was not observed in PBMCs from allergic or control patients. Additionally, this upregulation was only seen with relevant antigen stimulation and not upon stimulation with unrelated antigen.

CONCLUSION

The increased CD3+CD4+CD25+CD127lo cells at baseline and upon stimulation and increased induction of IL-10-producing cells of several types, including Tr1 cells, from naturally tolerant patients suggests an important role for regulatory T cell subsets in the acquisition of natural tolerance.

Optimizing the diagnosis of food allergy

Accurately diagnosing a patient with a possible food allergy is important to avoid unnecessary dietary restrictions and prevent life-threatening reactions. Routine testing modalities have limited accuracy, and an oral food challenge is often required to make a definitive diagnosis. Given that they are labor intensive and risk inducing an allergic reaction, several alternative diagnostic modalities have been investigated. Testing for IgE antibodies to particular protein components in foods has shown promise to improve diagnostics and has entered clinical practice. Additional modalities show potential, including epitope binding, T-cell studies, and basophil activation.

Hypersensitivity linked to exposure of broad bean protein(s) in allergic patients and BALB/c mice

OBJECTIVE

Broad bean (Vicia faba L.), a common vegetable, belongs to the family Fabaceae and is consumed worldwide. Limited studies have been done on allergenicity of broad beans. The aim of this study was to determine if broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

METHODS

Simulated gastric fluid (SGF) assay and immunoglobulin E (IgE) immunoblotting were carried out to identify pepsin-resistant and IgE-binding proteins. The allergenicity of broad beans was assessed in allergic patients, BALB/c mice, splenocytes, and RBL-2H3 cells.

RESULTS

Eight broad bean proteins of approximate molecular weight 70, 60, 48, 32, 23, 19, 15, and 10 kDa that remained undigested in SGF, showed IgE-binding capacity as well. Of 127 allergic patients studied, broad bean allergy was evident in 16 (12%). Mice sensitized with broad bean showed increased levels of histamine, total and specific IgE, and severe signs of systemic anaphylaxis compared with controls. Enhanced levels of histamine, prostaglandin D2, cysteinyl leukotriene, and β-hexosaminidase release were observed in the primed RBL-2H3 cells following broad bean exposure. The levels of interleukin IL-4, IL-5, IL-13 and regulated on activation, normal T-cell expressed and secreted were found enhanced in broad bean-treated splenocytes culture supernatant compared with controls.

CONCLUSION

This study inferred that broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

Oral immunotherapy and tolerance induction in childhood

Prevalence rates of food allergy have increased rapidly in recent decades. Of concern, rates of increase are greatest among children under 5 yrs of age and for those food allergies that persist into adulthood such as peanut or tree nut allergy and shellfish allergy. Given these trends, the overall prevalence of food allergy will compound over time as the number of children affected by food allergy soars and a greater proportion of food-allergic children are left with persistent disease into adulthood. It is therefore vital to identify novel curative treatment approaches for food allergy. Acquisition of oral tolerance to the diverse array of ingested food antigens and intestinal microbiota is an active immunologic process that is successfully established in the majority of individuals. In subjects who develop food allergy, there is a failure or loss of oral tolerance acquisition to a limited number of food allergens. Oral immunotherapy (OIT) offers a promising approach to induce specific oral tolerance to selected food allergens and represents a potential strategy for long-term curative treatment of food allergy. This review will summarize the current understanding of oral tolerance and clinical trials of OIT for the treatment of food allergy.

Immune responses to inhalant allergens

This overview describes the nature of the immune responses induced by the inhalation of allergens. There is a dichotomy in that B cells have multiple mechanisms that limit the amount of immunoglobulin E (IgE) antibody production, whereas T-cell responses are large even in nonallergic subjects. With the possible exception of responses to cat allergen, however, T cells from nonallergic subjects have limited effector function of helping IgG antibody, and in house-dust mite allergy, this declines with age. Regulation by interleukin 10 (IL-10)-producing cells and CD25⁺ T-regulatory cells has been proposed, but critically, there is limited evidence for this, and many studies show the highest IL-10 production by cells from allergic subjects. Recent studies have shown the importance of nonlymphoid chemokines thymic stromal lymphopoietin and IL-27, so studying responses in situ is critical. Most sources of allergens have 1 or 2 dominant allergens, and for house-dust mite, it has been shown that people have a predictable responsiveness to high-, mid-and poor-IgE-binding proteins regardless of the total size of their response. This allergen hierarchy can be used to design improved allergen preparations and to investigate how antiallergen responses are regulated.

Beyond skin testing: state of the art and new horizons in food allergy diagnostic testing

Food allergy affects approximately 1% to 10.8% of the general population, and its prevalence seems to be increasing. An accurate diagnosis is particularly important because a misdiagnosis could lead to life-threatening reactions or to unnecessary restrictive diets. However, allergy tests currently used in clinical practice have limited accuracy, and an oral food challenge, considered as the gold standard, is often required to confirm or exclude a food allergy. This article reviews several promising novel approaches for the diagnosis of food allergy, such as new molecular diagnostic technologies and functional assays, along with their potential clinical applications.

Food allergy: recent advances in pathophysiology and diagnosis

Approximately 5% of young children and 3-4% of adults exhibit adverse immune responses to foods in westernized countries, with a tendency to increase. The pathophysiology of food allergy (FA) relies on immune reactions triggered by epitopes, i.e. small amino-acid sequences able to bind to antibodies or cells. Some food allergens share specific physicochemical characteristics that allow them to resist digestion, thus enhancing allergenicity. These allergens encounter specialized dendritic cell populations in the gut, which leads to T-cell priming. In case of IgE-mediated allergy, this process triggers the production of allergen-specific IgE by B cells. Tissue-resident reactive cells, including mast cells, then bind IgE, and allergic reactions are elicited when these cells, with adjacent IgE molecules bound to their surface, are re-exposed to allergen. Allergic reactions occurring in the absence of detectable IgE are labeled non-IgE mediated. The abrogation of oral tolerance which leads to FA is likely favored by genetic disposition and environmental factors (e.g. increased hygiene or enhanced allergenicity of some foods). For an accurate diagnosis, complete medical history, laboratory tests and, in most cases, an oral food challenge are needed. Noticeably, the detection of food-specific IgE (sensitization) does not necessarily indicate clinical allergy. Novel diagnostic methods currently under study focus on the immune responses to specific food proteins or epitopes of specific proteins. Food-induced allergic reactions represent a large array of symptoms involving the skin and gastrointestinal and respiratory systems. They can be attributed to IgE-mediated and non-IgE-mediated (cellular) mechanisms and thus differ in their nature, severity and outcome. Outcome also differs according to allergens.

Immunologic similarities between selected autoimmune diseases and peanut allergy: possible new therapeutic approaches

Food allergies are an important medical problem in Westernized countries. Allergy to peanuts is a dramatic example of a food allergy that tends to be particularly severe and long-lived. This article examines food allergy-specifically peanut allergy-from the perspective that tolerance to foods is a normal state, just as tolerance to self-proteins is a normal state. From this vantage point, loss of tolerance to foods in food-allergic individuals can be viewed as parallel to the loss of tolerance to self-proteins in those with autoimmune diseases. Although our knowledge base is far from satisfactory, there are important similarities in the immunologic abnormalities that are characteristic of both peanut allergy and several autoimmune diseases. Delineation of these similarities may open the door to new therapeutic approaches for the treatment of severe food allergies.

Dendritic cell and T cell responses in children with food allergy

BACKGROUND

Food allergy (FA) and eosinophilic oesophagitis (EE) are increasingly common clinical problems. Dendritic cells (DCs) are key regulators of the sensitization and effector phases of allergic immune responses, but their role in these diseases is largely unknown.

OBJECTIVE

To evaluate for alterations in the phenotype and function of DCs in children with IgE-mediated milk allergy or EE compared with their non-affected siblings.

METHODS

Plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) were prepared from peripheral blood of children with milk allergy (FA), EE, and non-affected siblings (CON). Purified pDCs and mDCs were cultured alone or with autologous CD4(+) lymphocytes. Cytokine levels in plasma, or culture supernatants following stimulation, were measured using multiplex array immunoassay. Cell-surface molecule expression was determined by flow cytometry.

RESULTS

DCs from FA subjects produced greater levels of pro-inflammatory cytokines (IL-6, TNF-α), granulocyte macrophage-colony forming factor, and mDC-derived IL-10 compared with controls following allergen exposure. T(H) 2 but not T(H) 1 cytokines were spontaneously produced in DC-CD4(+) T cell co-cultures from children with FA and were not significantly increased after stimulation with milk extract, suggesting an ongoing activation in vivo. This hypothesis was further supported by evidence for elevated IL-5 and IL-13 protein in the plasma of children with both FA and EE. The only significant DC phenotypic differences were: (1) reduced levels of CD80 in EE subjects and (2) FcɛRI expression that correlated with serum IgE levels in both groups of subjects.

CONCLUSION

This study suggests that DCs from children with FA and EE produce more pro-inflammatory cytokines, and that their CD4(+) T cells are spontaneously activated to produce T(H) 2 cytokines in the presence of FcɛRI-bearing DCs.

Eosinophilic gastrointestinal disease and peanut allergy are alternatively associated with IL-5+ and IL-5(-) T(H)2 responses

BACKGROUND

Both anaphylactic food allergy and eosinophil-associated gastrointestinal disorders are associated with T(H)2 responses and food-specific IgE, yet they have very different clinical presentations.

OBJECTIVE

To determine whether the clinical differences between anaphylactic food allergy and eosinophil-associated gastrointestinal disorders are reflected in different T(H)2 responses to foods.

METHODS

Subjects with peanut allergy (PA), subjects with allergic eosinophilic gastroenteritis (AEG), and nonatopic subjects were enrolled. Antigen-specific IL-4, IL-5, IFN-gamma, and TNF T-cell responses to peanut, soy, and shrimp were measured by using intracellular cytokine staining and polychromatic flow cytometry.

RESULTS

Two distinct subpopulations of T(H)2 cells were found: IL-5+ T(H)2 (IL-4+, IL-5+) and IL-5(-) T(H)2 (IL-4+, IL-5(-)) cells. Peanut-specific IL-5+ T(H)2 cells were present at a 20-fold greater frequency in AEG versus PA (81 vs 4 per 10(6) CD4 cells; P = .05), whereas there were similar frequencies of IL-5(-) T(H)2 cells (67 vs 41 per 10(6)). For all foods, IL-5+ T(H)2 cells accounted for a significantly greater fraction of the antigen-specific cells in AEG relative to PA (29% vs 4%; P < .0001). In PA but not AEG, IL-5(-) T(H)2 responses to peanut were highly correlated with peanut-specific IgE (r = 0.87 vs 0.55, respectively). All subject groups elicited similar very low-magnitude T(H)1 responses to food antigens.

CONCLUSION

T(H)2 responses are composed of 2 subpopulations: IL-5+ T(H)2 and IL-5(-) T(H)2 cells. IL-5+ T(H)2 food allergen-specific T cells are singularly associated with AEG, whereas PA is associated with a dominant IL-5(-) T(H)2 response. These results suggest heterogeneity within the T(H)2 cytokine response, with different T(H)2 responses alternatively favoring IgE-mediated or eosinophil-dominant immunopathology.

T cell responses to major peanut allergens in children with and without peanut allergy

BACKGROUND

T cell responses involved in peanut allergy are poorly understood.

OBJECTIVE

To investigate T cell responses towards major peanut allergens in peanut-allergic (PA) subjects compared with peanut-sensitized (PS) non-allergic children and non-atopic (NA) controls.

METHODS

Eighteen PA children, seven non-allergic PS children and 11 NA adults were included. Peripheral blood mononuclear cells were stimulated with a crude peanut extract (CPE). Short-term T cell lines were generated and subsequently stimulated with CPE and purified Ara h 1, Ara h 2, Ara h 3 and Ara h 6. The proliferation and production of IL-13, IFN-gamma, IL-10 and TNF-alpha were analysed.

RESULTS

Proliferation to CPE and major allergens was enhanced in PA subjects. The primary response to CPE was comparable with PS subjects, with increased production of IL-13 and IFN-gamma compared with NA. Production of IL-10 was not observed. In short-term T cell lines, the response to CPE was stronger in PA than in PS and NA subjects. Only PA children had a detectable response to major peanut allergens, characterized by IL-13 production. The response was the highest after Ara h 3 stimulation, and the lowest after Ara h 2 stimulation. No significant correlation was observed between peanut-specific IgE levels and T cell responses to CPE.

CONCLUSION

T cell responses to CPE in PA and PS children were characterized by Th1 and Th2 cytokines. Only PA children showed enhanced Th2 responses to Ara h 1, Ara h 3 and Ara h 6.

Food allergy

Adverse immune responses to foods affect approximately 5% of young children and 3% to 4% of adults in westernized countries and appear to have increased in prevalence. Food-induced allergic reactions are responsible for a variety of symptoms and disorders involving the skin and gastrointestinal and respiratory tracts and can be attributed to IgE-mediated and non-IgE-mediated (cellular) mechanisms. Genetic disposition and environmental factors might abrogate oral tolerance, leading to food allergy. Disease outcomes are influenced by the characteristics of the immune response and of the triggering allergen. Diagnosis is complicated by the observation that detection of food-specific IgE (sensitization) does not necessarily indicate clinical allergy. Therefore diagnosis requires a careful medical history, laboratory studies, and, in many cases, an oral food challenge to confirm a diagnosis. Novel diagnostic methods, including ones that focus on immune responses to specific food proteins or epitopes of specific proteins, are under study. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and to initiate therapy (eg, with injected epinephrine for anaphylaxis) in case of an unintended ingestion. Improved therapeutic strategies under study include oral and sublingual immunotherapy, Chinese herbal medicine, anti-IgE antibodies, and modified vaccines.

Food allergy: recent advances in pathophysiology and treatment

Food allergies, defined as an adverse immune response to food proteins, affect as many as 6% of young children and 3%-4% of adults in westernized countries, and their prevalence appears to be rising. In addition to well-recognized acute allergic reactions and anaphylaxis triggered by IgE antibody-mediated immune responses to food proteins, there is an increasing recognition of cell-mediated disorders such as eosinophilic gastroenteropathies and food protein-induced enterocolitis syndrome. We are gaining an increasing understanding of the pathophysiology of food allergic disorders and are beginning to comprehend how these result from a failure to establish or maintain normal oral tolerance. Many food allergens have been characterized at a molecular level, and this knowledge, combined with an increasing appreciation of the nature of humoral and cellular immune responses resulting in allergy or tolerance, is leading to novel therapeutic approaches. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and initiating therapy if ingestion occurs. However, numerous strategies for definitive treatment are being studied, including sublingual/oral immunotherapy, injection of anti-IgE antibodies, cytokine/anticytokine therapies, Chinese herbal therapies, and novel immunotherapies utilizing engineered proteins and strategic immunomodulators.

T cell proliferation and cytokine responses to ovalbumin and ovomucoid detected in children with and without egg allergy

BACKGROUND

The specific T cell responses in egg allergy and resolution have not been fully elucidated.

OBJECTIVE

To characterize egg allergen-specific T cells of children with active and resolved egg allergy, in comparison with non-allergic controls.

METHOD

We studied children with active (n=35) or resolved (n=20) egg allergy determined by oral challenge, and non-allergic controls (n=15). Peripheral blood mononuclear cells were labelled with carboxyfluorescein succinimidyl ester (CFSE) and stimulated with ovalbumin (OVA), ovomucoid (OM) or tetanus toxoid. Flow cytometry was used to detect divided CD3+ CFSE(lo) cells that expressed intra-cytoplasmic IL-4 or IFN-gamma. The cell division index (CDI) was calculated as a measure of allergen-specific proliferation. Peanut-specific T cells of a subgroup of children who also had peanut allergy were also studied.

RESULTS

OVA-specific T cells were found in subjects with active (87%) or resolved (75%) egg allergy and in controls (67%), with a trend towards increased T cell proliferation in allergy. OM-induced weaker T cell responses than OVA, stimulating fewer responders (46% allergic, 50% resolved, 60% controls) and 10-fold less proliferation [CDI(OVA) 2.0 (median), 25.6 (maximum) vs. CDI(OM) 0.2 (median), 15.1 (maximum); P<0.01]. Both egg allergens induced significant IL-4+ (median 10%, range 1.4-58%) and IFN-gamma+ (median 28%, range 4.5-63%) cells in responders, including non-allergics. There were no significant differences in IFN-gamma+ or IL-4+ cells or in IFN-gamma/IL-4 ratios between groups. Peanut-specific T cell proliferation was significantly higher in peanut allergy [CDI(CPE) 16.5 (median), 24.8 (maximum)] compared with controls [CDI(CPE) 2.1 (median), 16.1 (maximum)] but cytokine profiles were not different. Tetanus-specific T cells were seen in 90% of the subjects, with no significant inter-group differences in responses.

CONCLUSION

Egg allergen-specific T cells are readily detected in all groups and not restricted to egg allergy. In contrast, peanut-specific proliferation was significantly higher in peanut allergy. This suggests that T cell responses in peanut and egg allergy may differ. We did not find T helper type 2-deviated cytokine responses in egg or peanut allergy.

Peanut allergy: Emerging concepts and approaches for an apparent epidemic

Peanut allergy is typically lifelong, often severe, and potentially fatal. Because reactions can occur from small amounts, the allergy presents patients with significant obstacles to avoid allergic reactions. In North America and the United Kingdom, prevalence rates among schoolchildren are now in excess of 1%, framing an increasing public health concern and raising research questions about environmental, immunologic, and genetic factors that may influence outcomes of peanut allergy. This review focuses on recent observations that continue to question the influences of maternal and infant diet on outcomes of peanut allergy, and explore how peanut may be uniquely suited to induce an allergic response. We highlight studies that affect current diagnosis, management, and the nature of advice that can be provided to patients, including the utility of diagnostic tests, doses that elicit reactions, characteristics of reactions from exposure, issues of cross-reactivity, concerns about peanut contamination of manufactured goods, and the natural course of the allergy. Clinical, molecular, and immunologic advances are reviewed, highlighting research discoveries that influence strategies for improved diagnosis, prevention, and treatment. Among the therapeutic strategies reviewed are sublingual and oral immunotherapy, anti-IgE, Chinese herbal medicine, and vaccine strategies.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects

This review highlights some of the research advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported primarily in the Journal in 2006. Advances in diagnosis include identification of food proteins to which IgE binding is associated with severe reactions; elucidation of diagnostic relationships of skin prick test wheal size with outcomes of egg, tree nut, and sesame allergy; evaluation of the diagnostic utility of atopy patch testing for food; and the observation that yellow jacket sting outcomes are influenced by species. Mechanistic observations include the following: heating of birch pollen-related foods disrupts IgE binding but not T-cell epitopes; a simple imbalance of T(H)1/T(H)2 response does not explain variations in clinical expression of peanut allergy; and elucidation of the role of dendritic cells in drug hypersensitivity. With regard to treatment, a rapidly disintegrating epinephrine tablet showed promise for sublingual treatment of anaphylaxis, RNA interference techniques showed promise in creating lower-allergenic foods, and anti-IL-5 showed promise for treatment of eosinophilic esophagitis. Progress in our understanding of the immunology and the etiology of skin barrier dysfunction in atopic dermatitis has also been made. These observations will likely contribute toward optimizing management of these common allergic disorders.