Asthma in the desert: spectrum of the sensitizing aeroallergens

Food and Aeroallergen Sensitization in IgE -Mediated Asthma in Egypt

Purpose:

Identifying the distribution of allergens is valuable to the effective diagnosis and treatment of allergic disease. So, our aim is to explore the sensitization of food and aeroallergens in Egyptian patients with atopic asthma.

Methods:

Cross-sectional study recruited 268 Egyptian patients with atopic asthma. Asthmatic patients were assessed by the enzyme allegro sorbent test (EAST) method for specific IgE to a panel of 19 common regional inhaled allergens and 15 food allergens.

Results and Discussion:

One hundred percent of the patients were sensitive to at least one allergen. Allergy to food allergens only was 2.9%; inhaled allergens only were 26.2% and both were70.9%. Fungi (62%) were the most frequent sensitizing aeroallergen amongst our asthmatic patients, followed by the pollen allergens (42.5%) and house dust mites (HDMs) (26%). Cows’ milk (30.5%) was the most frequent sensitizing food amongst our asthmatic patients, followed by eggs (22.4%) and fish (21.6%). Mono-sensitized patients accounted for 6.7% of all cases, while polysensitized was 93.3%. Moderate and severe asthma showed a significantly higher frequency of polysensitization compared to mild asthma.

Conclusion:

Fungi and cow's milk are the chief sensitizing allergens in Egyptian patients with atopic asthma. This study represents the first report of sensitization in atopic adult asthma using a large extract panel in Upper Egypt.

Novel Mouse Models of Fungal Asthma

Alternaria alternata is a ubiquitous fungus and a major allergen associated with the development of asthma. Inhalation of intact spores is the primary cause of human exposure to fungal allergen. However, allergen-rich cultured fungal filtrates are oftentimes used in the current models of fungal sensitization that do not fully reflect real-life exposures. Thus, establishing novel spore exposure models is imperative. In this study, we established novel fungal exposure models of both adult and neonate to live spores. We examined pathophysiological changes in the spore models as compared to the non-exposure controls and also to the conventional filtrate models. While both Alternaria filtrate- and spore-exposed adult BALB/c mice developed elevated airway hyperresponsiveness (AHR), filtrates induced a greater IgE mediated response and higher broncholavage eosinophils than spores. In contrast, the mice exposed to Alternaria spores had higher numbers of neutrophils. Both exposures induced comparable levels of lung tissue inflammation and mucous cell metaplasia (MCM). In the neonatal model, exposure to Alternaria spores resulted in a significant increase of AHR in both adult and neonatal mice. Increased levels of IgE in both neonatal and adult mice exposed to spores was associated with increased eosinophilia in the treatment groups. Adult demonstrated increased numbers of lymphocytes that was paralleled by increased IgG1 production. Both adults and neonates demonstrated similarly increased eosinophilia, IgE, tissue inflammation and MCM.

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.

Prevalence of Aeroallergens in Allergic Rhinitis in a Tertiary Care Hospital

INTRODUCTION

The prevalence of allergic rhinitis has increased significantly globally over the last two decades. Detection of sensitizing aeroallergens plays a crucial role in the diagnosis and management of this troublesome disease. This study aims to investigate the spectrum of aeroallergens sensitization in patients with allergic rhinitis in a tertiary care hospital.

METHODS

A descriptive cross-sectional study conducted in the Department of Otorhinolaryngology of our hospital between January 2016 to December 2019. Ethical approval was taken from the Institutional Review Committee (No: 210/19). Patients diagnosed with allergic rhinitis were enrolled using the convenience sampling technique. Data entry and analysis was done using IBM Statistical Package for Social Sciences version 20.0.

RESULTS

Among 170 patients, altogether 103 (60.6%) patients yielded positive responses on the skin prick test. The most prevalent aeroallergens were Lepidoglyphus 86 (50.60%), Dermatophagoides pteronyssinus 85 (50%), Dermatophagoides farina 82 (48.20%), Thyrophagus 50 (29.40%), Blomia 46 (27.10%), Acarus 43 (25.30%), cat dander 26 (15.30%), dog dander 24 (14.10%), cow and buffalo dander 20 (11.8%), ragweed 20 (11.8%), grass pollen 18 (10.60%) and mugwort 17 (10%).

CONCLUSIONS

This study highlights that the frequency of aeroallergens based on skin prick test in patients presenting to a tertiary care hospital which showed the dominance of house dust mites, dog and cat hair, pollen, and grasses. Reduced exposure and training of patients about protection against these agents will possibly help in controlling the severity of allergic rhinitis in this region.

Health in dust belt cities and beyond-an essay by Nick Middleton

Desert dust is associated with morbidity and mortality, and distant spread means lessons for mitigating the harms can be found by looking beyond cities in arid regions, writes Nick Middleton

ARIA 2019 Care Pathways for Allergic Rhinitis in the Kuwait Health Care System

A worldwide increase in prevalence of allergic diseases has led to adaptations in national and international health care systems. ARIA (Allergic Rhinitis and Its Impact on Asthma) initiative develops internationally applicable guidelines for allergic respiratory diseases. In collaboration with international initiatives, ARIA offers updates of real-life integrated care pathways (ICPs) for digitally assisted, integrated, and individualized treatment of allergic rhinitis (AR). This article presents certain aspects of the health care system in Kuwait with reference to the management of AR and the objective of introducing ICPs and adopting the latest ARIA recommendations. Guidelines for ICPs include aspects of patients and health care providers and cover key areas of management of AR. This model of guidelines supports real-life health care better than traditional models. ARIA recommendations will be locally integrated in the health care system with the aim of improving both pharmacotherapy and allergy immunotherapy.

The association between airborne pollen monitoring and sensitization in the hot desert climate

Background

Pollen is a major cause of allergic respiratory diseases. In Qatar, data on the presence and prevalence of allergenic airborne types of pollen is quite limited.

Methods

The study aimed to determine and correlate the most frequently implicated airborne pollen detected by aerobiological monitoring samplers in respiratory allergy symptoms. An aerobiological survey was started on May 8, 2017. Airborne pollen was collected using two Hirst type seven-day recorder volumetric traps. Skin prick test in patients attending allergy clinics in Doha using commercial extracts was conducted.

Results

Twenty-five pollen types representing the native, as well as the introduced plants, with a relatively low daily mean concentration were observed from May 2017 to May 2019. The highest pollen concentrations were reached by Amaranthaceae (58.9%), followed by Poaceae (21.7%). SPT revealed a comparatively higher degree of sensitization to pollen. Among 940 patients, 204 were sensitized to pollen (54% female) with 135 (66.2%) and 114 (55.8%) to Amaranthaceae and Poaceae, respectively. Some patients had polysensitization. There was a statistically significant association between Amaranthaceae, and asthma (r = 0.169, P = 0.016) and allergic rhinitis (r = 0.177, P = 0.012).

Conclusions

This is the first study to monitor airborne pollen in the state of Qatar. The main pollen detected were Amaranthaceae and Poaceae. Pollen may represent a possible exacerbating factor in adult patients with allergic diseases such as asthma and allergic rhinitis.

Prevalence of common sensitizing aeroallergens in Egyptian asthmatic patients

Background

Aeroallergens and food allergens play a key role in the pathogenesis of asthma; they are the target for future immunotherapy worldwide. Food allergens have been studied often in Egypt, but data are defective concerning the prevalent Egyptian aeroallergens that can be affected by the climatic conditions in Egypt. So, our study aimed to explore the dominant sensitizing aeroallergens in Egyptian patients with bronchial asthma.

Methods

Cross-sectional study performed on 122 Egyptian asthmatic patients. Sera from all patients were examined by enzyme allegro sorbent test (EAST) method for specific IgE to a panel of 18 inhaled allergens.

Results

Positive specific IgE to aeroallergens was detected in 43.44% of our patients. German cockroach (18.9%) was the most frequent sensitizing aeroallergen amongst our asthmatic patients, followed by the fungal allergens (15.57%) and house dust mites (HDMs) (13.93%).

Conclusion

German cockroach, fungi, and house dust mite are the chief sensitizing aeroallergens in Egyptian asthmatic patients.

Trends of sensitization to aeroallergens in patients with allergic rhinitis and asthma in the city of Bursa, South Marmara Sea Region of Turkey

Background/aim

Allergic rhinitis (AR) and asthma are the most common allergic disorders worldwide. Aeroallergens are critical causative factors in the pathogenesis of these disorders and sensitization to aeroallergens differs in various countries and regions. Identification of the most common aeroallergen sensitization is crucial in the diagnosis and management of AR and asthma. We examined the distribution of aeroallergen sensitizations detected by skin prick tests (SPTs) in adult patients with AR and/or asthma in the city of Bursa.

Materials and methods

Five hundred forty-five patients who underwent a SPT and were diagnosed with rhinitis and/or asthma in the Uludağ University Faculty of Medicine’s Department of Immunology and Allergic Diseases Outpatient Clinic from March 2018 to August 2018 were retrospectively evaluated. SPTs with standard extracts including house dust mites, pollens, molds, animal dander, and latex were performed for patients.

Results

A total of 545 patients were included and most of the patients (270; 49.5%) were between 30 and 49 years of age. The prevalence of atopy was 57.9%. The most common aeroallergens detected in SPTs were Dermatophagoides farinae (50%) and D. pteronyssinus (44%), followed by grass-rye mix (43%), grass mix (38.6%), olive (33.2%), and wheat (32.3%). The sensitization to olive pollen was higher in cases of mild asthma (52%), while sensitization to D. farinae was higher in patients with mild and moderate asthma (54.5%, 54.2%) (P < 0.05) .

Conclusions

Our study revealed that house dust mite was the most common sensitizing aeroallergen in patients with AR and asthma while pollens were the most common allergen in patients with only AR. The sensitization to grass and olive pollen was higher in cases of mild asthma than moderate and severe. Regional allergy panels may provide important clinical clues for characteristics and courses of allergic diseases.

Invasive Mesquite (Prosopis juliflora), an Allergy and Health Challenge

Mesquite (Prosopis juliflora (Sw.) DC), is an medium-sized tree (family Fabaceae, subfamily Mimosoideae), that has been intorcuded around the world. It is a noxious invasive species in Africa, Asia, and the Arabian Peninsula and a source of highly allergenic pollen in. The present article reviews the adverse allergenic effects of P. juliflora pollen on human and animal health. Several studies have diagnosed that allergenic pollens from Prosopis spp. can provoke respiratory problems. Prosopis pollen extracts have 16 allergenic components of which nine proteins were recognized as major allergens with some of them showing cross-reactivity. Clinically, understanding Prosopis pollen production, flowering seasonality, pollen load, and dispersal in the atmosphere are important to avoid allergic consequences for local inhabitants. Climate change and other pollution can also help to further facilitate allergenic issues. Furthermore, we document other human and animal health problems caused by invasive Prosopis trees. This includes flesh injuries, dental and gastric problems, and the facilitation of malaria. This review summarizes and enhances the existing knowledge about Prosopis flowering phenology, aeroallergen, and other human and animal health risks associated with this noxious plant.

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.

House Dust Mite Allergy Under Changing Environments

Environmental variations induced by industrialization and climate change partially explain the increase in prevalence and severity of allergic disease. One possible mechanism is the increase in allergen production leading to more exposure and sensitization in susceptible individuals. House dust mites (HDMs) are important sources of allergens inducing asthma and rhinitis, and experimentally they have been demonstrated to be very sensitive to microenvironment modifications; therefore, global or regional changes in temperature, humidity, air pollution or other environmental conditions could modify natural HDM growth, survival and allergen production. There is evidence that sensitization to HDMs has increased in some regions of the world, especially in the subtropical and tropical areas; however, the relationship of this increase with environmental changes is not so clear as has reported for pollen allergens. In this review, we address this point and explore the effects of current and predicted environmental changes on HDM growth, survival and allergen production, which could lead to immunoglobulin E (IgE) sensitization and allergic disease prevalence. We also assess the role of adjuvants of IgE responses, such as air pollution and helminth infections, and discuss the genetic and epigenetic aspects that could influence the adaptive process of humans to drastic and relatively recent environmental changes we are experiencing.

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.

THE ROLE OF TARGET ORGAN DIAGNOSTIC APPROACH IN SEASONAL ALLERGIC RHINITIS: NASAL SMEAR EOSINOPHILS

BACKGROUND

Allergic rhinitis (AR) related to local weeds pollen sensitization (Chenopodiaceous family) is the most common cause of respiratory allergy in Kuwait. Local nasal accumulation of different cells typical of allergic inflammation is responsible for clinical symptoms of AR. Although nasal smear for Eosinophils (NSE) is one of the earliest included valuable test in diagnosis of AR, with time is underestimated.

AIM

Explore possible correlation of natural pollen allergen stimulation with appearance and quantity of Eosinophils in nasal smear.

METHODS

A group of randomly selected patients with clinical history suggestive for seasonal AR (SAR), who came to Al Rashed Allergy Center in period from October 2014 to October 2015, obtain Nasal Smear for Eosinophils as a screening test before further diagnostic evaluation. Nasal samples were collected by passing a sterile swab, from each nasal cavity, along the medial surface of the inferior turbinate 2 to 3 times and the specimen smeared on a clear glass slide. Nasal smears were examined by light microscopy after staining with hematoxylin and eosin stain. Skin prick test is performed in all symptomatic patients with a battery of inhalant allergens that include local pollens. The control group was recruited, with their voluntary consent, from the medical stuff with a negative history of any allergic nasal symptoms. In this group we performed only nasal smear for Eosinophils. Air Biology Laboratory Kuwait provided us with daily pollen count.

RESULTS

From total 158 study participants, 132 had SAR symptoms and are divided in four groups. Fifth, control, group is non symptomatic. For 38.6% of symptomatic patients NSE were positive, while 45% of these patients have negative SPT. From 62.1% NSE negative patients, 37.8% have negative SPT. Our results showed expected positive correlation of NSE positive patients with pollen season in Kuwait, in SPT positive group. However, presence of Eosinophils in nasal smear was moderate to high also in patients with negative SPT during the highest peak of season, in contrast to control group.

CONCLUSION

NES showed moderate sensitivity, relatively high specificity and importance as screening test in SPT negative patients. Evaluation of AR demand wide and improved diagnostic approach due to significant number of SPT negative patients with positive NSE based on natural allergen stimulation. Our results emphasize locale allergic response of nasal mucosa and importance of target organ diagnostic approach.

Evaluation of allergenic potential for rice seed protein components utilizing a rice proteome database and an allergen database in combination with IgE-binding of recombinant proteins

Among 131 rice endosperm proteins previously identified by MS-based proteomics, most of the proteins showed low or almost no sequence similarity to known allergens in databases, whereas nine proteins did it significantly. The sequence of two proteins showed high overall identity with Hsp70-like hazel tree pollen allergen (Cor a 10) and barley α-amylase (Hor v 16), respectively, whereas the others showed low identity (28–58%) with lemon germin-like protein (Cit l 1), corn zein (Zea m 50 K), wheat chitinase-like xylanase inhibitor (Tri a XI), and kinase-like pollen allergen of Russian thistle (Sal k 1). Immuno-dot blot analysis showed that recombinant proteins for these rice seed homologs were positive in the IgE-binding, but not necessarily similarity dependent, from some allergic patients. These results suggest that utilization of proteome and sequence databases in combination with IgE-binding analysis was effective to screen and evaluate allergenic potential of rice seed protein components.

[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.

Environmental behaviour of airborne Amaranthaceae pollen in the southern part of the Iberian Peninsula, and its role in future climate scenarios

The Amaranthaceae family includes a number of species which, through a series of specific adaptations, thrive in salty soils, arid environments and altered human settlements. Their ability to tolerate high temperatures favours summer flowering, giving rise to the widespread involvement of Amaranthaceae pollen grains in summer allergies, both in Mediterranean Europe and in areas with arid climates. This study analysed a 21-year set of historical airborne Amaranthaceae pollen records for an area located in the southern part of the Iberian Peninsula, in order to chart species' environmental reaction to changing climate conditions which occurred in the last decades. Airborne pollen data were collected from January 1991 to December 2011 using a Hirst-type volumetric impact sampler. Results showed that Amaranthaceae pollen remained in the atmosphere for over 6 months along the year, from early spring until early autumn. The annual Pollen Index ranged from barely 200 grains to almost 2000 grains, and was strongly influenced by rainfall during the flowering period, which prompted the development of new individuals and thus an increase in pollen production. A trend was noted towards increasingly early pollen peak dates; peaks were recorded in August-September in years with summer rainfall, but as early as May-June in years when over 50% of annual rainfall was recorded in the months prior to flowering. The gradual decline in the annual Pollen Index over later years is attributable not only to growing urbanisation of the area but also to a change in rainfall distribution pattern. High maximum temperatures in spring were also directly related to the peak date and the Pollen Index. This ability to adapt to changeable and occasionally stressful and restrictive, environmental conditions places Amaranthaceae at a competitive advantage with respect to other species sharing the same ecological niche. An increased presence of Amaranthaceae is likely to have a greater impact on future scenarios for pollen allergy diseases associated with climate change.

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.

Allergenicity and cross-reactivity of booklice (Liposcelis bostrichophila): a common household insect pest in Japan

BACKGROUND

Booklice (Liposcelis bostrichophila) are a common household insect pest distributed worldwide. Particularly in Japan, they infest 'tatami' mats and are the most frequently detected insect among all detectable insects, present at a frequency of about 90% in dust samples. Although it has been hypothesized that they are an important indoor allergen, studies on their allergenicity have been limited.

METHODS

To clarify the allergenicity of booklice and the cross-reactivity of this insect allergen with allergens of other insects, patients sensitized to booklice were identified from 185 Japanese adults with allergic asthma using skin tests and IgE-ELISA. IgE-inhibition analysis, immunoblotting and immunoblotting-inhibition analysis were performed using sera from these patients. Allergenic proteins contributing to specific sensitization to booklice were identified by two-dimensional electrophoresis and two-dimensional immunoblotting.

RESULTS

The booklouse-specific IgE antibody was detected in sera from 41 patients (22% of studied patients). IgE inhibition analysis revealed that IgE reactivity to the booklouse allergen in the sera from one third of booklouse-sensitized patients was not inhibited by preincubation with extracts from any other environmental insects in this study. Immunoblotting identified a 26-kD protein from booklouse extract as the allergenic protein contributing to specific sensitization to booklice. The amino acid sequence of peptide fragments of this protein showed no homology to those of previously described allergenic proteins, indicating that this protein is a new allergen.

CONCLUSIONS

Sensitization to booklice was relatively common and specific sensitization to this insect not related to insect panallergy was indicated in this population.

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.

Climate change and health research in the Eastern Mediterranean Region

Anthropologically induced climate change, caused by an increased concentration of greenhouse gases in the atmosphere, is an emerging threat to human health. Consequences of climate change may affect the prevalence of various diseases and environmental and social maladies that affect population health. In this article, we reviewed the literature on climate change and health in the Eastern Mediterranean Region. This region already faces numerous humanitarian crises, from conflicts to natural hazards and a high burden of disease. Climate change is likely to aggravate these emergencies, necessitating a strengthening of health systems and capacities in the region. However, the existing literature on climate change from the region is sparse and informational gaps stand in the way of regional preparedness and adaptation. Further research is needed to assess climatic changes and related health impacts in the Eastern Mediterranean Region. Such knowledge will allow countries to identify preparedness vulnerabilities, evaluate capacity to adapt to climate change, and develop adaptation strategies to allay the health impacts of climate change.

Expression of the recombinant major allergen of Salsola kali pollen (Sal k 1) and comparison with its low-immunoglobulin E-binding mutant

BACKGROUND

The inhalation of Salsola kali pollen is an important cause of pollinosis during summer and early fall throughout desert and semi-desert areas. Sal k 1 has been previously reported as a major allergen of S. kali pollen. In this study, we produced the recombinant Sal k 1 and also its low IgE-binding mutant form. We further compared the IgE binding ability of these two recombinant molecules.

METHODS

The recombinant Sal k 1 and its low IgE-binding variant, obtained by three amino acid exchanges (R(142)-->S, P(143)-->A, D(144)-->V), were cloned and expressed in E. coli, as proteins fused with thioredoxin and His-tags, and then purified by Ni2+ affinity chromatography. The IgE-binding capacity of the wild-type and mutated rSal k 1 was compared using immunoblotting, ELISA and inhibition assays by ten sera from S. kali allergic patients. Moreover, in vivo IgE-reactivity was investigated by the skin prick test.

RESULTS

Both the recombinant and the mutated form of Sal k 1 were expressed in E. coli at a relatively high amount and soluble form. All sera recognized rSal k 1 via immunoassay analysis. In addition, inhibition assays demonstrated that the purified rSal k 1 was similar to its counterpart in the crude extract. The mutated rSal k 1 exhibited a reduced IgE-binding capacity against wild-type rSal k 1.

CONCLUSIONS

This study demonstrates that purified rSal k 1 is comprised of IgE-epitopes similar to that of its natural counterpart and that the mutated variant showed a reduced IgE-binding capacity based on in vitro assays and in vivo provocation testing.

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

BACKGROUND

Allergic rhinitis is the most common allergic disease with negative impacts on patients' quality of life. The prevalence and pattern of sensitisation vary between different countries and populations. Identification of the most prevalent aeroallergens in each area has a very important role in diagnosis and treatment of allergic rhinitis. Iran is a fairly large country with different geo-climatic conditions and there are no data about the most prevalent aeroallergen in Mashhad City, which is the second largest city in Iran, with a semiarid climate. The aim of this study was to evaluate the prevalence of positive skin test to various common aeroallergens among allergic rhinitis patients in the city of Mashhad.

MATERIALS AND METHODS

Skin prick tests were performed with 27 common regional aeroallergens including grass, weed, tree, mite and mould in 311 patients with allergic rhinitis.

RESULTS

The overall rate of sensitisation to any allergen was 81 %. 76 % of patients were poly-sensitised and weed and grass were the most prevalent allergens (77 % and 62 % respectively). Salsola Kali and mould were the most and the least prevalent individual allergens (72.5 % and 6.5 % respectively). Mean total IgE in patients with positive skin prick test was significantly higher than in patients without any positive skin prick test (308 vs 128 IU/mL, P = 0.016). 97 % of atopic patients were sensitised to Salsola kali and or Fraxinus americana.

CONCLUSIONS

Our work showed the importance of weeds, especially the Amaranthaceae and Chenopodiaceae families. Diagnosis of pollen allergy can be simplified by using a combination of a few common aeroallergens.

Genetic-environmental interactions in asthma and allergy: a study in a closed population exposed to different environments

BACKGROUND

Asthma and allergy are common chronic diseases caused by genetic and environmental factors.

OBJECTIVE

To study the effect of different environments on the prevalence of both diseases in an isolated founder population that resettled in different geographic and environmental areas (namely, the genetically homogeneous population that immigrated to Israel from Cochin, India, 50 years ago).

METHODS

Respiratory and allergy symptoms were recorded by a questionnaire. The relative contribution of genetic factors on asthma and allergy was established by comparing Cochin with non-Cochin Jews living in the Jerusalem mountains; the relative contribution of the environment was determined by comparing mountain Cochin Jews with those living in the desert. The study was conducted from January to October 2004.

RESULTS

A total of 983 individuals (481 mountain Cochins, 353 desert Cochins, and 149 non-Cochins) were studied. The overall prevalence of asthma in Cochins was 23.7%; and of allergy, 29.5%. The rate of asthma and/or allergy in Cochins in the mountains was significantly higher than in control non-Cochins. The rates of both asthma and allergy among Cochin Jews in the mountains were significantly higher than those among Cochin Jews in the desert, the former because of a higher prevalence of allergic asthma. The rates of nonallergic asthma and allergy without asthma were similar in both environments.

CONCLUSIONS

Two different asthma and allergy phenotypes were detected that share a distinct genetic background but differ in the environmental influences. Allergic asthma is strongly determined by both genetic and environmental factors, whereas nonallergic asthma or atopy without asthma is determined mainly by genetic factors and is less influenced by environmental factors.

Meteorological factors, aeroallergens and asthma-related visits in Kuwait: a 12-month retrospective study

BACKGROUND

The increasing prevalence of asthma in many countries has been related to weather factors and aeroallergen concentrations, but this has not been studied in Kuwait. We evaluated the effect of meteorological factors and the occurrence of aerobiologicals on the number of asthma cases in Kuwait.

METHODS

The number of daily asthma visits to the allergy center and emergency department at Al-Sabha Hospital for 1 year were examined on a monthly basis for correlation with major metereological factors (temperature, relative humidity, rain, wind speed and direction). Spore and pollen counts were collected hourly.

RESULTS

A total of 4353 patients received asthma treatment during the year. The highest pollen count was in the month of September with a maximum relative humidity of 47% and no precipitation, but with a high mean temperature of 39.7 degrees C. Pollen counts were higher in the late summer (September) and occurred with a high patient visit to the allergy center. Fungal spore counts were significantly higher in early winter (December). The high fungal spore count seemed related to with high relative humidity and high precipitation with a low mean average temperature of 19.7 degrees C. The increase number of patients with bronchial asthma visiting an emergency clinic during December was significantly associated with high aerial counts for fungal spores (P<.03), and the months of September and October were more significant for pollen.

CONCLUSION

This study indicates that meteorological factors, aeroallergen concentrations and asthma-related visits are interrelated. The results may prove useful in the generation of hypotheses and development of designs for more comprehensive, individual-based epidemiological studies.

Atmospheric movement of microorganisms in clouds of desert dust and implications for human health

Billions of tons of desert dust move through the atmosphere each year. The primary source regions, which include the Sahara and Sahel regions of North Africa and the Gobi and Takla Makan regions of Asia, are capable of dispersing significant quantities of desert dust across the traditionally viewed oceanic barriers. While a considerable amount of research by scientists has addressed atmospheric pathways and aerosol chemistry, very few studies to determine the numbers and types of microorganisms transported within these desert dust clouds and the roles that they may play in human health have been conducted. This review is a summary of the current state of knowledge of desert dust microbiology and the health impact that desert dust and its microbial constituents may have in downwind environments both close to and far from their sources.

A pectin methylesterase as an allergenic marker for the sensitization to Russian thistle (Salsola kali) pollen

BACKGROUND

Chenopodiaceae pollen is considered the main cause of pollen allergy in desert countries and its incidence is world-wide increasing by the desertization of extensive zones. Although the correlation between the sensitization to Chenopodium album and Salsola kali pollens of patients suffering from allergy to Chenopodiaceae pollens is high, a significant number of patients exhibited IgE sensitivity exclusively towards S. kali.

OBJECTIVE

To analyse this differential reactivity and to purify, clone and characterize the putative responsible allergen.

METHODS

Immunoblotting was used to analyse the IgE binding to pollen extract for S. kali and C. album. The protein was isolated by two chromatographic steps and characterized by Edman degradation, mass spectrometry, finger print analysis and Concanavalin A lectin staining. Specific cDNA was amplified by polymerase chain reaction, cloned in Escherichia coli and sequenced. Immunologic characterization was performed by immunoblotting, enzyme-linked immunoassay detection and inhibition experiments using sera from 11 patients allergic to S. kali pollen.

RESULTS

cDNA codifies for a mature protein of 339 amino acids plus a putative signal peptide of 23 residues and it belongs to the plant pectin methylesterase (PME) family. It is a mildly basic and polymorphic protein and was recognized by the IgE from all the patients allergic to S. kali included in the study, and was called Sal k 1. The protein was not recognized in the C. album pollen extract using the sera of these patients.

CONCLUSION

Sal k 1 is a protein from the PME family with a high allergenic relevance. Considering this allergen as responsible for the different sensitization between S. kali and C. album pollen, it may be a useful marker to classify patients allergic to Chenopodiaceae allowing a safer and more specific immunotherapy.

Possible reasons for lack of effect of allergen avoidance in atopy-prone infants and sensitive asthmatic patients

The basic paradigm that allergen exposure produces atopic sensitization, and that continued exposure leads to clinical asthma throughout the development of airway inflammation and bronchial hyperreactivity has been challenged. However, because it was observed that epidemiological evidence suggests that around 40% of asthma cases are attributable to atopy (even using restrictive criteria), the obvious corollary is that if allergen avoidance begins before the onset of sensitization (primary prevention), then it should be associated with a reduced number of new cases of the disease. However, there are conflicting results regarding the effect of allergen avoidance on primary prevention of atopic sensitization and asthma onset. Instead, more uniform and positive results are available from secondary prevention studies. Secondary prevention obviously is an attractive opportunity for pediatricians who may recognize the patients who might benefit from these interventions simply by screening for food allergy in young children with atopic dermatitis. The conflicting results of tertiary prevention are most frequently observed in adult patients and sometimes result from incomplete avoidance of allergens responsible for the sensitization.

Asthma and sensitization in a community with low indoor allergen levels and low pet-keeping frequency

BACKGROUND

Little is known about causes of asthma and sensitization in desert countries.

OBJECTIVE

To investigate risk factors associated with asthma and sensitization in Kuwait.

METHODS

One hundred sixty children (9-16 years) with physician-diagnosed asthma were recruited and matched (age, sex) with 303 healthy controls. Risk factors were assessed by questionnaires, determination of sensitization status (skin tests and IgE), and home allergen exposure (mite, cat, dog, cockroach; ELISA).

RESULTS

Home allergen levels and frequency of pet ownership were very low (cat, 4.1%; dog, 1.5%). The risk of cat sensitization increased significantly among cat owners (odds ratio [OR], 3.53; 95% CI, 1.33-9.41; P = .01), and in children with reported contact with cats during the first year of life (OR, 2.60; 95% CI, 1.17-5.80; P = .019). In the multivariate analysis, maternal atopy (OR, 1.77; 95% CI, 1.13-2.75; P = .01) and cat ownership (OR, 3.32; 95% CI, 1.19-9.25; P = .02) remained significant associates of cat sensitization. Current dog ownership significantly increased the risk of sensitization to dog (OR, 6.05; 95% CI, 1.33-27.54; P = .02). In the multivariate analysis, dog ownership remained the only significant associate of dog sensitization (OR, 6.02; 95% CI, 1.30-27.96; P = .02). Sensitization to Alternaria was the strongest independent associate of the asthma group. Family history of asthma, history of whooping cough, current cat ownership, and breast-feeding <2 months were other significant and independent risk factors for asthma.

CONCLUSIONS

Pet ownership markedly increased the risk of sensitization to pets. Despite low allergen exposure, the pattern of childhood asthma in Kuwait follows that described in Western communities (strong association with sensitization).

Che a 1: Recombinant Expression, Purification and Correspondence to the Natural Form

BACKGROUND

Pollinosis to chenopods is one of the main causes of allergy in desertic regions and it is increasing in the South of Europe and Western USA. Che a 1 is a major allergen for chenopod-allergic subjects and belongs to the Ole-e-1-like family of proteins.

METHODS

Pichia pastoris yeast has been used as expression system to produce the recombinant form of Che a 1 (rChe a 1). The allergen was isolated using a gel permeation column and reverse-phase/high-performance liquid chromatography. Molecular characterization was performed using Edman degradation, mass spectrometry and concanavalin A staining. Sera from patients allergic to chenopod pollen, as well as polyclonal and monoclonal antibodies raised against Ole e 1, were used in immunoblotting, ELISA and inhibition assays for immunological characterization of rChe a 1.

RESULTS

The allergen was purified to homogeneity with a final yield of 15 mg/l of cell culture and showed a glycosylated character. N-terminal amino acid sequence of rChe a 1 and molecular mass were according to those of the protein isolated from chenopod pollen. The recombinant allergen maintained the IgG and IgE epitopes of the natural allergen deduced from the immunological assays.

CONCLUSIONS

Structural and in vitro immunological properties of rChe a 1 produced in P. pastoris were equivalent to those of the natural form of the allergen and, thus, it could be used in testing patients allergic to chenopods.

Indoor airborne fungal spores and home characteristics in asthmatic children from Edirne region of Turkey

BACKGROUND

The contribution of indoor fungal exposure to childhood asthma is not completely clear.

OBJECTIVE

To investigate airborne fungal flora within the homes of asthmatic and control children, and to assess the influence of housing characteristics regarding indoor fungi.

METHODS

Forty-seven atopic asthmatic and 23 nonatopic control children were studied. Allergen sensitivity was determined by skin prick tests. A thorough assessment, using a questionnaire and inspection surveys, was carried out. Home visits were made between October 2000 and February 2001. Samples of airborne fungal spores were collected from four rooms by the "open Petri dish" method. Indoor temperature and humidity were measured.

RESULTS

The total indoor fungal colony counts from the living rooms and bedrooms were significantly higher in the asthma group than in controls (p = .012 and p = .003, respectively). The most commonly isolated genus was Cladosporium. Twelve of the asthmatic patients (25.53 %) were found to be sensitive to fungal allergens. The factors found to be associated with indoor fungal growth in logistic regression were visible fungal patches in the bathrooms [(odds ratio (OR) = 5.75; 95 % CI 1.19 to 27.70)], and the age of the house [OR = 4.24; 95 % CI 1.34 to 13.45]. Total fungal colony numbers did not correlate with indoor temperature or humidity.

CONCLUSION

Fungal colony numbers were higher in the homes of asthmatic children than in those of controls. Therefore, indoor fungal exposure may contribute to childhood asthma. Bathrooms were the main source of fungal propagules. Old houses were more prone to fungal growth.

The human allergens of mesquite (Prosopis juliflora)

Background

A computerized statistical analysis of allergy skin test results correlating patient reactivities initiated our interest in the cross-reactive allergens of mesquite tree pollen. In-vitro testing with mesquite-sensitized rabbits and a variety of deciduous tree pollens revealed so many cross-reactivities that it became apparent there could be more allergens in mesquite than previously described in the world literature. Our purpose was to examine the allergens of mesquite tree pollen (Prosopis juliflora) which elicit an IgE response in allergic humans so that future research could determine if these human allergens cross-react with various tree pollens in the same manner as did the mesquite antiserum from sensitized rabbits.

Methods

Proteins from commercial mesquite tree pollen were separated by polyacrylamide gel electrophoresis in the presence of sodium-dodecyl-sulphate. These mesquite proteins were subjected to Western blotting using pooled sera from ten mesquite-sensitive patients and goat anti-human IgE. The allergens were detected using an Amplified Opti-4-CN kit, scanned, and then interpreted by Gel-Pro software.

Results

Thirteen human allergens of mesquite pollen were detected in this study.

Conclusion

The number of allergens in this study of mesquite exceeded the number identified previously in the literature. With the increased exposure to mesquite through its use in "greening the desert", increased travel to desert areas and exposure to mesquite in cooking smoke, the possible clinical significance of these allergens and their suggested cross-reactivity with other tree pollens merit further study.

Salsola pollen as a predominant cause of respiratory allergies in Kuwait

BACKGROUND

Respiratory allergies are common in Kuwait, and the role of certain allergens has been previously documented.

OBJECTIVE

To evaluate the results of skin prick tests to a range of allergens that were considered relevant to the vegetation surveys and aerobiological studies performed in Kuwait.

METHOD

New patients attending our center during August 2002 to February 2003 with asthma or allergic rhinitis underwent skin prick tests to a battery of allergens.

RESULTS

A total of 451 patients aged 5 to 60 years (mean age, 29.5 years) were tested. Of these patients, 403 (89.4%) had a positive test result to at least one allergen and were considered allergic. A total of 76.7% of the allergic patients had a positive reaction to Salsola pollen, with a mean wheal diameter of 8.25 mm (median, 8 mm). Chenopodium album was positive in 57.6% and Bermuda grass was positive in 38.2% of the allergic cases. Indoor allergens seemed to play a lesser role than pollens: Dermatophagoides pteronyssinus was positive in only 37.5%, and American and German cockroaches were positive in 33.2% and 22.3%, respectively. All the allergens other than Salsola elicited a mean wheal diameter of less than 6.25 mm (median, < or = 6 mm).

CONCLUSIONS

Indoor allergens seem to play a lesser role in respiratory allergies in Kuwait. Most allergic patients become sensitized to pollens; the strongest and most frequent reaction is from Salsola pollen. Salsola imbricata is found growing extensively in most areas of the country, flowering mainly in autumn, when the most common pollen is of the Chenopod-Amaranth type and when most patients with seasonal allergic rhinitis become symptomatic.

Addressing the prevalence of respiratory allergy in the home environment

Respiratory allergy prevalence has always depended both on genetic predisposition and specific environmental allergenic stimulation that leads to sensitization and eventual symptomatic disease. Changes brought about by modern technology that have afforded a higher quality of life have also accidentally increased the levels of many respirable and ingestible allergens in the environment. In many cases these higher levels of exposure have exceeded individual thresholds, resulting in the phenotypic expression of allergy in many individuals who were previously asymptomatic even though they were genotypically predisposed to developing allergies. Prevalence can be decreased only if susceptible populations are identified as early as possible through careful family history taking and appropriate testing for sensitivity and if exposure to selected allergens is controlled.

Immunochemical characterization of Russian thistle (Salsola kali) pollen extracts. Purification of the allergen Sal k 1

BACKGROUND

Salsola kali (Russian thistle) is a weed which belongs to the Chaenopodiacea family. It is widely distributed along the coasts of Europe, North Africa, USA and Australia. The objectives of this study were to study the allergenic composition of S. kali pollen and to purify an important allergen from the pollen extracts of this plant.

METHODS

A population of 66 individuals with specific IgE-mediated allergic symptoms and positive skin tests to S. kali were included in the study. Specific IgE to S. kali was determined by direct enzyme-linked immunosorbent assay (ELISA). The antigenic and allergenic profile of S. kali was evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focussing (IEF) and immunoblot. Allergen purification was conducted by preparative SDS-PAGE. The allergenicity of the protein was evaluated by skin testing, direct ELISA, ELISA inhibition and immunoblots.

RESULTS

Specific IgE to S. kali was detected in 39 of the 66 individuals (59%). An allergen with a molecular weight of approximately 43 kDa was purified. This allergen was termed Sal k 1. A partial sequencing was obtained and no homology was found with other known proteins/allergens. The allergenicity of Sal k 1 was tested in vitro and in vivo. Of the 39 individuals with a positive specific IgE determination to S. kali, 26 (66.6%) had detectable specific IgE to Sal k 1. Twenty of these 39 individuals were skin-prick tested with the purified allergen (0.5 mg/ml) and all of them had a positive skin test to the purified allergen. Ten additional individuals, used as negative controls, had a negative response.

CONCLUSIONS

Sal k 1, an important allergen of S. kali, is recognized, in vitro, by approximately 67% of the patients sensitized to S. kali. Twenty patients with a positive skin test to a standardized S. kali extract had a positive reaction to the purified allergen.

A relatively high prevalence and severity of asthma, allergic rhinitis and atopic eczema in schoolchildren in the Sultanate of Oman

OBJECTIVES

Although asthma, allergic rhinitis and eczema are among the most common chronic diseases in children worldwide, there is very limited information about the burden of these conditions in Oman. The aim of this study was to determine the prevalence and severity of symptoms of asthma, allergic rhinitis and eczema in Omani schoolchildren using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase I questionnaire.

METHODS

An Arabic version of the ISAAC Phase I questionnaire was completed by parents of 3893 children aged 6-7 years and self-completed by 3174 children aged 13-14 years, randomly selected from a nationwide sample of public schools.

RESULTS

The prevalence rates of reported diagnoses of asthma, allergic rhinitis and eczema were higher in older children (20.7%, 10.5% and 14.4% compared with 10.5%, 7.4% and 7.5%, respectively, in young children). In young children, 277 were current wheezers and of these 40.8% had sleep-disturbing wheeze at least once a week and 45.1% had speech-limiting wheeze during the past year. Similarly, 283 older children were current wheezers, and of these 30.0% had sleep-disturbing wheeze at least once a week and 37.5% had speech-limiting wheeze during the past year. Exercise-induced wheeze was higher in older children (19.2% vs 6.9%; P < 0.001). Allergic rhinitis and eczema were also associated with significant sleep disturbance and limitation of activity in both age groups.

CONCLUSION

Allergic conditions in Omani schoolchildren are common and associated with significant morbidity. Further research is required to identify the local risk factors for allergy to allow better understanding and management of these conditions.

The prevalence of IgE antibody reactivity against the alkaline serine protease major allergen of Penicillium chrysogenum increases with the age of asthmatic patients

BACKGROUND

Penicillium species are prevalent airborne fungi. However, the prevalence of allergic sensitization to Penicillium antigens and the true impact of these ubiquitous fungi on atopic respiratory disorders remain to be determined.

OBJECTIVE

The purpose of this study was to analyze the prevalence of immunoglobulin (Ig)E and IgG antibodies against Penicillium chrysogenum (Pen ch 13), the alkaline serine protease major allergen of P. chrysogenum, in asthmatic patients of different age groups.

METHODS

Pen ch 13 was purified from a culture medium of P. chrysogenum. The reactivity of IgE and IgG antibodies to Pen ch 13 in the serum samples of 212 asthmatic patients was analyzed by immunoblotting methods.

RESULTS

Sixty-nine (33%) of the 212 sera analyzed showed IgE and/or IgG immunoblot reactivity to Pen ch 13. Significant differences in the prevalence of IgE and/or IgG antibody reactivity to Pen ch 13 were found among eight different age groups of 212 asthmatic patients. The frequency of IgE-binding reactivity to Pen ch 13 increased significantly with the age of the patients. It was 7% for the group less than 10 years old and 42% for the group older than 70 years old. In addition, a significant difference between the prevalence of IgE (7%) and IgG (33%) antibodies against Pen ch 13 in the group aged 10 or less was also found.

CONCLUSIONS

Our study demonstrates that IgE and IgG antibodies specific for Pen ch 13 were detected in approximately one-third of the 212 asthmatic patients analyzed. Our results suggest that allergic sensitization to Pen ch 13, and possibly to other airborne Penicillium species, is more common in older asthmatic patients.

Prevalence of immunoglobulin E for fungi in atopic children

BACKGROUND

The prevalence of sensitization to fungi in young atopic patients in relation to age and clinical importance is largely unknown.

OBJECTIVE

The aim of this study was to investigate the prevalence of sensitization to different fungi in atopic children in relation to age and other aeroallergens.

METHODS

A total of 137 atopic children (male 62%, female 38%; mean age 5 years and 9 months, range 5 months-14 years) were studied. Sera of all patients were routinely tested for total IgE and specific IgE against aeroallergens and milk. Positive sera were also tested for IgE against Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum and Penicillium chrysogenum, using the Pharmacia Enzyme CAP procedure.

RESULTS

In this study in atopic children total IgE showed a significant linear relation with age, whereas specific IgE against outdoor fungi, indoor fungi and house dust mite showed significant non-linearity with age. Prevalence of specific IgE for Cladosporium ranked first, followed closely by Aspergillus and Alternaria. Calculation of the sensitization of indoor and outdoor fungi showed maximum prevalence at 7.8 years, followed by lower values at higher ages. A similar significant relation was also found for Alternaria, while this relation was not significant for the other individual fungi. Specific IgE for indoor and outdoor fungi was associated with the presence of specific IgE for aeroallergen and milk. We found that all children aged 4 years and older showed IgE for house dust mite that did not decline with increasing age.

CONCLUSIONS

Sensitization to fungi is prevalent in childhood, with an age-dependent distribution reaching maximum values at 7.7-7.8 years, followed by a decline for all fungal sensitization with increasing age. The importance and relative contribution of fungal sensitization to airway disease, compared with the other allergens, remains to be established.