Particularities of allergy in the Tropics

Monitoring, distribution and clinical relevance of airborne pollen and fern spores in Southeast Asia - A systematic review

Southeast Asia is witnessing a rapid increase in the prevalence of allergic diseases, including asthma and allergic rhinitis. Pollen grains stand out as one of the primary triggers for allergy, and monitoring aeroallergens plays a pivotal role in allergy prevention. However, our understanding of the diversity and abundance of allergenic pollen in tropical regions, as well as their clinical significance, remains limited. This review aims to address this issue by identifying the most potentially allergenic plants in Southeast Asia, examining sensitization rates to their pollen allergens, describing the dynamics of pollen seasons, and discussing the current state of aerobiological monitoring in the region. The selection of plants was conducted through a systematic review process (following PRISMA guidelines), by screening the Scopus and PubMed databases, and focusing on studies that provided clinical and aerobiological data. As a result, 73 studies related to pollen allergy in Southeast Asia were identified and reviewed. The list of potentially allergenic plants posing the highest risk in Southeast Asia has been narrowed down to 10, including 5 woody species, 2 primarily weed families, grasses, palms, and ferns. The descriptions of these plants are supplemented with information on their ecology, pollen seasons dynamics, and clinical significance.

The Allergy Crossroads of Subtropical Regions: Mites, Crustaceans, and the Rise of Edible Insects

Background: Edible insects (EIs) are increasingly recognized as a sustainable protein source, yet concerns persist regarding allergic reactions, even in individuals without prior known consumption. This study examines the immune response profile in patients from a subtropical area to improve understanding of mite-related cross-reactivity and emerging food sensitizations. Methods: To assess sensitization to edible insects, we analyzed 634 patients from a tertiary care allergy institution with high perennial exposure to house dust mites and storage mites. Sensitization patterns were assessed using the ALEX²® MacroArray platform, a multiplex IgE diagnostic tool covering 282 allergens, including Locusta migratoria (Lm), Acheta domesticus (Ad), and T. molitor (Tm). Patients with IgE levels ≥0.3 kU/L were evaluated for cross-reactivity to both mite allergens and pan-allergens. Results: Of the 634 patients, 138 (21.76%) exhibited IgE sensitization to at least one EI extract. Tropomyosin was the most prevalent pan-allergen (63.76%), followed by troponin-C (28.98%) and arginine kinase (26.81%). Notably, 95.66% of EI-sensitized individuals also reacted to mite allergens. However, 23.18% lacked reactivity to common pan-allergens, suggesting alternative sensitization mechanisms. Conclusions: This investigation can highlight regional variations in EI sensitization, where high mite exposure in subtropical climates appears to influence IgE responses to insect proteins. The findings suggest that EI sensitization is not merely incidental but represents a distinct immunological phenomenon shaped by environmental factors and allergen cross-reactivity. Since the presence of food-specific IgE does not reliably indicate clinical allergy, and the lack of food challenge data constrains diagnostic certainty, acknowledging EI sensitization as a potential risk factor remains essential for ensuring food safety and protecting public health.

Exposure to smoking and greenspace are associated with allergy medicine use - A study of wastewaterin 28 cities of China

Allergies have become an important public health issue as their occurrence is reportedly on the rise around the world. Exposure to environmental factors is considered as trigger for allergic diseases. However, there was limited data on the importance of each factor, particularly in China. In this study, we aimed to investigate the association between occurrence of allergic diseases with exposure to multiple environmental factors via wastewater surveillance across 28 cities in China. The surveillance was conducted by measuring biomarkers of proxies of allergic diseases, i.e. antihistamines, asthma drug, and of smoking, i.e. cotinine in wastewater. Data of green space and air quality were also collected. We observed the level of antihistamine use were significantly associated with smoking, green space and pollen but not significant with air pollution. People in Northern China used more antihistamines than their compatriots in Southern China, an observation aligning with previous reporting of more allergy prevalence in the North than the South of China. Our study affirmed that in China smoking is responsible for a rise in allergy and asthma in the population. Meanwhile, selected sensitizing pollens (occurring during summer) could have stronger impact to trigger allergies than other pollens (occurring in winter).

Environmental exposures associated with atopy in a rural community in Gwanda district, Zimbabwe: a cross-sectional study

Introduction

The increasing prevalence of allergic diseases in Zimbabwe may be attributed to changing environmental exposure patterns. In this study, we sought to identify the most influential environmental and lifestyle factors that may explain the observed atopy in a rural community in Zimbabwe.

Methods

Using a cross-sectional study, information on a wide array of environmental and lifestyle exposures was self-reported by a sample of participants (children aged <18 years and adults aged ≥18 years) in the Gwanda district, Zimbabwe. To consenting participants, we performed skin prick testing (SPT) at a local clinic in Gwanda district to identify atopic individuals. Variables with a p value <0.25 from univariate analysis were included in backward-elimination multiple logistic regression analysis. Separate regression analyses were conducted for children (n = 108), adults (n = 388), and a subgroup of adults who reported ever being employed in any potentially harmful occupation (n = 153).

Results

Compared with boys, girls were more likely to be sensitised to at least one allergen (OR = 4.87, 95% CI = 1.22-19.51). Among adults, the likelihood of sensitisation increased with increasing age (OR = 1.02, 95% CI = 1.01-1.03) and with a history of bloody urine and/or schistosomiasis (OR = 2.20, 95% CI = 0.98-4.95). In the subgroup of adults who reported ever being employed in any potentially harmful occupation, atopic sensitisation was associated with a history of tuberculosis (TB; OR = 3.37, 95% CI = 1.08-10.52) and a history of bloody urine and/or schistosomiasis (OR = 4.36, 95% CI = 1.40-13.65). Other notable, though not significant, factors were passive or parental smoking, alcohol consumption, indoor dampness and visible mould on walls.

Conclusion

Girls were more likely to be sensitised to at least one allergen when compared to boys. Among adults, atopic sensitisation was positively associated with age, parental smoking, alcohol consumption and history of bloody urine or schistosomiasis but negatively associated with indoor cooking. A history of TB or helminth infection increased the likelihood of atopy among adults with history of employment. Longitudinal studies to explore the temporal and causal relationships between these factors and allergic outcomes are essential. There is a need for early public health interventions to address environmental and lifestyle factors for the prevention and control of allergic diseases in African rural communities.

Factors associated with asthma symptoms in Colombian subpopulations aged 1 to 17 and 18 to 59: Secondary analysis of the study "Prevalence of asthma and other allergic diseases in Colombia 2009-2010"

BACKGROUND

Asthma, a chronic inflammatory lung disease, is one of the leading causes of disability, demands on health resources, and poor quality of life. It is necessary to identify asthma-related risk factors to reduce the presence and development of symptoms.

OBJECTIVE

This study aimed to explore the association of multiple possible factors with asthma symptoms in two subpopulations, children, adolescents, and adults, in six cities in Colombia.

MATERIALS AND METHODS

This was an observational analytical case-control study based on a cross-sectional study conducted as a secondary analysis of the prevalence of asthma and other allergic diseases in Colombia during 2009 and 2010. Weighted logistic regressions were conducted for each population.

RESULTS

Out of the 5978 subjects in the cross-sectional survey, 747 were identified as cases, and 3109 were identified as controls. The prevalence of asthma was 30.8% in the child and adolescent population and 14.7% in the adult population. Among the various factors studied, those associated with asthma symptoms in children/adolescents were: a family history of asthma (OR 2.4; 95% CI 1.3-4.7) and rhinitis (OR 2.0; 95% CI 1.1-3.6); acetaminophen consumption at least once a month (OR 3.6; 95% CI 2.1-6.2); and the presence of birds at home (OR 2.0; 95% CI 1.1-3.8). Regarding food consumption: fruit consumption (OR 3.8; 95% CI 1.1-12.7). In adults, the factors that showed significant association were: a family history of allergic diseases (rhinitis OR 3.3; 95% CI 2.3-4.6), atopic eczema (OR 4.4; 95% CI 2.8-7.0), or asthma (OR 1.8;95% CI 1.3-2.6); acetaminophen consumption at least once a month (OR 2.0; 1.5-2.8); the presence of dogs at home (OR 1.4;95% CI 1.03-1.8), exposure to second-hand smoke (OR 1.7; 95% CI 1.2-2.2), and exposure to exhaust fumes during the day (OR 1.7; 95% CI 1.04-2.7).

CONCLUSIONS

Our findings suggest that different cultural, environmental, and family factors are associated with asthma symptoms in children and adolescents, and these associations are evident in both males and females.

Airborne pollen concentrations overpass expectations in the tropical city of Medellín, Colombia

Aerobiology in the tropics is still a science in development, where very little about their dynamics is known. Airborne pollen concentrations in the city of Medellín (Colombia) were measured using a Hirst-type sampler and correlated with meteorological parameters (relative humidity, rainfall, temperature, wind speed, and wind direction, this last analyzed by using circular statistics). Sampling was conducted over three years (2019-2022), and pollen grains were detected on all days of sampling, at higher concentrations than expected for tropical conditions. The highest pollen concentrations were observed from December to January and July-August, corresponding to the months with the lowest rainfall, which sheds light about how La Niña phenomena influenced pollen concentrations during the sampling period. The Main Pollen Season (MPS) ranged in length from 277 to 342 days. The highest intra-diurnal peaks pollen concentrations occurred around noon, whilst something very different and rarely reported occurs with Cecropia, which is much more abundant at night, from 20:00 to 1:00 h. Circular statistics revealed statistically significant wind direction patterns from SW, matching the same intra-diurnal pollen variations. This work helps to complete the blurred situation of the Aerobiology in the Neotropics and the dynamics of particles in the tropical atmosphere, being a first step towards the construction of pollen calendars to help pollen sufferers to mitigate symptoms.

[Consensus for the treatment of atopic dermatitis in primary care: resolving myths and legends based on evidence]

Atopic dermatitis (AD) is a disease that significantly impacts the quality of life of patients. Although there are multiple evidence-based guidelines, they are usually aimed at providing recommendations to AD specialists rather than primary care physicians (PCPs). The aim of this study was to construct a consensus document for PCPs, with the aim of presenting evidence-based recommendations that allow general practitioners, family physicians, pediatricians, internists and emergency physicians to provide appropriate care to AD patients, facilitating their diagnosis, management, and avoiding delays that can deteriorate patients' f quality of life. As a central source of information, we used the recommendations of different international AD guidelines. Delegates from distinct medical societies identify barriers to care and possible solutions for the application of recommendations in primary care. Subsequently, a second evaluation for physicians from different Latin American countries was carried out. The main doubts and barriers that PCPs face in applying the recommendations proposed by the guidelines were identified across different areas, diagnostic criteria, non-pharmacological therapies, pharmacological therapies, management in special conditions and guidelines for referral to a specialist. Consensus solutions were proposed for each identified issue. In conclusion, this consensus contains recommendations regarding the management and treatment of AD in children and adults, which clarify doubts and provide tools to primary care physicians to offer effective treatment for patients and their families.

Blomia tropicalis: A 50-Year History

The genus Blomia tropicalis was described 50 years ago. Since then, great progress has been made on the clinical impact of this house dust mite (HDM). Blomia tropicalis is widely distributed in tropical and subtropical zones, where it induces IgE sensitization and clinical symptoms. The discovery of this mite not only provided additional support for the causal relationship between HDM sensitization and allergic respiratory symptoms, it changed the scope of the diagnosis and management of these diseases. There are now 26 officially accepted B tropicalis allergens, several of them with cross-reactivity with mites such as Dermatophagoides spp and some storage mites, which adds complexity to the diagnosis of sensitization and the choice of extracts for allergen specific immunotherapy. Fortunately, the discovery and characterization of molecules useful for component-resolved diagnostic testing provide the tools for this challenge. Immunotherapy with B tropicalis extract is successfully used in several countries of Latin America, Africa, and Asia; however, the availability of standardized extracts in subtropical regions remains limited. During the 50 years of research on B tropicalis, several groups have made contributions to allergen characterization, their mechanisms of action and clinical impact; the immunogenetics of sensitization; the possible effects of climate change; and the design and testing of new vaccines.

Global change, climate change, and asthma in children: Direct and indirect effects - A WAO Pediatric Asthma Committee Report

The twenty-first century has seen a fundamental shift in disease epidemiology with anthropogenic environmental change emerging as the likely dominant factor affecting the distribution and severity of current and future human disease. This is especially true of allergic diseases and asthma with their intimate relationship with the natural environment. Climate change-related variables including increased ambient temperature, heat waves, extreme weather events, air pollution, and rainfall distribution, all can directly affect asthma in children, but each of these variables also indirectly affects asthma via alterations in pollen production and release, outdoor allergen exposure or the microbiome. Air pollution, with its many and varied respiratory consequences, is likely to have the greatest effect, as it has increased globally due to rapid increases in fossil fuel combustion, global population, crowding, and megacities, as well as forest burning and trees succumbing to an increasingly hostile environment. Human activities have also caused substantial deterioration of the global microbiome with reductions in biodiversity for molds, bacteria, and viruses. Reduced microbiome diversity has, in turn, been associated with increases in Th2 allergic responses and allergic disease. The collective effect of these changes has already shifted allergy and asthma disease patterns. Given that changes in climate have been relatively small to date, the unavoidable, much greater shifts in climate in the future are concerning. Determining the relative scale of the direct versus indirect effects of climate change variables is needed if effective avoidance and adaptive measures are to be implemented. This would also require much more basic, epidemiological, and clinical research to understand the causal mechanisms, the most relevant climate factors involved, the regions most affected and, most importantly, effective and actionable adaptation measures. We suggest that allergy and respiratory health workers should follow current guidance to reduce present risks related to climate change and watch for new recommendations to reduce future risks. Since the respiratory system is the one most affected by climate change, they also need to call for more research in this area and show strong leadership in advocating for urgent action to protect children by reducing or reversing factors that have led to our deteriorating climate.

Molecular characteristics of atopic dermatitis patients with clinical remission

Introduction

Atopic dermatitis (AD) is a frequent disease in infants with diverse clinical evolution. Although multiple studies have assessed inflammatory changes in chronic AD, little is known about the molecular transition from symptomatic stage to clinical remission without pharmacotherapy.

Objective

The aim of the study was to evaluate clinical and inflammatory factors and its relationship with AD clinical evolution.

Methods

Three groups of participants older than 10 years of age were recruited; 2 AD groups and 1 non-AD group. The AD-remission group (more than 1 year without AD symptoms and without pharmacotherapy), the AD-persistent group (AD symptoms and pharmacotherapy), and 1 non-AD group. We measured eosinophil peroxidase (EPX), eosinophil cationic protein (ECP), IgE autoantibodies against these antigens, and natural moisturizing factor (NMF).

Results

Different inflammatory profiles within each group were observed: AD-persistent group is characterized by a high frequency of IgE autoantibodies (55.5%), contrasting with the low occurrence in the non-AD group (2%) and a moderate frequency in the AD-remission group (21.4%). A similar distribution was observed for the other type 2 inflammatory biomarkers (Eosinophils, total IgE, EPX, ECP) and NMF.

Conclusion

Patients with AD-remission maintain a minimal T2 inflammation. We identified different potential biomarkers for prognosis of AD evolution. Further studies are necessary to evaluate the mechanisms that allow the coexistence of the inflammatory process without clinical symptoms.

Nasal allergen challenge with Blomia tropicalis in children and adolescents

BACKGROUND

Local allergic rhinitis (LAR) is a well-defined phenotype in adults, but still there is little data available on children. This scarcity of data can be partly attributed to the lack of standardized protocols for Nasal Allergen Challenges (NAC) in this demographic.

METHODS

20 controls (control group) and 24 patients (rhinitis group) with allergic rhinitis diagnosis sensitized to Blomia tropicalis (Bt) underwent the NAC with Bt. The acoustic rhinometry was performed after instillation of increasing concentrations of Bt (5,000 BU/mL).

RESULTS

The median reduction in the volume of the nasal cavity in its first five centimeters (V5) by the conclusion of the NAC in the rhinitis group was markedly higher than that observed in the control group, at -22.9% (range: -21.1% to -26.2%) compared to -7.7% (ranging: -4.8% to +12.8%).

CONCLUSIONS

Our research demonstrates the efficacy and safety of the NAC protocol utilizing Bt in distinguishing allergic from non-allergic children.

Role of specific immunoglobulin-E in chronic rhinosinusitis: Its clinical relevance according to nasal challenge test

Background

Guidelines for chronic rhinosinusitis (CRS) propose total IgE and eosinophils as important biomarkers to identify type-2 inflammation. Despite the fact that specific IgE (sIgE) have been identified as a clinical predictor in some type-2 diseases for different clinical outcomes, its role in CRS has yet to be explored in detail.

Objetive

To describe systemic and local sIgE in CRS and explore its possible association with clinical outcomes using nasal challenge tests (NCT).

Methods

In CRS patients, we measure total IgE, serum sIgE (SsIgE) and nasosinusal sIgE (NsIgE) against 9 allergenic sources; Der p, Der f, Blo t, Can f, Fel d, Per a, grasses, Staphylococcus enterotoxin A, and B. NCT was done using the allergen with the higher sIgE prevalence (Der p).

Results

A total of 174 patients were included. Prevalence of SsIgE was 52.8% and NsIgE 46.5%; Der p was the principal allergen for SsIgE and NsIgE. The presence of nasal polyps, asthma comorbidity, NSAID hypersensitivity, and hyposmia, were significantly associated with the presence of SsIgE and NsIgE but not with total IgE. NCT-Der p was performed in 73 CRS patients, being positive in 33 (45.2%). SsIgE have the best diagnostic accuracy (79.4%) to predict NCT results (NsIgE 67.5% total IgE 52%).

Conclusion

Specific IgE is a better biomarker in CRS than total IgE. Patients with clinically relevant SsIgE have a pheno-endotype associated with different clinical outcomes. Considering the clinical relevance of SsIgE demonstrated by NCT, interventions like allergen immunotherapy in CRS must be study.

Changes in Prevalence of IgE Sensitization and Allergenic Exposition over a 10-Year Period in a Tropical Region

INTRODUCTION

Multiple antigen environmental sources have been identified as possible causes of allergies, but few studies have evaluated changes in the sensitization profiles over time. The aim of this study was to evaluate the changes in IgE sensitization and exposure to dust mites, cats, dogs, and cockroaches over a 10-year period.

METHODS

During a period of 10 years among patients with asthma, rhinitis and/or atopic dermatitis, we evaluated the annual frequency of atopy to Dermatophagoides farinae, Dermatophagoides pteronyssinus, Blomia tropicalis, Canis familiaris, Felis domesticus and cockroaches (Periplaneta americana and Blatella germanica). Exposure to sources was also assessed using questionnaires (Pets) or direct counts (House dust mites and cockroaches). The association between some risk factors and the prevalence of atopy was explored.

RESULTS

A total of 6,000 records were included. Among the patients, 82% had IgE sensitization to at least one of the six allergenic sources. Sensitization to Dermatophagoides spp. was the most frequent (>78%). Exposure and sensitization in the first decade of life to Dermatophagoides spp. seem to determine the molecular spreading to other allergenic sources. Exposure to Blomia tropical increases significantly over time (year 2015; 38% vs. year 2022; 51%, p 0.03). Exposure to dogs was higher than with cats but association between atopy and exposure was stronger with cats (OR 27.4, 95% CI: 22.3-33.6, p < 0.01).

CONCLUSION

Exposure and sensitization in the first decade of life to Dermatophagoides spp. determine the molecular spreading of IgE antibodies to other allergenic sources. Household exposure to dogs and cats seems to be important for the subsequent development of atopy. Sensitization to B. tropicalis and cockroach appears to be mostly from cross-reactivity rather than direct exposure.

Selection of allergen extract for immunotherapy in polysensitized allergic rhinitis patients

Aim: To evaluate the criteria used by allergists in selecting an immunotherapy extract (allergen immunotherapy [AIT]-extract) in rhinitis patients with polysensitization. Methods: First, a cross-sectional study was carried out by evaluating different factors that influence the medical choice of AIT-extract. Second, a literature review was performed by evaluating the diagnostic performance of atopy tests. Results: A total of 419 patients were included (84 children, 149 adolescents and 186 adults). Anamnesis, atopy tests and exposure to pets were the main factors for choosing the AIT extract. The sensitivity and specificity of atopy tests were high for Dermatophagoides spp., (>80%), moderate for pets (60%) and indeterminate for Blomia tropicalis. Conclusion: NCTs could be necessary for AIT-extract selection in polysensitized allergic rhinitis patients.

Toward Consensus Epitopes B and T of Tropomyosin Involved in Cross-Reactivity across Diverse Allergens: An In Silico Study

Tropomyosin (TM) is a pan-allergen with cross-reactivity to arthropods, insects, and nematodes in tropical regions. While IgE epitopes of TM contribute to sensitization, T-cell (MHC-II) epitopes polarize the Th2 immune response. This study aimed to identify linear B and T consensus epitopes among house dust mites, cockroaches, Ascaris lumbricoides, shrimp, and mosquitoes, exploring the molecular basis of cross-reactivity in allergic diseases. Amino acid sequences of Der p 10, Der f 10, Blo t 10, Lit v 1, Pen a 1, Pen m 1, rAsc l 3, Per a 7, Bla g 7, and Aed a 10 were collected from Allergen Nomenclature and UniProt. B epitopes were predicted using AlgPred 2.0 and BepiPred 3.0. T epitopes were predicted with NetMHCIIpan 4.1 against 10 HLA-II alleles. Consensus epitopes were obtained through analysis and Epitope Cluster Analysis in the Immune Epitope Database. We found 7 B-cell epitopes and 28 linear T-cell epitopes binding to MHC II. A unique peptide (residues 160-174) exhibited overlap between linear B-cell and T-cell epitopes, highly conserved across tropomyosin sequences. These findings shed light on IgE cross-reactivity among the tested species. The described immuno-informatics pipeline and epitopes can inform in vitro research and guide synthetic multi-epitope proteins' design for potential allergology immunotherapies. Further in silico studies are warranted to confirm epitope accuracy and guide future experimental protocols.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Correlation of Blomia tropicalis-specific immunoglobulin epsilon profiles with family history of atopy in a Filipino population

Background

House dust mites are the major source of indoor allergens in the tropical and subtropical regions with Blomia tropicalis (Bt) allergens as one of the leading causative agents of sensitization among patients from the tropics. Despite the clinical importance of Bt in various populations, its allergenicity remains unclear among Filipino allergic patients.

Objective

This study determined the sensitization profiles of allergic Filipinos against Bt allergens and its correlation with atopy.

Methods

Total immunoglobulin epsilon (IgE) (n = 960), Bt-specific IgE (n = 247), and Blomia tropicalis 5 (Blo t 5)-specific IgE (n = 87) profiles of allergic and nonallergic subjects were measured through enzyme-linked immunosorbent assay (ELISA). Point-biserial correlation coefficient was used to determine the association between Bt-specific IgE levels and selected demographics. Inhibition ELISA was performed to measure the inhibition capacity of recombinant Blo t 5 (rBlo t 5) against Bt allergen extracts.

Results

Mean total IgE levels of allergic cases (n = 171) were significantly higher (P < 0.001) compared to the mean IgE levels of nonallergic controls (n = 76). Among allergic subjects, 58% were sensitized to Blo t extract and 80% of which were sensitized to rBlo t 5 allergen. A positive correlation was observed between Bt-specific IgE and family history of atopic disease (P = 0.031). Inhibition assay revealed that 54% mean reactivity of 7 plasma samples was caused by rBlo t 5, validating that rBlo t 5 is a major allergen in Bt.

Conclusions

This study has shown the importance of Bt as an allergen source that sensitizes atopic Filipino subjects. Hence, inclusion of Bt allergen extract and rBlo t 5 in the panel for allergy diagnosis and immunotherapy in Filipino populations is strongly recommended.

Phenotypes, endotypes and genotypes of atopic dermatitis and allergy in populations of African ancestry on the continent and diaspora

Atopic dermatitis is a complex inflammatory condition characterized by synergist interactions between epidermal and immune related genotypes, skin barrier defects and immune dysregulation as well as microbial dysbiosis. Ethnicity-specific variations in clinical presentation, immune endotypes and genetic susceptibility have been described in diverse populations. We summarize available data with specific consideration of AD in populations of African ancestry. Some highlights include the observation of AD lesions on extensor surfaces, lichen planus-like AD, prurigo type AD and follicular AD in African populations. In addition, a consistent absence of dominant filaggrin gene defects has been reported. The detection of normal filaggrin protein content in AD skin implicates the contribution of alternative mechanisms in the pathogenesis of AD in African patients. Markedly high IgE has been described in paediatric and adult African AD. While Th2, Th22 and Th17 activation in African AD skin shares the same direction as with other populations, it has been noted that the magnitude of activation is dissimilar. Reduced Th17 cytokines have been observed in the circulation of moderate to severe paediatric AD.

Mosquito allergy: Immunological aspects and clinical management

Mosquito allergy has been conceived as the cutaneous reactions that appears during and after mosquito biting process; a perception that is supported by several scientific research. Additional data have led to conceive that other manifestations of allergic responses may occur as a cause of the exposure to somatic mosquito allergens. Two main phenotypes of mosquito allergy are identifiable: the cutaneous allergic reactions, induced by salivary allergens, and other manifestations of the allergic responses such as asthma and allergic rhino conjunctivitis that are caused by somatic allergens. The cutaneous reactions have kept the focus of attention of the scientific community. It appears as skin lesions that resembles the phenotype of papular urticaria with a defined natural history of the disease. Although these two phenotypes of mosquito allergy seem to be well differentiated in terms of the allergens that are involved and the routes of exposures, other factors such as geographical distribution, may participate. Mosquitoes have adapted to the host immune response against bites, producing immunomodulatory molecules that counteract such defensive response. The role that the immunomodulatory molecules have on the allergic immune response has not been studied yet and it is still not known if affects all mosquito allergy phenotypes. Only a few studies of allergen specific immunotherapy for cutaneous allergic reactions induced by mosquito bites have been done, and none for respiratory allergic responses. The clinical practice focuses on symptom management and avoiding mosquito bites as much as possible. Avoiding mosquitoes, using different well described methods, is still the best option to limit contact with these insects. The lack of knowledge of mosquito allergy have raised several questions that affects the clinical management of this allergic disease, from its diagnosis, prevention and immunotherapy.

Burden of and Trends in Urticaria Globally, Regionally, and Nationally from 1990 to 2019: Systematic Analysis

BACKGROUND

Urticaria presents a significant global health challenge due to its sudden onset and potential for severe allergic reactions. Past data on worldwide prevalence and incidence is inconsistent due to differing study methodologies, regional differences, and evolving diagnostic criteria. Past studies have often provided broad ranges instead of specific figures, underscoring the necessity for a cohesive global perspective to inform public health strategies.

OBJECTIVE

We aimed to assess the global burden of urticaria using the 2019 Global Burden of Disease (GBD) study data and systematically analyze urticaria prevalence, incidence, and disability-adjusted life years (DALYs) at global, regional, and national levels, thereby informing more effective prevention and treatment strategies.

METHODS

We analyzed the global, regional, and national burden of urticaria from 1990 to 2019 using the 2019 GBD study coordinated by the Institute for Health Metrics and Evaluation. Estimations of urticaria prevalence, incidence, and DALYs were derived using DisMod-MR 2.1, a Bayesian meta-regression tool. The Socio-demographic Index (SDI) was used to correlate development status with health outcomes. The GBD's division of the world into 21 regions and 204 countries and territories facilitated a comprehensive assessment. Age-standardized estimated annual percentage changes were generated for urticaria metrics to quantify temporal trends, with age standardization adjusting for potential confounding from age structure.

RESULTS

From 1990 to 2019, the global age-standardized prevalence, incidence, and DALY rates of urticaria showed marginal changes. In 2019, 65.14 million individuals were affected, with a prevalence rate of 841.88 per 100,000 population. The DALY rate was 50.39 per 100,000 population. Compared to 1990, the global age-standardized prevalence, incidence, and DALY rates saw increases of 2.92, 4.84, and 0.31 per 100,000 population, respectively. Women persistently had higher rates than men. At a regional level in 2019, low-middle SDI regions exhibited the highest age-standardized metrics, whereas high SDI regions reported the lowest. Central Europe showed the highest rates, contrasting with Western Europe's lowest rates. Nationally, urticaria prevalence in 2019 varied dramatically, from a low of 27.1 per 100,000 population in Portugal to a high of 92.0 per 100,000 population in Nepal. India reported the most DALYs at 749,495.9, followed by China, Pakistan, and the United States. Agewise data showed higher rates in younger age groups, which diminished with age and then experienced a slight resurgence in the oldest populations. This pattern was pronounced in women and younger populations, with the largest rises seen in those aged less than 40 years and the smallest in those aged more than 70 years.

CONCLUSIONS

Urticaria remains a significant global health issue, with considerable variation across regions, countries, and territories. The increased burden among women, the rising burden in younger populations, and the regional differences in disease burden call for tailored interventions and policies to tackle this emerging public health issue.

The hybrid protein BTH2 suppresses allergic airway inflammation in a murine model of HDM-specific immunotherapy

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment approach to change disease-causing allergens. Hypoallergenic derivatives show promise as potential therapeutics, amongst which BTH2 was designed to induce tolerance against Blomia tropicalis allergy. Our aim was to investigate the hypoallergenicity and immunoregulatory activity of BTH2 in vitro and its therapeutic potential in a mouse model of AIT.

METHODS

Recombinant Blo t 5 and Blo t 21 allergens and their hybrid derivatives (BTH1 and BTH2) were expressed and purified. IgE binding capacity was tested by ELISA using sera from Brazilian, Colombian, and Ecuadorian subjects. Secretion of cytokines in supernatants from human cell cultures was measured following stimulation with the four recombinants and controls. The capacity of BTH2 to ameliorate allergic airway inflammation induced by B. tropicalis extract was evaluated in a murine model of AIT.

RESULTS

rBlo t 5 and rBlo t 21 were identified as major allergens in Latin American patients, and BTH2 had the lowest IgE binding. In vitro stimulation of human cells induced greater levels of IL-10 and IFN-γ and reduced the secretion of Th2 cytokines. BTH2 ameliorated allergic airway inflammation in B. tropicalis-challenged A/J mice, as evidenced by the histopathological and humoral biomarkers: decreased Th2 cytokines and cellular infiltration (especially eosinophils), lower activity of eosinophil peroxidase, an increase in IgG blocking antibodies and strong reduction of mucus production by goblet cells.

CONCLUSIONS

Our study shows that BTH2 represents a promising candidate for the treatment of B. tropicalis allergy with hypoallergenic, immune regulatory and therapeutic properties. Further pre-clinical studies are required in murine models of chronic asthma to further address the efficacy and safety of BTH2 as a vaccine against B. tropicalis-induced allergy.

Factors associated with allergic rhinitis and combined allergic rhinitis and asthma syndrome (CARAS) in adults undergoing immunotherapy in a tropical country: Is ISAAC-III questionnaire useful in adult populations?

BACKGROUND

Allergic diseases affect about 10-30% of the population in low- or middle-income tropical countries. Few studies describe the factors associated with allergic diseases in adult patients undergoing immunotherapy in Latin American countries.

OBJECTIVE

This study aimed to determine the factors associated with allergic rhinitis (AR) and AR in comorbidity with asthma (CARAS) in adults treated with immunotherapy in two allergy referral centers in Bogotá (Colombia).

MATERIAL AND METHODS

Observational, cross-sectional study conducted between January 2018 and January 2019. ISAAC-III and sociodemographic questionnaires were applied to determine the factors associated with AR and CARAS in adults treated with immunotherapy who attended the allergy consult at the Fundación Santa Fe de Bogotá and Unimeq-Orl.

RESULTS

Among 416 adults aged 18-68 years, 71.4% (n = 297) were women. Regarding the sensitization results obtained by skin prick test, the most frequent allergens were house dust mites (64.18%): 49.03% were positive for both Dermatophagoides pteronyssinus and Dermatophagoides farinae, while 28.61% were positive for Blomia tropicalis. Excluding house dust mites, the most frequent allergens were dog hair (31.01%), cat hair (15.1%), grasses (15.9%), and food (15.9%). The main factor associated with exclusive AR was regular acetaminophen use more than four times a year: Prevalence ratio (PR) = 1.77 (95% CI: 1.12-2.25). The main factor associated with CARAS was cesarean delivery PR: 1.44 (95% CI: 1.09-1.78).

CONCLUSION

The main factor associated with AR was regular acetaminophen use, while that associated with CARAS was cesarean delivery. The ISAAC-III questionnaire can be a useful low-cost tool to assess the factors associated with allergic diseases in adults in tropical countries.

Atopic Dermatitis in Latin America: Considerations on Epidemiology, Clinical and Laboratory Features, Ethnic/Racial Variations, and Therapeutic Management

Latin America (LA) encompasses about 8.5% of the world's population, exhibits ethnic/racial heterogeneity and social inequality. We hereby present a 20-year literature review (2004-2023) on epidemiology, diagnosis, clinical and laboratory features, quality of life and management of atopic dermatitis (AD) in LA. Highest AD prevalence for children aged 6-7 years was reported in Ecuador (22.5%) and Colombia (20.9%), for adolescents in Colombia (24.6%) and for all ages, in Brazil (20.1%). Regions with a predominantly Black population in LA varied significantly, ranging from 4.4% in Northern Brazil to 10.1% in Cuba, indicating genetic variation among African subgroups. Filaggrin loss-of-function mutations showed variants seen in Europeans in 9.3% of Chilean patients and studies in Brazil revealed impaired expression of filaggrin and claudin-1 in the skin but increased expression in conjunctival epithelia of AD patients. The most reported AD features included erythema, pruritus, and dry skin, with marked lichenification. Severe pruritus was reported by 54.4% of patients and a high impact on quality of life was detected in 50% of adults with AD. In Brazilian referral hospitals, 65.6% of patients were classified as having severe AD, and 56% had one or more hospitalizations during their lifetime, indicating a need for better disease control. Diagnosing AD is challenging due to broad clinical features, ethnoracial variations and lack of universal diagnostic criteria. Furthermore, lack of physician training, barriers to medication access, and socioeconomic inequalities hinder effective disease management in LA.

Effectiveness and safety of dupilumab in adults with moderate and severe atopic dermatitis in Colombia: Real-life experience

Background

Dupilumab is a treatment approved for uncontrolled moderate-to-severe atopic dermatitis (AD). Tropical and developing countries such as Colombia have characteristics that may impact the natural history of AD and access to medical treatments. In that sense, we aimed to describe the effectiveness and safety of dupilumab in adults with moderate to severe AD in a Colombian multicenter cohort.

Methods

Multicenter descriptive study that included patients who started treatment between March 2018 and May 2020 in 6 centers. Disease severity was assessed using the following: Scoring Atopic Dermatitis (SCORAD), Eczema Area and Severity Index (EASI), Patient Oriented Eczema Measure (POEM), and Dermatology Life Quality Index (DLQI). These measurements were collected according to availability at baseline, 3-5 months, 6-12 months, and more than 12 months. Days of sick leave, hospitalizations, and AD flares before and after dupilumab treatment were reported. Adverse events (AEs) were recorded during follow-up.

Results

Ninety-three patients were included, with a median age of 32 years (IQR: 24.0; 40.0) and a disease evolution time of 21 years (IQR: 16.0; 29.5). 88.2% had at least 1 allergic disease other than AD. An improvement greater than or equal to 75% EASI was observed in 41.7% of patients at 3-5 months, in 73.7% of patients at 6-12 months, and in 75.0% of patients after 12 months. For those reporting SCORAD and POEM, the median percent change ([IQR], n) from baseline in SCORAD was -67.1 ([-79.2; -54.2], n = 16), -70.5 ([-85.8; -47.9], n = 36) and -66.7 ([-77.3; -51.0], n = 13); and POEM, -58.6 ([-66.4; -55.5], n = 4), -73.0 ([-86.5; -66.7], n = 16) and -87.3 ([-93.4; -69.6], n = 8), respectively. Before initiation of dupilumab treatment, 82 (88.2%) patients reported at least 1 flare of AD in the past 12 months. During the follow-up period, 30 (32.3%) patients reported at least 1 exacerbation or flare. Twelve patients (12.9%) presented an AE and 3 (3.2%) patients discontinued dupilumab for this cause.

Conclusions

Dupilumab was effective and safe for the treatment of moderate to severe AD in point-of-care settings, with results similar to randomized controlled and other real-life studies. These positive results are still maintained even though a high number of patients had short interruptions in the use of dupilumab due to administrative problems.

The Allergenic Activity of Blo t 2, a Blomia tropicalis IgE-Binding Molecule

Only few allergens derived from house dust mite (HDM) species have been evaluated in terms of their potential to induce allergic inflammation. In this study, we aimed to evaluate different aspects of the allergenicity and allergenic activity of Blo t 2, a Blomia tropicalis allergen. Blo t 2 was produced as a recombinant protein in Escherichia coli. Its allergenic activity was tested in humans by skin prick test and basophil activation assays, and in mice, by passive cutaneous anaphylaxis and a model of allergic airway inflammation. Sensitization rate to Blo t 2 (54.3%) was similar to that found to Blo t 21 (57.2%) and higher than to Der p 2 (37.5%). Most Blo t 2-sensitized patients showed a low intensity response (99.5%). Blo t 2 elicited CD203c upregulation and allergen induced skin inflammation. Additionally, immunized animals produced anti-Blo t 2 IgE antibodies and passive transfer of their serum to non-immunized animals induced skin inflammation after allergen exposure. Immunized animals developed bronchial hyperreactivity and a strong inflammatory lung reaction (eosinophils and neutrophils). These results confirm the allergenic activity of Blo t 2 and supports its clinical relevance.

Real-world study: drug reduction in children with allergic rhinitis and asthma receiving immunotherapy

Background: The reduction of pharmacological treatment after allergen immunotherapy (AIT) for house dust mites (HDMs) has been little studied in children. Objective: To evaluate the reduction of pharmacological treatment comparing children that receive HDM immunotherapy (AIT group) versus only pharmacotherapy. Methods: A historic cohort of children with rhinitis or asthma was assessed. The main outcome was the frequency of complete drug discontinuation. Results: 100% drug reduction was higher for rhinitis (4-year cumulative incidence: 30 vs 10.7%) and asthma (24.1 vs 10.5%) in the AIT group (n = 987) than in the pharmacotherapy group (n = 2012). Conclusion: Immunotherapy is associated with a significant reduction of pharmacotherapy in children. This is a marker of clinical control and could be associated with positive economic impact.

Immunoglobulin E and G autoantibodies against eosinophil proteins in children and adults with asthma and healthy subjects

Background

Autoimmune IgG response has been described in the pathogenesis of asthma in adults, but IgE autoimmunity has been little explored. Considering high levels of blood eosinophils and immunoglobulin E in asthmatic patients, the possibility of IgE autoantibody response to eosinophil proteins arises.

Objective

To explore the presence of IgE and IgG autoantibodies against Eosinophil peroxidase (EPX) and Eosinophil cationic protein (ECP).

Methods

Three steps were followed: 1) The frequency of IgE and IgG autoantibodies against EPX and ECP was investigated among asthmatic and healthy subjects. 2) The ability of IgE autoantibodies to induce an inflammatory response (basophil activation) was performed. 3) The capacity of autoantibodies to identify patients with severe asthma was evaluated.

Results

Asthmatic and healthy subjects had IgE and IgG autoantibodies against EPX and ECP. Anti-EPX IgE was significantly higher in asthmatic patients. Severe asthmatic patients had a higher frequency and higher levels of IgE and IgG autoantibodies compared to healthy subjects. There was not a correlation between autoantibodies and blood eosinophils. Children younger than 14 years of age had IgE and IgG autoantibodies against to EPX and ECP. IgE autoantibodies to EPX and ECP induced basophil activation in asthmatic patients.

Conclusion

In this study, we identify for the first time IgE autoantibodies against EPX and ECP in adults and children patients with asthma; IgE and IgG autoantibodies against EPX and ECP could serve as a predictive biomarker of the clinical severity.

Factors associated with allergic rhinitis and combined allergic rhinitis and asthma syndrome (CARAS) in children aged 5-18 years undergoing immunotherapy in a tropical low- or middle-income country

BACKGROUND

Tropics have some particularities that can impact the natural history and factors associated with allergic diseases. However, few studies described the characteristics of patients with allergic rhinitis (AR) and combined AR and asthma syndrome (CARAS) in Latin American tropical countries.

OBJECTIVE

This study aimed to determine the medical, social, and environmental factors associated with AR and CARAS in children aged 5-18 years treated with immunotherapy in two allergy referral centers in Bogotá (Colombia).

MATERIAL

and methods: An observational, cross-sectional study was conducted between January 2018 and January 2019. International Study Asthma Allergies Childhood-III and sociodemographic questionnaires were applied to adolescents and parents of children undergoing immunotherapy at the allergy consult in the Hospital Universitario Fundación Santa Fe de Bogotá and UNIMEQ-ORL.

RESULTS

Among 830 children aged 5-18 years, 38.1% (n = 316) were women. Up to 63.25% of the population had a positive skin prick test for house dust mites: 63.25% for Dermatophagoides pteronyssinus, 61.81% for Dermatophagoides farinae, and 31.57% for Blomia tropicalis. The factors associated with AR were male sex (PR: 1.31, 95% CI: 1.08-1.57), antibiotic consumption during the first year of life (PR: 0.80; 95% CI: 0.63-0.99), and exposure to dogs (PR: 1.32; 95% CI: 1.06-2.66). The factors associated with CARAS were older age (PR=0.95; 95% CI: 0.95-0.99), acetaminophen consumption over four times a year (PR: 1.31; 95% CI: 1.03-1.55), and antibiotic consumption during the first year of life (PR: 1.21; 95% CI: 1.06-1.34).

CONCLUSION

A high prevalence of B. tropicalis was found in this study. The factors associated with AR and CARAS are like those described in high-income tropical countries. Further studies are needed in low- or middle-income tropical countries to identify modifiable factors associated with allergic diseases.

Real-world effectiveness of omalizumab for severe allergic asthma treatment in Colombia

Background

The allergic phenotype is responsible for more than 50% of severe asthma cases. In a stepwise approach, add-on treatments such as anti-IgE are used for severe allergic asthma (SAA). This study was aimed to describe the real-world effectiveness of omalizumab in adult and pediatric patients with SAA in Colombia.

Methods

This was an observational, non-interventional, retrospective study. Data from patients with SAA that received at least one month of treatment with omalizumab was obtained from medical records at eight sites in Colombia. Time-zero (t − 0) was defined as the date of initiation of omalizumab, and data was gathered for a 12-month period before t − 0 and a 12-month period after t − 0. Clinical outcomes, including exacerbations, were assessed at 6 and 12 months. Effectiveness of omalizumab was evaluated in terms of the reduction of the risk of exacerbations (annualized rate).

Results

We included 143 patients with SAA. There was a decrease of 72.4% of the annualized rate of clinically significant asthma exacerbations during the year after omalizumab (from 1.74 before to 0.48 after) with a substantial reduction of the risk of exacerbations by 56.7% (RR [95% CI] 0.43 [0.30–0.63] p < 0,001).

Conclusion

The use of omalizumab in Colombia as a treatment for SAA notably reduced the risk of clinically significant exacerbations. This study is the first to evaluate omalizumab real-life effectiveness in pediatric and adult patients in the country.

Prospective analysis of clinical evolution in chronic urticaria: Persistence, remission, recurrence, and pruritus alone

Background

Population and study's methodology heterogenicity became clinical evolution of chronic spontaneous urticaria (CSU) highly variable.

Objective

In a prospective cohort, we evaluated the different pathways of clinical evolution of CSU and identified possible risk factors.

Methods

A total of 685 CSU patients (>12 years) were prospectively followed over 5 years. Diagnosis and follow-up of urticaria were based on medical evaluation and photographic records. Remission was defined as at least 6 months without symptoms (hives, angioedema, or pruritus) and medication. The follow-up included at least 2 visits per year, with photographic registration and clinical evaluation. Predefined clinical and paraclinical variables were included in the regression analyses.

Results

We identified four clinical evolution pathways; The cumulative prevalence of remission at 5 years was 59.1%, recurrence was 17.1%, persistence was 11.6%, and chronic pruritus without hives or angioedema was 12.2%. The probability of persistence increased with hypothyroidism diagnosis (HR 0.425, 95% CI 0.290-0.621) and each point in the UAS7 (HR 0.931 95% CI 0.918-0.945).

Conclusion

Chronic urticaria has different evolutions. Disease activity and hypothyroidism predict persistence and remission. Recurrence and chronic pruritus phenotypes require further study to evaluate their causality and prognosis.

EAST in Children with Allergic rhinitis: Experience from Indian Tertiary Centre

Allergic rhinitis (AR) is recognized as a growing global health disease with considerable importance among children and adolescents. This study aims to study the clinical and sensitization profile of children with allergic rhinitis using EAST. All children presenting to pediatric ENT outpatient with a clinical diagnosis of AR were prospectively recruited. Detailed demographic and clinical history including self-reported allergens, predominant symptoms and associated comorbid conditions were obtained. Severity of symptoms was graded on a visual analogue scale. Specific Ig E antibodies to 20 inhalant allergens was measured using EAST (EUROIMMUN, Germany).The pattern of sensitization was analyzed with respect to age, symptoms, associated comorbid conditions and urbanization. We recruited 328 children with a clinical diagnosis of AR (Mean age 10.3 year, IQR 8-13 years) Nasal block was the predominant symptom across all age groups, sneezing became more troublesome during adolescence. In 191 children sera were tested for allergen specific IgE, 119 (62.3%) showed positive sensitization. The most common sensitization noted was for cockroach, followed by dust mite and pollens. Majority had polysensitization (73%). Those who were predominantly sneezers were more likely to be sensitized with indoor allergens (p < 0.05). Among the comorbid conditions, asthma and atopic dermatitis accounted for maximum non ENT physician visits. The pattern of sensitization did not vary with age, urbanization or comorbid condition. This study highlights the clinical and sensitization profile of children with AR in South East India. Various peculiarities of this community has been presented which needs further attention.

Factors affecting the occurrence of otitis media with effusion in preschool and elementary school children: a comparative cross-sectional study

OBJECTIVE

Identify the risk factors for otitis media with effusion (OME), especially laryngopharyngeal reflux (LPR), adenoid hypertrophy and allergic rhinitis, that could be used to develop prevention strategies in children.

DESIGN

A comparative cross-sectional study was conducted to make sure the adequacy of proportions of OME and non-OME cases in finding the related factors.

SETTING

History taking, ear/nose/throat (ENT) examination, and tympanometry were performed in preschool and elementary schools. Flexible fibreoptic nasopharyngolaryngoscopy was performed in a bronchoesophagology outpatient clinic in a tertiary referral hospital in Jakarta, Indonesia.

PARTICIPANTS

Preschool and elementary children in East Jakarta, Indonesia were recruited for this study. A total of 2016 participants underwent history taking, ENT examination and tympanometry. The case group was 46 children with OME, and the control group was 46 children without OME. The number of subjects fulfilled the minimum sample size for two proportions comparison.

MAIN OUTCOME MEASURES

A type B tympanogram indicated OME. A Reflux Finding Score of more than 7 indicated LPR. Adenoid hypertrophy was diagnosed using flexible fibreoptic nasopharyngolaryngoscopy. Allergic rhinitis was diagnosed using a questionnaire based on the International Study of Asthma and Allergies in Childhood phase III that has been validated for Indonesians.

RESULTS

The proportion of LPR in the OME group was significantly higher than in the non-OME group, at 78.3% and 52.2%. The probability of OME occurrence in patients with LPR was 3.3 times higher than in patients without LPR (OR 3.3; 95% CI 1.33 to 8.189; p=0.01). There was no significant relationship between adenoid hypertrophy and OME (p=0.211; 95% CI 0.71 to 3.97), and also between allergic rhinitis and OME (p=0.463; 95% CI 0.61 to 4.28).

CONCLUSION

The probability of OME occurrence in patients with LPR was 3.3 times higher than in patients without LPR. LPR should be considered in patients with OME and vice versa.

Efficacy and safety of subcutaneous immunotherapy with a mixture of glutaraldehyde-modified extracts of Dermatophagoides pteronyssinus, Dermatophagoides farinae , and Blomia tropicalis

Background

Allergen Immunotherapy (AIT) is an effective treatment of allergic respiratory diseases induced by the inhalation of house dust mite allergens.

Objectives

To evaluate the efficacy and safety of glutaraldehyde polymerized allergen extracts using a mixture of Dermatophagoides pteronyssinus, D. farinae and Blomia tropicalis in mite allergic individuals residing in Colombia.

Methods

Two hundred and fifty (250) patients with allergic rhinoconjunctivitis with, or without asthma and sensitized to D. pteronyssinus, D. farinae and B. tropicalis were included. A glutaraldehyde-modified extract containing a mixture of D. pteronyssinus, D. farinae and B. tropicalis was employed, using a cluster up-dosing schedule followed by a monthly maintenance dose. The primary endpoints to evaluate the clinical impact were the Combined Symptom and Medication Scores (CSMS) for allergic rhinitis, the Asthma Control Test (ACT) and the reduction in medication consumption.

Results

Significant improvement was found after 3 months of treatment regarding CSMS (p < 0.0001) and ACT (p < 0.0001). Additionally, a significant decrease in medication consumption was found after 3 months of treatment (p < 0.0001). Adverse reactions, either local or systemic were mild and no severe reactions related to the vaccines were observed.

Conclusion

After 12 months of allergen immunotherapy, glutaraldehyde-modified mixture of D. pteronyssinus, D. farinae and B. tropicalis proved to be safe and effective in the treatment of patients with rhinoconjunctivitis with or without asthma due to allergy to mites.

Conjunctival Provocation Test With Blomia tropicalis

Background: Conjunctival provocation test (CPT) is used to demonstrate clinical relevance to a specific allergen. Blomia tropicalis (Bt) is a prevalent allergen in tropical regions. Its major allergen Blo t 5 is commonly detected in house dust in Brazil. Patients with allergic rhinoconjunctivitis (ARC) have IgE antibodies to Bt although it may not indicate clinical allergy. Objective: The purpose of this study is to demonstrate the role of CPT in clinical allergy to Bt in allergic conjunctivitis (AC). Methods: CPT was performed in asymptomatic subjects with ARC (n = 26) outside the grass pollen season. They had positive skin prick tests (SPT) to Bt and other common inhalant allergens and they were off topical or systemic antihistamines. Standardized allergens were used for CPT (Blo t 5 462.5 ng/mL in 1:1 solution, Alk Abelló). CPT was conducted on a control group of subjects (n = 29) without symptoms of ARC and with negative SPT. CPT was performed with progressive doses of allergen solutions in normal saline (1:32, 1:16, 1:8, 1:4, 1:2). CPT with the same allergen dose that elicited a positive reaction was repeated one week later. The protocol was approved by the local Ethics Board and signed informed consent was obtained from all participants. Results: There were 92% (24/26) of positive CPT in subjects sensitized to Bt. Significant association was found between SPT and CPT results with Bt (p < 0.0001). CPT had 92% sensitivity and 100% specificity when compared to SPT results. Positive reactions with the same dose or one immediately higher occurred in 21 out of 22 subjects who repeated TPC 1 week later. Mild transient nasal symptoms (21/24) were the major side effects of positive CPT followed by moderate periorbital edema which occurred in 41% (10/24). One controlled asthmatic BT-sensitized subject developed wheezing and dyspnea during a positive CPT with Bt that cleared with inhaled albuterol (400 mcg). There were no reactions whatsoever of CPT in non-allergic subjects. Conclusion: This study demonstrated that Bt may cause allergic conjunctivitis in our population. In addition, CPT is a safe and reproducible test if standardized allergens are used.

Impact of the COVID‐19 national lockdown in the allergic rhinitis symptoms in patients treated with immunotherapy at two allergy referral centers in Bogotá, Colombia

Background

Methods

Results

Conclusion

Environmental allergens house dust mite-induced asthma is associated with ferroptosis in the lungs

Previous studies have indicated that allergens such as house dust mites (HDM) in the environment can induce allergic asthma. Ferroptosis is a newly discovered form of regulatory cell death characterized by aberrant lipid peroxidation and the accumulation of reactive oxygen species (ROS) in cells. However, whether ferroptosis participates in the pathological process of asthma remains to be elucidated. The present study used a HDM-induced mouse asthma model to determine the effect of HDM exposure on allergic asthma and its underlying mechanisms. Female BALB/c mice were intranasally exposed to HDM to induce allergic asthma. Airway hyperresponsiveness (AHR), lung inflammation, mucus secretion, IgE levels, cytokine levels and inflammatory cell counts in bronchoalveolar lavage fluid (BALF) were investigated. In addition, the morphological changes of mitochondria, ROS levels, glutathione (GSH) levels and changes in ferroptosis pathway proteins were also determined in murine lungs. As a result, HDM exposure significantly increased AHR, inflammatory cell infiltration and mucus secretion around the airways. Furthermore, elevated IgE levels in the BALF, lung eosinophilia and a concomitant increase in IL-13 and IL-5 levels in BALF were observed. HDM inhalation increased ROS and decreased GSH levels in the lungs. HDM inhalation induced dysmorphic small mitochondria with decreased crista, as well as condensed, ruptured outer membranes. Western blotting demonstrated that the activities of glutathione peroxidase 4 and catalytic subunit solute carrier family 7 member 11 were significantly decreased, and that protein expression levels of acyl-CoA synthetase long-chain family member 4 and 15 lipoxygenase 1 were upregulated compared with mice in the normal control group. Overall, these results indicated that the AHR, airway inflammation, lipid peroxidation and ROS levels increased in HDM-induced asthma, and that HDM inhalation induced ferroptosis in the lungs, which helped to form an improved understanding of the pathogenesis of allergic asthma.

Identification of B cell epitopes of Per a 5 allergen using bioinformatic approach

BACKGROUND

Immune epitopes of allergens are pivotal for development of novel diagnostic and therapeutic modalities. Present study aims to identify antigenic determinants of Per a 5, a clinically relevant cross reactive cockroach allergen.

METHODS

The three dimensional structure of Per a 5 was modelled using Modeller 9v11 software. A combination of sequence and structure based computational tools were employed for predicting B cell epitopes. Epitopes were synthesized and immunoreactivity was assessed by ELISA using cockroach hypersensitive patient's sera. Cross-reactivity potential of predicted epitopes was assessed with SDAP and ConSurf and validated by IgE ELISA with fungal and mite hypersensitive patient's sera.

RESULTS

Per a 5 structure exhibited good quality factor in ERRAT and high stereochemical stability. In silico analysis revealed six B cell epitopes (BC-P1 to P6). BC-P3 demonstrated significant IgE binding followed by BC-P2 and BC-P1 with cockroach hypersensitive patient's sera. Per a 5 epitopes demonstrate considerable similarity with broad spectrum of allergens from fungal, mites, helminths, fruits and nuts. Analysis of PD values indicate BC-P4 to be well conserved among dust mite and helminth GSTs (8.89, 10.63 and 10.69 with D. pteronyssinus, W. bancrofti and F. hepatica respectively). ConSurf analysis of Per a 5 revealed specific enrichment of evolutionarily similar amino acid residues in BC-P2 (with fungal and mite GSTs) and BC-P4 (with mite and helminth GSTs). Further, IgE binding analysis of epitopes demonstrate BC-P2, BC-P3 and BC-P5 as high IgE binders in fungal hypersensitive sera while BC-P1, BC-P2, BC-P4 and BC-P5 demonstrated significant IgE binding with mite hypersensitive sera.

CONCLUSIONS

Among the predicted epitopes, BC-P3 demonstrates maximal IgE binding ability. Computational analysis suggests strong evolutionary conservation and cross reactive potential of BC-P4 with allergens in dust mite and helminths. ELISA highlights predictive potential of analysing evolutionarily conserved residues for uncovering potentially cross reactive antigenic determinants.

GENERAL SIGNIFICANCE

Immune epitopes of Per a 5 were identified for aiding molecular diagnosis and potential cross reactivity.

Outdoor Mold and Respiratory Health: State of Science of Epidemiological Studies

BACKGROUND

Fungal spores are the predominant biological particulates in outdoor air. However, in contrast to pollens or outdoor air pollution, little is known about their respiratory health risks.

OBJECTIVES

The objectives were to conduct the first review of epidemiological studies on the short- and long-term effects of outdoor mold exposure on respiratory health in children and adults.

METHODS

Health outcomes included asthma, lung function, and rhinitis. Cross-sectional and longitudinal epidemiological studies using quantitative measures of outdoor mold exposure (optical microscopy, culture-based methods) were selected, providing that important confounding factors including temporal trends or meteorological factors were accounted for. A systematic literature search was performed up to June 2020, leading to the selection of 37 publications.

RESULTS

Most studies were longitudinal and investigated short-term effects. There is evidence of an association between outdoor fungal exposure and an increase in asthma exacerbation among children for total spores, 2 phyla (ascomycetes, basidiomycetes), and 2 taxa (Cladosporium, Alternaria). A few studies also suggested an association for Coprinus, Ganoderma, Aspergillus-Penicillium, Botrytis, and Epicoccum in children, but this needs to be confirmed. Some studies reported mold associations with rhinitis, lung function, and among adults, but these were few in number or inconsistent.

DISCUSSION

Further ecological studies in different regions that measure exposure to all taxa over several years are required to better understand their impact on rhinitis, asthma exacerbations and lung function. Larger panel studies are necessary to identify threshold effects in susceptible individuals. Finally, further research should assess the long-term effects of outdoor mold.

The Unmet Needs in Atopic Dermatitis Control in Latin America: A Multidisciplinary Expert Perspective

Introduction

Adoption of control tools for atopic dermatitis (AD) in Latin America (LA) is currently very limited. Clinical assessment tools represent a practical method to measure the impact of treatment on disease activity and on the quality of life of patients. However, the use of these tools in the LA clinical practice setting is limited.

Methods

A selected panel of Latin American experts in fields related to atopic dermatitis were provided with a series of relevant questions to address prior to the multi-day conference. Within this conference, each narrative was discussed and edited by the entire group, through numerous drafts and rounds of discussion, until a consensus was achieved.

Results

The panel proposes specific and realistic recommendations for implementing control tools for AD care in LA. In creating these recommendations, the authors strove to address all barriers to the widespread use of these tools.

Conclusion

This article includes a narrative analysis of barriers to AD control in LA and provides necessary recommendations to integrate and increase the use of validated AD control assessment tools throughout the region.

Patterns of allergic sensitization and factors associated with emergence of sensitization in the rural tropics early in the life course: findings of an Ecuadorian birth cohort

Introduction

There are limited data on emergence of allergic sensitization (or atopy) during childhood in tropical regions.

Methods

We followed a birth cohort of 2404 newborns to 8 years in tropical Ecuador and collected: risk factor data by maternal questionnaires periodically from birth; atopy was measured by skin prick test reactivity (SPT) to aeroallergens in parents, and aeroallergens and food allergens in children at 2, 3, 5, and 8 years; and stool samples for soil-transmitted helminths (STH) from children periodically to 8 years and from parents and household members at the time of recruitment of cohort children. Data on risk factors were measured either at birth or repeatedly (time-varying) from birth to 8 years. Longitudinal repeated-measures analyses were done using generalized estimating equations to estimate an the age-dependent risk of positive SPT (SPT+) to any allergen or mite during early childhood to school age.

Results

SPT+ to any allergen was present in 29.0% of fathers and 24.8% of mothers, and in cohort children increased with age, initially to mite but later to cockroach, reaching 14.8% to any allergen (10.7% mite and 5.3% cockroach) at 8 years. Maternal SPT+, particularly presence of polysensitization (OR 2.04, 95% CI 1.49-2.77) significantly increased the risk of SPT+ during childhood, while household overcrowding at birth decreased the risk (OR 0.84, 95% CI 0.72-0.98). For mite sensitization, maternal polysensitization increased (OR 2.14, 95% CI 1.40-3.27) but rural residence (OR 0.69, 95% CI 0.50-0.94) and birth order (3^rd -4^th vs. 1^st - 2^nd: OR 0.71, 95% CI 0.52-0.98) decreased the risk. Time-varying exposures to agricultural activities (OR 0.77, 95% CI 0.60-0.98) and STH parasites (OR 0.70, 95% CI 0.64-0.91) during childhood decreased while anthelmintics increased the childhood risk (OR 1.47, 95% CI 1.05-2.05) of mite sensitization.

Conclusion

Our data showed the emergence of allergic sensitization, primarily to mite and cockroach allergens, during childhood in tropical Ecuador. A role for both antenatal and postnatal factors acting as potential determinants of SPT+ emergence was observed.

Altered IgA Response to Gut Bacteria Is Associated with Childhood Asthma in Peru

Alterations in gut microbiota in early life have been associated with the development of asthma; however, the role of gut bacteria or the IgA response to gut bacteria in school-aged children with asthma is unclear. To address this question, we profiled the microbial populations in fecal and nasal swab samples by 16S rRNA sequencing from 40 asthma and 40 control children aged 9-17 y from Peru. Clinical history and laboratory evaluation of asthma and allergy were obtained. Fecal samples were analyzed by flow cytometry and sorted into IgA+ and IgA- subsets for 16S rRNA sequencing. We found that the fecal or nasal microbial 16S rRNA diversity and frequency of IgA+ fecal bacteria did not differ between children with or without asthma. However, the α diversity of fecal IgA+ bacteria was decreased in asthma compared with control. Machine learning analysis of fecal bacterial IgA-enrichment data revealed loss of IgA binding to the Blautia, Ruminococcus, and Lachnospiraceae taxa in children with asthma compared with controls. In addition, this loss of IgA binding was associated with worse asthma control (Asthma Control Test) and increased odds of severe as opposed to mild to moderate asthma. Thus, despite little to no change in the microbiota, children with asthma exhibit an altered host IgA response to gut bacteria compared with control participants. Notably, the signature of altered IgA responses is loss of IgA binding, in particular to members of Clostridia spp., which is associated with greater severity of asthma.

Mosquitoes: Important Sources of Allergens in the Tropics

There are more than 3,000 mosquito species. Aedes aegypti, Ae. communis, and C. quinquefasciatus are, among others, three of the most important mosquito allergen sources in the tropics, western, and industrialized countries. Several individuals are sensitized to mosquito allergens, but the epidemiological data indicates that the frequency of sensitization markedly differs depending on the geographical region. Additionally, the geographical localization of mosquito species has been affected by global warming and some mosquito species have invaded areas where they were not previously found, at the same time as other species have been displaced. This phenomenon has repercussions in the pathogenesis and the accuracy of the diagnosis of mosquito allergy. Allergic individuals are sensitized to mosquito allergens from two origins: saliva and body allergens. Exposure to saliva allergens occurs during mosquito bite and induces cutaneous allergic reactions. Experimental and clinical data suggest that body allergens mediate different manifestations of allergic reactions such as asthma and rhinitis. The most studied mosquito species is Ae. aegypti, from which four and five allergens of the saliva and body, respectively, have been reported. Many characterized allergens are homologs to arthropod-derived allergens, which cause strong cross-reactivity at the humoral and cellular level. The generalized use of whole body Ae. communis or C. quinquefasciatus extracts complicates the diagnosis of mosquito allergy because they have low concentration of saliva allergens and may result in poor diagnosis of the affected population when other species are the primary sensitizer. This review article discusses the current knowledge about mosquito allergy, allergens, cross-reactivity, and proposals of component resolved approaches based on mixtures of purified recombinant allergens to replace saliva-based or whole-body extracts, in order to perform an accurate diagnosis of allergy induced by mosquito allergen exposure.

Purification and characterisation of the dimeric group 12 allergen from Blomia tropicalis heterologously expressed by Escherichia coli Top10F´

Successful research in the wide-ranging field of allergy is usually achieved by definition not only of physicochemical and immunological properties of natural, but also recombinant allergens. Blomia tropicalis mite is a well-known source for various groups of hypersensitivity-causing proteins. The goal of the present work was to produce, purify and characterise by in silico, biochemical and immunological methods the recombinant group-12 allergen of B. tropicalis. The recombinant Blo t 12 aggregation capacity as well as the affinity to antibodies from BALB/c immunised mice and B. tropicalis-sensitised human donors were investigated through in silico analyses, dynamic light scattering, SDS-PAGE, ELISA and Western blot. The presence of Blo t 12 within B. tropicalis extracts was also determined by ELISA and Western blot. High concentrations of dimeric rBlo t 12 were detected through SDS-PAGE next to other aggregates and the results were confirmed by data from DLS and Western blot. The YITVM peptide was predicted to be the most aggregation-prone region. The IgE-reactivity of rBlo t 12 was not completely abolished by aggregate formation but it was significantly decreased compared to rBlo t 5, or B. tropicalis extracts. Natural Blo t 12 may naturally dimerises, but it was detected in non-delipidified B. tropicalis extracts in low amounts. Given that this allergen may be a specific marker for B. tropicalis allergy, the recombinant Blo t 12 herein obtained is characterised as a mid-tier allergen in Brazilian atopic patients and may be useful for the improvement in precision allergy molecular diagnostic applications.

IgE, blood eosinophils and FeNO are not enough for choosing a monoclonal therapy among the approved options in patients with type 2 severe asthma

Type-2 inflammation is the most frequent endophenotype of asthma. Different biomarkers have been proposed to identify this inflammation because highly effective therapies have improved type-2 severe asthma control. We investigated the frequency of some biomarkers of type-2 inflammation (total IgE, sIgE, blood eosinophil, and FeNO) in the framework of severe asthma and assessed its ability to help us to choose the best biological therapy for each patient. Different scenarios (sensitivity analysis) were evaluated according to the biomarkers proposed for each biological therapy in 72 patients with type-2 severe asthma. Between 54.1% and 68% of patients could receive at least 2 different biological therapies and 34.7%-40.2% could receive any of the 3 types of therapies (anti-IgE, anti-eosinophil, anti-IL4). Biomarkers help to identify type-2 severe asthma but total IgE, sIgE, blood eosinophil, and FeNO are not enough to select 1 specific therapy. With the increasing arrival of new biological therapies, it is necessary to identify new biomarkers that allow us to improve our selection criteria for the best therapy for each patient or to construct a prediction rule.

A feasibility study to assess Imbrasia belina (mopane worm) sensitisation and related respiratory health outcomes in a rural community in Gwanda district, Zimbabwe

Background

Allergic diseases are considered to be some of the fastest growing chronic conditions in Africa. Of concern is the paucity of knowledge about the local environment and its role in allergic disease development. In response to this, we explored whether Imbrasia belina, a popular indigenous edible insect commonly known as mopane worm, is a potential allergen of clinical and public health significance in Zimbabwe. This study was intended to assess the plausibility and feasibility of this hypothesis with a view to evaluate the insect’s health impact in a larger study.

Methods

The study participants included male and female villagers aged 10 years and above in Gwanda district, Zimbabwe. Eligible participants who completed the household questionnaire were referred to the local clinic for skin prick tests and to measure lung function and allergic airway inflammation. Allergen sensitisation patterns were evaluated using 10 different inhalant allergen extracts including an in-house preparation of mopane worm. Lung function was measured with a Koko Legend spirometer, and fractional exhaled nitric oxide levels (FeNO) (NIOX VERO) were measured in participants with at least one abnormal spirometric parameter. Data was analysed using Stata version 13 software.

Results

Of the 46 eligible participants that completed the household questionnaire, 17 went to the clinic giving a response rate of 37%. The majority who completed the questionnaire were adults (91%) and the children (9%) were all female. The prevalence of sensitisation to Imbrasia belina was 50%, and the prevalence ranged from 22 to 72% for the other allergens including cockroach, mosquito and house dust mites. The data collection tools were safe and well tolerated by participants with no adverse events reported. Self-reported respiratory symptoms, abnormal lung function and elevated FeNO were recorded amongst participants sensitised to mopane worm.

Conclusion

Pre-defined feasibility criteria were met with the exception of a lower than expected response rate for clinic data collection in this pilot study. For the main study, modifying the sampling strategy and applying more consistent community engagement will improve the response rates.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00780-9.

Identification and Physicochemical Characterization of a New Allergen from Ascaris lumbricoides

To analyze the impact of Ascaris lumbricoides infection on the pathogenesis and diagnosis of allergic diseases, new allergens should be identified. We report the identification of a new Ascaris lumbricoides allergen, Asc l 5. The aim of this study was to evaluate the physicochemical and immunological features of the Asc l 5 allergen. We constructed an A. lumbricoides cDNA library and Asc l 5 was identified by immunoscreening. After purification, rAsc l 5 was physicochemically characterized. Evaluation of its allergenic activity included determination of Immunoglobulin E (IgE) binding frequency (in two populations: 254 children and 298 all-age subjects), CD203c based-basophil activation tests (BAT) and a passive cutaneous anaphylaxis (PCA) mouse model. We found by amino acid sequence analysis that Asc l 5 belongs to the SXP/RAL-2 protein family of nematodes. rAsc l 5 is a monomeric protein with an alpha-helical folding. IgE sensitization to rAsc l 5 was around 52% in general population; positive BAT rate was 60%. rAsc l 5 induced specific IgE production in mice and a positive PCA reaction. These results show that Asc l 5 has structural and immunological characteristics to be considered as a new allergen from A. lumbricoides.

A descriptive study of allergen-specific IgE serological tests for canine atopic dermatitis in Thailand

Background

This study describes the usefulness of allergen-specific Immunoglobulin E (IgE) serology (ASIS) for identifying allergens in dogs with atopic dermatitis. ASIS tests were conducted in 23 dogs diagnosed with atopic dermatitis for indoor allergens (yeast and mites), outdoor allergens (grass pollen, weed pollen, and tree pollen), and fleas. The relationship among positive ASIS tests were determined using Pearson’s correlation coefficient (r).

Results

Of the atopic dogs, 26.09%, 4.35%, and 47.83% had positive ASIS tests for only indoor allergens, only outdoor allergens, and both indoor and outdoor allergens, respectively. The prevalence of positive ASIS tests was highest for mites (69.57%) and did not differ between indoor and outdoor allergens by age, breed, or sex. The prevalence of positive ASIS tests for indoor allergens during the rainy season (84.21%) was significantly higher than during winter (25.00%, P-value = 0.030). The correlation coefficient of the ASIS results among the outdoor allergens indicated a strong correlation between grass and tree pollen (r = 0.840, P-value < 0.01), grass and weed pollen (r = 0.812, P-value < 0.01), and tree and weed pollen (r = 0.714, P-value < 0.01). The correlation coefficient of the ASIS results of D. farinae indicated a strong correlation with A. siro (r = 0.951, P-value < 0.01) and a moderate correlation with B. tropicalis (r = 0.656, P-value < 0.01) and T. putrescentie (r = 0.672, P-value < 0.01).

Conclusions

ASIS tests are useful in screening for multiple allergens in dogs with atopic dermatitis. Dust mites are an important source of indoor allergens and may be responsible for a higher titer of IgE antibodies against indoor allergens during the rainy season.