Progenitor cell-derived basophils: A novel barcoded passive degranulation assay in allergic diseases.

BACKGROUND: Effector cells assays provide an overall measure of responsiveness to allergen, but the lack of reliable and high-throughput assays limits the clinical utility. We aimed to develop a high-throughput basophil activation test based on human progenitor cell-derived basophils (PCB) and investigate the role of PCB activation test (PCBAT) in allergic diseases. METHODS: Progenitor cell-derived basophils were differentiated from CD34+ progenitor cells and sensitized with sera from subjects sensitized to cat, peanut or atopic controls. Sensitized PCBs were stimulated with increasing concentrations of the corresponding allergens in vitro. Degranulation was assessed by measuring CD63 expression using flow cytometry. The correlations between PCBAT and clinical allergy were assessed. RESULTS: Following passive sensitization of the mature PCBs with serum and allergen stimulation, an allergen specific dose-dependent increase in CD63 expression was observed. Sera from subjects sensitized to cat (n = 35, of which 17 subjects had clinical reactivity quantified using inhaled allergen challenge), peanut allergic (n = 30, of which 15 subjects had clinical reactivity validated using double blind, placebo controlled food challenges [DBPCFC]), peanut-sensitized but tolerant subjects (n = 5) were used to sensitize PCBs. PCBAT area under the curve (AUC) correlated with sIgE (r2  = .49, p = .001) in subjects sensitized to cat (sIgE ≥ 0.35KU/L). The provocation concentration of inhaled cat allergen (PC20 ) correlated with PCBAT AUC (r2  = .33, p = .016). In subjects sensitized to peanut, PCBAT AUC was highly correlated with sIgE to Ara h 2 (r2  = .59, p < .0001). Peanut threshold cumulative dose during DBPCFC was negatively correlated with PCBAT AUC (r2  = .57, p = .001) and IgE to Ara h1 (r2  = .55, p = .007), but not with sIgE to whole peanut or Ara h2. All peanut-sensitized but tolerant subjects showed no reaction to peanut on PCBAT. CONCLUSION: Progenitor cell-derived basophils activation test is a high-throughput assay, which correlates with clinical allergy and may confer a powerful alternative tool in allergy testing.

Mast cell activation test in the diagnosis of allergic disease and anaphylaxis.

BACKGROUND: Food allergy is an increasing public health issue and the most common cause of life-threatening anaphylactic reactions. Conventional allergy tests assess for the presence of allergen-specific IgE, significantly overestimating the rate of true clinical allergy and resulting in overdiagnosis and adverse effect on health-related quality of life. OBJECTIVE: To undertake initial validation and assessment of a novel diagnostic tool, we used the mast cell activation test (MAT). METHODS: Primary human blood-derived mast cells (MCs) were generated from peripheral blood precursors, sensitized with patients' sera, and then incubated with allergen. MC degranulation was assessed by means of flow cytometry and mediator release. We compared the diagnostic performance of MATs with that of existing diagnostic tools to assess in a cohort of peanut-sensitized subjects undergoing double-blind, placebo-controlled challenge. RESULTS: Human blood-derived MCs sensitized with sera from patients with peanut, grass pollen, and Hymenoptera (wasp venom) allergy demonstrated allergen-specific and dose-dependent degranulation, as determined based on both expression of surface activation markers (CD63 and CD107a) and functional assays (prostaglandin D2 and ß-hexosaminidase release). In this cohort of peanut-sensitized subjects, the MAT was found to have superior discrimination performance compared with other testing modalities, including component-resolved diagnostics and basophil activation tests. Using functional principle component analysis, we identified 5 clusters or patterns of reactivity in the resulting dose-response curves, which at preliminary analysis corresponded to the reaction phenotypes seen at challenge. CONCLUSION: The MAT is a robust tool that can confer superior diagnostic performance compared with existing allergy diagnostics and might be useful to explore differences in effector cell function between basophils and MCs during allergic reactions.

Physicians' experience and opinion on contraindications to allergen immunotherapy: The CONSIT survey.

BACKGROUND: Allergen immunotherapy (AIT) is the only disease-modifying treatment in allergy but several contraindications limit its use. OBJECTIVE: To collect the outcome of using AIT in theoretically contraindicated situations in real patients in the Contraindications to Specific ImmunoTherapy (CONSIT) survey. METHODS: The CONSIT is an electronic European Academy of Allergy and Clinical Immunology survey conducted to gather the safety outcomes of patients undergoing subcutaneous, sublingual, or venom AIT and the opinions of physicians on each of 17 selected conditions: children younger than 5 years; starting AIT during pregnancy; controlled severe asthma; arrhythmias; coronary disease; cancer; autoimmune disease; bone marrow and solid organ transplantation; human immunodeficiency virus and acquired immunodeficiency syndrome; previous anaphylaxis during AIT; use of ß-blockers, angiotensin-converting inhibitors, cyclosporine, and methotrexate; and inability to communicate. Safety using AIT was reported in a 3-point scale: 1, "no problems"; 2, "minor problems" (requiring only dose modifications); and 3, "major problems" (AIT not tolerated). Each physician was asked about the degree of contraindication that each condition should have: no contraindication (score 1), relative contraindication (score 2), or absolute contraindication (score 3). RESULTS: Five hundred twenty physicians (75% Europeans, 89% allergists) reported on approximately 45,000 patients undergoing AIT with any of these conditions. Major problems were infrequent, occurring more frequently in patients with asthma (9.9%) and with previous anaphylaxis from AIT (9.5%). Regarding opinions, experienced physicians scored a significantly lower mean for all conditions than non-experienced physicians for all routes. CONCLUSION: Major problems were infrequent and experienced physicians were less likely to be restrictive in the use of AIT.

Allergy to Peanuts imPacting Emotions And Life (APPEAL): The impact of peanut allergy on children, teenagers, adults and caregivers in the UK and Ireland.

The Allergy to Peanuts imPacting Emotions And Life study (APPEAL) explored the psychosocial burden of living with self-reported peanut allergy experienced by children, teenagers, adults and caregivers in the UK and Ireland. A two-stage (quantitative survey and qualitative interview [APPEAL-1]), cross-sectional study of the psychosocial burden of peanut allergy (APPEAL-2) was conducted. Quantitative data were evaluated using descriptive statistics and qualitative data were analysed using MAXQDA software. A conceptual model specific to UK and Ireland was developed using the concepts identified during the analysis. A total of 284 adults in the UK and Ireland completed the APPEAL-1 survey and 42 individuals participated in APPEAL-2. Respondents reported that peanut allergy restricts their choices in various situations, especially with regard to choosing food when eating out (87% moderately or severely restricted), choosing where to eat (82%), special occasions (76%) and when buying food from a shop (71%). Fifty-two percent of survey participants and 40% of interview participants reported being bullied because of PA. Psychological impact of peanut allergy included feeling at least moderate levels of frustration (70%), uncertainty (79%), and stress (71%). The qualitative analysis identified three different types of coping strategies (daily monitoring or vigilance, communication and planning) and four main areas of individuals' lives that are impacted by peanut allergy (social activities, relationships, emotions and work [adults and caregivers only]). The extent of the impact reported varied substantially between participants, with some reporting many negative consequences of living with peanut allergy and others feeling it has minimal impact on their health-related quality of life. This large survey and interview study highlight the psychosocial burden of peanut allergy for adults, teenagers, children and caregivers in the UK and Ireland. The analysis demonstrates the wide variation in level of impact of peanut allergy and the unmet need for those individuals who experience a substantial burden from living with peanut allergy.

Relationship of Allergy with Asthma: There Are More Than the Allergy "Eggs" in the Asthma "Basket".

Asthma and allergy share a similar and very close course, especially through childhood. Considerable research effort has been put in untangling these associations; however, it is now becoming obvious that this is an exceedingly difficult task. In fact, each research breakthrough further perplexes this picture, as we are steadily moving toward the era of personalized medicine and we begin to appreciate that what we thought to be a single disease, asthma, is in fact an accumulation of distinct entities. In the context of this "syndrome," which is characterized by several, as of yet poorly defined endotypes and phenotypes, the question of the link of "asthma" with allergy probably becomes non-relevant. In this review, we will revisit this question while putting the emphasis on the multifaceted nature of asthma.