Screening asthmatics for atopic status using the ALergy EXplorer (ALEX2) macroarray

BACKGROUND

Screening asthma patients for atopy facilitates management. Since 2010, the core biomarker for screening asthma subjects for atopic status has been the qualitative Phadiatop. multi-aeroallergen screen. A more quantitative macroarray, the Allergy Explorer (ALEX2), shows promise as an alternative.

OBJECTIVE

The study's goal was to examine the pros and cons of the use of ALEX2 in the screening of asthma patients for atopic status.

METHODS

We evaluated the atopic (IgE-sensitization) status in asthmatic Amish and Hutterite farm children using the ImmunoCAP and ALEX2 assays in Phadiatop equivocal and positive subjects.

RESULTS

All 42 asthmatic children were analyzed by Phadiatop and total serum IgE. Of these, 22 had a negative Phadiatop (<0.1 kUa/L) and total IgE <100 kU/L which defined them as non-atopic and they were excluded from ALEX2 testing. Of six children with equivocal Phadiatops (0.1-0.2 kUa/L-Group 1) and three children with a negative Phadiatop but total IgE >100 kUa/L (group 3), 44% (n = 4) had detectable IgE antibody by ALEX2 to mite, tree pollen, and other allergens not detected by Phadiatop, but confirmed by allergen-specific ImmunoCAP testing. In 11 Phadiatop positive subjects (>0.2 kUa/L-group 2), all but one were positive by ALEX2. IgE antibody specific for mold and rabbit aeroallergens matched their agricultural and pet exposure history. Three children were positive for IgE antibody to allergens in the profilin, nsLTP, or PR-10 cross-reactive protein families.

CONCLUSION

Judicious use of ALEX2's enhanced specificity data not provided by the Phadiatop can aid in the interpretation of sensitization patterns and planning management of atopic asthmatics, but sensitization relevance must be confirmed by the patient's clinical history.

Asthma-protective agents in dust from traditional farm environments

BACKGROUND

Growing up on traditional European or US Amish dairy farms in close contact with cows and hay protects children against asthma, and airway administration of extracts from dust collected from cowsheds of those farms prevents allergic asthma in mice.

OBJECTIVES

This study sought to begin identifying farm-derived asthma-protective agents.

METHODS

Our work unfolded along 2 unbiased and independent but complementary discovery paths. Dust extracts (DEs) from protective and nonprotective farms (European and Amish cowsheds vs European sheep sheds) were analyzed by comparative nuclear magnetic resonance profiling and differential proteomics. Bioactivity-guided size fractionation focused on protective Amish cowshed DEs. Multiple in vitro and in vivo functional assays were used in both paths. Some of the proteins thus identified were characterized by in-solution and in-gel sodium dodecyl sulfate-polyacrylamide gel electrophoresis enzymatic digestion/peptide mapping followed by liquid chromatography/mass spectrometry. The cargo carried by these proteins was analyzed by untargeted liquid chromatography-high-resolution mass spectrometry.

RESULTS

Twelve carrier proteins of animal and plant origin, including the bovine lipocalins Bos d 2 and odorant binding protein, were enriched in DEs from protective European cowsheds. A potent asthma-protective fraction of Amish cowshed DEs (≈0.5% of the total carbon content of unfractionated extracts) contained 7 animal and plant proteins, including Bos d 2 and odorant binding protein loaded with fatty acid metabolites from plants, bacteria, and fungi.

CONCLUSIONS

Animals and plants from traditional farms produce proteins that transport hydrophobic microbial and plant metabolites. When delivered to mucosal surfaces, these agents might regulate airway responses.

A case report of flaxseed anaphylaxis in an infant: Lessons to be learned

Flaxseed allergy is uncommon. An 11-month-old infant developed severe anaphylaxis after ingesting flaxseed.

Food-induced immediate response of the esophagus-A newly identified syndrome in patients with eosinophilic esophagitis

BACKGROUND

Dysphagia is the main symptom of adult eosinophilic esophagitis (EoE). We describe a novel syndrome, referred to as "food-induced immediate response of the esophagus" (FIRE), observed in EoE patients.

METHODS

Food-induced immediate response of the esophagus is an unpleasant/painful sensation, unrelated to dysphagia, occurring immediately after esophageal contact with specific foods. Eosinophilic esophagitis experts were surveyed to estimate the prevalence of FIRE, characterize symptoms, and identify food triggers. We also surveyed a large group of EoE patients enrolled in the Swiss EoE Cohort Study for FIRE.

RESULTS

Response rates were 82% (47/57) for the expert and 65% (239/368) for the patient survey, respectively. Almost, 90% of EoE experts had observed the FIRE symptom complex in their patients. Forty percent of EoE patients reported experiencing FIRE, more commonly in patients who developed EoE symptoms at a younger age (mean age of 46.4 years vs 54.1 years without FIRE; P < .01) and in those with high allergic comorbidity. Food-induced immediate response of the esophagus symptoms included narrowing, burning, choking, and pressure in the esophagus appearing within 5 minutes of ingesting a provoking food that lasted less than 2 hours. Symptom severity rated a median 7 points on a visual analogue scale from 1 to 10. Fresh fruits/vegetables and wine were the most frequent triggers. Endoscopic food removal was significantly more commonly reported in male patients with vs without FIRE (44.3% vs 27.6%; P = .03).

CONCLUSIONS

Food-induced immediate response of the esophagus is a novel syndrome frequently reported in EoE patients, characterized by an intense, unpleasant/painful sensation occurring rapidly and reproducibly in 40% of surveyed EoE patients after esophageal contact with specific foods.

T-cell phenotypes are associated with serum IgE levels in Amish and Hutterite children

OBJECTIVES

Amish children raised on traditional farms have lower atopy and asthma risk than Hutterite children raised on modern farms. In our previous study we established that the Amish environment affects the innate immune response to decrease asthma and atopy risk. Here we investigated T-cell phenotypes in the same Amish and Hutterite children as in our earlier study to elucidate how this altered innate immunity affects adaptive T cells.

METHODS

Blood was collected from 30 Amish and 30 Hutterite age- and sex-matched children; cells were cryopreserved until analysis. Flow cytometry was used to analyze cell subsets. Atopy was determined based on allergen-specific and total IgE levels.

RESULTS

Children exposed to Amish farms had increased activated regulatory CD4⁺ T-cell phenotypes, whereas conventional CD4 T cells expressed lower levels of costimulation molecules and other activation markers. The increase in numbers of circulating activated regulatory CD4⁺ T cells was associated with an increase in inhibitory receptors on monocytes in Amish, but not Hutterite, children. Strikingly, the Amish children had a higher proportion of CD28^null CD8 T cells than the Hutterite children (P < .0001, nonparametric t test), a difference that remained even after accounting for the effects of age and sex (conditional log regression exponential β = 1.08, P = .0053). The proportion of these cells correlated with high T-cell IFN-γ production (r_s = 0.573, P = .005) and low serum IgE levels (r_s = -0.417, P = .025). Furthermore, CD28^null CD8 T-cell numbers were increased in Amish children, with high expression of the innate genes TNF and TNF-α-induced protein 3 (TNFAIP3) in peripheral blood leukocytes.

CONCLUSION

Amish children's blood leukocytes are not only altered in their innate immune status but also have distinct T-cell phenotypes that are often associated with increased antigen exposure.

Pearls and pitfalls in the management of eosinophilic esophagitis

Background: Eosinophilic esophagitis is a newly recognized condition driven by allergen exposure. The management of eosinophilic esophagitis can be a challenge for the practicing allergist. Objective: Provide the allergist with the skills needed to effectively manage eosinophilic esophagitis. Methods: A literature review of the important aspects of evaluation and management. Results: More effective care of patients with eosinophilic esophagitis. Conclusion: This review provided the allergist who sees patients with eosinophilic esophagitis some additional tools to help avoid the pitfalls and use the pearls in disease management.

Dietary Therapy and Nutrition Management of Eosinophilic Esophagitis: A Work Group Report of the American Academy of Allergy, Asthma, and Immunology

Eosinophilic esophagitis (EoE) is a chronic/immune-antigen-mediated disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation. Dietary elimination therapy has been shown to be an effective, drug-free prescription for the treatment of EoE. A range of different dietary elimination therapies have been used. Regardless of the elimination diet chosen, dietary therapy requires in-depth nutrition assessment and management. Elimination diets are not without risk and may impact nutritional status, eating pleasure, and overall quality of life. With adequate guidance, dietary therapy can be effective and nutritionally balanced, and the adverse impact on lifestyle can be minimized. This work group report addresses the potential challenges of implementing an elimination diet for the management of EoE and provides instructions and tools for physicians, dietitians, and other allied health professionals to help guide them in planning elimination diets for both children and adults.

Innate Immunity and Asthma Risk in Amish and Hutterite Farm Children

BACKGROUND

The Amish and Hutterites are U.S. agricultural populations whose lifestyles are remarkably similar in many respects but whose farming practices, in particular, are distinct; the former follow traditional farming practices whereas the latter use industrialized farming practices. The populations also show striking disparities in the prevalence of asthma, and little is known about the immune responses underlying these disparities.

METHODS

We studied environmental exposures, genetic ancestry, and immune profiles among 60 Amish and Hutterite children, measuring levels of allergens and endotoxins and assessing the microbiome composition of indoor dust samples. Whole blood was collected to measure serum IgE levels, cytokine responses, and gene expression, and peripheral-blood leukocytes were phenotyped with flow cytometry. The effects of dust extracts obtained from Amish and Hutterite homes on immune and airway responses were assessed in a murine model of experimental allergic asthma.

RESULTS

Despite the similar genetic ancestries and lifestyles of Amish and Hutterite children, the prevalence of asthma and allergic sensitization was 4 and 6 times as low in the Amish, whereas median endotoxin levels in Amish house dust was 6.8 times as high. Differences in microbial composition were also observed in dust samples from Amish and Hutterite homes. Profound differences in the proportions, phenotypes, and functions of innate immune cells were also found between the two groups of children. In a mouse model of experimental allergic asthma, the intranasal instillation of dust extracts from Amish but not Hutterite homes significantly inhibited airway hyperreactivity and eosinophilia. These protective effects were abrogated in mice that were deficient in MyD88 and Trif, molecules that are critical in innate immune signaling.

CONCLUSIONS

The results of our studies in humans and mice indicate that the Amish environment provides protection against asthma by engaging and shaping the innate immune response. (Funded by the National Institutes of Health and others.).

Eosinophilic esophagitis is characterized by a non-IgE-mediated food hypersensitivity

Eosinophilic esophagitis (EoE) is a chronic disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. EoE is frequently associated with concomitant atopic diseases and immunoglobulin E (IgE) sensitization to food allergens in children as well as to aeroallergens and cross-reactive plant allergen components in adults. Patients with EoE respond well to elemental and empirical food elimination diets. Recent research has, however, indicated that the pathogenesis of EoE is distinct from IgE-mediated food allergy. In this review, we discuss the individual roles of epithelial barrier defects, dysregulated innate and adaptive immune responses, and of microbiota in the pathogenesis of EoE. Although food has been recognized as a trigger factor of EoE, the mechanism by which it initiates or facilitates eosinophilic inflammation appears to be largely independent of IgE and needs to be further investigated. Understanding the pathogenic role of food in EoE is a prerequisite for the development of specific diagnostic tools and targeted therapeutic procedures.

Monocyte and Treg phenotypes in two U.S. farming populations mirror differential asthma and atopy risk: studies in Amish and Hutterite children (HYP7P.254)

The differences in asthma prevalence between farming and non-farming families in central Europe are recapitulated in two unique U.S. farming populations, the Amish of Indiana and the Hutterites of South Dakota. The prevalence of asthma and allergic sensitization was 5.2% and 7.2%, respectively, in Amish children and &gt;15% and &gt;40%, respectively, in Hutterite children. Compared to Hutterite children, Amish children’s PBLs had lower eosinophils, but higher neutrophils. Amish had higher gene expression of IRF7 and TNFA, which may be the result of the elevated levels of endotoxin found in Amish homes. To determine how the Amish environment alters antigen presentation, we measured the activation status of monocytes. The Amish had increased percentages of inhibitory monocytes that expressed low HLA-DR and high ILT3 and ILT5. We investigated how these changes in innate activation influenced the adaptive immune response. Amish had low ICOS expression on their CD4 effector cells and high ICOS expression on their Tregs. The expression of ILT5 on monocytes correlated to the level of CD45RO+ICOS+ Tregs. Consistent with the idea that microbial exposure could be promoting a regulatory immune phenotype similar to endotoxin-induced tolerance, PBLs from the Amish were hyporesponsive to LPS. These results indicate that environmental exposure has a profound impact on baseline immune function and may prevent the induction of atopic disease in children.

Scratching the surface: towards understanding the pathogenesis of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a steadily increasing prevalence affecting 10%-20% of infants and 1%-3% of adults globally. It is often the first clinical manifestation of atopic disease preceding asthma and allergic rhinitis. At least half of the children with AD develop some other form of atopic disease later in life. The pathogenesis of AD involves a complex interplay of factors, including genetic predisposition due to altered immune or skin barrier function, interactions with the environment, and infectious triggers of inflammation. In this review, we summarize the recent advances in understanding the contribution of different factors in the pathophysiology of AD in human and animal model systems. These insights provide new therapeutic potential for the treatment of human AD.

Clinical correlations of recent developments in the pathogenesis of atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin disease with a steadily increasing prevalence affecting 10-20 of infants and 1-3 of adults globally. It is often the first clinical manifestation of atopic disease preceding asthma and allergic rhinitis. Probably half of the children with atopic dermatitis develop some other form of atopic disease later in life. The pathogenesis involves a complex interplay of factors including genetic predisposition due to altered immune or skin barrier function, interactions with the environment such as food and allergen exposures, and infectious triggers of inflammation. In this review, we summarize the recent advances in understanding the contribution of different factors in the pathophysiology of atopic dermatitis and how insights provide new therapeutic potential for its treatment.

Effect of tree and grass pollens and fungal spores on spring allergic rhinitis: a comparative study

BACKGROUND

Current literature indicates tree pollen is less important than grass pollen as the cause of spring allergic rhinitis. The role of fungal spores is secondary and uncertain.

OBJECTIVE

To assess the relative allergenicity of tree and grass pollen and fungal spores as the cause of spring allergic rhinitis in central Indiana.

METHODS

(1) Chart review of 189 Indiana natives with seasonal allergic rhinitis to ascertain clinical sensitivity to tree or grass pollens. (2) A prospective study conducted in the spring of 1997 in 51 patients, correlating patients' symptom and medication scores with daily pollen and spore counts, obtained with a Burkard spore trap.

RESULTS

One hundred thirty of 189 patients (69%) reported symptoms before May with positive prick test to at least one tree pollen. One hundred thirty-four patients (71%) had symptoms in May and June with positive test to grass pollen. The ratio between the two groups is 1:1, in contrast to a ratio of 1:4 derived from the literature. The prospective study revealed a symptom score increase parallel to the rise of tree pollen counts beginning in mid-March and reaching a plateau in early May prior to the onset of grass season. Medication use continued to increase and peaked at the height of grass pollination. Spore counts increased in late May and stayed at high levels throughout June, yet symptom and medication scores steadily declined following the peak of grass pollination in early June.

CONCLUSIONS

This study suggests that in central Indiana, tree pollen is more important as the cause of spring allergic rhinitis than that suggested by the literature. This study confirmed previous observations that fungal spores are substantially less allergenic than pollens.

Champ Camp: the Colorado Children's Asthma Camp experience

To encourage children with asthma to enjoy outdoor activities without physical or psychosocial impairment, children's asthma camps are established throughout the country sponsored by organizations including local and state allergy societies. We wish to describe our Colorado "Champ Camp" experience as a model and reference for future similar efforts and to encourage networking by medical leadership for information sharing and guidelines development nationally. Statistics from parents' satisfaction surveys over 8 years demonstrate a positive influence on attitudes toward asthma and confidence to enter activities and sports with children without asthma.

Asthma and other allergic disorders in pregnancy

About 1 percent of pregnancies are complicated by asthma. Morbidity and mortality, both maternal and fetal, are significantly increased in cases of severe asthma. In selecting therapy, the physician must weigh the potential risks and benefits of any medication. Theophylline and beta-adrenergic agonists are the drugs of choice. Carefully selected antihistamines, decongestants and immunotherapy are safe and effective in the management of most other allergic problems. A few commonly used medications are teratogenic.

Exercise-induced bronchospasm in children

Exercise-induced bronchospasm (EIB) is common among asthmatic children. After vigorous exercise, about 80 percent of childhood asthmatics develop significant bronchoconstriction. The mechanism is probably related to heat loss from the respiratory tract during exercise. Jogging, soccer and basketball are the activities most often implicated. Adequate bronchodilator therapy can prevent most EIB episodes. Recognition and treatment of EIB will allow full participation in sports.