A pilot study of the usefulness and safety of a ready-to-use atopy patch test (Diallertest) versus a comparator (Finn Chamber) during cow's milk allergy in children

The role of the atopy patch test in the diagnostic work-up of non-IgE gastrointestinal food allergy in children: a systematic review

The "Atopy Patch Test" (APT) has been proposed as a diagnostic tool for food allergies (FA), especially in children with FA-related gastrointestinal symptoms. However, its diagnostic accuracy is debated, and its usefulness is controversial. The aim of this systematic review was to evaluate the APT diagnostic accuracy compared with the diagnostic gold standard, i.e., the oral food challenge (OFC), in children affected by non-IgE mediated gastrointestinal food allergies, including the evaluation in milk allergic subgroup. Both classical non-IgE mediated clinical pictures and food induced motility disorders (FPIMD) were considered. The search was conducted in PubMed and Scopus from January 2000 to June 2022 by two independent researchers. The patient, intervention, comparators, outcome, and study design approach (PICOS) format was used for developing key questions, to address the APT diagnostic accuracy compared with the oral food challenge (OFC). The quality of the studies was assessed by the QUADAS-2 system. The meta-analysis was performed to calculate the pooled sensitivity, specificity, DOR (diagnostic odds ratio), PLR (positive likelihood ratio), and NLR (negative likelihood ratio) with their 95% confidence intervals (CI). Out of the 457 citations initially identified via the search (196 on PubMed and 261 on Scopus), 37 advanced to full-text screening, and 16 studies were identified to be included in the systematic review. Reference lists from relevant retrievals were searched, and one additional article was added. Finally, 17 studies were included in the systematic review. The analysis showed that APT has a high specificity of 94% (95%CI: 0.88-0.97) in the group of patients affected by FPIMD. Data showed a high pooled specificity of 96% (95% CI: 0.89-0.98) and the highest accuracy of APT in patients affected by cow's milk allergy (AUC = 0.93).      Conclusion: APT is effective in identifying causative food in children with food-induced motility disorders.  What is Known: • Atopy patch test could be a useful diagnostic test for diagnosing food allergy, especially in children with food allergy-related gastrointestinal symptoms. What is New: • Atopy patch test may be a useful tool in diagnosing non IgE food allergy, especially in children with food-induced gastrointestinal motility disorders and cow's milk allergy.

Cows' Milk Allergy-Associated Constipation: When to Look for It? A Narrative Review

Constipation is a very common disorder, mostly functional in nature, that may persist for years in up to 35-52% of children. Food allergy prevalence, severity and persistence are increasing over time, and cows' milk protein is the commonest food allergen recognised to affect gastrointestinal motility in children. There is mounting evidence of the role of cows' milk (CM) allergy (CMA) in children with constipation. With this narrative review, we aim to provide clinicians with an updated and critical overview of food allergy-associated constipation. We searched Embase, Medline and the Cochrane Library, using keywords related to the topic. Only reviews and studies including children aged 0-17 years that were published in English were considered. Constipation has been reported in 4.6% of infants with CMA; the prevalence of food allergy underlying chronic constipation in children resistant to conventional treatment and presenting to tertiary clinics ranges between 28% and 78%. The identification of predisposing risk factors and of a specific phenotype of food allergy-induced constipation remains elusive. No allergic tests, radiological or motility investigations achieve sufficient sensitivity and specificity to screen children for CMA-related constipation. A 4-week cows' milk protein (CMP) elimination diet may be considered for children with chronic constipation resistant to conventional treatment and who lack alarm sign/symptoms of organic diseases. In subjects with ameliorated symptoms on CMP elimination, the diagnosis of CMA should be confirmed by a food challenge to avoid an unnecessary protracted diet.

The diagnostic value of APT for food allergy in children: a systematic review and meta-analysis

BACKGROUND

The role of atopy patch test (APT) in the diagnosis of food allergy (FA) remains largely controversial. In our meta-analysis, we aimed to evaluate the accuracy of APT for diagnosing FA in children.

METHODS

Pubmed, Embase and Cochrane Library were searched for studies regarding the diagnostic value of APT for FA in children compared to oral food challenge (double-blind placebo-controlled food challenge and/or open food challenge). The last search was conducted on November 11, 2017. Two reviewers independently screened relevant studies and assessed the quality by QUADAS-2. Meta-analysis was performed to calculate the pooled sensitivity, specificity, DOR (diagnostic odds ratio), PLR (positive likelihood ratio), NLR (negative likelihood ratio) with their 95% confidence intervals (CIs). Subgroup analyses were conducted according to different food allergens, atopic dermatitis, gastrointestinal symptoms, and age younger than 3 years.

RESULTS

Forty-one studies were included in the meta-analysis. The pooled sensitivity, specificity, PLR, NLR and DOR were 50.30% (95% CI 48.40%-52.30%), 86.60% (95% CI 85.30%-87.80%), 3.405 (95% CI 2.594-4.470), 0.545 (95% CI 0.469-0.634) and 7.528 (95% CI 5.507-11.206), respectively. However, for children with FA-related gastrointestinal symptoms, the pooled sensitivity and specificity were 57.40% (95% CI 52.10%-62.50%) and 91.50% (95% CI 88.30%-94.10%) respectively.

CONCLUSIONS

Our findings suggest that APT is specific but not sensitive for diagnosing FA in children, especially in children with FA-related gastrointestinal symptoms.

Experimental Models for Studying Food Allergy

Immunoglobulin E-mediated food allergy is rapidly developing into a global health problem. Publicly available therapeutic intervention strategies are currently restricted to allergen avoidance and emergency treatments. To gain a better understanding of the disease pathophysiology so that new therapies can be developed, major research efforts have been put into studying food allergy in mice. Animal models should reflect the human pathology as closely as possible to allow for a rapid translation of basic science observations to the bedside. In this regard, experimental models of food allergy provide significant challenges for research because of discrepancies between the presentation of disease in humans and mice. The goal of this review is to give a summary of commonly used murine disease models and to discuss how they relate to the human condition. We will focus on epicutaneous sensitization models, on mouse strains that sensitize spontaneously to food as seen in humans, and on models in humanized animals. In summary, expanding the research toolbox of experimental food allergy provides an important step toward closing gaps in our understanding of the derailing immune mechanism that underlies the human disease. The availability of additional experimental models will provide exciting opportunities to discover new intervention points for the treatment of food allergies. (Cell Mol Gastroenterol Hepatol 2018;x:x).

Eosinophilic Esophagitis: A Comprehensive Review

Eosinophilic esophagitis (EoE) is an emerging chronic atopic clinical-pathologic disease with an estimated prevalence of 1/1000 similar to the one of Crohn's diseases. Usually, EoE is firstly suspected due to symptoms that are caused by esophageal dysfunction and/or fibrosis. EoE diagnosis is confirmed if the esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf) as a peak value in one or more of at least four specimens obtained randomly from the esophagus. Most of the patients affected by EoE have other atopic diseases such as allergic rhinitis, asthma, IgE-mediated food allergies, and/or atopic dermatitis. The local inflammation is a T helper type 2 (Th2) flogosis, which most likely is driven by a mixed IgE and non-IgE-mediated reaction to food and/or environmental allergens. Recently published genetic studies showed also that EoE is associated with single nucleotide polymorphism (SNP) on genes which are important in atopic inflammation such as thymic stromal lymphopoietin (TSLP) located close to the Th2 cytokine cluster (IL-4, IL-5, IL-13) on chromosome 5q22. When the EoE diagnosis is made, it is imperative to control the local eosinophilic inflammation not only to give symptomatic relief to the patient but also to prevent complications such as esophageal stricture and food impaction. EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance.

Novel Delivery Routes for Allergy Immunotherapy: Intralymphatic, Epicutaneous, and Intradermal

Current allergy immunotherapy protocols suffer from two main problems: long treatment duration and systemic allergic side effects of the allergen administrations. The immunologic effects of allergen administration could be enhanced and the number of allergen administrations and treatment duration reduced by choosing a tissue for administration that contains a high density of antigen-presenting cells. Local side effects could be reduced by choosing a route characterized by a low density of mast cells, and systemic side effects could be reduced by administration to nonvascularized tissues, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Epicutaneous immunotherapy for food allergy as a novel pathway for oral tolerance induction

Epicutaneous immunotherapy is a developing technique, aiming at desensitizing patients with food allergy with less risks that oral ingestion or injection could generate. Several clinical trials have been performed and are currently running, in milk and peanut allergy, assessing the safety of the technique and its efficacy. Preclinical models indicate a major role in the mechanisms of desensitization, for example, Tregs and epigenetic modifications.

An allergist's perspective to the evaluation of Eosinophilic Esophagitis

Eosinophilic Esophagitis (EoE) is a classic atopic disease as it shares features with other atopic disease on all levels including pathogenesis, genetics, epidemiology, and treatment options. EoE has elements of Th2 pathogenesis with increase levels of Th2 cytokines (IL4, 5, and 13). In addition, it shares atopic genetic risk factors including thymic stromal lymphopoietin (TSLP) loci as a risk factor in genome wide association studies. EoE patients have a higher rate of other atopic disease (asthma, allergic rhinitis and food allergy) compared to the general population indicating their atopic phenotype. Like asthma, atopic dermatitis or food allergy, EoE has increased in the last 20 years. Treatment options include the basic principle of other atopic diseases include using topical steroids or avoidance of the triggers (food or pollen). An allergist provides a critical role as they are experts in the treatment of atopic disease including avoidance strategies.

Needle-free and adjuvant-free epicutaneous boosting of pertussis immunity: Preclinical proof of concept

The limited durability of pertussis vaccine-induced protection requires novel approaches to reactivate immunity and limit pertussis resurgence in older children and adults. We propose that periodic boosters could be delivered using a novel epicutaneous delivery system (Viaskin) to deliver optimized pertussis antigens such as genetically-detoxified pertussis toxin (rPT). To best mimic the human situation in which vaccine-induced memory cells persist, whereas antibodies wane, we developed a novel adoptive transfer murine model of pertussis immunity. This allowed demonstrating that a single application of Viaskin delivering rPT and/or pertactin and filamentous hemagglutinin effectively reactivates vaccine-induced pertussis immunity and protects against Bordetella pertussis challenge. Recalling pertussis immunity without needles nor adjuvant may considerably facilitate the acceptance and application of periodic boosters.

The impact of dietary therapy on clinical and biologic parameters of pediatric patients with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a clinicopathologic disease that presents with a massive infiltration of the esophagus by eosinophils triggered by food antigen(s).

OBJECTIVE

To determine the impact of dietary therapy on nutritional parameters in patients who present with EoE.

METHODS

A convenience retrospective study analyzed patients with EoE after a 2-month dietary therapy (6-food elimination diet, avoidance of the 6 most common allergenic foods, plus avoidance of those eliciting positive skin testing, plus amino-acid formula as replacement for dairy products). Pre- and postdiet allergic and nutritional status were evaluated.

RESULTS

Of 111 eligible patients, 59 patients, with a median age of 77.7 months (range, 9-189 months) were enrolled. Dietary therapy significantly increased the return to normal endoscopic appearance (47.4%, P < .0009) and led to complete remission (<5 eosinophils/esophageal HPF and disappearance of symptoms) in 59.3%. All symptoms improved, digestive (98.3%), cutaneous (80%), and respiratory (92.8%). The prediet median weight-for-height (WFH) z score was -0.75 (-3.00 to 5.69), and the postdiet WFH did not significantly differ, -0.51 (-3.09 to 5.00). The prediet WFH z score was less than -2 (moderate malnutrition) in 10.1%. Postdiet blood eosinophils counts decreased in absolute numbers and in counts ≥ 500 × 10(6)/L (P < .0001). Evaluation after 1 year of progressive reintroduction of eliminated foods was available in 33 children: the median WFH z score did not significantly improve, from -0.89 (range, -3.00 to 0.67) at enrollment to -0.59 (range, -3.66 to 2.24).

CONCLUSION

The nutritional status of children with EoE was mildly affected and not worsened by the 2-month dietary therapy.

Epicutaneous Immunotherapy for Aeroallergen and Food Allergy

IgE-mediated allergies today affect up to 30 % of the population in industrialized countries. Allergen immunotherapy is the only disease-modifying treatment option with a long-term effect. However, very few patients (<5 %) choose immunotherapy, due to the long treatment duration (between 3-5 years) and possible local and systemic allergic side effects of the allergen administrations. The latter occur when an allergen accidentally reaches the blood circulation. Therefore, the ideal application route for allergen immunotherapy should be characterized by two hallmarks: firstly, by a high number of potent antigen-presenting cells, which enhance efficacy and thus shorten treatment duration. Secondly, the allergen administration site is ideally non-vascularized, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized. The epidermis contains high numbers of potent antigen-presenting Langerhans cells and, as an epithelium, is non-vascularized. Therefore, the epidermis represents an interesting administration route. Historical evidence for the clinical efficacy of epicutaneous allergy immunotherapy (EPIT) has now been strengthened by a number of recent double-blinded placebo-controlled clinical trials performed by independent groups. We review the immunological rationale, history and clinical experience with epicutaneous allergy immunotherapy.

Treating cow's milk protein allergy: a double-blind randomized trial comparing two extensively hydrolysed formulas with probiotics

AIM

The treatment for cow's milk protein allergy (CMPA) is a diet with an extensive hydrolysate. This study aimed to determine whether a whey (eWH) or casein hydrolysate (eCH) is the best option.

METHODS

Infants with suspected CMPA were treated with an eWH or eCH, and efficacy was assessed with a symptom-based score developed by the authors. Diagnosis of CMPA was based on a positive challenge. If positive, the same eHF/eCH was continued. If negative, a standard starter and follow-up formula were given up to the age of 12 months.

RESULTS

An open challenge was performed on 85/116 (73%) infants suspected of CMPA on clinical grounds and was positive in 59/85 (69%). After 1 month, the symptom-based scores in both groups showed significant statistical and clinical reductions, and total and specific IgE and skin prick test results were similar. Both hydrolysates were enriched with probiotics, which were recovered in the gastrointestinal flora. The eWH-Standard Formula sequence led to better growth at the age of 1 year than the other three feeding regimens tested.

CONCLUSION

The eWH and eCH are equally effective. The symptom-based score is a useful tool to evaluate the efficacy of dietary treatment in infants with CMPA.

Intact skin and not stripped skin is crucial for the safety and efficacy of peanut epicutaneous immunotherapy (EPIT) in mice

Background

Epicutaneous immunotherapy (EPIT) on intact skin with an epicutaneous delivery system has already been used in preclinical and clinical studies. In epicutaneous vaccination and immunotherapy, the stripping of skin before application of the allergen is suggested to facilitate the passage of allergen through immune cells.

Objectives

The aim of this study was to compare the immunological response induced by EPIT performed on intact and stripped skin in a mouse model of peanut allergy.

Methods

After oral sensitization with peanut and cholera toxin, BALB/c mice were epicutaneously treated using an epicutaneous delivery system (Viaskin® (DBV Technologies, Paris) applied either on intact skin or on stripped skin. Following EPIT, mice received an exclusive oral peanut regimen, aimed at triggering esophageal and jejunal lesions. We assessed eosinophil infiltration by histology, mRNA expression in the esophagus, antibody levels and peripheral T-cell response.

Results

EPIT on intact skin significantly reduced Th2 immunological response (IgE response and splenocyte secretion of Th2 cytokines) as well as esophageal eosinophilia (2.7 ± 0.9, compared to Sham 19.9 ± 1.5, p < 0.01), mRNA expression of Th2 cytokines in tissue and intestinal villus sub-atrophia (2.9 ± 0.2 vs Sham, 2.1 ± 0.2, p < 0.05). By contrast, EPIT on stripped skin reinforced Th2 systemic immunological response as well as eosinophil infiltration (26.8 ± 15.1), mRNA expression of Th2 cytokines and duodenal villus/crypt-ratio (2.4 ± 0.3).

Conclusions

Epicutaneous allergen-specific immunotherapy needs the integrity of superficial layers of the stratum corneum to warranty safety of treatment and to induce a tolerogenic profile of the immune response.

Diagnostic approach and management of cow's-milk protein allergy in infants and children: ESPGHAN GI Committee practical guidelines

OBJECTIVES

This guideline provides recommendations for the diagnosis and management of suspected cow's-milk protein allergy (CMPA) in Europe. It presents a practical approach with a diagnostic algorithm and is based on recently published evidence-based guidelines on CMPA.

DIAGNOSIS

If CMPA is suspected by history and examination, then strict allergen avoidance is initiated. In certain circumstances (eg, a clear history of immediate symptoms, a life-threatening reaction with a positive test for CMP-specific IgE), the diagnosis can be made without a milk challenge. In all other circumstances, a controlled oral food challenge (open or blind) under medical supervision is required to confirm or exclude the diagnosis of CMPA.

TREATMENT

In breast-fed infants, the mother should start a strict CMP-free diet. Non-breast-fed infants with confirmed CMPA should receive an extensively hydrolyzed protein-based formula with proven efficacy in appropriate clinical trials; amino acids-based formulae are reserved for certain situations. Soy protein formula, if tolerated, is an option beyond 6 months of age. Nutritional counseling and regular monitoring of growth are mandatory in all age groups requiring CMP exclusion. REEVALUATION: Patients should be reevaluated every 6 to 12 months to assess whether they have developed tolerance to CMP. This is achieved in >75% by 3 years of age and >90% by 6 years of age. Inappropriate or overly long dietary eliminations should be avoided. Such restrictions may impair the quality of life of both child and family, induce improper growth, and incur unnecessary health care costs.

Epicutaneous immunotherapy (EPIT) blocks the allergic esophago-gastro-enteropathy induced by sustained oral exposure to peanuts in sensitized mice

Background

Food allergy may affect the gastrointestinal tract and eosinophilia is often associated with allergic gastrointestinal disorders. Allergy to peanuts is a life-threatening condition and effective and safe treatments still need to be developed. The present study aimed to evaluate the effects of sustained oral exposure to peanuts on the esophageal and jejunal mucosa in sensitized mice. We also evaluated the effects of desensitization with epicutaneous immunotherapy (EPIT) on these processes.

Methods

Mice were sensitized by gavages with whole peanut protein extract (PPE) given with cholera toxin. Sensitized mice were subsequently exposed to peanuts via a specific regimen and were then analysed for eosinophilia in the esophagus and gut. We also assessed mRNA expression in the esophagus, antibody levels, and peripheral T-cell response. The effects of EPIT were tested when intercalated with sensitization and sustained oral peanut exposure.

Results

Sustained oral exposure to peanuts in sensitized mice led to severe esophageal eosinophilia and intestinal villus sub-atrophia, i.e. significantly increased influx of eosinophils into the esophageal mucosa (136 eosinophils/mm²) and reduced villus/crypt ratios (1.6±0.15). In the sera, specific IgE levels significantly increased as did secretion of Th2 cytokines by peanut-reactivated splenocytes. EPIT of sensitized mice significantly reduced Th2 immunological response (IgE response and splenocyte secretion of Th2 cytokines) as well as esophageal eosinophilia (50 eosinophils/mm², p<0.05), mRNA expression of Th2 cytokines in tissue - eotaxin (p<0.05), IL-5 (p<0.05), and IL-13 (p<0.05) -, GATA-3 (p<0.05), and intestinal villus sub-atrophia (2.3±0.15). EPIT also increased specific IgG2a (p<0.05) and mRNA expression of Foxp3 (p<0.05) in the esophageal mucosa.

Conclusions

Gastro-intestinal lesions induced by sustained oral exposure in sensitized mice are efficaciously treated by allergen specific EPIT.

Epicutaneous Immunotherapy Compared with Sublingual Immunotherapy in Mice Sensitized to Pollen (Phleum pratense)

Background. The aim of this study was to compare the efficacy of epicutaneous immunotherapy (EPIT) to sublingual immunotherapy (SLIT) in a model of mice sensitized to Phleum pratense pollen. Methods. BALB/c mice were sensitized by sub-cutaneous route to pollen protein extract mixed treated for 8 weeks, using sham, EPIT, or SLIT. Measurements involved the serological response and cytokine profile from reactivated splenocytes, plethysmography after aerosol challenge to pollen, cell, and cytokine contents in the bronchoalveolar lavages (BALs). Results. After immunotherapy, sIgE was significantly decreased in the treated groups compared to sham (P < 0.001), whereas sIgG2a increased with EPIT and SLIT (P < 0.001 and P < 0.005 versus sham). Reactivated splenocytes secreted higher levels of Th2 cytokines with sham (P < 0.01). Penh values were higher in sham than EPIT and SLIT. Eosinophil recruitment in BAL was significantly reduced only by EPIT (P < 0.01). Conclusion. In this model of mice sensitized to pollen, EPIT was at least as efficient as SLIT.

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.

Epicutaneous allergen administration: is this the future of allergen-specific immunotherapy?

IgE-mediated allergies, such as allergic rhinoconjunctivitis and asthma, have become highly prevalent, today affecting up to 30% of the population in industrialized countries. Allergen-specific immunotherapy (SIT) either subcutaneously or via the sublingual route is effective, but only few patients (<5%) choose immunotherapy, as treatment takes several years and because allergen administrations are associated with local and, in some cases, even systemic allergic side-effects because of allergen accidentally reaching the circulation. In order to resolve these two major drawbacks, the ideal application site of SIT should have two characteristics. First, it should contain a high number of potent antigen-presenting cells to enhance efficacy and shorten treatment duration. Secondly, it should be nonvascularized in order to minimize inadvertent systemic distribution of the allergen and therefore systemic allergic side-effects. The epidermis, a nonvascularized multilayer epithelium, that contains high numbers of potent antigen-presenting Langerhans cells (LC) could therefore be an interesting administration route. The present review will discuss the immunological rational, history and actual clinical experience with epicutaneous allergen-specific immunotherapy.

Atopy patch test for early diagnosis of cow's milk allergy in preterm infants

Atopy patch test may help early diagnosis of cow-milk allergy in preterm infants. In the retrospective analysis of 5 girls and 9 boys, born at 31 +/- 2 (mean +/- SD) weeks of gestation and presenting digestive symptoms at age 42 +/- 18 days, 10 had a complete recovery following the shift to an exclusive feeding with an amino acid-based formula. Cow-milk-skin prick tests and specific immunoglobulin E were always negative, whereas the atopy patch test was positive in 7 of the 10 infants with complete recovery.

Epicutaneous immunotherapy on intact skin using a new delivery system in a murine model of allergy

BACKGROUND

Allergen-specific immunotherapy, subcutaneous immunotherapy (SCIT) or oral, has been used for almost a century to redirect inappropriate immune responses in atopic patients. A new mode of administration through the intact skin [epicutaneous immunotherapy (EPIT)], using an original epicutaneous delivery system, may represent an alternative to these classical methods.

OBJECTIVE

Proof of concept of efficacy of EPIT on intact skin in mice sensitized to aeroallergens or food allergens.

METHODS

Mice were sensitized to pollen (n=18), house dust mite (HDM, n=24), ovalbumin (OVA, n=18) or peanut (n=18), and allocated to four groups: EPIT, SCIT, not treated (NT) and control. Specific Ig (sIg)E, sIgG1 and sIgG2a were monitored. After 8 weeks of treatment, plethysmography was performed after aerosol provocation with appropriate allergens.

RESULTS

At the highest doses of methacholine, pause enhancement (Penh) values were significantly decreased in the EPIT group vs. the sensitized NT groups (7.5 vs. 12.3 - pollen, 7.6 vs. 8.9 - HDM, 11.5 vs. 14.5 - OVA, 7.6 vs. 12.8 - peanut, respectively) (P<0.05). With all the allergens tested, Penh values were similar in SCIT, EPIT and control. IgG2a for pollen, HDM, OVA and peanuts were significantly increased in the EPIT group vs. NT: 0.97 vs. 0.42 microg/mL, 2.5 vs. 0.46 microg/mL, 0.39 vs. 0.05 microg/mL and 15.0 vs. 5.5 microg/mL, respectively (P<0.05). There were no significant differences between EPIT and SCIT groups. The IgE/IgG2a ratio decreased significantly in the EPIT group for the four allergens from 70 to 58 (pollen), 175 to 26 (HDM), 5433 to 120 (OVA) and 49 to 6 (peanut), respectively (P<0.05).

CONCLUSION

In mice sensitized to the four allergens tested, EPIT was as efficacious as SCIT, considered as the reference immunotherapy. These first results have to be confirmed by clinical studies.

Patch test in the diagnosis of food allergy

Double-blind, placebo-controlled food challenges (DBPCFC) are the gold standard method for diagnosing food allergies. However, due to the difficulty of their performance on routine clinic, there is a need for laboratory tools in order to minimise the frequency of DBPCFC. Atopy patch test (APT) represents a promising manner of diagnosing delayed-type allergic reactions. The APT may identify patients with food allergies with negative specific IgE. However, the clinical relevance of positive APT reactions is still to be proven by standardised outcome definitions.

Tomato atopy patch test in adult atopic dermatitis: diagnostic value and comparison among different methods

Tomato atopy patch test in adult atopic dermatitis.

A method for the analysis of milk and egg allergens for the atopy patch test

The patch test with food antigens (atopy patch test, APT) has been reported as a more specific method than prick or RAST for the early detection of cow's milk and/or egg sensitizations in children. Standardization of APT extracts is a major issue on the road towards full clinical exploitation of this assay. Here, we used sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to characterize sensitivity and specificity of commercial preparations of APT for milk and egg allergies, which are expected to improve the reliability of this test, when compared with fresh food allergen sources. We found that: (i) SDS-PAGE is an appropriate technique for quality control of APT and (ii) commercial milk and egg APT are equivalent to fresh food preparations in terms of allergen content. Clinical trials aimed at characterizing sensitivity and specificity of APT in the diagnosis of food allergy in children will benefit from this technique.

The diagnosis of food allergy in children

PURPOSE OF REVIEW

To give an update about the optimal diagnostic work-up for children with suspected food allergy.

RECENT FINDINGS

Food allergy has become a very severe health problem not only for many children and parents, but also for the entire medical and paramedical community. The financial and social costs related to these conditions are increasing, but, contemporarily, basic and clinical research are deeply involved in the search of possible solutions to facilitate the management of these patients.

SUMMARY

Food allergy is defined as an abnormal immunological reaction to food proteins, which causes an adverse clinical reaction. Over 90% of food allergies in childhood are caused by eight foods: cow's milk, hen's egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The evaluation of a child with suspected food allergy includes detailed medical history, physical examination, screening tests and response to elimination diet and to oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude it. The main principle of food allergy management is avoidance of the offending antigen. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child's nutritional status and growth.

Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment

During the last decade, clinical practice saw a rapid increase of patients with esophageal eosinophilia who were thought to have gastroesophageal reflux disease (GERD) but who did not respond to medical and/or surgical GERD management. Subsequent studies demonstrated that these patients had a "new" disease termed eosinophilic esophagitis (EE). As recognition of EE grew, so did confusion surrounding diagnostic criteria and treatment. To address these issues, a multidisciplinary task force of 31 physicians assembled with the goal of determining diagnostic criteria and making recommendations for evaluation and treatment of children and adults with suspected EE. Consensus recommendations were based upon a systematic review of the literature and expert opinion. EE is a clinicopathological disease characterized by (1) Symptoms including but not restricted to food impaction and dysphagia in adults, and feeding intolerance and GERD symptoms in children; (2) > or = 15 eosinophils/HPF; (3) Exclusion of other disorders associated with similar clinical, histological, or endoscopic features, especially GERD. (Use of high dose proton pump inhibitor treatment or normal pH monitoring). Appropriate treatments include dietary approaches based upon eliminating exposure to food allergens, or topical corticosteroids. Since EE is a relatively new disease, the intent of this report is to provide current recommendations for care of affected patients and defining gaps in knowledge for future research studies.

Diagnostic accuracy of the atopy patch test in children with food allergy-related gastrointestinal symptoms

BACKGROUND

Little is known about the diagnostic accuracy of atopy patch tests (APT) in the clinical practice of pediatric gastroenterology. Moreover, APTs containing purified food extracts have recently become available, but their diagnostic accuracy is largely undefined.

PATIENTS AND METHODS

We evaluated the diagnostic accuracy of food challenge, skin prick test (SPT), serum specific IgE determination, and APT using fresh food and commercial food extracts in parallel in children referred for suspected food allergy-related gastrointestinal symptoms.

RESULTS

Eighty-nine food challenges were performed in 60 patients (38 boys, median age 23 months, range 3-48 months): 31 tested positive for cow's milk (CM), 19 for hen's egg (HE), and two for wheat. Specific immunoglobulin E (IgE) determination, and SPT, respectively, were positive in 7/31 and 14/31 of patients with cow's milk allergy (CMA), and in 7/19 and 7/19 with HE allergy. The results of APT with fresh food vs a commercial assay were (1) CM: sensitivity: 64.5%vs 6.4%, specificity 95.8%vs 95.6%, positive predictive value (PPV) 95.2%vs 66.6% and negative predictive value (NPV) 67.6%vs 43.1%; (2) HE: sensitivity 84.2%vs 5.2%, specificity 100%vs 100%, PPV 100%vs 100% and NPV 75.0%vs 33.3%.

CONCLUSIONS

Atopy patch test is a useful tool in the diagnostic work up of children with food-allergy-related gastrointestinal symptoms. The diagnostic accuracy of ATP was higher with fresh food than with commercial food extracts.

Atopy patch test in the diagnosis of food allergy in children with atopic dermatitis

Atopic eczema/dermatitis syndrome (AEDS) is one of the most common chronic allergic diseases in children. Among the allergens found to be relevant in AEDS, aeroallergens and food allergens are the most important. The exposure of these patients to their relevant protein allergens can trigger an exacerbation or maintain the disease. AEDS is frequently associated with food allergy, which complicates the management in approximately 40% of these children. Atopy patch test (APT) can help in detecting food allergies in children with AEDS. The earliest publication on patch testing in eczema was described in 1937 by Rostenberg, but the first controlled clinical trial was provided by Mitchell in 1982. APT with food allergens were introduced into clinical use in 1996 by the group of Isolauri. APT test is performed epicutaneously with typical immediate-type allergens (aeroallergens or foods). As a number of apparently minor test modifications greatly influence the sensitivity, specificity, and reproducibility of the APT, the European Task Force on Atopic Dermatitis (ETFAD) has developed a standardized APT technique. APT has developed into a valuable additional tool in the diagnostic work-up of food allergy in infants and children with atopic dermatitis.

Food allergy in gastroenterologic diseases: Review of literature

Food allergy is a common and increasing problem worldwide. The newly-found knowledge might provide novel experimental strategies, especially for laboratory diagnosis. Approximately 20% of the population alters their diet for a perceived adverse reaction to food, but the application of double-blind placebo-controlled oral food challenge, the “gold standard” for diagnosis of food allergy, shows that questionnaire-based studies overestimate the prevalence of food allergies. The clinical disorders determined by adverse reactions to food can be classified on the basis of immunologic or nonimmunologic mechanisms and the organ system or systems affected. Diagnosis of food allergy is based on clinical history, skin prick tests, and laboratory tests to detect serum-food specific IgE, elimination diets and challenges. The primary therapy for food allergy is to avoid the responsible food. Antihistamines might partially relieve oral allergy syndrome and IgE-mediated skin symptoms, but they do not block systemic reactions. Systemic corticosteroids are generally effective in treating chronic IgE-mediated disorders. Epinephrine is the mainstay of treatment for anaphylaxis. Experimental therapies for IgE-mediated food allergy have been evaluated, such as humanized IgG anti-IgE antibodies and allergen specific immunotherapy.

EAACI/GA2LEN position paper: present status of the atopy patch test

A number of scientific reports have been published on patch tests with protein allergens performed on patients with atopic eczema (AE). Evaluation of eczematous skin lesions with an atopy patch test (APT) can be used as a diagnostic tool in characterizing patients with aeroallergen- and food-triggered AE. Indications for testing with APT, choice of allergens (aeroallergens and foods), test materials and technique, including present knowledge on sensitivity and specificity, are reviewed on the basis of available literature. This position paper also points out the need for future research on the clinical use of the APT.