A Review of Shared Decision-Making, Published Protocols, and Post-desensitization Strategies in Oral Immunotherapy (OIT).

PURPOSE OF REVIEW: The aim of this review is to highlight key published oral immunotherapy (OIT) protocols and post-desensitization strategies for the major food allergens and to cover important concepts to consider when evaluating OIT for food-allergic patients. Shared decision-making should help identify patient and family values which will help influence the type of evidence-based protocol and maintenance strategy to use. RECENT FINDINGS: With food OIT emerging as a treatment option, there is a pressing need for patients, physicians, and other providers to have a nuanced understanding of the management choices available to them. There are now randomized controlled trials (RCT) of OIT for peanut, egg, milk, and wheat, and reports of cohorts of patients who have undergone OIT for tree nuts and sesame clinically. The current published protocols contain significant diversity in terms of starting dose, build-up schedule, maintenance dose, and even the product used for desensitization. Emerging data can help direct the long-term maintenance strategy for patients on OIT. Based on patient and family values elicited through the shared decision-making process, an OIT protocol may be selected that balances the level of desensitization, potential side effects, frequency of clinic visits, and potential to induce sustained unresponsiveness, among other factors. Once maintenance dosing is reached, most patients will need to maintain regular exposure to the food allergen to remain desensitized. The option to transition to commercial food products with equivalent amounts of food protein as the OIT maintenance dose would simplify the dosing process and perhaps improve palatability as well. Less frequent or decreased OIT dosing can provide practical benefits but may affect the level of desensitization and safety for some patients.

Identification of cow milk epitopes to characterize and quantify disease-specific T cells in allergic children.

BACKGROUND: Cow milk (CM) allergy is the most prevalent food allergy in young children in the United States and Great Britain. Current diagnostic tests are either unreliable (IgE test and skin prick test) or resource-intensive with risks (food challenges). OBJECTIVE: We sought to determine whether allergen-specific T cells in CM-allergic (CMA) patients have a distinct quality and/or quantity that could potentially be used as a diagnostic marker. METHODS: Using PBMCs from 147 food-allergic pediatric subjects, we mapped T-cell responses to a set of reactive epitopes in CM that we compiled in a peptide pool. This pool induced cytokine responses in in vitro cultured cells distinguishing subjects with CMA from subjects without CMA. We further used the pool to isolate and characterize antigen-specific CD4 memory T cells using flow cytometry and single-cell RNA/TCR sequencing assays. RESULTS: We detected significant changes in the transcriptional program and clonality of CM antigen-specific (CM+) T cells elicited by the pool in subjects with CMA versus subjects without CMA ex vivo. CM+ T cells from subjects with CMA had increased percentages of FOXP3+ cells over FOXP3- cells. FOXP3+ cells are often equated with regulatory T cells that have suppressive activity, but CM+ FOXP3+ cells from subjects with CMA showed significant expression of interferon-responsive genes and dysregulated chemokine receptor expression compared with subjects without CMA, suggesting that these are not conventional regulatory T cells. The CM+ FOXP3+ cells were also more clonally expanded than the FOXP3- population. We were further able to use surface markers (CD25, CD127, and CCR7) in combination with our peptide pool stimulation to quantify these CM+ FOXP3+ cells by a simple flow-cytometry assay. We show increased percentages of CM+ CD127-CD25+ cells from subjects with CMA in an independent cohort, which could be used for diagnostic purposes. Looking specifically for TH2 cells normally associated with allergic diseases, we found a small population of clonally expanded CM+ cells that were significantly increased in subjects with CMA and that had high expression of TH2 cytokines and pathogenic TH2/T follicular helper markers. CONCLUSIONS: Overall, these findings suggest that there are several differences in the phenotypes of CM+ T cells with CM allergy and that the increase in CM+ FOXP3+ cells is a potential diagnostic marker of an allergic state. Such markers have promising applications in monitoring natural disease outgrowth and/or the efficacy of immunotherapy that will need to be validated in future studies.

Qualitative interviews to understand health care providers' experiences of prescribing licensed peanut oral immunotherapy.

OBJECTIVE: This research sought to explore health care providers' (HCPs) experiences of delivering the first US Food and Drug Administration (FDA) and European Commission (EC) approved peanut oral immunotherapy (peanut OIT; Palforzia). Semi-structured qualitative interviews with HCPs who had initiated treatment with ≥ 3 patients in the first nine months following FDA approval sought to identify challenges faced and successful implementation strategies. RESULTS: Eight allergists and three nurse practitioners from eight sites based in the United States participated. The HCPs included in this research were motivated to implement this novel treatment, however, entered the process with some reservations. HCPs described how successful implementation of peanut OIT requires them to be thoughtful about their clinic's abilities to integrate complex, time-consuming treatments into their daily practice. Prior experience of OIT was deemed beneficial, but not essential for implementation and learning from others' experience was suggested as a way of helping new prescribers overcome perceived and actual implementation challenges. Delivering licensed peanut OIT during the COVID-19 pandemic posed both challenges and unexpected opportunities for implementation. The experiences described have the potential to benefit the wider allergy community by providing practical solutions, successful implementation strategies and opportunities to enhance training and resources.

Integrating oral immunotherapy into clinical practice.

In 2020, the first food allergy treatment, an oral immunotherapy (OIT) product for peanut allergy, was approved by the Food and Drug Administration, and a peanut epicutaneous immunotherapy patch was under review. As food allergy therapies become available and widespread, allergy offices will need to adjust practices to be able to offer their patients these new treatments. OIT is an intensive therapy that requires commitment from patients and their families, and open communication with the practice is paramount. OIT may not be the right therapy for every patient, and although identifying good candidates is still an area rich for research opportunity, experience from cohorts and clinical trials provides some insight. It is important to understand the scope of practice for each member of the OIT team based on state regulations for a particular location. Staffing and space will likely dictate how many patients at an individual office could be on active OIT at one time. Emergency medications, supplies, and protocols must be in place. Screening, scheduling, visit procedures, monitoring, home dosing, dose modifications, safety precautions, adverse reactions, and maintenance will be addressed in this article. Finally, adjunct therapies under investigation will be reviewed.

Physician well-being in allergy and immunology: Creating a culture of wellness.

OBJECTIVE: There are 3 domains of physician wellness: (1) the culture of wellness, (2) efficiency of practice, and (3) physician resilience. The culture of wellness encompasses an organization's values, environment, and behaviors that foster compassion and growth in its physicians. DATA SOURCES: Studies have reported that burnout affects a physician's professionalism, altruism, and a sense of calling. Furthermore, burnout increases the risk of cardiovascular disease, alcohol abuse, divorce, depression, and even suicide among physicians. Physician burnout is associated with decreased efficiency at work, which can affect patient care, patient satisfaction, and even patient safety. As such, it is imperative that we develop a culture of wellness. STUDY SELECTIONS: A culture of wellness reflects shared values and a sense of community within an organization. When a culture of wellness is present, leaders prioritize the personal and professional growth of its team members. RESULTS: This article instructs readers on methods that can be used to develop a culture of wellness. CONCLUSION: We need to address burnout at every level in health care, namely at health care organization and system levels, individual teams and offices, and at an individual level. In doing so, it becomes obvious that a lack of wellness (burnout) is a systems problem and not an individual's fault. We are all responsible for taking steps to change the culture to one of wellness. Working within our practices, organization, and allergy societies, we can change the culture to one of wellness.

Analysis of Allergen-Specific T Cell and IgE Reactivity to Different Preparations of Cow's Milk-Containing Food Extracts.

BACKGROUND: cow's milk allergy (CM) is among the most common food allergies in young children and is often outgrown by adulthood. Prior to developing a tolerance to CM, a majority of CM-allergic children may tolerate extensively-heated CM. This study aims to characterize the IgE- and T cell-reactivity to unheated CM and the progressively more heated CM-containing foods. METHODS: CM-containing food extracts from muffin, baked cheese, custard and raw, pasteurized CM commercial extract were tested for skin prick test reactivity, IgE binding and T cell reactivity as assessed by IL-5 and IFNγ production. RESULTS: the skin prick test (SPT) reactivity was significantly decreased to muffin extract compared to raw, pasteurized CM. Both IgE- and T-cell reactivity were readily detectable against food extracts from all forms of CM. Western blot analysis of IgE reactivity revealed variability between extracts that was protein-specific. T cell-reactivity was detected against all four extracts with no significant difference in IL-5 or IFNγ production between them. CONCLUSION: our data indicate that despite reduced clinical reactivity, extracts from heated CM-containing foods retain immunogenicity when tested in vitro, particularly at the T cell level.

Concomitant diagnosis of immune deficiency and Pseudomonas sepsis in a 19 month old with ecthyma gangrenosum by host whole-genome sequencing.

X-linked agammaglobulinemia (XLA, OMIM#300300) is a rare monogenic primary immunodeficiency caused by mutations in the Bruton tyrosine kinase (BTK) gene. XLA is characterized by insufficient immunoglobulin levels and susceptibility to life-threatening bacterial infections. We report on a patient that presented with ecthyma gangrenosum and septicemia. Rapid trio whole-genome sequencing (rWGS) revealed an apparently de novo hemizygous pathogenic variant (c.726dupT; p.Ile243TyrfsTer15) in the BTK gene. Metagenomic analysis of rWGS sequences that did not align to the human genome revealed 770 aligned to the Pseudomonas aeruginosa PAO1 genome. The patient was diagnosed with XLA and pseudomonal sepsis.

Preventing Peanut Allergy.

The rising prevalence of food allergy and specifically peanut allergy has had significant implications for affected patients, families, and society. The current standard of care remains strict avoidance and the use of emergency medications for accidental ingestions. There is recent evidence-based information to suggest that one approach to preventing peanut allergy lies in early introduction of peanut. This represents a paradigm shift from previous recommendations and has led to updated guidelines in the United States, Europe, and Australasia on the introduction of potentially allergenic foods in the infant diet. This new approach to prevention has some practical obstacles and challenges associated with its implementation. There is also growing interest in the role of maintaining a healthy skin barrier in prevention of sensitization and food allergy. Other approaches, including pro- and prebiotics, prenatal maternal dietary avoidance, breastfeeding, and the use of specific formulas, have not shown reproducibly favorable results. As children with peanut allergy are unlikely to outgrow their food allergy, early oral immunotherapy in those with established peanut allergy is being investigated with the hopes of altering the natural history of an otherwise lifelong disease.

Efficacy and Safety of AR101 in Oral Immunotherapy for Peanut Allergy: Results of ARC001, a Randomized, Double-Blind, Placebo-Controlled Phase 2 Clinical Trial.

BACKGROUND: Peanut oral immunotherapy, using a variety of approaches, has been previously shown to induce desensitization in peanut-allergic subjects, but no products have been approved for clinical use by regulatory agencies. OBJECTIVE: We performed the first phase 2 multicentered study to assess the safety and efficacy of AR101, a novel oral biologic drug product. METHODS: A randomized, double-blind, placebo-controlled trial was conducted at 8 US centers. Eligible subjects were 4 to 26 years old, sensitized to peanut, and had dose-limiting symptoms to ≤143 mg of peanut protein in a screening double-blind, placebo-controlled food challenge (DBPCFC). Subjects were randomized 1:1 to daily AR101 or placebo and gradually up-dosed from 0.5 to 300 mg/day. The primary endpoint was the proportion of subjects in each arm able to tolerate ≥443 mg (cumulative peanut protein) at exit DBPCFC with no or mild symptoms. RESULTS: Fifty-five subjects (29 AR101, 26 placebo) were enrolled. In the intention-to-treat analysis, 23 of 29 (79%) and 18 of 29 (62%) AR101 subjects tolerated ≥443 mg and 1043 mg at exit DBPCFC, respectively, versus 5 of 26 (19%) and 0 of 26 (0%) placebo subjects (both P < .0001). Compared with placebo, AR101 significantly reduced symptom severity during exit DBPCFCs and modulated peanut-specific cellular and humoral immune responses. Gastrointestinal (GI) symptoms were the most common treatment-related adverse events (AEs) in both groups, with 6 AR101 subjects (21%) withdrawing, 4 of those due primarily to recurrent GI AEs. CONCLUSIONS: In this study, AR101 demonstrated an acceptable safety profile and demonstrated clinical activity as a potential immunomodulatory treatment option in peanut-allergic children over the age of 4, adolescents, and young adults.

Posttussive emesis as a symptom of asthma in children.

BACKGROUND: Emesis can be triggered by cough in children, and cough is a common symptom of asthma. OBJECTIVE: To explore the association between posttussive emesis and asthma in the pediatric population. METHODS: A questionnaire was distributed to parents of children between the ages of 2 and 17 years in the pediatric and allergy-immunology clinics at our institution from August 16 through November 3, 2008. Prevalence of posttussive emesis was determined and compared among children with physician-diagnosed asthma, children with no evidence of asthma, and those not formally diagnosed as having asthma but with surrogate markers suggestive of asthma. The predictive value of posttussive emesis was compared with those of known markers of asthma. The prevalence of gastroesophageal reflux and pertussis was evaluated because these conditions might also cause posttussive emesis. RESULTS: The prevalence of posttussive emesis was 33% in our study population of 500 children. Among those with physician-diagnosed asthma (n = 122), 56% reported a history of posttussive emesis. For patients not formally diagnosed as having asthma but with surrogate markers suggestive of asthma (n = 62), 71% had a history of posttussive emesis. Both of these were significantly higher than in those with no evidence of asthma (n = 316), in whom 16% reported a history of posttussive emesis (P < .0005). Children with posttussive emesis were significantly more likely to have asthma than those without posttussive emesis (odds ratio, 7.9; 95% confidence interval, 5.2-12). Neither pertussis nor gastroesophageal reflux accounted for the degree of posttussive emesis reported. CONCLUSIONS: Posttussive emesis is more common among children with asthma than among nonasthmatic children. In children with cough and a history of posttussive emesis, asthma should be strongly considered in the differential diagnosis.

Sublingual immunotherapy for peanut allergy: clinical and immunologic evidence of desensitization.

BACKGROUND: There are no treatments currently available for peanut allergy. Sublingual immunotherapy (SLIT) is a novel approach to the treatment of peanut allergy. OBJECTIVE: We sought to investigate the safety, clinical effectiveness, and immunologic changes with SLIT in children with peanut allergy. METHODS: In this double-blind, placebo-controlled study subjects underwent 6 months of dose escalation and 6 months of maintenance dosing followed by a double-blind, placebo-controlled food challenge. RESULTS: Eighteen children aged 1 to 11 years completed 12 months of dosing and the food challenge. Dosing side effects were primarily oropharyngeal and uncommonly required treatment. During the double-blind, placebo-controlled food challenge, the treatment group safely ingested 20 times more peanut protein than the placebo group (median, 1,710 vs 85 mg; P = .011). Mechanistic studies demonstrated a decrease in skin prick test wheal size (P = .020) and decreased basophil responsiveness after stimulation with 10(-2) µg/mL (P = .009) and 10(-3) µg/mL (P = .009) of peanut. Peanut-specific IgE levels increased over the initial 4 months (P = .002) and then steadily decreased over the remaining 8 months (P = .003), whereas peanut-specific IgG4 levels increased during the 12 months (P = .014). Lastly, IL-5 levels decreased after 12 months (P = .015). No statistically significant changes were found in IL-13 levels, the percentage of regulatory T cells, or IL-10 and IFN-γ production. CONCLUSION: Peanut SLIT is able to safely induce clinical desensitization in children with peanut allergy, with evidence of immunologic changes suggesting a significant change in the allergic response. Further study is required to determine whether continued peanut SLIT is able to induce long-term immune tolerance.

Profiling families enrolled in food allergy immunotherapy studies.

BACKGROUND: Little is known about specific psychological factors that affect parents' decisions to take part in clinical studies. We examined factors, related to health-related quality of life (HRQoL), that may influence parents' decision to allow their children to participate in research on clinical food allergy. METHODS: Parents of children with food allergies were offered investigational oral immunotherapy (OIT) in a regular outpatient clinic. Forty parents (group A) declined, and 25 parents (group B) agreed to take part. Both groups agreed to complete the Food Allergy Quality of Life-Parent Form and the Food Allergy Independent Measure. RESULTS: Children were aged between 1 and 12 years (mean: 6.5 years). Groups A and B displayed a similar and typical distribution for gender, age, number of foods, severity and number of symptoms, and socioeconomic variables. Parents who chose to enroll their children in the OIT trial reported a similar impact of food allergy on the HRQoL of their children as parents of children who did not volunteer for the study. Participating parents perceived a significantly higher likelihood (odds ratio: 6.753) of their child having a severe reaction and dying if food is ingested. By using this model, the likelihood of taking part in immunotherapy could be predicted accurately in 90% of cases. CONCLUSIONS: Parents who had higher anxiety about negative outcomes from accidental ingestion were more likely to consent to experimental therapy for their child. This finding has ethical implications for investigators and supports the need to create mechanisms to avoid unintended coercion in vulnerable groups.

Oral tolerance, food allergy, and immunotherapy: implications for future treatment.

The lumen of the gastrointestinal tract is exposed daily to an array of dietary proteins. The vast majority of proteins are tolerated through suppression of cellular or humoral responses, a process known as oral tolerance. However, in approximately 6% of children and 4% of adults in the United States, tolerance to a given dietary antigen either is not established or breaks down, resulting in food hypersensitivity. Although food allergies can result in sudden and life-threatening symptoms, their prevalence is remarkably low considering the complexities of the gut-associated mucosal system. Suppression involves signaling by an array of nonprofessional antigen-presenting cells, dendritic cells, and regulatory T cells, as well as lymphocyte anergy or deletion. Several factors, including antigen properties, route of exposure, and genetics and age of the host, contribute to the development of oral tolerance. Although the current standard of care for patients with food allergies is based on avoidance of the trigger, increased understanding of the mechanisms involved in tolerance has shifted focus of treatment and prevention toward inducing tolerance. Data from early-phase clinical trials suggest both sublingual and oral immunotherapy are effective in reducing sensitivity to allergens. In this article we review the mechanisms of tolerance, discuss aberrations in oral tolerance, and provide information on novel prevention and treatment paradigms for food allergy.