Gut microbiome is associated with asthma and race in children with food allergy

BACKGROUND

The composition of the gut microbiome has been associated with development of atopic conditions such as food allergy (FA) and asthma. African American or Black children with FA have higher rate of asthma compared to their White counterparts.

OBJECTIVE

We sought to investigate whether the diversity and relative abundance (RA) of gut microbiota is different between children with FA from different racial backgrounds living in the same cities. Furthermore, we aimed to understand whether the difference in the gut microbiota is associated with asthma in children with FA.

METHODS

We analyzed and compared the stool microbiome of a cohort of Black and White children with FA by shotgun genomic sequencing.

RESULTS

A total of 152 children with IgE-mediated FA enrolled onto FORWARD (Food Allergy Outcomes Related to White and African American Racial Differences); 30 Black and 122 White children were included. The RA of several bacteria was associated with race and asthma. Most notably the RA of Bacteroides thetaiotaomicron, Chlamydia thrachomatis, Parabacteroides goldsteinii, and Bacteroides eggerthii were significantly higher, while the RA of Bifidobacterium sp CAG:754, Parabacterium johnsonii, Bacteroides intestinalis, and Bifidobacterium breve were significantly lower in stool samples of Black children compared to White children. Asthma was associated with lower RA of B breve, Bifidobacterium catenulatum, Prevotella copri, Veilloella sp CAG:933, and Bacteroides plebius, and higher RA of 3 Bacteroides species.

CONCLUSIONS

The observed variations in the gut microbiota of Black and White children such as differences in the Bacteroides and Bifidobacterium species along with their association to history of asthma in our cohort is indicative of their potential role in the higher rate of asthma observed among Black children with FA.

Prevalence and burden of coconut allergy in the United States

BACKGROUND

Epidemiologic data on coconut allergy remains sparse in the United States despite the labeling requirement by the Food Allergen Labeling and Consumer Protection Act for products containing coconut.

OBJECTIVE

To provide current estimates of the prevalence, severity, determinants, and distribution of coconut allergy in the United States.

METHODS

A comprehensive food allergy prevalence survey was administered to a nationally representative, probability-based sample of US households between October 1, 2015 and September 30, 2016. Eligible respondents included adults who were able to complete self- and parent-proxy report surveys in English or Spanish by means of web or phone.

RESULTS

Using survey responses from 78,851 individuals, 0.39% (95% confidence interval [CI], 0.33-0.45) of the US general population were categorized as having convincing coconut allergy. Among children, 0.22% (95% CI, 0.16-0.30) were estimated to have coconut allergy compared with 0.43% (95% CI, 0.37-0.51) of adults, whereas only 0.12% (95% CI, 0.08-0.18) of these children and 0.20% (95% CI, 0.16-0.24) of adults with convincing immunoglobulin E (IgE)-mediated coconut allergy reported physician-confirmed diagnoses. A current epinephrine prescription was reported by 40.1% (95% CI, 33.3-47.4) of those with convincing coconut allergy. Reactions involving multiple organ systems were reported by 47.5% (95% CI, 40.1-54.9) of those with convincing coconut allergy.

CONCLUSION

Roughly 1 in 260 Americans report symptoms consistent with an IgE-mediated allergy to coconut, although fewer than half of these individuals report receiving a physician diagnosis. Our data indicate that most individuals with reported coconut allergy meeting symptom-based criteria for convincingly IgE-mediated disease have comorbid FAs, and for many patients, clinical management seems to be suboptimal.

Assessing Disparities in the Prevalence of Atopic Comorbidities Among Food-Allergic Children

BACKGROUND

Previous studies have reported that Black children with food allergy (FA) have higher risk of atopic comorbidities than White children.

OBJECTIVE

Our study sought to understand if disparities in the prevalence of atopic comorbidities among children with FA are driven by individual and community-level socioeconomic status (SES).

METHODS

We analyzed data from a prospective, multicenter cohort investigating the natural history of pediatric atopy: the Food Allergy Outcomes Related to White and African American Racial Differences (FORWARD) study. A validated, multicomponent area deprivation index (ADI) percentile score was tabulated by the census block group for each subject's home address. The association of ADI with atopic comorbidities in FA was assessed via multivariable regression analysis.

RESULTS

Of the 700 children in this study, the mean ADI was 37.7 (95% confidence interval: 35.6-39.7). The mean ADI was higher in children with asthma (43.3) compared with those without asthma (31.8), which remained significant after adjusting for race (P < .0001). Children with allergic rhinitis (AR) had a higher mean ADI (39.1) compared with those without (33.4) (P = .008). ADI was associated with secondhand smoking, parents' education, and household income. Black children had a higher risk for asthma after adjusting for ADI and SES-related factors.

CONCLUSION

The independent association of ADI with asthma and AR, regardless of race, suggests a role of neighborhood-level socioeconomic deprivation in the development of these conditions among children with FA. Black children with FA remained at higher risk for asthma after adjusting for SES-related variables, which can indicate an independent risk for asthma in these children.

The epidemiology of food allergy in adults

The prevalence and awareness of food allergy (FA) among US adults is arguably at a historical high, both with respect to primary immunoglobulin E-mediated food hypersensitivity and other food-triggered conditions that operate through a variety of immunologic mechanisms (eg, pollen-FA syndrome, alpha-gal syndrome, food protein-induced enterocolitis syndrome, eosinophilic esophagitis). Worryingly, not only are many adults retaining childhood-onset food allergies as they age into adulthood, it seems that many adults are experiencing adult-onset allergies to previously tolerated foods, with correspondingly adverse physical, and psychological health impacts. Consequently, this review aims to summarize what is currently known about the epidemiology and population-level burden of FA among adult populations in North America and around the globe. This article also provides insights into the natural history of these conditions and what we need to know as we look to the future to support effective care and prevent FA.

Accelerating Food Allergy Research: Need for a Data Commons

Food allergy is a significant health problem affecting approximately 8% of children and 11% of adults in the United States. It exhibits all the characteristics of a "complex" genetic trait; therefore, it is necessary to look at very large numbers of patients, far more than exist at any single organization, to eliminate gaps in the current understanding of this complex chronic disorder. Advances may be achieved by bringing together food allergy data from large numbers of patients into a Data Commons, a secure and efficient platform for researchers, comprising standardized data, available in a common interface for download and/or analysis, in accordance with the FAIR (Findable, Accessible, Interoperable, and Reusable) principles. Prior data commons initiatives indicate that research community consensus and support, formal food allergy ontology, data standards, an accepted platform and data management tools, an agreed upon infrastructure, and trusted governance are the foundation of any successful data commons. In this article, we will present the justification for the creation of a food allergy data commons and describe the core principles that can make it successful and sustainable.

Food allergen introduction patterns in the first year of life: A US nationwide survey

BACKGROUND

Prevention guidelines have changed over the past decade and now recommend the earlier introduction of peanut and egg without delaying the introduction of other food allergens. This paper explored caregiver practices regarding the introduction of food allergens during infancy.

METHODS

A survey was administered (2021) to a US population-based sample of 3062 caregivers (children 7 months - 3.5 years). Demographics and feeding practices were collected. Weighted frequencies and proportions were calculated using the svyr package in R 4.1. Survey-weighted chi-square statistics and covariate-adjusted, survey-weighted logistic regression models were used for statistical inference.

RESULTS

Cow's milk, wheat, and soy were the top three allergens introduced. Peanut and egg were introduced by 17.2% and 15.5% of caregivers before 7 months and 58.8% and 66.4% before 1 year, respectively. The age of peanut and egg introduction differed significantly by race/ethnicity (p < .001) and caregiver age (p < .001). Peanut and egg introduction before 7 months was significantly associated with the increased introduction of other allergenic foods before 1 year (p = <.001; peanut and p = < .001; egg). Caregivers who introduced peanut and egg before 7 months infant age fed an additional mean of 5.4 and 4.5 food allergens, respectively, before 1 year. Few caregivers (0.9%) reported feeding an "early food allergen introduction product" ≥ 3 times, which was significantly associated with parental food allergy (OR = 2.2) and previously seen an allergist (OR = 6.7).

CONCLUSION

More than half of the caregivers are not introducing peanut by age of one year and one-third are not introducing egg, though an observed shift toward earlier peanut and egg introduction was seen in the past 5 years. Peanut and egg introduction seem to co-occur and are associated with increased intake of other food allergens.

Socioeconomic Determinants of Food Allergy Burden-A clinical introduction

OBJECTIVE

This review characterizes what is currently known about how prevalence, severity, distribution, and management of food allergy (FA) differs across socioeconomic strata and provides guidance for practicing clinicians about how to improve equity in research participation, healthcare delivery, and patient outcomes through a deeper understanding of the socioeconomic determinants of FA.

DATA SOURCES

Epidemiological and biomedical literature published prior to April 2022.

RESULTS

Socioeconomic status (SES) is a complex concept that not only encompasses economic resources (e.g., income, wealth) but also a person's social, economic and political power and standing, each of which can impact health. However, in many studies of individuals and families with FA, assessment of SES has been limited and often a respondent's membership within a racial and ethnic group is utilized as a proxy for low SES. As a whole, findings from US-population-based studies indicate a consistent trend: those who self-identify as non-Hispanic Black, and to a lesser extent other subpopulations who identify as being of non-White race and ethnicity, experience a greater burden of food-allergic sensitization and disease including higher rates of emergency health care utilization and food-induced anaphylactic fatality as compared to those identifying as White.

CONCLUSION

Reports of FA management and outcomes highlight inequities among specific low SES populations in the US. Clinicians can and should act to reduce inequities by engaging more diverse populations in clinical research, equitably implementing FA risk screening and prevention, thoughtfully utilizing emerging technologies to ameliorate disparities based on SES in healthcare delivery and outcomes, and advocating for social change.

High dose inhaled fluticasone propionate improves FEV1 and results in reduction of oral glucocorticoid dose in glucocorticoid-dependent children with severe asthma

A retrospective chart review was performed on eight pediatric patients with glucocorticoid (GC)-dependent asthma who had been switched to fluticasone propionate (FP). A significant increase was noted in average forced expiratory volume in 1 second (FEV1) and forced expiratory flow 25-75% (FEF25-75) at 6 and 12 months. Significant reductions were noted in the oral GC dose at 6 and 12 months with a reduction at 12 months of almost 16.5 mg/day or 65% of the initial oral GC dose. This study suggests that high-dose FP use in children with oral GC-dependent asthma has oral GC sparing effects while improving FEV1 and FEF25-75.

Undiluted albuterol aerosols in the pediatric emergency department

OBJECTIVE

To evaluate the efficacy and efficiency of a short treatment method of administering albuterol aerosols.

METHODS

Fifty children 6 to 18 years of age with severe acute asthma (peak flow rates <60% of predicted) were enrolled in a single-blind, controlled trial in an urban pediatric emergency department. Patients were randomized to receive either the study short treatment (3.5 mL of undiluted albuterol nebulized for 20 inhalations) or the control treatment (albuterol diluted [.5 mL] and nebulized in normal saline [3 mL]) every 20 minutes for a total of 3 treatments. Peak flow and spirometric measurements were performed before and after each treatment.

RESULTS

There were 25 patients in the study group and 25 in the control group. There were no demographic differences between groups; both had comparable pulmonary function at presentation. The mean forced expiratory volume in 1 second percent predicted improvement between 0 and 60 minutes was 18.8% in the study group and 14.5% in the control group. The total time of treatment delivery for the study group was 6.4 minutes versus 32.7 minutes for the control group.

CONCLUSION

Undiluted albuterol short treatments seem to be as effective as standard diluted albuterol in severe asthmatics, while offering the ease and efficiency of shorter treatment administration time.

Neuroleptic malignant syndrome after venlafaxine

A patient developed neuroleptic malignant syndrome after a single dose of venlafaxine with trifluoperazine treatment. A dopamine-inhibition effect induced by one dose of venlafaxine may have augmented dopamine-receptor inhibition by trifluoperazine.

Allergy: etiology and epidemiology

The occurrence of atopic disease throughout the world is subject to many variables. Differences in methodology and diagnostic criteria for measuring the incidence could account for some disparities, but they cannot explain all of them. Despite our increasing knowledge of the atopic diseases, improved treatments, and early diagnosis, the incidence and prevalence of asthma, allergic rhinitis, and atopic dermatitis continue to rise. Ongoing research into the etiology and potential risk factors for atopic diseases could lead to the early diagnosis, effective treatment, and prevention.

Fluticasone propionate results in improved glucocorticoid receptor binding affinity and reduced oral glucocorticoid requirements in severe asthma

BACKGROUND

Inhaled glucocorticoids (iGC) have become important first line agents in the management of moderate-to-severe asthma. Severe asthma is associated with reduced glucocorticoid receptor (GCR) binding affinity.

METHODS

To evaluate the potential impact of inhaled fluticasone propionate on markers of airway inflammation [GCR binding affinity (Kd) and eosinophil cationic protein (ECP)] and oral GC requirements in steroid-dependent asthmatics, we examined the effects of fluticasone propionate (FP) 500 microg or 1000 microg BID and placebo in a double-blind, randomized study of 13 steroid-dependent asthmatics at a single center. Glucocorticoid receptor binding affinity and ECP values were obtained at baseline, 4, 6, 26, and 52 weeks after patients were enrolled into the study. Oral GC dose and FEV1 values were also recorded at each visit.

RESULTS

Inhaled FP resulted in large reductions in oral GC requirement by 6 weeks of therapy while no reduction was seen in the placebo group. All patients in the FP 2000 microg/d group who continued double-blind therapy at 52 weeks were able to eliminate oral prednisone use. In contrast, every patient in the placebo group had to be withdrawn from the study due to poor asthma control. Associated with the oral GC dose reduction on high dose FP therapy, were improvements in GCR binding affinity with the GCR Kd falling from 42.5 nM at baseline to 19.5 nM at 6 weeks (P=.08). The GCR KD values remained stable thereafter with values of 23.5 nM at 26 weeks (P=.02) and 19.5 nM at 52 weeks (P=.01). In addition, high dose FP therapy resulted in reductions in serum ECP values.

CONCLUSION

This study suggests that high dose FP therapy results in significant oral GC sparing effects associated with improved GCR binding affinity and reductions in serum ECP levels in patients with steroid-dependent asthma.

Allergen exposure decreases glucocorticoid receptor binding affinity and steroid responsiveness in atopic asthmatics

Allergen exposure can confound the management of asthma. To understand the potential mechanisms by which allergens increase the steroid requirements in atopic asthmatics, we examined the effects of allergens on glucocorticoid receptor (GCR) binding affinity and glucocorticoid (GC) responsiveness of peripheral blood mononuclear cells (PBMC) from atopic asthmatics. A significant reduction (p < 0.001) in the GCR binding affinity (Kd) was observed in ragweed-allergic asthmatics during ragweed pollen season compared with PBMC obtained before and after ragweed season. In vitro effects of allergen on PBMC GCR Kd were also examined by incubating PBMC from atopic asthmatics with allergen (ragweed and cat) versus Candida albicans. GCR binding affinity was significantly reduced after incubation with ragweed (p < 0.001) or cat allergen (p < 0.001) compared with baseline or C. albicans stimulation. This effect was limited to atopic asthmatics in that in vitro cat allergen incubation for 48 h failed to significantly alter GCR binding affinity in nonasthmatic, atopic individuals. These allergen-induced reductions in GCR binding affinity also rendered the PBMC less sensitive to the inhibitory effects of hydrocortisone and dexamethasone on allergen-induced proliferation (p < 0.01). To test the hypothesis that allergen-induced alterations in GCR binding affinity were cytokine-induced, we examined the effects of interleukin-2 (IL-2)and IL-4 neutralization using anticytokine antibodies. Addition of both anti-lL-2 and anti-lL-4 antibodies resulted in a significant (p < 0.001) inhibition of allergen-induced alterations in GCR binding affinity. Furthermore incubation with cat allergen induced significantly higher concentrations of IL-2 (p = 0.03) and IL-4 (p = 0.02) by PBMC from atopic as compared with nonatopic subjects. Our current observations suggest that allergen exposure may contribute to poor asthma control by reducing GCR binding affinity in mononuclear cells. This appears to be mediated through IL-2 and IL-4. These findings may have important implications for novel approaches to the treatment of poorly controlled asthma.

Steroid-resistant asthma: evaluation and management

LEARNING OBJECTIVES

Reading this article will reinforce the reader's knowledge of the definition, pathophysiology, differential diagnosis, and treatment of the steroid-resistant asthmatic patient.

DATA SOURCES

Prospective and retrospective data from the authors' experience were evaluated. In addition, a Medline database was searched from 1981, using the key words "asthma," "glucocorticoids," and "glucocorticoid resistance" with the restrictions of English language and human subjects. Relevant articles referenced in retrieved sources and current texts on severe asthma were also utilized.

STUDY SELECTION

Data source abstracts, pertinent articles, and book chapters meeting the objectives were critically reviewed.

RESULTS

Although rare, individuals with steroid-resistant asthma are often the most difficult-to-manage asthmatic patients in that they have severe disease yet fail to respond to glucocorticoids. To make the diagnosis of steroid-resistant asthma, the patient must fail to respond to a 7 to 14-day course of daily prednisone as measured by less than a 15% improvement in morning prebronchodilator FEV1 following the glucocorticoid course. Ongoing inflammation is thought to play a major role in the pathogenesis of steroid-resistant asthma, and recent studies have demonstrated diminished glucocorticoid receptor to glucocorticoid, or diminished glucocorticoid receptor to DNA binding as possible mechanisms for diminished glucocorticoid responsiveness. Alternative asthma therapies such as methotrexate, cyclosporine, and intravenous gammaglobulin are often used in this group of asthmatic patients.

CONCLUSIONS

The patient with steroid-resistant asthma presents several challenges. These individuals often display many of the sequelae of long-term systemic glucocorticoid use while achieving little therapeutic benefit. Prior to making the diagnosis of steroid-resistant asthma, diseases that can contribute to poor control of asthma must be ruled out, and noncompliance issues addressed. Alternative asthma therapies are often used; however, they also carry the potential for adverse effects, and have not been thoroughly studied in this population of asthmatic patients.

A novel action of IL-13: induction of diminished monocyte glucocorticoid receptor-binding affinity

We have recently demonstrated that the combination of IL-2 and IL-4 blunts T cell responses to glucocorticoids in steroid resistant (SR) asthma by reducing glucocorticoid receptor (GCR)-binding affinity. Since immune activation appears to be involved in the acquisition of steroid resistance, we sought to identify whether other cytokines could also induce diminished GCR-binding affinity. In the current report, utilizing a [3H]dexamethasone radioligand-binding assay and Scatchard analysis, we found that IL-13, a cytokine with similar actions as IL-4, could induce diminished GCR binding-affinity (GCR Kd = 34.4 +/- 2.3 nM with IL-13 vs Kd = 8.8 +/- 0.7 nM for unstimulated control cells; p < 0.001) in PBMC from normal subjects. In contrast, PBMC incubated with IL-1, IL-3, IL-5, IL-7, IL-8, IL-12, or granulocyte-macrophage-CSF had no effect on GCR-binding affinity; and no additive effect to the decreased GCR-binding affinity was noted when IL-13 was cocultured with IL-2 or IL-4. The cell target of IL-13-induced GCR effects was studied and found to reside in the non-T cell population; specifically, the monocyte fraction. To determine the functional significance of the decreased GCR-binding affinity, monocytes were pretreated with and without IL-1 3 prior to stimulation with LPS and hydrocortisone. IL-13 pretreatment of monocytes significantly diminished (p = 0.005) the suppressive effects of hydrocortisone on LPS-induced IL-6 production. IL-13, by virtue of its ability to induce diminished GCR-binding affinity, may contribute to impaired GC responsiveness during inflammatory illnesses.

A novel action of IL-13: induction of diminished monocyte glucocorticoid receptor-binding affinity

We have recently demonstrated that the combination of IL-2 and IL-4 blunts T cell responses to glucocorticoids in steroid resistant (SR) asthma by reducing glucocorticoid receptor (GCR)-binding affinity. Since immune activation appears to be involved in the acquisition of steroid resistance, we sought to identify whether other cytokines could also induce diminished GCR-binding affinity. In the current report, utilizing a [3H]dexamethasone radioligand-binding assay and Scatchard analysis, we found that IL-13, a cytokine with similar actions as IL-4, could induce diminished GCR binding-affinity (GCR Kd = 34.4 +/- 2.3 nM with IL-13 vs Kd = 8.8 +/- 0.7 nM for unstimulated control cells; p &lt; 0.001) in PBMC from normal subjects. In contrast, PBMC incubated with IL-1, IL-3, IL-5, IL-7, IL-8, IL-12, or granulocyte-macrophage-CSF had no effect on GCR-binding affinity; and no additive effect to the decreased GCR-binding affinity was noted when IL-13 was cocultured with IL-2 or IL-4. The cell target of IL-13-induced GCR effects was studied and found to reside in the non-T cell population; specifically, the monocyte fraction. To determine the functional significance of the decreased GCR-binding affinity, monocytes were pretreated with and without IL-1 3 prior to stimulation with LPS and hydrocortisone. IL-13 pretreatment of monocytes significantly diminished (p = 0.005) the suppressive effects of hydrocortisone on LPS-induced IL-6 production. IL-13, by virtue of its ability to induce diminished GCR-binding affinity, may contribute to impaired GC responsiveness during inflammatory illnesses.

Diaphragmatic flutter presenting as inspiratory stridor

Diaphragmatic flutter is a rarely reported disorder in which the diaphragm involuntarily contracts at a rapid rate. We report a unique case in which diaphragmatic flutter was associated with inspiratory stridor and was severely disabling. A new approach to the treatment of this condition, phrenic nerve crush, provided an optimal outcome, with resolution of symptoms and the return of normal diaphragmatic function. Pathophysiology and treatment of this condition are discussed.