Skin prick test reactivity to common aeroallergens among allergic rhinitis patients in Iran

An emerging aeroallergen in Europe: Tree-of-Heaven (Ailanthus altissima [Mill.] Swingle) inventory and pollen concentrations - Taking a metropolitan region in Germany as an example

Urban areas are often hotspots for the dissemination of non-native (invasive) plant species, some of which release (potentially) allergenic pollen. Given the high population density in cities, a considerable number of people can be regularly and potentially intensively exposed to the pollen from these plants. This study delves into the Tree-of-Heaven (Ailanthus altissima, [Mill.] Swingle), native to East Asia, which is known for its high invasiveness in temperate regions worldwide, particularly favoring urban colonization. This study explores the botanical and aerobiological dimensions of this species using the central European metropolitan region of Berlin, Germany, as a case study, and provides a comprehensive global overview of allergological insights. The number of Ailanthus trees decreased markedly from the center to the periphery of Berlin City, following a temperature gradient. The same spatial trend was mirrored by airborne Ailanthus pollen concentrations measured with volumetric spore traps (Hirst-type) at five sites using seven traps. Ailanthus pollen was most abundant around midday and in the afternoon, with concentrations tenfold higher at street level than at roof level. The Ailanthus flowering period in June and July coincided well with the pollen season. To the best of our knowledge this is the first study to investigate Ailanthus altissima pollen production. On average, 5539 pollen grains were found per anther. A literature review on the allergy relevance of Ailanthus altissima pollen indicates the high allergenic potential of pollen from this species. Considering the anticipated expansion of suitable habitats for Ailanthus owing to global warming and the allergological significance of its pollen, it is recommended to include Ailanthus pollen in routine pollen monitoring, particularly in areas colonized by this species. This comprehensive study provides new insights into a pollen taxon whose significance as an emerging aeroallergen should be factored into plant selection and greenspace management in all temperate regions.

Evaluation of The Safety and Efficacy of Newly Developed Domestic Allergenic Extracts for Skin Prick Testing

Background

Allergic disorders are common health problems worldwide with significant socio-economic impacts. The best diagnostic method using allergenic extract is the skin prick test. Regarding the effects of geo-climatic factors and allergenic extract source material quality, the aim of study was to determine the safety and efficacy of some in-house-developed allergenic extracts.

Methods

Forty-five different allergenic extracts, including common regional pollen, foods, and dog and cat hair, as well as positive and negative extracts, were prepared from domestic sources using optimum extraction methods. All extracts passed stability and sterility testing, and sterile final products containing 50% glycerin in 10 and 20 w/v concentrations were used. Skin prick testing was performed on volunteers and immediate or late side effects were recorded.

Results

In total, 56 students (mean age: 21.2±2.3y, M/F ratio: 1.07) participated in this study. For inhalant allergens, all extracts except dog hair extract caused positive responses. Salsola kali (Russian thistle) and Fraxinus velutina (ash tree) were the most common grass and tree pollen extracts, respectively. Of 18 different food extracts, five, including egg white, tomato, fig, melon, and green pepper caused skin reactivity in only one person. No participant reported any immediate or late side effects, including large local reaction or systemic response.

Conclusion

The result of the current study confirmed the safety of all our in-house-developed allergenic extracts. Regarding efficacy, almost all inhalant and five food allergens caused positive skin responses.

Association between serum zonulin level and severity of house dust mite allergic asthma

BACKGROUND

Increased intestinal permeability, either due to the exposure to antigens in asthmatic patients or due to a barrier defect, plays a critical role in susceptibility to environmental allergens. House dust mite allergy occurs more commonly than any other type of allergy among Egyptian asthmatic patients.

AIM

To assess the relation between serum zonulin level as a marker of increased intestinal permeability and the severity of house dust mite allergic asthma.

METHODS

A case-control study which included 48 patients with house dust mite allergic asthma and 48 healthy control subjects attending the Allergy and Immunology Unit, Microbiology and Immunology Department, Faculty of Medicine, Zagazig University.

RESULTS

A statistically significant difference was detected between the two studied groups with respect to serum IgE and serum zonulin levels (p ˂ 0.001 and ˂ 0.001, respectively). The mean serum zonulin was equal to 258.3 ± 153.01 ng/ml in the asthmatic group and 80 ± 13 ng/ml in the control group. Serum zonulin level significantly increased with the increase of asthma severity (p ˂ 0.001). The cut off value of serum zonulin was ≥ 198 ng/ml, and the area under the curve was 0.76. It displayed sensitivity equal to 80% and specificity equal to 71.4%. Its negative predictive value was equal to 83.3%.

CONCLUSION

Intestinal barrier dysfunction contributes to the pathogenesis of allergic asthma. Serum zonulin level reflects an increase in intestinal permeability. Zonulin acts as prognostic factor of severity in asthma. Correction of the gut barrier defect may have a potential positive prognostic effect in asthma.

The Influence of Indoor Environmental Factors on the Prevalence of House Dust Mites as Aeroallergens in Bandar Abbas Student Dormitories, South of Iran, 2019

This study was conducted to determine the influence of environmental factors on the prevalence of house dust mites in student dormitories of Bandar Abbas city. In this study, 64 dust samples were collected from seven randomly selected dormitories located in various areas of the Bandar Abbas. The collected mites were isolated and mounted in Hoyer's medium and identified using a morphological key. The associations between the environmental factors and the density of house dust mites were investigated. In total, 1,093 adult mites were collected and identified. They consisted of four species including Dermatophagoides pteronyssinus Trouessart (57.6%), Dermatophagoides farinae Hughes (24.3%) and Dermatophagoides evansi Fain (14.9%) (Acari: Pyroglyphidae), and Cheyletus malaccensis Oudemans (3.2%) (Acari: Cheyletidae). All of the dormitories were contaminated by more than one house dust mites species and the mean density of house dust mites in dormitories was 8.3 ± 0.2 mites/g of dust. There was a significant relationship between average house dust mites density and some of environmental factors such as relative humidity, temperature, floor covering type, and number of occupants (P < 0.05). Results of this study revealed that two major allergenic dust mites, D. pteronyssinus and D. farinae, were the most prevalent and collected from all of dormitories and some of indoor environmental factors found to influence mites' population.

Sensitization to Inhaled Allergens in Atopic Children in Jordan Capital, Amman: A Cross-sectional Study

Background:

As the prevalence of allergic diseases is increasing all over the world, it is vital to identify the specific allergens, which contribute to the development and persistence of such conditions.

Objectives:

This study aims to assess the prevalence of aeroallergen sensitization and, to evaluate the profile of skin prick test among atopic Jordanian children who are visiting Jordan University Hospital (JUH).

Methods:

A retrospective analysis of all Skin Prick Test (SPT) and results of atopic children and adolescents aged (1.5-18 years) who visited the pediatrics clinics at JUH from January 2018 until December 2019.

Results:

Over two years, a total of 171 children (male: female ratio of 1.9) with a median age of 6.2 years (1.5-18) were subjected to SPT. One hundred and seven children (62.5%) were found to be sensitized to at least one of the ten aeroallergen extracts tested. The most common sensitizations were to olive pollen (45.6%), Mites Dermatophagoides Petronyssinus (42.0%), and Dog Dander (38.6%). The highest sensitization rate was among the age group 2-4 years (28.1%). The sensitization rates increased in conjunction with an increase in age in the first age groups (preschool and school-age groups).

Conclusion:

The study’s findings provide an understanding of the locally prevalent aeroallergens, yet a multi-center review would be more useful for creating an optimized SPT panel specific to the Jordanian pediatric population.

Molecular and immunochemical characterization of Pop n 2: A new allergen of Populus nigra pollen

BACKGROUND

Pollen is one of the most common allergens that cause respiratory allergies worldwide. Pollen grains from poplars have been reported as important sources of pollinosis in many countries.

OBJECTIVE

The aim of the present study was to determine the molecular and immunochemical characterization of Pop n 2, a novel allergen of Populus nigra (P nigra) pollen extract.

METHODS

In this study, the pollen extract of P nigra was analysed by SDS-PAGE, and the allergenic profile was determined by IgE immunoblotting and specific ELISA using the sera of twenty allergic patients. The coding sequence of Pop n 2 was cloned and expressed in the Escherichia coli BL21 (DE3) using plasmid the pET-21b (+). Finally, the expressed recombinant Pop n 2 was purified by affinity chromatography.

RESULTS

Pop n 2 belongs to the profilin family with a molecular weight of approximately 14 kDa. Pop n 2 is the most IgE-reactive protein (about 65%) in the P nigra pollen extract. The cDNA sequencing results indicated an open reading frame 396 bp that encodes 131 amino acid residues. The results of ELISA and Immunoblotting assays showed that recombinant Pop n 2 could react with the IgE antibody in patients' sera, like its natural counterpart.

CONCLUSION

Our data revealed that Pop n 2 is a significant allergen in the P nigra pollen extract. Moreover, we observed that the recombinant Pop n 2 produced by the pET-21b (+) vector in the E colisystem acts as its natural counterpart.

Analysis of different signal peptides for the secretory production of Ama r 2 in gram-positive systems (Lactococcus lactis)

Prokaryotic systems have been considered the most affordable and simplest hosts which are being employed to express recombinant proteins such as allergens; nevertheless, without appropriate signal peptide (SP), these systems cannot be used for secretory proteins. Recently, a lot of effort has been put into assessing the potential of gram-positive strains such as lactic acid bacteria for new applications in the production of heterologous proteins. Ama r 2 is a respiratory allergen from Amaranthus retroflexus, whose recombinant production in the probiotic host could be introduced as a specific and effective way to rapid diagnosis and immunotherapy of this allergy. Consequently, the production of this recombinant protein using the prokaryotic system, requires a suitable SP to protect disulfide bonds and to prevent misfolding. This study was designed to predict the best SPs for the expression of Ama r 2 protein in Lactococcus lactis as the host. In this study, 42 signal sequences were selected from SP databases and the most important features of them were evaluated. First, n, h and c regions of the SPs and their probabilities were investigated by signalP software version 4.1. Then, their physicochemical properties were evaluated by Portparam and SOLpro. Moreover, the secretion sorting and sub-cellular localization sites were evaluated by PRED-TAT and ProtcompB software programs. The results revealed that yjgB, entC2 (Entrotoxine type C-2), ent B (Entrotoxine type), blaZ (Beta lactamase), dex (number 21), blm (Beta lactamase 2), dex (Dextranase; number 20) and number 26 were introduced theatrically as the best SPs to express Ama r 2 in Lactococcus lactis.

Identification of polcalcin as a novel allergen of Amaranthus retroflexus pollen

INTRODUCTION

Amaranthus retroflexus (Redroot Pigweed) is one of the main sources of allergenic pollens in temperate areas. Polcalcin is a well-known panallergen involved in cross-reactivity between different plants. The aim of this study was the molecular cloning and expression of polcalcin, as well as evaluating its IgE-reactivity with A. retroflexus sensitive patients' sera.

METHODS

Allergenic extract was prepared from A. retroflexus pollen and the IgE-reactivity profile was determined by ELISA and immunoblotting using sera from twenty A. retroflexus sensitive patients. Polcalcin-coding sequence was amplified by conventional PCR method and the product was inserted into pET-21b(+) vector. The recombinant protein was expressed in E. coli BL21 and purified by metal affinity chromatography. The IgE-binding capability of the recombinant protein was analyzed by ELISA and immunoblotting assays, and compared with crude extract.

RESULTS

Of 20 skin prick test positive patients, 17 patients were positive in IgE-specific ELISA. Western blotting confirmed that approximately 53% of ELISA positive patients reacted with 10kDa protein in crude extract. The A. retroflexus polcalcin gene, encoding to 80 amino acid residues was cloned and expressed as a soluble protein and designated as Ama r 3. The recombinant polcalcin showed rather identical IgE-reactivity in ELISA and western blotting with 10kDa protein in crude extract. These results were confirmed by inhibition methods, too.

CONCLUSION

The recombinant form of A. retroflexus polcalcin (Ama r 3) could be easily produced in E. coli in a soluble form and shows rather similar IgE-reactivity with its natural counterpart.

Year-to-year variation of the elemental and allergenic contents of Ailanthus altissima pollen grains: an allergomic study

The Ailanthus altissima pollen (AAP) has been reported as an emerging aeroallergen worldwide. This paper aims at examining the allergen pattern and the elemental composition of A. altissima pollen collected during two consecutive seasons (2014 and 2015). A gel-based allergomic study and SEM coupled to energy-dispersive X-ray (EDX) analysis have been carried out in order to evaluate the allergenic and elemental composition of AAP in two consecutive years. The IgE reactive patterns of 2014 and 2015 AAP PBS extracts were compared using the serum of a 31-year-old woman suffering from severe pollinosis symptoms to AAP. The EDX analysis revealed an important year-to-year variation in the ratios of some polluting elements such as nickel, sulfur, aluminum, lead, and copper. Gel alignments and comparative immunoproteomic analyses showed differential protein expression and IgE reactive patterns between AAPs collected in 2014 and 2015 pollinating seasons. From 20 distinct IgE-reactive spots detected in AAP extracts, 13 proteins showed higher expression in 2014 sample, while 7 allergen candidates exhibited an increased expression in AAP collected in 2015. Matrix-assisted laser desorption ionization-MS/MS analyses led to the identification of 13 IgE-binding proteins with confidence, all belonging to well-known allergenic protein families, i.e., enolase, calreticulin, and pectate lyase. Overall, the 2014 AAP showed higher concentrations of urban polluting elements as well as an increased expression of allergenic pectate lyase isoforms of about 52 kDa. This study demonstrates that the implementation of allergomic tools for the safety assessment of newly introduced and invasive plant species would help to the comprehensive monitoring of proteomic and transcriptomic alterations involving environmental allergens.

A review on hypersensitivity reactions to fungal aeroallergens in patients with allergic disorders in Iran

Fungal agents account for the clinical manifestation of allergic disorders. The aim of the present study was to review the prevalence of hypersensitivity reactions to fungal aeroallergens in patients with allergic disorders, including allergic rhinitis, asthma, urticaria, and eczema, in Iran. The initial literature search resulted in the identification of 50 records, 26 cases of which met the inclusion criteria. Regarding the methods adopted for the detection of fungal allergens, serum-specific IgE and skin prick tests were used in 6 and 20 studies, respectively. Aspergillus fumigatus and Alternaria alternata sensitization was the most common allergic sensitization among the patients with allergic disorders. According to the reviewed studies, despite the humid climate of the north of Iran, fungal sensitization has a prevalence range of 5-70% in this region. In other regions, such as central and southern Iran, which have a dry and warm climate, fungal sensitization reportedly has a prevalence range of 5-65%. The prevalence of fungal sensitizations varies in different allergic disorders due to the factors related to geographic and genetic issues, gender, sample size, test operator, and assessment method.

Preparation allergenic pollen extracts; the points should be considered to make high-quality products

Atopic diseases have an increasing trend worldwide during the last two decades. Determining the main cause of allergic diseases, allergens, is the first step in managing and improving the issue, usually is done by Skin Prick tests (SPTs). Having allergenic extract in high quality is desired to perform a reliable SPT. Several parameters of extracts are considered including composition, stability, potency, preservation conditions, and unit definition. In this review, these factors have been explained pointing to factors might have profitable points or harmful drawback in the quality of allergen extracts.

Design and evaluation of a hypoallergenic peptide-based vaccine for Salsola kali allergy

BACKGROUND

The Salsola kali (S. kali) pollen is one of the most important causes of allergic rhinitis in the deserts and semi-desert areas. Immunotherapy with allergen extracts remains the only available treatment addressing the underlying mechanism of allergy. However, given the low efficacy of this method, it is necessary to find more effective and alternative therapeutic interventions using molecular biology and bioinformatics tools. In this study, a hypoallergenic vaccine was designed on the basis of B-cell epitope approach for S. kali immunotherapy.

METHODS

Using the Immune Epitope Database (IEDB), a 35-mer peptide was selected and chemically conjugated to a keyhole limpet hemocyanin (KLH) molecule. Specific IgG and IgE from immunized BALB/c mice sera against the vaccine (Sal k 1-KLH), S. kali extract and the recombinant protein, rSal k 1, were measured using ELISA. Also, inhibition of IgE by mouse IgG was evaluated using an inhibitory ELISA. Finally, the IgE reactivity and T-cell reactivity of the designed vaccine were evaluated by dot blot assay and MTT assay.

RESULTS

Vaccination with the vaccine produced high levels of protective IgG in mice, which inhibited the binding of patients IgE to recombinant proteins. The result showed that the designed vaccine, unlike the recombinant protein and extract, did not induce T-cell lymphocytes response and also exhibited decreased IgE reactivity.

CONCLUSION

The designed vaccine can be considered as a promising candidate for therapeutic allergen-specific immunotherapy.

Sensitization to common allergens among patients with allergies in major Iranian cities: a systematic review and meta-analysis

Various allergens are implicated in the pathogenesis of allergic diseases in different regions. This study attempted to identify the most common allergens among patients with allergies based on the results of skin prick tests in different parts of Iran. Relevant studies conducted from 2000 to 2016 were identified from the MEDLINE database. Six common groups of allergen types, including animal, cockroach, food, fungus, house dust mite, and pollen were considered. Subgroup analysis was performed to determine the prevalence of each type of allergen. The Egger test was used to assess publication bias. We included 44 studies in this meta-analysis. The overall prevalence of positive skin test results for at least one allergen was estimated to be 59% in patients with allergies in various parts of Iran. The number of patients was 11,646 (56% male and 44% female), with a mean age of 17.46±11.12 years. The most common allergen sources were pollen (47.0%), mites (35.2%), and food (15.3%). The prevalence of sensitization to food and cockroach allergens among children was greater than among adults. Pollen is the most common allergen sensitization in cities of Iran with a warm and dry climate; however, sensitization to house dust mites is predominant in northern and southern coastal areas of Iran.

Immunoproteomics of tree of heaven (Ailanthus atltissima) pollen allergens

Ailanthus altissima pollen (AAP) is considered as an emerging cause of respiratory allergy in United States, Italy and Iran. However, the allergenic composition of AAP is still unknown and has yet to be characterized. The present study aimed to identify AAP allergens using a proteomics-based approach. For this purpose, optimized AAP protein extracts were analyzed using 1D- and 2D- gel electrophoresis and confronted to twenty sera from individuals with respiratory allergy during the AAP season. Candidate allergens were detected using the serum from an allergic patient with clinical history of AAP pollinosis. IgE-binding spots were identified using MALDI-TOF/TOF mass spectrometry and database searching. According to our results, AAP extracts were rich in proteins (up to 16.25mg/ml) with a molecular-weight distribution ranging from 10 to 175kDa. Two-D electrophoresis of AAP extracts revealed 125 protein spots from which 13 were IgE reactive. These IgE-binding proteins were identified as enolase, calreticulin, probable pectate lyase 6, conserved hypothetical protein and ras-related protein RHN1-like. By our knowledge, this study is the first report identifying AAP allergens. These findings will open up further avenues for the diagnosis and immunotherapy of the AAP allergy as well as for the cloning and molecular characterization of relevant allergens.

BIOLOGICAL SIGNIFICANCE

Ailanthus altissima colonizes new areas every year in Iran and is spreading aggressively worldwide. According to USDA, the tree of heaven is now present as an invasive plant in 30 states in US (www.invasivespeciesinfo.gov/plants/treeheaven.shtml) and come to dominate large areas in many regions. Up to now, several cases of allergy to A. altissima pollen have been reported in United States, Italy and Iran [1-4]. However, there is still no information on the sensitizing allergens and the molecular origin of these clinical symptoms, which constitutes a serious threat to patients suffering from respiratory allergies in these regions. To our knowledge, the current study describes, therefore, the first panel of proteins responsible for IgE-mediated A. altissima pollinosis by using a gel-based proteomic approach. This work represents the pioneer proteomic investigation on Simaroubaceae spp. and provides useful insights for further studies on the allergens of this widely distributed plant family.

Cloning and expression of Aca f 1: a new allergen of Acacia farnesiana pollen

Acacia farnesiana is the main source of allergenic pollen and one of the most important causes of respiratory allergic disease in tropical and subtropical regions of the world. The purpose of this study was to produce a recombinant variety of allergenic Ole e 1-like protein from the pollen of this tree. To predict its allergenic cross-reactivity with other members of the Ole e 1-like protein family of common allergenic plants, the nucleotide sequence homology of the Acacia Ole e 1-like protein was evaluated. Amplification of cDNA strands encoding Acacia Ole e 1-like protein was performed by polymerase chain reaction (PCR) and sequenced. Following expression in Escherichia coli using the pET-21b(+) vector, the recombinant protein was purified using metal-affinity chromatography. IgE-binding competence of purified recombinant Ole e 1- like protein (rAca f 1) was analysed by immunoassay using 25 sera collected from Acacia pollen-sensitised patients. Nucleotide sequencing revealed an open reading frame of 453 bp encoding 150 amino acid residues that belonged to the Ole e 1-like protein family, and 11 patients (44%) had considerable specific IgE levels for the rAca f 1. Immunodetection and inhibition assays indicated that the purified rAca f 1 may be the same as that in the crude extract. Aca f 1, the second allergen from Acacia pollen, was identified as a member of the family of Ole e 1-like protein. A high degree of homology was found among amino acid sequences of Aca f 1 and several allergenic members of Ole e 1-like protein family.

Identification and Prevalence of Allergic, Nonallergic, and Local Allergic Rhinitis Patients in Western Area, Saudi Arabia

OBJECTIVES

To evaluate the diagnostic yield of skin prick test (SPT) and serum total immunoglobulin E (IgE) antibodies level in patients with allergic rhinitis (AR) and the role of nasal provocation test (NPT) for the determination of local allergic rhinitis (LAR) in patients with nonallergic rhinitis (NAR).

METHODOLOGY

This multi-center study included 1230 patients with clinical manifestations for ≥2 years. Patients were classified according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) and scored according to the quantitative Score for Allergic Rhinitis (SFAR). The SPT and total IgE antibody levels were done for all patients. Patients gave negative SPT underwent NPT, and its result was interpreted using Lebel Symptom Score Scale.

RESULTS

The SPT was positive in 77.8% of patients, mostly for grass pollen and dust mites. All patients were sensitive to multiple allergens. Median serum IgE antibody level for total study population was 162 IU/ml. Forty-two patients (3.4%) with negative SPT showed a weak response to NPT, while 231 patients (18.7%) with negative SPT had a high response to NPT and were considered to have LAR.

CONCLUSION

The SPT could discriminate between AR and NAR patients. The NPT could identify LAR in 84.6% of patients with rhinitis among those considered as NAR.

Sensitization Rates for Various Allergens in Children with Allergic Rhinitis in Qingdao, China

The aim of this study was to determine the prevalence of sensitization to common allergens in children with allergic rhinitis (AR) living in Qingdao, China. We conducted a retrospective analysis for AR cases, who underwent skin prick tests (SPT) in Qingdao. A total of 2841 children with AR qualified for the inclusion criteria (Age 3-5 years: 1500 children; Age 6-12 years: 1341 children). The most common inhaled allergens to which the AR children were sensitive were Dermatophagoides pteronyssinus (69.3%), Dermatophagoides farinae (66.2%) and mould 1 (Penicillium notatum 38.9%); while the corresponding ingested allergens were mussel (39.2%), shrimp (36.3%) and carp (36.5%). The prevalence of sensitization to inhaled allergens and food allergens was higher in children >6 years of age as compared to that in children 3-5 years of age (all p < 0.05). Children >6 years old were more sensitive to dust mite as compared to children 3-5 years old (p < 0.05). Sensitization to dust mite was more common in males than in females (p = 0.05). In this study, Dermatophagoides pteronyssinus and Dermatophagoides farinae were the most common allergens causing AR in children in Qingdao, China. Older children with AR, particularly males, were found to be more sensitive to dust mite.

Prevalence and triggers of allergic rhinitis in the United Arab Emirates

BACKGROUND AND OBJECTIVES

Allergic rhinitis is a morbid condition that is frequently overlooked by patients and physicians. This type of atopy has not been adequately investigated in the United Arab Emirates.

METHODS

This cross-sectional, population-based observational study was conducted in the seven Emirates (Abu Dhabi, Dubai, Sharjah, Ajman, Umm Al-Quwain, Ras Al-Khaimah, and Fujairah). It used the European Community Respiratory Health Survey (ECRHS II) to screen for allergic rhinitis in people living in this region.

RESULTS

Symptoms of allergic rhinitis were present in 85 (7%) of the 1,229 study population. Only 33 (39%) patients received treatment. Seventy-six (89%) patients had asthma. Thirty-seven (44%) patients were poly-sensitized. Symptoms were aggravated by dust (59%), grass/pollens (44%) and proximity to animals (21%). Winter was the peak season (37%), followed by spring (30%), autumn (18%) and summer (15%). Grass/pollen allergies were clustered in the winter, spring and summer (p ≤ 0.001). Dust was non-seasonal (p ≥ 0.121) and animal allergy was worse in the winter (p = 0.024) and spring (p = 0.044). Spring symptoms were less common in people living in the inner city (p = 0.003).

CONCLUSIONS

At least 7% of the studied population had allergic rhinitis. Most (71%) of these patients had environmental triggers and remained untreated. Allergic rhinitis awareness and measures to control allergens and dust are needed. The impact of preventing allergic rhinitis on other common atopies in the region deserves future studies.

Immunochemical characterization of acacia pollen allergens and evaluation of cross-reactivity pattern with the common allergenic pollens

Pollen from the Acacia has been reported as an important source of pollinosis in tropical and subtropical regions of the world. The aim of this study was to characterize the IgE binding protein of Acacia farnesiana pollen extract and evaluate cross-reactivity with the most allergenic pollens. In this study, pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting and specific ELISA using forty-two Acacia allergic patients. Potential cross-reactivity among Acacia and selected allergenic plants was evaluated with ELISA and immunoblotting inhibition experiments. There were several resolved protein fractions on SDS-PAGE which ranged from 12 to 85 kDa. Several allergenic protein bands with molecular weights approximately between 12 and 85 kDa were recognized by IgE-specific antibodies from Acacia allergic patients in the immunoblot assay. The inhibition by the Prosopis juliflora pollen extract was more than those by other pollen extracts. Moreover, the wheal diameters generated by the Acacia pollen extract were highly correlated with those of P. juliflora pollen extracts. The findings suggest that several proteins such as 15, 23, 45, and 50 kDa proteins could be used as diagnostic and therapeutic reagents for patients allergic to A. farnesiana and P. juliflora.

[Choosing the best panel of aeroallergen prick-tests for patients in Lebanon with rhinitis and asthma: A retrospective study of 2350 patients]

INTRODUCTION

The aim of this study was to evaluate the profile of skin prick-test reactivity to different aeroallergens in patients with rhinitis and asthma in Lebanon and its geographic variation within the country. It was also to suggest a minimal panel of allergens that should be used to detect sensitized patients.

METHODS

All patients who underwent skin prick-testing, because of rhinitis and/or symptoms suggesting asthma, between 2004 to 2011 in the hôtel-Dieu de France university hospital of Beirut, were studied. The total number of patients was 2350 and all were tested with the same panel of 24 aeroallergens. A further series of 208 patients were added because Cupressaceae antigens were not included in the initial series.

RESULTS

The overall rate of sensitization to any allergen was 75.6%. A battery of eleven allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia, Parietaria, grass, Salicaceae, oak, Oleaceae, dog, cat, and cockroaches) was found to identify sensitized patients with a sensitivity of 96% and a negative predictive value of 90%. Cupressaceae should be added to this battery in view of the results of the additional series. The Bekaa region had a unique profile of sensitization.

CONCLUSION

Twelve allergens are able to detect almost all sensitized patients suffering from respiratory symptoms in Lebanon.

Evaluation of the level of house dust mite allergens, Der p 1 and Der f 1 in Iranian homes, a nationwide study

BACKGROUND

Exposure to house dust mites (HDMs) is a major risk factor for the development of allergic symptoms. HDMs are worldwide in distribution. Assessing these allergens in each area is a critical step in evaluating the risk of sensitisation and controlling allergic symptoms. The aim of the present study was to evaluate the level of major HDMs, Der p 1 and Der f 1, in various parts of Iran.

METHODS

In 2009, 257 dust samples were obtained from living rooms' carpets in seven cities throughout Iran with different geoclimatic conditions. The level of Der p 1 and Der f 1 was measured by commercial ELISA.

RESULTS

Detectable level of Der p 1 and Der f 1 levels were only found in Gorgan and Sari, two cities near the Caspian Sea with moderate temperatures and high relative humidity. In both of these cities, Der f 1 was more frequent than Der p 1 (100% vs. 85%) and was found to be at a higher level than Der p 1 (geometric mean 3128 vs. 439ng/g dust, P<0.001).

CONCLUSION

The results of this study confirm that house dust mites in Iran are restricted to the Caspian Sea coastal areas, and in other parts, due to seasonal variations of temperature and humidity mites are not able to grow well and therefore are not an important risk factor for sensitisation and respiratory allergies.

The most common aeroallergens in a tropical region in Southwestern Iran

Background

Respiratory allergies are the most important public health issues in the world. They are caused by aeroallergens which play great role in pathogenesis of respiratory allergic diseases.

Methods

The current study was conducted to evaluate the prevalence of positive skin test for various aeroallergens among allergic patients in Ahvaz, southwest Iran. 299 participants with allergic rhinitis (seasonal or perennial) were selected. Skin prick test using twenty three common allergen extracts was performed on all patients.

Results

The overall frequency of sensitization to any allergen was 85.6%. In outdoor allergens the most prevalent aeroallergen category was weeds (89%) followed by tree and grasses, and in indoor allergens, mites (43%) were the most prevalent aeroallergen. The mean and median numbers of positive test reactions among those with positive test responses were 11.5 and 13.0, respectively. 84% of patients were poly-sensitised and about 50% of them were sensitised to more than twelve different allergens.

Conclusion

The results of the study revealed that prevalence of the skin prick reactivity to weed pollens is significant in southwest Iran and multiple sensitizations were common.

The prevalence of allergic fungal rhinosinusitis in sinonasal polyposis

Allergic fungal sinusitis (AFS) is a noninvasive form of fungal rhinosinusitis with a prevalence of 6-9 % among all rhinosinusitis cases requiring surgery. The fungi causing AFRS have a great diversity and regional variation in the incidence of AFS has been reported worldwide. The aim of this study was to evaluate the prevalence of AFS among rhinosinusitis patients in the north east of Iran. In a prospective cross-sectional study 127 patients with sinonasal polyposis who were candidates for surgery were recruited. All cases were evaluated by sinonasal CT scan, Prick test for common regional allergens, total serum immunoglobulin E (IgE) level, and allergic mucin culture for fungi in suspected cases. Data analyses were done using SPSS version 13.0. Their mean age was 37.4 ± 11.6 years, the male-to-female ratio was 69/58. Eleven patients (9.45 %) met the AFS criteria. Nine cases had a positive culture for Aspergillus specimen and three for Alternaria. Prick test was positive for at least one allergen in 28 cases (22.05 %). The most common allergen was weed. The total IgE level was significantly higher in AFS patients. This study showed the prevalence of AFS among patients with nasal polyposis to be 9.45 %.

Sensitization to indigenous pollen and molds and other outdoor and indoor allergens in allergic patients from saudi arabia, United arab emirates, and Sudan

Background

Airborne allergens vary from one climatic region to another. Therefore, it is important to analyze the environment of the region to select the most prevalent allergens for the diagnosis and treatment of allergic patients.

Objective

To evaluate the prevalence of positive skin tests to pollen and fungal allergens collected from local indigenous plants or isolated molds, as well as other outdoor and indoor allergens in allergic patients in 6 different geographical areas in the Kingdom of Saudi Arabia (KSA), the United Arab Emirates, and Sudan.

Materials and methods

Four hundred ninety-two consecutive patients evaluated at different Allergy Clinics (276 women and 256 men; mean age, 30 years) participated in this study. The selection of indigenous allergens was based on research findings in different areas from Riyadh and adjoining areas. Indigenous raw material for pollen grains was collected from the desert near the capital city of Riyadh, KSA. The following plants were included: Chenopodium murale, Salsola imbricata, Rumex vesicarius, Ricinus communis, Artiplex nummularia, Amaranthus viridis, Artemisia monosperma, Plantago boissieri, and Prosopis juliflora. Indigenous molds were isolated from air sampling in Riyadh and grown to obtain the raw material. These included the following: Ulocladium spp., Penicillium spp., Aspergillus fumigatus, Cladosporium spp., and Alternaria spp. The raw material was processed under Good Manufacturing Practices for skin testing. Other commercially available outdoor (grass and tree pollens) and indoor (mites, cockroach, and cat dander) allergens were also tested.

Results

The highest sensitization to indigenous pollens was detected to C. murale (32%) in Khartoum (Sudan) and S. imbricata (30%) and P. juliflora (24%) in the Riyadh region. The highest sensitization to molds was detected in Khartoum, especially to Cladosporium spp. (42%), Aspergillus (40%), and Alternaria spp. (38%). Sensitization to mites was also very prevalent in Khartoum (72%), as well as in Abu Dhabi (United Arab Emirates) (46%) and Jeddah (KSA) (30%).

Conclusions

The allergenicity of several indigenous pollens and molds derived from autochthonous sources was demonstrated. Prevalence studies in different regions of KSA and neighbor countries indicate different sensitization rates to these and other outdoor and indoor allergens.

Prevalence and diversity of allergic rhinitis in regions of the world beyond Europe and North America

BACKGROUND

There is comparatively little information in the public domain on the diversity in prevalence and triggers/factors associated with allergic rhinitis (AR) or allergic rhinoconjunctivitis (AR/C) in countries beyond western-Europe and North America.

OBJECTIVE

To review the prevalence and the sensitizing agents/triggers and factors associated with AR/C in several countries in Africa, the Asia-Pacific region, Australia, Eastern Europe, Latin America, Middle East and Turkey.

METHODS

Articles published in English in peer-reviewed journals were assessed and selected for further review, following an extensive literature search using the Medline database.

RESULTS

This review demonstrated that prevalence of AR and AR/C in these regions has predominantly been investigated in children; with studies indicating wide inter- and intra-regional variations ranging from 2.9% AR and 3.8% AR/C in 10-18-years-old children from one region in Turkey to 54.1% AR and 39.2% AR/C in 13-14-years-old children in one region in Nigeria. Moreover, the prevalence of AR and AR/C has increased markedly over the last decade particularly in some of the more affluent African countries, China-Taiwan and several Middle East countries, likely as a consequence of improved living standards leading to increased exposure to multiple traditional and non-traditional sensitizing agents and risk factors similar to those noted in western-Europe and North America.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings suggest that the greater diversity in prevalence of AR or AR/C in populations in these regions is in contrast to the lower diversity of AR or AR/C in the 'western populations (USA and Europe), which tend to be more uniform. This review provides a comprehensive database of the important allergens and triggers which are likely to influence the prevalence of allergic rhinitis in these diverse regions, where the prevalence of allergic rhinitis is increasing and its adverse impact on the quality of life of affected individuals is increasingly recognised.

Identification of a new allergen from Amaranthus retroflexus pollen, Ama r 2

BACKGROUND

Pollinosis from Amaranthus retroflexus pollen is a common cause of respiratory allergy in Iran with a high positive rate (68.8%) among Iranian allergic patients. The aim of the present study was to evaluate the allergenicity of the A. retroflexus pollen profilin.

METHODS

Using sera from twelve patients allergic to A. retroflexus pollen, IgE-binding proteins from the A. retroflexus pollen extract was identified by immunoblotting. The cDNA of A. retroflexus pollen profilin was amplified, then cloned into the pET-21b (+) vector, expressed in Escherichia coli, and finally purified by metal affinity chromatography. The IgE-binding capacity of the recombinant protein was then analyzed by the ELISA, immunoblotting, and inhibition assays, as well as by the skin prick test (SPT).

RESULTS

Immunoblotting results indicated a 14.6kDa protein with IgE-reactivity to 33% (4/12) among A. retroflexus pollen-allergic patients. Nucleotide sequencing of the cDNA revealed an open reading frame of 399 bp encoding for 133 amino acid residues which was belonged to the profilin family and designated as Ama r 2. A recombinant Ama r 2 (rAma r 2) was then produced in E. coli as a soluble protein which showed a strong IgE-reactivity via ELISA confirmed by the SPT. Inhibition experiments revealed high IgE cross-reactivities with the profilins from other plants.

CONCLUSIONS

The profilin from the A. retroflexus pollen, Ama r 2, was firstly identified as an allergen. Moreover, rAma r 2 was produced in E. coli as a soluble immunoreactive protein with an IgE-reactivity similar to that of its natural counterpart.

Diagnosis of Chenopodium album allergy with a cocktail of recombinant allergens as a tool for component-resolved diagnosis

Chenopodium album pollen is one of the main sources of pollen allergy in desert and semi-desert areas and contains three identified allergens, so the aim of this study is comparison of the diagnostic potential of C. album recombinant allergens in an allergenic cocktail and C. album pollen extract. Diagnostic potential of the allergenic cocktail was investigated in 32 individuals using skin prick test and obtained results were compared with the acquired results from C. album pollen extract. Specific IgE reactivity against the pollen extract and allergenic cocktail was determined by ELISA and western blotting tests. Inhibition assays were performed for the allergenic cocktail characterization. The exact sensitization profile of all patients was identified which showed that 72, 81 and 46% of allergic patients had IgE reactivity to rChe a 1, rChe a 2 and rChe a 3, respectively. Almost all of C. album allergic patients (30/32) had specific IgE against the allergenic cocktail. In addition, there was a high correlation between IgE levels against the allergenic cocktail and IgE levels against the pollen extract. The allergenic cocktail was able to completely inhibit IgE binding to natural Che a 1, Che a 2 and Che a 3 in C. album extract. In addition, positive skin test reactions were seen in allergic patients that tested by the allergenic cocktail. The reliable results obtained from this study confirmed that the allergenic cocktail with high diagnostic potential could be replaced with natural C. album allergen extracts in skin prick test and serologic tests.

Chenopodium album pollen profilin (Che a 2): homology modeling and evaluation of cross-reactivity with allergenic profilins based on predicted potential IgE epitopes and IgE reactivity analysis

The inhalation of Chenopodium album (C. album) pollen has been reported as an important cause of allergic respiratory symptoms. The aim of this study was to produce the recombinant profilin of C. album (rChe a 2) pollen and to investigate its cross-reactivity with other plant-derived profilins based on potential conformational epitopes and IgE reactivity analysis. Che a 2-coding sequence was cloned, expressed, and purified using one step metal affinity chromatography to recover high-purity target protein. We assessed cross-reactivity and predicted IgE potential epitopes among rChe a 2 and other plant-derived profilins. Immunodetection and inhibition assays using sixteen individual sera from C. album allergic patients demonstrated that purified rChe a 2 could be the same as that in the crude extract. The results of inhibition assays among rChe a 2 and other plant-derived profilins were in accordance with those of the homology of predicted conserved conformational regions. In this study, amino acid sequence homology analysis showed that a high degree of IgE cross-reactivity among plant-derived profilins may depend on predicted potential IgE epitopes.