IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Update on Insect Sting Anaphylaxis

PURPOSE OF REVIEW

This review describes improvement in diagnostic accuracy, prediction of outcomes, identifying high-risk factors, and refinements of treatment that continue to evolve over the past 5-10 years.

RECENT FINDINGS

The risk of anaphylaxis is relatively low (< 5%) in patients with previous large local reactions or strictly cutaneous systemic reactions, but much higher in those with moderate-to-severe anaphylaxis (40%-70%) or mastocytosis (> 90%). Use of recombinant venom allergens and basophil activation tests may improve diagnostic accuracy. Elevated serum tryptase (and possible mastocytosis) occurs in 10% of patients with insect sting allergy, and in 25% of those with hypotensive reactions. Rush VIT is proven safe and rapidly effective. There are known high-risk factors that justify treatment beyond 5 years. Diagnostic accuracy and prediction of risk have improved in recent years. There are still knowledge gaps related to prediction and management of risk with current diagnostic and therapeutic modalities.

Diagnostic workup including CD203c-based basophil activation test in immediate hypersensitivity due to metronidazole and ornidazole and evaluation of cross-reactivity in between

BACKGROUND

Little is known about the diagnostic approaches for immediate hypersensitivity reactions (IHRs) due to 5-nitroimidazole antibiotics. The aim was to evaluate the usefulness of in vivo tests and basophil activation test (BAT) for the diagnosis of IHRs due to metronidazole and ornidazole and to determine possible cross-reactivity in between.

METHODS

Forty-nine patients with a clear history of IHRs due to these drugs and 20 healthy subjects who were known to tolerate these drugs were included. Skin tests (STs) and single-blind placebo-controlled drug provocation tests (SBPCDPTs) were performed with both drugs whereas BAT was applied only with the culprit drug.

RESULTS

The most and least common reaction types were urticaria/angioedema (34.7%) and anaphylaxis (14.3%), respectively. SBPCDPTs were positive in 15 out of 47 patients, and only 7 had positive STs. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of STs for metronidazole/ornidazole were 33.3%/16.6%, 94.2%/97.3%, 60%/50%, and 84.6%/88.1%, respectively. BAT was positive in 12 out of 15 patients and negative in 10 control subjects, giving a sensitivity rate of 71.4% (CI, 29.0%-96.3%) for metronidazole and 83.3% (CI, 35.8%-99.5%) for ornidazole. The optimal concentration of both drugs for BAT was determined as 5 mg/mL. No cross-reactivity among two drugs was observed according to in vivo tests.

CONCLUSIONS

Our study showed that SBPCDPT and BAT are both useful diagnostic tools for IHRs due to 5-nitroimidazole antibiotics and can be used as supplementary to each other. No cross-reactivity between metronidazole and ornidazole in IHRs exists.

IgE-mediated food allergy throughout life

Food allergy (FA) has become an increasing problem throughout the world. Over the last 2 decades, the frequency of FA has increased in both children and adults. The prevalence differs according to the research methodology, age, and geographic regions, ranging between 2.0% and 10.0%. The most common form of FA is immunoglobulin E (IgE)-mediated FA. In this form, patients may present with life-threatening conditions, such as anaphylaxis, or milder conditions, such as urticaria, angioedema, sneezing, and nausea alone. The gold standard in the diagnosis of FA is oral provocation tests. Epidermal skin prick tests and specific IgE measurements, as well as component-resolved diagnostic techniques are helpful in the diagnosis and follow-up of patients. In this review, the epidemiology, diagnosis, follow-up, and prognosis of IgE-mediated FA in children and adults were discussed and some specific forms of FA, such as pollen FA syndrome, alpha-gal allergy, and food-dependent exercise-induced anaphylaxis were explained.

Minireview: Mas-related G protein-coupled receptor X2 activation by therapeutic drugs

Symptoms that resemble allergic reactions, such as pruritus, flushing, and hypotension, are common side effects of therapeutic drugs. In a true allergic reaction, Immunoglobulin E (IgE) antibodies recognize the drug and trigger mediator release from mast cells through cross-linking of IgE receptors. However, many drugs can bypass this pathway and can activate mast cells directly through MRGPRX2, a G protein-coupled receptor that responds to a wide range of small molecules, peptides, and proteins that have little in common except for a net positive charge. This review will provide an overview of MRGPRX2, including its expression pattern, studies of its pharmacology, and its orthologs. It also will review evidence for MRGPRX2 activation by many drugs closely associated with these reactions.

IgE in the pathophysiology and therapy of food allergy

Food allergy is becoming a major public health issue, with no regulatory approved therapy to date. Food allergy symptoms range from skin rash and gastrointestinal symptoms to anaphylaxis, a potentially fatal systemic allergic shock reaction. IgE antibodies are thought to contribute importantly to key features of food allergy and anaphylaxis, and measurement of allergen-specific IgE is fundamental in diagnosing food allergy. This review will discuss recent advances in the regulation of IgE production and IgE repertoires in food allergy. We will describe the current understanding of the role of IgE and its high-affinity receptor FcεRI in food allergy and anaphylaxis, by reviewing insights gained from analyses of mouse models. Finally, we will review data derived from clinical studies of the effect of anti-IgE therapeutic monoclonal antibodies (mAbs) in food allergy, and recent insight on the efficiency and mechanisms through which these mAbs block IgE effector functions.

Modulating Th2 Cell Immunity for the Treatment of Asthma

It is estimated that more than 339 million people worldwide suffer from asthma. The leading cause of asthma development is the breakdown of immune tolerance to inhaled allergens, prompting the immune system's aberrant activation. During the early phase, also known as the sensitization phase, allergen-specific T cells are activated and become central players in orchestrating the subsequent development of allergic asthma following secondary exposure to the same allergens. It is well-established that allergen-specific T helper 2 (Th2) cells play central roles in developing allergic asthma. As such, 80% of children and 60% of adult asthma cases are linked to an unwarranted Th2 cell response against respiratory allergens. Thus, targeting essential components of Th2-type inflammation using neutralizing antibodies against key Th2 modulators has recently become an attractive option for asthmatic patients with moderate to severe symptoms. In addition to directly targeting Th2 mediators, allergen immunotherapy, also known as desensitization, is focused on redirecting the allergen-specific T cells response from a Th2-type profile to a tolerogenic one. This review highlights the current understanding of the heterogeneity of the Th2 cell compartment, their contribution to allergen-induced airway inflammation, and the therapies targeting the Th2 cell pathway in asthma. Further, we discuss available new leads for successful targeting pulmonary Th2 cell responses for future therapeutics.

Allergic rhinitis, asthma and laryngopharyngeal reflux disease: a cross-sectional study on their reciprocal relations

Allergic rhinitis (AR) is a common medical condition worldwide. It is an inflammation in the nasal mucosa due to allergen exposure throughout the year. Laryngopharyngeal reflux (LPR) is another medical condition that can overlap with AR. LPR can be considered an extra oesophageal manifestation of gastro-oesophageal reflux disease (GORD) or a different entity. Its diagnosis imposes a real challenge as it has a wide range of unspecific symptoms. Although AR and LPR are not life-threatening, they can severely affect the quality of life for years and cause substantial distress. Moreover, having AR is associated with having asthma which is also in turn associated with GORD. This is a cross-sectional study which used surveys distributed online on Social Media and targeted people across Syria. All participants who responded to the key questions were included. Reflux symptom index (RSI) was used for LPR, and score for allergic rhinitis (SFAR) was used for AR. Demographic questions and whether the participant had asthma were also included in the survey. We found that there was an association between the symptoms of LPR and AR p < 0.0001 (OR, 2.592; 95% CI 1.846-3.639), and their scores were significantly correlated (r = 0.334). Having asthma was associated with LPR symptoms p = 0.0002 (OR 3.096; 95% CI 1.665-5.759) and AR p < 0.0001 (OR 6.772; 95% CI 2.823-16.248). We concluded that there was a significant association between having LPR, AR, and asthma. We need more studies to distinguish between their common symptoms and aetiologies.

Non-IgE- or Mixed IgE/Non-IgE-Mediated Gastrointestinal Food Allergies in the First Years of Life: Old and New Tools for Diagnosis

non-IgE and mixed gastrointestinal food allergies present various specific, well-characterized clinical pictures such as food protein-induced allergic proctocolitis, food protein-induced enterocolitis and food protein-induced enteropathy syndrome as well as eosinophilic gastrointestinal disorders such as eosinophilic esophagitis, allergic eosinophilic gastroenteritis and eosinophilic colitis. The aim of this article is to provide an updated review of their different clinical presentations, to suggest a correct approach to their diagnosis and to discuss the usefulness of both old and new diagnostic tools, including fecal biomarkers, atopy patch tests, endoscopy, specific IgG and IgG4 testing, allergen-specific lymphocyte stimulation test (ALST) and clinical score (CoMiss).

The use of microarray and other multiplex technologies in the diagnosis of allergy

OBJECTIVE

To give an overview and describe the strengths and weaknesses of immunoglobulin E (IgE) microarray and other multiplex assays that have been developed and are being used for allergy diagnostics.

DATA SOURCES

Queries for IgE microarray and multiplex assays were conducted with PubMed and Google Scholar, searching for primary articles and review papers.

STUDY SELECTIONS

We focused on articles written in English on commercially available IgE multiplex assays that were reported in the allergy and immunology literature.

RESULTS

Several commercial IgE assays that use microarray or other multiplex technology have been developed, and some have been implemented into clinical practice in Europe and Asia, with the Immuno Solid-Phase Allergen Chip being the most widely studied. Results of these assays generally correlate with results using "singleplex" IgE assays (eg, ImmunoCAP), though there can be variability among products and among allergens. A strength of the microarray technology is that IgE to a large number of allergens can be detected simultaneously in a single test, and only a small amount of patient serum is required. Cost, inadequate sensitivity under some scenarios, and difficulties with data interpretation, in some cases of 100 or more allergens, can be limitations.

CONCLUSION

IgE microarray assays are already a valuable tool in research applications. These assays, and also other forms of IgE multiplex assays, are likely to play an important role in the clinical practice of allergy in the future. Additional studies focused on clinical outcomes, and the development of more targeted allergen panels could facilitate increased clinical use.

Methods to Detect MHC-Specific IgE in Mice and Men

Humoral immunity is a major barrier limiting long-term outcome after organ transplantation. Especially, the production of antibodies directed against donor HLA/MHC antigens (i.e. donor-specific antibodies (DSA)) leading to antibody-mediated rejection (ABMR) is considered to be a major factor negatively affecting allograft survival. DSAs of the IgG isotype are routinely measured in transplant patients. However, not all patients diagnosed with IgG-DSA develop ABMR events. Therefore, research in better understanding the mechanisms of ABMR is of great importance. We recently demonstrated the production of MHC-specific IgE upon allograft rejection in mice and in transplant patients. IgE is classically connected with allergy and is known to be important for the humoral defense against helminths and worms. However, its role in autoimmune diseases and cancer has been reported recently as well. The concentration of IgE in blood is extremely low compared to other antibody isotypes. Therefore, detection of MHC-specific IgE from serum requires methods of high sensitivity. Since MHC-specific IgG-typically present at much higher serum levels-develops as well, high specificity is also required of IgE detection methods. In the murine model we developed an enzyme linked immunosorbent assay (ELISA) using MHC monomers for measurement of MHC-specific IgE, allowing us to distinguish between specificities of antibodies against different class I and class II antigens. For measurement of functional activity of MHC-specific IgE in vitro, a release assay using a rat basophil cell line (RBL-2H3) was established. For functional analysis of MHC-specific IgE in vivo, a cutaneous hypersensitivity reaction assay was adapted for this purpose using MHC monomers. Humanized RBL-2H3 cells transfected with cDNA coding for the human-high affinity IgE receptor were used for functionality measurement of donor-specific IgE in sensitized transplant patients. For detection of HLA-specific IgE, a bead assay was adapted, using beads expressing single HLA antigens. The aim of this publication is to demonstrate currently established methods for the detection and characterization of MHC-specific IgE in the murine and human setting.

Investigation of Serum Total IgE and Eosinophil Levels in Different Allergic Diseases Together with the Study of Their Correlations with Various Possible Allergens in Mosul City

Serum total IgE (tIgE) is frequently used in the diagnosis of allergic diseases in Mosul city and Iraq. However, neither normal nor elevated levels can exclude or confirm the diagnosis of these diseases. Here, we tried to evaluate the validity of tIgE in the diagnosis of allergic asthma(AS), allergic rhinitis(AR) and atopic dermatitis(AD) in a sample of Mosul population, to set up an optimum cut-off value for diagnosis of these diseases and to study its correlation with different parameters that might affect its level. 38 patients with AS, 27 with AR, 46 with AD and 45 healthy controls were included in this study. tIgE were determined by ELISA and compared between allergic diseases and controls. Blood eosinophilia was ascertained and correlated with tIgE levels. The geometric means of tIgE were 316.87 IU/ml (95% CI: 234.69 to 427.82) in AS, 262.07 IU/ml (95% CI:174.24 to 394.18) in AR and 270.48 IU/ml (95% CI:202.57 to 361.16) in AD compared to 16.90 IU/ml (95% CI:12.32 to 23.18) in healthy controls. tIgE in allergic diseases was significantly increased in comparison to healthy controls (P <.0001). Female gender influenced tIgE in AS, but not in AR or AD. tIgE predominated in younger age groups; however, no significant difference was found between younger and older groups. Optimum values for tIgE with best discriminative accuracy were 77 IU/ml for AS and 81 IU/ml for AR and AD. Eosinophils count appeared to be a useful adjunct, and correlate well with tIgE in the diagnosis of allergic diseases.

Longitudinal analysis of total serum IgE levels with allergen sensitization and atopic diseases in early childhood

There are few studies addressing the longitudinal analysis of serum IgE levels and its impact to the development of atopic diseases in early childhood. We investigated 170 children who regularly followed up at our clinic for 4 years in a birth cohort study with at least 3 time-points of serum samples. The pattern of total serum IgE levels from 6 months to 4 years of age was clustered using K-means method in R software. Specific immunoglobulin E antibodies against food (egg white and milk) and inhalant allergens (D. pteronyssinus and D. farinae) were measured at 0.5, 1, 1.5, 2, 3 and 4 years of age. By using K-means clustering, the dynamic changes in serum IgE levels was significantly stratified into 3 clusters (cluster A, < 100 kU/L, n = 106; cluster B, 100–200 kU/L, n = 35; cluster C, ≥ 200 kU/L, n = 29). A persistent total IgE levels higher than 100 kU/L appeared to be associated with higher prevalence of sensitization to food but not mite. However, a persistent IgE levels higher than 200 kU/L was not only remarkably related to increased prevalence of mite sensitization, but also risk of eczema at age 1 and allergic rhinitis and asthma at age 2, 3 and 4. In conclusion, a persistent total serum IgE level ≥ 200 kU/L since infancy is strongly associated with the presence of food and mite sensitization, as well as the development of eczema in infants, and rhinitis and asthma later in early childhood.

Serum immunoglobulin E responses to aeroallergens in cats with naturally occurring airway eosinophilia compared to unaffected control cats

BACKGROUND

Eosinophilic airway disease in cats is sometimes described as allergic in origin, but controversy exists in the documentation of allergy in cats and the utility of allergy testing for respiratory tract diseases.

OBJECTIVE

To examine serum immunoglobulin E (IgE) response to aeroallergens in cats with airway eosinophilia.

ANIMALS

Fifteen cats with idiopathic eosinophilic airway inflammation and 9 control cats.

METHODS

Prospective, case-control study. Surplus serum from cats with airway eosinophilia documented by bronchoscopic bronchoalveolar lavage was submitted for IgE measurement using ELISA polyclonal antibody methodology. Responses for regional allergens (fungal organisms, weeds, grasses, trees, mites, insects) were assessed. Results were reported as ELISA absorbance units with scores 0 to 79 considered negative, scores between 80 and 300 considered intermediate, and scores >300 considered positive.

RESULTS

Cats with airway eosinophilia had significantly more positive serum IgE responses (25/720) than did healthy controls (5/432, P = .02); however, the number of cats with positive IgE responses (5/15) did not differ from controls (1/9, P = .35). The allergen that most commonly resulted in positive serum IgE response in cats with airway eosinophilia was dust mite (n = 4) followed by 2 types of storage mites (n = 3 each). No control cat tested positive for these allergens.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum IgE production against aeroallergens was found in some cats with eosinophilic airway inflammation, but the number of affected cats with positive results did not differ from controls. Further investigation in cats with eosinophilic, mixed, and neutrophilic airway disease in comparison to control cats is warranted.

Role of in vitro testing in food allergy

Oral food challenges remain the gold standard for the diagnosis of food allergy. Nevertheless, the allergy workup is based on the presence of a clinical history, which is evocative of an immune-allergic reaction, and the first assessment is usually the performance of skin prick tests. Based on these results, allergists are used to evaluate the presence of serum-specific IgE, which are today the most commonly prescribed in vitro test for the evaluation of a possible food allergy. Other in vitro tests include the basophil activation test, that is becoming more and more employed by clinicians and not only by researchers, and the evaluation of serum IgG4, which is still an issue of debate in the allergy community. The present paper reviews the use of these in vitro tests for the diagnosis of food allergy.

A Proposal from the Montpellier World Health Organization Collaborating Centre for Better Management and Prevention of Anaphylaxis

Since the first description of anaphylaxis in 1902, its clinical importance as an emergency condition has been recognized worldwide. Anaphylaxis is a severe, potentially life-threatening systemic hypersensitivity reaction characterized by rapid onset and the potential to endanger life through respiratory or circulatory compromise. It is usually, although not always, associated with skin and mucosal changes. Although the academic/scientific communities have advocated to promote greater awareness and protocols for the management of anaphylaxis based on best evidence, there are few efforts documenting feedback as to the success of these efforts. In this article, we review the key unmet needs related to the diagnosis and management of anaphylaxis, and propose a public health initiative for prevention measures and a timetable action plan that intends to strengthen the collaboration among health professionals and especially primary care physicians dealing with anaphylaxis, which can encourage enhanced quality of care of patients with anaphylaxis. More than calling for a harmonized action for the best management of anaphylaxis to prevent undue morbidity and mortality, the Montpellier World Health Organization Collaborating Centre here proposes an action plan as a baseline for a global initiative against anaphylaxis. We strongly believe that these collaborative efforts are a strong public health and societal priority that is consistent with the overarching goals of providing optimal care of allergic patients and best practices of allergology.

Design of an Optimally-Diagnostic Skin Test for Diagnosis of Sensitivity to Eight Allergens: A First-in-Human Study of Dose Escalation and Simultaneous Administration in Chinese Subjects

Background

Eight extracts from common native allergens, Artemisia annua pollen, Platanus pollen, Humulus pollen, Betula platyphylla pollen, Ambrosia artemisiifolia pollen, Blattella germanica, cat dander and dog dander were developed for skin prick test (SPT). Since standardization and composition alone cannot guarantee that the allergen extracts are within the concentration range that give the best chance of a true diagnosis, it is necessary to explore the optimal diagnostic concentration (ODC) of allergens in SPT.

Objective

To identify the optimal diagnostic concentration of eight allergen extracts in SPT and assess the safety of simultaneous administration.

Patients and Methods

Patients with a history of allergic disease were enrolled in this two-part open-label, parallel study. In Study 1, 92 patients were enrolled into eight groups according to their disease-causing allergens and were given three increasing concentrations of the corresponding allergen. In Study 2, 20 patients were divided into two concentration groups and were given all of the eight allergens. Safety and sensitivity were evaluated to determine the optimal diagnostic concentration.

Results

In Study 1, the sensitivity of seven allergen extracts was >80% at middle and high concentrations, except for Ambrosia artemisiifolia pollen. The optimal diagnostic concentration (in DU/mL) for eight allergens was 33,333, 12,000, 8667, 50,000, 40,000, 3333, 7000, and 5000. In Study 2, the prevalence of adverse events in the two groups was 70% and 80%, respectively. A total of 10 wheals of 8 patients did not subside <24 h after SPTs.

Conclusion

The eight allergens showed high sensitivity and safety at a certain concentration, which was defined as optimal diagnostic concentration. The results support further clinical research of investigated allergens and our study offers a scheme to determine the ODC of allergens in SPT.

Medical devices in allergy practice

Medical devices provide people with some health benefits in terms of diagnosis, prevention, treatment, and monitoring of disease processes. Different medical specialties use varieties of medical devices more or less specific for them. Allergology is an interdisciplinary field of medical science and teaches that allergic reactions are of systemic nature but can express themselves at the level of different organs across the life cycle of an individual. Subsequently, medical devices used in allergology could be regarded as: 1) general, servicing the integral diagnostic and management principles and features of allergology, and 2) organ specific, which are shared by organ specific disciplines like pulmonology, otorhinolaryngology, dermatology, and others. The present position paper of the World Allergy Organization (WAO) is meant to be the first integral document providing structured information on medical devices in allergology used in daily routine but also needed for sophisticated diagnostic purposes and modern disease management. It is supposed to contribute to the transformation of the health care system into integrated care pathways for interrelated comorbidities.

IgE Epitope Profiling for Allergy Diagnosis and Therapy - Parallel Analysis of a Multitude of Potential Linear Epitopes Using a High Throughput Screening Platform

Immunoglobulin E (IgE) is pivotal for manifestation and persistence of most immediate-type allergies and some asthma phenotypes. Consequently, IgE represents a crucial target for both, diagnostic purposes as well as therapeutic approaches. In fact, allergen-specific immunotherapy – aiming to re-route an IgE-based inflammatory response into an innocuous immune reaction against the allergen – is the only curative approach for IgE-mediated allergic diseases known so far. However, this requires the cognate allergen to be known. Unfortunately, even in well-characterized allergics or asthmatics, often just a small fraction of total IgE can be assigned to specific target allergens. To overcome this knowledge gap, we have devised an analytical platform for unbiased IgE target epitope detection. The system relies on chemically produced random peptide libraries immobilized on polystyrene beads (“one-bead-one-compound (OBOC) libraries”) capable to present millions of different peptide motifs simultaneously to immunoglobulins from biological samples. Beads binding IgE are highlighted with a fluorophore-labeled anti-IgE antibody allowing fluorescence-based detection and isolation of positives, which then can be characterized by peptide sequencing. Setting-up this platform required an elaborate optimization process including proper choice of background suppressants, secondary antibody and fluorophore label as well as incubation conditions. For optimal performance our procedure involves a sophisticated pre-adsorption step to eliminate beads that react nonspecifically with anti-IgE secondary antibodies. This step turned out to be important for minimizing detection of “false positive” motifs that otherwise would erroneously be classified as IgE epitopes. In validation studies we were able to retrieve artificial test-peptide beads spiked into our library by using IgE directed against those test-peptides at physiological concentrations (≤20 IU/ml of specific IgE), and disease-relevant bead-bound epitopes of the major peanut allergen Ara h 2 by screening with sera from peanut allergics. Thus, we established a platform with which one can find and validate new immunoglobulin targets using patient material which displays a largely unknown immunoglobulin repertoire.

Aptamers against Immunoglobulins: Design, Selection and Bioanalytical Applications

Nucleic acid aptamers show clear promise as diagnostic reagents, as highly specific strands were reported against a large variety of biomarkers. They have appealing benefits in terms of reproducible generation by chemical synthesis, controlled modification with labels and functionalities providing versatile means for detection and oriented immobilization, as along with high biochemical and temperature resistance. Aptamers against immunoglobulin targets-IgA, IgM, IgG and IgE-have a clear niche for diagnostic applications, therefore numerous aptamers have been selected and used in combination with a variety of detection techniques. The aim of this review is to overview and evaluate aptamers selected for the recognition of antibodies, in terms of their design, analytical properties and diagnostic applications. Aptamer candidates showed convincing performance among others to identify stress and upper respiratory tract infection through SIgA detection, for cancer cell recognition using membrane bound IgM, to detect and treat hemolytic transfusion reactions, autoimmune diseases with IgG and detection of IgE for allergy diseases. However, in general, their use still lags significantly behind what their claimed benefits and the plethora of application opportunities would forecast.

An updated overview of spectrum of gluten-related disorders: clinical and diagnostic aspects

The incidence of gluten-related disorders (GRDs) continues to increase and its global prevalence is estimated at approximately 5% of the population. Celiac disease (CD), dermatitis herpetiformis (DH), gluten ataxia (GA), wheat allergy (WA), and non-celiac gluten sensitivity (NCGS) are the five major GRDs that present with a wide range of clinical manifestations. The diagnosis of GRDs can be challenging because the typical and atypical clinical manifestations of the GRDs overlap. In this review, the current definitions of gluten-related disorders, focusing on their clinical features, diagnostic and therapeutic approaches are presented. We concluded that GRDs are usually diagnosed using a combination of clinical features, serological tests, and histopathological findings. Treatment usually involves dietary modification.

Allergen exposure chambers: implementation in clinical trials in allergen immunotherapy

Allergen exposure chambers (AECs) have been developed for controlled allergen challenges of allergic patients mimicking natural exposure. As such, these facilities have been utilized e.g., for proof of concept, dose finding or the demonstration of onset of action and treatment effect sizes of antiallergic medication. Moreover, clinical effects of and immunological mechanisms in allergen immunotherapy (AIT) have been investigated in AECs. In Europe AIT products have to fulfill regulatory requirements for obtaining market authorization through Phase I to III clinical trials. Multiple Phase II (dose-range-finding or proof-of-concept) trials on AIT products have been performed in AECs. However, they are not accepted by regulatory bodies for pivotal (Phase III) trials and a more thorough technical and clinical validation is requested. Recently, a Position Paper of the European Academy of Allergy and Clinical Immunology (EAACI) has outlined unmet needs in further development of AECs. The following review aims to address some of these needs on the basis of recently published data in the first part, whereas the second part overviews published examples of most relevant Phase II trials in AIT performed in AEC facilities.

Skin prick reactivity among asthmatics in East Africa

Background

The burden of asthma in Africa is high, and yet the disease is not universally prioritised. Data on allergic asthma and its impact on asthma morbidity are limited in Africa. Our aim was to describe the distribution of skin prick positivity among asthmatics in Eastern Africa.

Methods

From August 2016 to May 2018, 1671 asthmatic patients were enrolled from Uganda, Kenya, and Ethiopia as part of the African Severe Asthma Program clinical study. Skin prick testing was performed at baseline using a panel of 12 allergens, and factors associated with skin prick reactivity determined.

Results

Of the 1, 671 patients recruited, 71% were female with a median age of 40 years, 93.6% were aged >15 years and the patterns of asthma symptom frequency was intermittent in 2.9%, mild persistent in 19.9%, moderate persistent in 42.6% and severe persistent in 34.6% at baseline. Self-reported triggers, were dust (92%), cold weather (89%), upper respiratory infections (84%), strong smells (79%) and exposure to tobacco (78%). The majority (90%) of the participants had at least 1 positive allergen reaction, with 0.9% participants reacting to all the 12 allergens. Participants commonly reacted to house dust mites (66%), Blomia tropicalis (62%), and the German cockroach (52%). Patients sensitized to more allergens (>2) had significantly reduced lung function (FEV ≤ 80%; p = 0.001) and were more likely to visit the emergency department due to asthma (p = 0.012). There was no significant relationship between number of allergens and measures of asthma control, quality of life, and other clinical outcomes. Only the country of origin was independently associated with atopy among African asthmatics.

Conclusion

There is a high prevalence of skin prick positivity among East African patients with asthma, with the commonest allergen being house dust mite. Skin reactivity did not correlate well with asthma severity and poor asthma control. The relation between atopy, measured through skin prick testing, and measures of asthma control among asthma patients in Eastern Africa is unclear and needs further study.

Trial registration

The ASAP study was registered prospectively. ClinicalTrials.gov Identifier: NCT03065920; Registration date: February 28, 2017; Last verified: February 28, 2017.