Milk-induced urticaria is associated with the expansion of T cells expressing cutaneous lymphocyte antigen

High-dimensional immune profiles correlate with phenotypes of peanut allergy during food-allergic reactions

BACKGROUND

Food challenges carry a burden of safety, effort and resources. Clinical reactivity and presentation, such as thresholds and symptoms, are considered challenging to predict ex vivo.

AIMS

To identify changes of peripheral immune signatures during oral food challenges (OFC) that correlate with the clinical outcome in patients with peanut allergy (PA).

METHODS

Children with a positive (OFC⁺ , n = 16) or a negative (OFC^- , n = 10) OFC-outcome were included (controls, n = 7). Single-cell mass cytometry/unsupervised analysis allowed unbiased immunophenotyping during OFC.

RESULTS

Peripheral immune profiles correlated with OFC outcome. OFC⁺ -profiles revealed mainly decreased Th2 cells, memory Treg and activated NK cells, which had an increased homing marker expression signifying immune cell migration into effector tissues along with symptom onset. OFC^- -profiles had also signs of ongoing inflammation, but with a signature of a controlled response, lacking homing marker expression and featuring a concomitant increase of Th2-shifted CD4⁺ T cells and Treg cells. Low versus high threshold reactivity-groups had differential frequencies of intermediate monocytes and myeloid dendritic cells at baseline. Low threshold was associated with increased CD8⁺ T cells and reduced memory cells (central memory [CM] CD4⁺ [Th2] T cells, CM CD8⁺ T cells, Treg). Immune signatures also discriminated patients with preferential skin versus gastrointestinal symptoms, whereby skin signs correlated with increased expression of CCR4, a molecule enabling skin trafficking, on various immune cell types.

CONCLUSION

We showed that peripheral immune signatures reflected dynamics of clinical outcome during OFC with peanut. Those immune alterations hold promise as a basis for predictive OFC biomarker discovery to monitor disease outcome and therapy of PA.

Are avoidance diets still warranted in children with atopic dermatitis?

Nearly 40% of children with moderate-to-severe atopic dermatitis (AD) have IgE-mediated food allergy (FA). This clinical observation has been extensively documented by experimental data linking skin inflammation in AD to FA, as well as by food challenges reproducing symptoms and avoidance diets improving AD. Although food avoidance may improve AD, avoidance diets do not cure AD, may even have detrimental effects such as progression to immediate-type allergy including anaphylactic reactions, and may significantly reduce the quality of life of the patient and the family. AD care should focus upon optimal medical management, rather than dietary elimination. Food allergy testing is primarily indicated when immediate-type allergic reactions are a concern. In recalcitrant AD, if food is being considered a possible chronic trigger, a limited panel of foods may be tested. An avoidance diet is only indicated in patients clearly identified as food allergic by an appropriate diagnostic food challenge, and after adequately informing the family of the limited benefits, and possible harms of an elimination diet.

Emerging therapies for food allergy

Food allergy is a common condition for which there are currently no approved treatments except avoidance of the allergenic food and treatment of accidental reactions. There are several potential treatments that are under active investigation in animal and human studies, but it is not yet clear what the best approach may be. Here, we review approaches that are currently in clinical trials, including oral, sublingual, and epicutaneous immunotherapy, immunotherapy combined with anti-IgE, and Chinese herbal medicine as well as approaches that are in preclinical or early clinical investigation, including modified protein immunotherapy, adjuvants, DNA vaccines, and helminth administration. We discuss the importance of fully exploring the risks and benefits of any treatment before it is taken to general clinical practice and the need for clarity about the goals of treatment.

T cell homing to epithelial barriers in allergic disease

Allergic inflammation develops in tissues that have large epithelial surface areas that are exposed to the environment, such as the lung, skin and gut. In the steady state, antigen-experienced memory T cells patrol these peripheral tissues to facilitate swift immune responses against invading pathogens. In at least two allergy-prone organs, the skin and the gut, memory T cells are programmed during the initial antigen priming to express trafficking receptors that enable them to preferentially home to these organs. In this review we propose that tissue-specific memory and inflammation-specific T cell trafficking facilitates the development of allergic disease in these organs. We thus review recent advances in our understanding of tissue-specific T cell trafficking and how regulation of T cell trafficking by the chemokine system contributes to allergic inflammation in mouse models and in human allergic diseases of the skin, lung and gut. Inflammation- and tissue-specific T lymphocyte trafficking pathways are currently being targeted as new treatments for non-allergic inflammatory diseases and may yield effective new therapeutics for allergic diseases.

Allergic triggers in atopic dermatitis

Food or environmental allergens play a significant pathogenic role in a subgroup of patients with atopic dermatitis (AD) and can trigger eczema flares. This review focuses on when and which diagnostic and allergen-avoidance measures are beneficial. Diagnosis of allergic triggers may be aided by skin-prick tests measuring serum-specific IgE and/or atopy patch tests (APT) based on the patient's history, and when necessary, oral food challenges (OFC). In a subset of patients, therapeutic measures, such as elimination of the incriminated allergen(s), can lead to marked improvement of AD; this is especially true for food allergens, but can also apply to inhalant allergens.

Characterization of the allergic T-cell response to Pru p 3, the nonspecific lipid transfer protein in peach

BACKGROUND

Pru p 3, the nonspecific lipid transfer protein from peach, is an important plant food allergen that frequently induces systemic reactions.

OBJECTIVE

We sought to analyze the allergic T-cell response to Pru p 3.

METHODS

PBMCs from Italian and Spanish patients with peach allergy were stimulated with purified natural Pru p 3. Allergen-specific T-cell lines were used to identify T-cell epitopes of Pru p 3. Pru p 3-specific T-cell clones (TCCs) were analyzed for allergen-induced secretion of IL-4, IFN-gamma, and IL-10 and expression of the integrin beta7, a receptor critical for gut homing.

RESULTS

No difference in T-cell responses of Italian and Spanish patients was found. Among several T cell-activating regions, Pru p 3(13-27), Pru p 3(34-48), Pru p 3(43-57), and Pru p 3(61-75) were most frequently recognized in 18 Pru p 3-specific T-cell lines. The majority of 32 Pru p 3-specific TCCs belonged to the T(H)2 subset. In contrast to TCCs specific for other plant food and pollen allergens, only a limited number of Pru p 3-specific TCCs produced significant amounts of IL-10. The expression of integrin beta7 on Pru p 3-specific TCCs was comparable with that observed on peanut-specific TCCs and higher compared with that seen in different pollen-specific TCCs.

CONCLUSION

The T-cell response to Pru p 3 is dominated by T(H)2 cells presumably primed in the gut. The identification of relevant T cell-activating regions provides a basis for engineering hypoallergenic variants of Pru p 3 with less IgE binding and retained T-cell stimulatory capacity for safe immunotherapy of peach allergy.

Isolation and phenotypic characterization of mucosal nasal lymphocytes by direct ex vivo analysis

Cellular inflammation of the nasal mucosa demonstrates a local immune response which plays an important role in allergic rhinitis. The aim of the present study was to characterize nasal mucosal lymphocytes regarding their activation and differentiation state by direct ex vivo flowcytometric analysis. Lymphocytes from the inferior turbinates were isolated by a mechanical method of preparation and, for comparison, from peripheral blood by Ficoll gradient centrifugation. Patients suffering from rhinitis or difficulty in nasal breathing were divided into an allergic (pollen-allergy, n = 13) and non-allergic group (n = 24). Expression of different T- and B-cell markers was determined by flowcytometric analysis. CD4+ T-cells from the nasal mucosa exhibited a memory phenotype (CD45RO+, 97%), were highly activated (CD69+, 43-73%), and showed low expression of the cutaneous lymphocyte antigen (CLA+, 5%). Nasal CD20+ B-lymphocytes expressed significantly higher levels of mIgE and lower levels of CD23 and CD80 than peripheral B-cells. Subsets of CD80+ (4%) and CD86+ (6%) CD20+ B-lymphocytes were identified in the nasal mucosa. No significant differences between allergic and non-allergic individuals were determined. As expected, the data show profound phenotypical differences between circulating peripheral blood and nasal mucosal lymphocytes. Activated memory lymphocytes are present in the nasal mucosa from allergic, but also non-allergic patients and may indicate to a significant role of a local inflammatory state without systemic criteria for allergy. In our study, we show that direct ex vivo isolation of lymphocytes is practicable method and offers a new technique to examine the local nasal allergic immune response using a multiparametric phenotypical analysis.

Acute urticaria[corrected]-like lesions in allergen-unexposed cutaneous tissues in a mouse model of late allergic rhinitis

The mechanisms of distant manifestation after a local allergic reaction are largely unknown. This study examined the development of cutaneous lesions in a mouse model of late allergic rhinitis (LAR). BALB/c mice were sensitized by ovalbumin (OVA) intraperitoneally two times (on days 0 and 10) and challenged by OVA intranasally on day 14. Four days after OVA challenge, nasal and cutaneous lesions including helper T (Th) responses, expression of adhesion molecules and presence of OVA and IgE were examined, and compared with unsensitized and unchallenged (control) mice. Compared with the control group, the LAR group developed LAR characterized by infiltration of lymphocytes and eosinophils, increased IgE values and increased productions of IL-4 and IL-5, but not IFN-gamma. A dominant infiltration of eosinophils and increase in mast cells, attachment of eosinophils to endothelium, intense expression of VCAM-1 on endothelium in venules and VLA-4 expression on eosinophils and mast cells were recognized in the cutaneous tissues. There were no differences in the expression of ICAM-1 on vascular endothelium and LFA-1 on infiltrated leucocytes between the two groups. CLA expression on lymphocytes was not detected, and the binding of OVA and IgE on mast cells and eosinophils was found in the cutaneous lesions in the LAR group, but not in the control group. This study suggests that acute urticaria[corrected]-like lesions in OVA-unexposed cutaneous tissues may be induced by immediate allergic reaction due to the systemic development of Th2-type response in a mouse model of LAR.

Other Allergic Skin Disorders

In this chapter we discuss allergic skin disorders other than atopic dermatitis (AD): the urticaria-angioedema syndrome, allergic contact dermatitis (ACD), protein contact dermatitis (PCD), phytodermatitis, allergic photodermatitis and allergic vasculitis.

Memory T cell proliferation in cow's milk allergy after CD25+ regulatory T cell removal suggests a role for casein-specific cellular immunity in IgE-mediated but not in non-IgE-mediated cow's milk allergy

BACKGROUND

Previously reported increased lymphocyte proliferative responses in cow's milk allergy (CMA) may have been influenced by the lipopolysaccharides (LPS) which contaminate most commercial cow's milk protein (CMPs). Moreover, peripheral blood mononuclear cells (PBMC) contain both B cells, CD45RA+ naïve T cells, CD25+ regulatory T cells (Tregs) in addition to antigen-specific CD45RA- memory T cells.

METHODS

PBMC from clinically reactive and tolerised patients with IgE- and non-IgE-mediated CMA were depleted of CD45RA+ T cells and putative CD25+ Tregs. The proliferative index to LPS-depleted alpha-, beta- and kappa-casein and beta-lactoglobulin was compared in the memory T-cell-enriched, Treg-depleted PBMC and in bulk PBMC.

RESULTS

Clinically reactive IgE-mediated CMA patients had increased responses to caseins only. Tolerised patients, particularly those with atopic dermatitis, had decreased responses to kappa-casein which were restored after Treg depletion. Interleukin-4 and interferon-gamma were generally not detected in the culture supernatants. No differences were seen between reactive and tolerant delayed non-IgE-mediated CMA patients.

CONCLUSIONS

Proliferative responses to alpha-, beta- and kappa-caseins (but not beta-lactoglobulin) were observed in clinically reactive IgE-mediated CMA patients only. A markedly decreased proliferative response to kappa-casein in tolerised IgE-mediated CMA patients with atopic dermatitis, which was abrogated by Treg depletion, suggested a role for kappa-casein in tolerance induction. Non-IgE-mediated CMA patients had no increased proliferative response to any milk proteins.

Food allergies: prevalence, molecular characterization, and treatment/prevention strategies

A significant proportion of the population is either affected by or concerned about food allergy. Our knowledge about food allergens and how they stimulate the immune system has increased dramatically over the past decade. However, reasons for the increased prevalence of food allergy are not clear. The diagnosis of food allergy requires that the patient and caregivers examine all foods for the presence of potential allergens in order to prevent inadvertent ingestion and further reactions. Fortunately, many children develop tolerance to allergenic foods after a period of dietary elimination. Various immunotherapy approaches are under investigation to alleviate or prevent food-induced reactions in those who have persistent food allergies.

New aspects on inflammation in allergic diseases

BACKGROUND

Allergic disease has currently reached epidemic proportions, with a high percentage of individuals in the developed world exhibiting an allergic response after exposure to some common environmental factors. Although new strategies for the treatment and management of allergic diseases have decreased the mortality rate, a high percentage of affected persons still require frequent hospitalization and experience decreased quality of life.

METHODS

An internet-based literature search was performed for recent contributions on the underlying mechanisms provoking an allergic response and their potential for therapeutic approaches.

RESULTS

Novel concepts on allergic responses have emerged: allergic disease may result from an imbalance between allergen activation of regulatory T cells and effector T helper 2 cells (Th2), a process in which dendritic cells are key players. Cytokines such as interleukin (IL)-6, IL-21, IL-25, and human thymic stromal lymphopoietin (TSLP) seem to be important contributors in allergic processes. New data on IgE effector responses and on the IgE-independent mechanisms involved in allergic reactions have resolved some unanswered questions about these reactions.

CONCLUSIONS

These new findings on allergic diseases have important implications for diagnosis and management, with potential improvements in prevention and treatment, which could provide a cure in the future.

Mechanistic analysis of experimental food allergen-induced cutaneous reactions

Individuals with food allergy often present with uritcaria and atopic dermatitis. Indeed, susceptibility to food allergy may predispose to the development of these cutaneous allergic disorders. Recently, we developed a model of food allergy, whereby oral consumption of food [pea Pisum sativum L.; expressing alpha-amylase inhibitor-1 (alphaAI) from the common bean Phaseolus vulgaris L. cv Tendergreen (pea-alphaAI)] promotes a T helper cell type 2 (Th2) inflammatory response and predisposes to cutaneous allergic reactions following subsequent food allergen (alphaAI) exposure. To delineate the kinetics of food allergen-induced cutaneous reactions and examine the inflammatory mechanisms involved in this allergic reaction, we used interleukin (IL)-13-, IL-4 receptor alpha-, and eotaxin-1-deficient mice and performed serum transfer and CD4+ T cell depletion studies. We demonstrate that consumption of pea-alphaAI promotes an alphaAI-specific immunoglobulin G1 (IgG1) and IgE antibody response. Furthermore, we show that subsequent food allergen (alphaAI) challenge in the skin induced an early (3 h)- and late-phase (24 h) cutaneous allergic reaction. The early-phase response was associated with mast cell degranulation and the presence of Ig, whereas the late-phase response was characterized by a lymphoid and eosinophilic infiltrate, which was critically regulated by CD4+ T cells, IL-13, and eotaxin-1. Collectively, these studies demonstrate that food allergy can predispose to cutaneous inflammatory reactions, and these processes are critically regulated by Th2 immune factors.

Nonimmunoglobulin e-mediated immune reactions to foods

: Adverse food reactions are abnormal responses to ingested foods. Reactions vary from immunologic to nonimmunologic immune reactions and can be either immunoglobulin E (IgE) mediated or non-IgE mediated. Food-induced IgE-mediated reactions range from localized urticaria to anaphylaxis and have been well studied. However, in comparison, there has been significantly less research into non-IgE-mediated food reactions. Non-IgE-mediated reactions can cause respiratory, gastrointestinal, and cutaneous symptoms. The most recent evidence suggests that these reactions are probably T-cell mediated as evidenced in lymphocyte proliferation assays. This review will explore the symptoms and testing methods of the most common non-IgE-mediated reactions.

Humoral and cellular responses to cow milk proteins in patients with milk-induced IgE-mediated and non-IgE-mediated disorders

BACKGROUND

Cow milk allergy (CMA) is one of the most common food allergies in childhood. Patients with CMA present with a wide range of immunoglobulin (Ig)E- and non-IgE-mediated clinical syndromes. Limited information is known about the specific humoral and cellular responses to cow milk proteins in these various forms of CMA.

OBJECTIVE

The aim of the study was to determine IgE, IgA, IgG1 and IgG4 antibody levels and lymphocyte proliferative responses to the major cow milk allergens in patients with IgE- and non-IgE-mediated CMA.

METHODS

One hundred and forty cow milk allergic patients, 6 months to 22 years of age, were included in the study. One hundred and thirteen patients had IgE-mediated CMA, 11 had milk protein-induced enterocolitis syndrome and 16 had allergic eosinophilic gastroenteritis. Twenty-one patients without food allergy, 8 months to 18 years of age, served as controls. Serum IgE, IgA, IgG1 and IgG4 antibodies to alpha-, beta-, and kappa-casein, alpha-lactalbumin and beta-lactoglobulin were measured using enzyme-linked immunosorbent assays. For a subset of these patients, we performed lymphocyte proliferation assays to the various milk allergens.

RESULTS

Patients with IgE-mediated CMA had higher specific IgE concentrations to casein compared with whey proteins (P < 0.001). In this group of patients, there was a positive correlation between IgE levels and levels of the other isotypes for all four milk proteins (P < 0.001). In general, the caseins were the more allergenic and antigenic proteins in all groups of patients. Patients with enterocolitis syndrome produced less milk protein-specific IgG4 (P < 0.05) and had a trend for higher IgA antibody levels when compared to the control group. Lymphocyte proliferative responses in all groups with CMA were significantly higher than controls (P < 0.05), although this response was similar in patients with IgE- and non-IgE-mediated CMA.

CONCLUSION

There is a distinct pattern of humoral antibody response in the different forms of CMA. Patients with IgE-mediated CMA have an elevated polyisotypic response to cow milk protein. The relative lack of specific IgG4 production in patients with enterocolitis syndrome may be involved in the pathogenesis of the disease. In general, caseins appear to be the predominant allergen in patients with CMA.

T lymphocytes and food allergy

Food allergy is a hypersensitivity reaction to normally harmless substances and involves humoral immune responses, mediated by immunoglobulin (IgE) synthesized by B lymphocytes, and cellular immune responses mediated by T lymphocytes. An IgE-mediated mechanism leads to clinical symptoms occurring immediately after food ingestion, e. g., "the oral allergy syndrome". For delayed reactions involving the gastrointestinal tract or the skin, the underlying immune mechanisms are less clear. In order to elucidate the cellular response to food allergens, human allergen-specific T cell cultures generated in vitro represent helpful tools. The majority of food allergen-specific CD4(+) T lymphocytes isolated from food-allergic individuals was found to synthesize high levels of IL-4 and IL-13, two cytokines required for initiation of IgE synthesis. Due to selective homing profiles, food-specific T cells seem also to be involved in defining the target organ of the allergic inflammation. Recent data provide evidence that in addition to IgE-mediated inflammation, food allergen-specific T lymphocytes may also cause inflammatory responses independently of IgE-mediated mechanisms.

Role of food allergy in atopic dermatitis

PURPOSE OF REVIEW

Food allergy and atopic dermatitis often occur in the same patient. Based on clinical data from the past few decades, it is clear that foods such as cow's milk and hen's eggs can directly provoke flares of atopic dermatitis particularly in sensitized infants, whereas inhaled allergens and pollen-related foods are of greater importance in older children, adolescents and adults. Because the role and immunology of food allergy in atopic dermatitis remain controversial, here we review data that mainly focus on skin eczema and food allergy.

RECENT FINDINGS

Clinical studies have revealed that more than 50% of all children with atopic dermatitis that can be exacerbated by certain foods will react with a worsening of skin eczema alone or in addition to immediate symptoms. Adolescents and adults also react to foods, but reactions to 'classical' food allergens such as hen's eggs and cow's milk are not as common as in childhood. Subgroups of children and of adults with atopic dermatitis do, however, react to pollen-associated foods. Both immunoglobulin E associated and independent T-cell mediated responses appear to be involved in clinical eczematous reactions.

SUMMARY

Food-induced eczema should be diagnosed only by a thorough diagnostic procedure, taking into account the patient's history, the degree of sensitization and the clinical relevance of the sensitization. More clinical and immunological studies are needed to unravel the pathophysiology and the different rates of clinical responsiveness to different foodstuffs in patients with atopic dermatitis.

Presence of IgE antibodies to bacterial superantigens and increased IL-13-producing T cells in myelitic patients with atopic diathesis

BACKGROUND

Superantigens are considered to exacerbate autoimmune inflammation through the expansion of autoreactive T cells; however, the immune response to bacterial superantigens has not been extensively studied in any type of myelitis. We recently reported the occurrence of a distinct type of myelitis in patients with atopic diathesis, which in a recent nationwide survey was reported to be widespread in Japan. The aim of this study was to investigate the presence of IgE antibodies to bacterial superantigens and the proportion of IL-13- or IL-5-producing CD4+ or CD8+ T cells in patients with myelitis and atopic diathesis.

METHODS

Twenty-four myelitic patients with and 12 myelitic patients without hyperIgEemia, 28 patients with multiple sclerosis (MS) and 34 healthy controls were enrolled in this study. IgE antibodies to staphylococcal enterotoxins A (SEA) and B (SEB) in sera were measured using a liquid-phase enzyme immunoassay, and the intracellular production of IL-5 and IL-13 in peripheral blood CD4+ and CD8+ T cells was measured by flow cytometry.

RESULTS

The myelitic patients with hyperIgEemia showed significantly higher positive rates of serum SEA/SEB-specific IgE antibodies (41.7 and 62.5%, respectively) than the healthy controls (5.9 and 8.8%), patients with MS (0 and 21.4%) and those with normoIgEemic myelitis (0 and 0%). Moreover, IL-13-producing CD4+ T cells and CD8+ T cells increased significantly in the myelitic patients with hyperIgEemia compared to the controls, while IL-5-producing CD4+ or CD8+ T cells did not.

CONCLUSIONS

The IgE response to staphylococcal superantigens is heightened in myelitic patients with atopic diathesis, which might contribute to increases in IL-13-producing T cells and thus the development of myelitis.

Management of food allergies

Worldwide, approximately 8 and 2% of children and adults, respectively, suffer from food allergy. Cow's milk, egg, peanut, soy, wheat, fish, shellfish and tree nuts are responsible for the majority of allergic reactions to foods. Allergic reactions to food can occur by a variety of immune mechanisms including: IgE-mediated; non-IgE-mediated (T-cell-mediated); and combined IgE- and T-cell-mediated. Food allergies can affect any organ system, but most frequently involve the gastrointestinal system, the skin and the respiratory system. Knowledge of the spectrum of food allergies is important in order to identify patients at risk for severe or life-threatening allergic reactions. This article will review the mechanisms of specific food allergy disorders. It will also summarise the diagnosis of food allergy including the history of a food reaction, skin tests and laboratory tests. The management of food allergy will also be discussed with particular emphasis on the avoidance of food allergens and the pharmacotherapy of allergic reactions. Future therapy for food allergies will also be discussed.

IgE and non-IgE food allergy

BACKGROUND

Food allergy (FA) is characterized by an abnormal immunologic reactivity to food proteins. The gastro-intestinal tract serves not only a nutritive function but also is a major immunologic organ. Although previously thought to be triggered primarily by an IgE-mediated mechanism of injury, considerable evidence now suggests that non-IgE mechanisms may also be involved in the pathogenesis of FA.

OBJECTIVE

To review the immunologic disturbances that occur in FA and to correlate these with the clinical manifestations expressed in affected target organs based upon a classification of IgE and non-IgE mechanisms.

METHODS

Data collected from a computerized MEDLINE search were used for the analysis of the following topics: immediate GI hypersensitivity, oral allergy syndrome, acute urticaria and angioedema, acute bronchospasm, celiac disease, cow's milk enteropathy, dietary protein enterocolitis, breast milk colitis, proctolitis, proctitis, dermatitis herpetiformis, Heiner syndrome, eosinophilic gastroenteritis, atopic dermatitis, asthma, attention-deficit-hyperactivity disorder and behavioral disorders, as well as systems affected by mucosal associated lymphoid tissue-mediated injury of associated lymphoid tissues and the immunologic deviation to Th1 or Th2 mechanisms of FA.

CONCLUSIONS

The results of this review allow the construction of a central, unifying hypothesis for a new classification of FA as follows: the clinical manifestations of FA, expressed in affected target organs, may be the result of immunologic injury mediated by interaction of food antigens with contiguous elements of mucosal associated lymphoid tissue. These appear to be modulated by relative imbalances of the Th1/Th2 paradigm, which may be the ultimate determinant governing the expression of FA as IgE-mediated, non--IgE-mediated, or mixed forms of IgE/non-IgE mechanisms of FA.

The T lymphocyte in food-allergy disorders

PURPOSE OF REVIEW

While much attention is focused upon the role of IgE antibodies in food-allergy disorders, the T cell remains central to all forms, both IgE and non-IgE-mediated, of food-hypersensitivity responses. This review considers the central role of the T cell in this group of disorders and provides a comprehensive overview of recent studies that elucidate our understanding of the mechanisms involved in the pathogenesis of food allergy in regard to the role of the T cell.

RECENT FINDINGS

Recent studies have defined a dynamic process involving T cell homing receptors (e.g. cutaneous lymphocyte antigen) and activation markers in food-hypersensitivity disorders. Modulation of the T-cell responses occurs through the recognition of dominant allergenic epitopes, the elaboration of regulatory cytokines (e.g. transforming growth factor-beta, IL-4, IL-5, tumor necrosis factor-alpha) and the influence of immunomodulatory microbial and environmental agents. The resulting disorders reflect T-cell dysregulation.

SUMMARY

Significant recent advances in our understanding of the role of the T cell in food hypersensitivity have been made and will probably contribute to improved diagnostic and treatment methods in the near future.

Advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insect venom

This review highlights some of the research advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insect venom that were reported primarily in this Journal from 2001 to 2002. Among the topics highlighted: Epinephrine injected intramuscularly into the thigh provides the most efficient absorption profile for adults and children; determination of serum IgE antibody-specific food allergen concentrations and atopy patch tests with foods show promise for enhanced diagnostic accuracy; numerous food allergens are now characterized on the molecular level, allowing for improved diagnostic and treatment modalities; the complex immunologic mechanisms underlying drug hypersensitivity reactions are being elucidated; venom immunotherapy improves quality of life for sufferers, and increased venom immunotherapy doses are useful in recalcitrant cases.

Advances in allergic skin diseases

During the past year there have been significant advances in our understanding of the mechanisms underlying allergic skin diseases. This article reviews some of these advances in atopic dermatitis and urticaria. The introduction of a new class of topical anti-inflammatory medications, topical calcineurin inhibitors, has significantly increased our treatment options and led to a rethinking of potential management approaches in atopic dermatitis.