Immunoglobulin E to allergen components of house dust mite in Korean children with allergic disease

Association of Mite Molecular Sensitization Profiles with Respiratory Allergies and Asthma Control in Children from East China

Background

Allergic conditions, identified as a significant global health challenge, are profoundly influenced by indoor allergens, especially house dust mites (HDM). Yet the relationship between mite sensitized components and respiratory allergies and asthma control remains poorly understood.

Methods

A cohort of 96 children, either with allergic rhinitis (AR) or rhinitis with asthma syndrome (ARAS), was assessed. Protein microarray technology was deployed to quantify sIgE responses to the allergenic components of Der p and Der f.

Results

The study cohort comprised 18 AR and 78 ARAS patients; with 43 mild and 53 moderate-to-severe AR; with 28 uncontrolled, 21 partially controlled, and 29 well-controlled asthma. Sensitization prevalence for HDM components was highest with Der p (97.9%), Der f 2 (97.9%), Der p 2 (94.8%), Der f 1(94.8%), Der p 1 (93.8%), Der p 23 (57.3%). Notably, sIgE concentrations for Der f and Der f 2 were significantly greater in the ARAS compared to AR (P < 0.05). While sIgE levels varied between mild and moderate-to-severe AR, the differences were not statistically significant (P > 0.05). However, Der p 23 sIgE levels demonstrated a significant fluctuation across the asthma control strata (P < 0.05), with the well-controlled group exhibiting the lowest readings.

Conclusion

The sIgE levels to HDM allergens were higher in ARAS group compared to AR group, especially Der f and Der f 2, indicating an association between sIgE reactivity and the diagnosis of asthma. Reduced Der p 23 sIgE levels were indicative of enhanced asthma control.

House dust mite allergy in Malaysia: review of research gaps in the current scenario and the way forward

The prevalence of house dust mite (HDM) allergy, especially in Asian countries with rapid urbanization, has been increasing. House dust mites thrive in places with relatively high humidity. With the combination of climate change, naturally high humidity, and urbanization, tropical countries like Malaysia are becoming a hotspot for HDM allergy fast. With a previously reported sensitization rate of between 60 and 80%, it is a worrying trend for Malaysia. However, due to incomplete and out-of-date data, as seen by the limited study coverage in the past, these numbers do not paint a complete picture of the true HDM allergy scene in Malaysia. This review briefly discusses the HDM fauna, the HDM sensitization rate, the common diagnosis and therapeutic tools for HDM allergy in Malaysia, and makes suggestions for possible improvements in the future. This review also highlights the need of more comprehensive population-based prevalence studies to be done in Malaysia, encompassing the three main HDMs-Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis-as the lack of up-to-date studies failed to give a clearer picture on the current scenario of HDM allergy in Malaysia. Future studies will be beneficial to the nation in preparing a better blueprint for the management and treatment of HDM allergy.

Retrospective Analysis of Allergen Distribution Dynamics in Central Taiwan

Introduction: Allergy is a type Ⅰ hypersensitivity reaction to certain substances (allergens) such as environmental factors, food and drugs. Allergies are a significant public health issue, and therefore, understanding the distribution patterns of allergens in specific regions is important. This study aimed to retrospectively analyse allergen distribution patterns in Central Taiwan over a 5 years period (2018-2022). Methods: Data of patients who had allergen sensitization testing using the OPTIGEN® Allergen-Specific IgE Assay from the 1st of January 2018 to the 31st of December 2022 were reviewed retrospectively. Statistical analyses were performed to determine the prevalence and distribution of allergens in our study population. Results: A total of 8,444 patients (3,784 males and 4,660 females) who attended the Asia University Hospital for allergen detection were enrolled in this study. Dermatophagoides farina (41.8%), Dermatophagoides pteronyssinus (37.9%), house dust (24.6%), cockroach mix (17.7%), crab (12.6%), clam (9.8%), shrimp (9.1%), cat dander (8.1%), pig weed (8%) and peanut (7.8%) were identified as the ten allergens that most commonly induced sensitization in our study population. Additionally, crab, clam, shrimp, peanut and beef were the five most common food allergens. Conclusion: In summary, our findings contribute significantly to the knowledge on allergen distribution in Central Taiwan. Our identification of prevalent allergens may contribute to an improved understanding of the epidemiology of allergies in this region.

Prevalence of allergen sensitization among 1,091 patients with urticaria

The etiology of urticaria is heterogeneous and allergic responses may be involved in it. The aim of the present study was to investigate the prevalence and distribution of sensitivity to inhaled and food allergens among patients with urticaria in Henan province (China). The levels of specific immunoglobulin E (sIgE) were detected using the AllergyScreen test and a total of 524/1,091 cases (48.0%) tested positive for sIgE to at least one of the 19 allergens. The most common inhaled allergens the urticaria patients were sensitive to were D. pteronyssinus (34.5%), cockroach (12.5%) and tree pollen mix (11.1%), while the food allergens with the highest rate of allergic reactions were cashew nut (8.1%), shrimp (6.8%) and crab (6.4%). The positive rates for D. pteronyssinus, dog hair, cockroach, mold mix, tree pollen mix and shrimp in the chronic urticaria group were higher than those in the acute urticaria group (P<0.05). Furthermore, positive rates for the majority of allergens were higher in males than in females and were significantly different between age groups (P<0.05). The results of the present study provided information on the characteristics of allergen sensitization of patients with urticaria and may facilitate the prevention, diagnosis and management of urticaria in Henan province.

House dust mite sensitisation and association with atopic dermatitis in Brunei: Allergen sensitization and allergic disease in Brunei

IgE sensitisation in tropical areas is under-reported. A 2 year retrospective cohort study of allergy data specific to aero and food allergens in Brunei demonstrated that specific IgE levels to house dust mite (Dermatophagoides pteronyssinus, D.farinae, Blomia tropicalis) were highest in this population and correlated with atopic dermatitis (p < 0.001). Shrimp and peanut were the most common food allergens. A dominance of house/storage mite sensitization is seen in Brunei which is consistent with other tropical countries.

Identification of Der f 23 as a new major allergen of Dermatophagoides farinae

House dust mites (HDM) are common allergen sources worldwide. At present, 32 of the 37 internationally recognized HDM allergen groups have been identified in Dermatophagoides farinae. The present study study describes the identification of the first known D. farinae Group 23 allergen (Der f 23). Recombinant Der f 23 protein (rDer f 23) was cloned, expressed and purified. The open reading frame of rDer f 23 was 525 base pairs and encoded a 174-amino acid protein (GenBank accession no., KU166910.1). ELISAs indicated that 72/129 HDM allergic serum samples (55.8%) had specific immunoglobulin E (sIgE) binding activity to rDer f 23. Additionally, 3/10 patients with HDM allergies (30%) exhibited positive skin prick test reactions to rDer f 23. IgE western blot analysis data suggested that only 4/11 HDM allergic sera had a positive sIgE binding result. Sequence homology analysis revealed an extra P2 region (Ser56-Thr117) in Der f 23 that was not present in the D. pteronyssinus homolog, which may affect sIgE binding. Der f 23ΔP2 demonstrated binding with HDM allergic sera, whereas the P2 peptide alone did not. The sIgE binding ability of Der f 23 ΔP2 (Der f 23 with a truncated P2 region) was more marked compared with that of Der f 23 in an IgE ELISA. These data indicate that P2 region in Der f 23 attenuates IgE binding ability. In conclusion, the results of the present study indicate that Der f 23 is a major HDM allergen with predominantly conformational sIgE binding epitopes. The allergenic identification of Der f 23 and its inclusion in World Health Organization/International Union of Immunological Societies database contributes to the theoretical basis underlying the diagnosis and treatment of HDM allergic diseases.

Component-resolved microarray analysis of IgE sensitization profiles to Felis catus major allergen molecules in Russian cat-allergic patients

We aimed to determine the profile of IgE reactivity to three major cat allergens, Fel d 1, Fel d 2 and Fel d 4, in cat-allergic patients in the Moscow region in Russia. sIgE levels to recombinant proteins expressed in Escherichia coli (Fel d 1 and Fel d 4) and to Fel d 2 protein purified from cat serum were measured using a microarray method developed in our laboratory. Sera from 174 anonymous subjects with a positive reaction (≥0.35 IU/mL) to cat dander extract (e1, ImmunoCAP) and 56 negative controls were used for IgE testing. Fel d 1 was recognized by 92.5%, Fel d 2 by 29.9% and Fel d 4 by 39.1% of the tested patient sera. The sensitivity to these three proteins was approximately 98% compared to cat dander extract (correlation coefficient to ImmunoCAP is 0.94 with PPV = 0.99 and NPV = 0.95). These predictive values appeared to be even more statistically significant than the divergence between the ISAC IgE test and the extract-based singleplex ImmunoCAP. The combination of the three investigated proteins (Fel d 1, Fel d 2 and Fel d 4) is suitable for in vitro molecular (serological) diagnosis of cat allergy in this region as a complement to cat dander extract. Moreover, with this method, we found distinction between Fel d 2 and other Feline sIgEs formation.

A cross-sectional observational study on allergen-specific IgE positivity in a southeast coastal versus a southwest inland region of China

Few studies addressed trans-regional differences in allergen sensitization between areas within a similar latitudinal range but with distinct geomorphological features. We investigated specific IgE (sIgE) positivity to common allergens in populations from two southern China provinces. Using a uniformed protocol, serum samples were collected from 2778 subjects with suspected atopy in coastal Guangdong and inland Yunnan. The overall prevalence of sIgE positivity were 57.8% (95% CI: 56.0%, 59.6%) from Guangdong vs 60.9% (95% CI: 59.1%, 62.7%) from Yunnan. House dust mite (d1) was the most common allergen in both regions. Among d1-sensitized subjects, only 35.7% (208/583) in Guangdong and 22.9% (147/642) in Yunnan tested positive for d1 alone. Among those poly-sensitized d1-positive subjects, cockroach was the most common co-sensitizing aeroallergen. 41.9% of the d1-sensitized Guangdong subjects showed high-class sIgE reactivity (≥class 4), in contrast to a very low percentage of such reactivity in Yunnan. However, 36.3% of d1-sensitized subjects in Yunnan were concomitantly positive for tree pollen mix. Surprisingly, Yunnan subjects showed high prevalence of sIgE positivity for crabs and shrimps, either by overall or by age-group analysis, compared with their Guangdong counterparts (both P < 0.05). These findings may add to data about local allergies in China and worldwide.

House Dust Mite Allergens: New Discoveries and Relevance to the Allergic Patient

PURPOSE OF REVIEW

Recent findings on house dust allergens and their contribution to knowledge that will significantly impact on current and future allergy treatments are appraised.

RECENT FINDINGS

Quantitation of IgE binding to a spectrum of allergen components in several independent studies in varying locations has largely affirmed the main components as the groups 1 and 2 and possibly 23 allergens with mid-tier contributions from the groups 4, 5, 7, and 21. Prevalent binding to Der p 23 has been recapitulated sometimes with low titers. The IgE of non-asthmatic atopic subjects binds at lower titer and to fewer components than that of asthmatics, and their IgG binding relative to IgE is higher especially for children hospitalized for exacerbation. The higher IgG ratios were associated with increased IL-10 a cytokine more readily induced from T cells of allergic subjects. Peptides representing the groups 1 and 2 allergens can be used to stimulate ex vivo T cells showing responses correlating with IgE binding and providing a valuable tool for ascertaining the contribution of IgE and T cells to disease. Also, the induction of Th2 and follicular helper T cells are shown to make different contributions in mice. Cross-reactivity of IgE binding assays with high-titer cross-reactive antibodies induced by scabies is a problem in the many areas of the world where scabies is highly prevalent and endemic and from recent increases in immigration. In the last few years, allergen research has produced results that warrant rapid translation into diagnostic tools and the formulation of allergen components for immunotherapy.

Dermatophagoides pteronyssinus: Changes in sensitisation in the past 11 years and comparison with other centres in Mexico

BACKGROUND

House dust mites are a ubiquitous air allergen in the human habitat. It has been shown that exposure to them is a fundamental factor in sensitisation and development of atopic disease. The objective of the study was to analyse changes in sensitisation to Dermatophagoides pteronyssinus (Der p.) in children treated in a tertiary level care hospital in Mexico City for a period of 11 years and compare with other studies carried out in Mexico.

METHODS

A retrospective study was performed at the Hospital Infantil de México Federico Gómez (HIMFG). Information was gathered from skin tests for Der p. performed in the Allergy Laboratory from January 2004 to April 2015. Patients 2-18 years old who presented for examination of some type of allergic condition and who had immediate hypersensitivity tests to Der p. were included in the study. Results were compared with prior reports from other institutions. Descriptive analysis and χ² statistics were used.

RESULTS

A total of 8794 patients were included in the study; 49.3% of the tests (95% CI 48-50) were positive for Der p. The percentage of monosensitised to mites was 2.7% for Der p. (95% CI 2-3). A significant difference was found between the results of older patients and those <6 years old. The frequency of sensitisation had a tendency to decrease during the 11 years analysed in all age groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The frequency of sensitisation to Der p. increased with age until reaching adolescence. In the last 11 years a decrease in sensitisation to this air allergen was observed.

Diagnostic value of Der p 1 and Der p 2 specific IgE in Dermatophagoides pteronyssinus IgE sensitization

OBJECTIVE

To assess the diagnostic performance of Der p 1 and Der p 2 specific IgE (sIgE).

DATA SOURCES

Studies were systematic computerized searches of the PubMed, EMBASE, and Cochrane libraries (published 1966 to September 5, 2015).

STUDY SELECTION

Records were screened by title and abstract and then by full-text articles of relevant studies. Eligible studies were selected according to inclusion criteria: (1) all house dust mite allergy diagnosed on the basis of clinical symptoms in combination with a dust mite extract skin prick test result; (2) the inclusion of controls in the study; and (3) enough data to construct the diagnostic 2 × 2 table. True-positive, false-positive, false-negative, and true-negative values were extracted from or calculated for each study. Then the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated. A summary receiver operating characteristic curve and area under the curve were used to evaluate the overall diagnostic performance.

RESULTS

Seven eligible studies that involved 1040 cases were included in this meta-analysis. The meta-analysis found that detection of Der p 1 or Der p 2 sIgE is of sufficient diagnostic accuracy for use in the diagnosis of Dermatophagoides pteronyssinus IgE sensitization.

CONCLUSION

Detection of Der p 1 or Der p 2 sIgE is a promising diagnostic tool in the diagnosis of D pteronyssinus IgE sensitization.