Animal Allergens Research Articles

Assessment of allergen-specific IgE by immunoblotting method in atopic dermatitis.

Background and Objectives. Stimulating the immune system by exposure to various allergens to produce specific IgE has a significant role in the pathogenesis of atopic dermatitis. Identifying disease-causing allergens, prevention of exposure to those allergens, and immunotherapy will play an important role in the treatment of Atopic Disease. The purpose of this study was to determine the common allergens of northwest of Iran in patients with atopic dermatitis that are resistant to treatment. Materials and methods. In this descriptive-analytical study, serum levels of total IgE and frequency of specific IgE were measured by Immunoblotting against 20 common allergens in 150 cases of patients with atopic dermatitis, attending to dermatology and asthma and allergy clinics from 2010 to 2011. The control group consisted of individuals who had been clinically healthy. Results. In the 90% of patients that were included in this study, total IgE levels were higher than in healthy people with mean serum levels of total IgE 227.51 ± 103 IU/ml. 136 patients (90.6%) had specific IgE for at least one allergen. The frequency of positive allergens among the patients who were included in this study were 53.34%, 26.8%, and 19.56% respectively in plants and fungus allergens group, animal allergens group and food allergens group. After avoiding of the allergens (which they had been sensitized to), 60% of patients were cured with immune therapy, and total IgE serum levels in the control group were not increased. Conclusion. Identifying the abundant allergens such as cultivated rye, Timothy grass, house dust mite, birch, cat, horse, potato, dog, egg white, cow milk, in order to advise patients to avoid them or to do immunotherapy and desensitization, is useful in this area.

Detecting Mycoplasma pneumoniae infections in nasopharyngeal specimens from Paediatric patients with asthma exacerbations in Baghdad: A Polymerase Chain Reaction – Gene based study

BackgroundNumerous viral infections have triggered acute asthma exacerbations. Despite the fact that diagnosis of M. pneumoniae infection is based on sero-prevalence studies but molecular diagnostic techniques, such as PCR, have offered improvements in sensitivity, specificity and rapidity over the latest methods. ObjectivesThe aim of this molecular study is to determine the infection rates of M. pneumoniae in acute asthma exacerbation in a group of Iraqi children from Baghdad and also to examine the correlation of the disease with different variable characteristics and symptoms. MethodsThis study included 94 children between 2 and 13years old; Fifty in-patient asthmatic children and 44 non-asthmatic children as control group who were out-patients of the same hospital. Throat and nasal swab samples were taken for DNA extraction and PCR procedures. ResultsPCR results show that 33.3% asthmatic patients were positive for M. pneumoniae while 66.7% were negative (p<0.001). 53.8% of M. pneumonia-positive asthmatic children were 2–5years while 46.2% were 6–14years old. Among asthmatic patients with positive PCR, 30.8% had positive history of seasonal pattern (p=0.026) and 69.2% have positive family history of atopy (p=0.05). ConclusionsFamily history of atopy has strong association with asthma (p=0.005), while factors such as sex, residence, seasonal allergen, animal allergen, passive smoking, mode of delivery or consanguinity has not been associated with asthma. M. pneumonia in a respective bulk among pediatric patients with asthma constituted an important risk factor for asthma exacerbation presented as cough and wheezy chest without fever or chest X-ray findings.

Respiratory Allergens from Furred Mammals: Environmental and Occupational Exposure.

Furry mammals kept as pets, farm and laboratory animals are important allergen sources. The prevalence of sensitization to furred mammals appears to be increasing worldwide. Several mammalian allergens from diverse species are well characterized with regard to their molecular structure and immunogenicity, and some are already available for component-resolved allergy diagnostics. The distribution of various mammalian allergens has been extensively studied during the past few decades. Animal allergens were found to be ubiquitous in the human environment, even in places where no animals reside, with concentrations differing considerably between locations and geographical regions. This review presents an overview of identified mammalian respiratory allergens classified according to protein families, and compiles the results of allergen exposure assessment studies conducted in different public and occupational environments.

Severity of Allergic Rhinitis and Body Mass Index: Is There Any Correlation?

Background : Allergic rhinitis is the inflammation of the nasal mucosa. It will be resulting in nasal itching, sneezing, discharge, or blockage which occurs for more than an hour on most days. Allergens such as plant pollens, fungi, animal allergens, and dust mites are the factors which initiate allergic rhinitis. There are many risk factors for allergic rhinitis, such as family history of atopic disease, asthma, age, gender and others. Besides, overweight is also considered one of the risk factors for developing allergic rhinitis. Thus, this study was conducted to investigate the correlation between allergic rhinitis and body mass index. Methods : This study involved a cross-sectional analytic study. Seventy three respondents both male and female medical students of Universitas Padjadjaran completed a questionnaire, and had their height and weight measured by a trained researcher. This study was carried out from September to October 2015. Statistical analyses were performed included the Rank Spearman test. Results : There was no significant relationship between allergic rhinitis and body mass index. Conclusions : There is no correlation between severity of allergic rhinitis and body mass index. [AMJ.2017;4(1):20–4] D OI: 10.15850/amj.v4n1.1018

Airborne exposure to laboratory animal allergens

Exposure to laboratory animal allergens remains a significant cause of IgE-mediated occupational allergy and asthma. Since 2005, we have measured the major mouse and rat allergens (mus m 1 and rat n 1) collected on filters from air sampling in a range of UK and non-UK animal facilities. Supplied core data allowed us to construct an anonymized database of atmospheric results in ng m–3 containing 3080 mouse and 1392 rat analyses. Roughly twice as many static samples compared to personal samples had been sent for analysis. The medians (90th percentiles) for the mouse and rat allergens employing personal atmospheric sampling were 2.6 (60.6) and 0.4 (12.4) ng m–3 respectively; for static samples the equivalent values were 0.2 (3.7) and 0.1 (1.4) ng m–3. Where unequivocal sample descriptors were provided with samples, results were categorised to activities/areas. Medians and 90th percentiles in these categories suggest that staff undertaking cleaning out, dumping of soiled bedding and cleaning cages can still have very substantial potential exposures in some facilities. The move to filtered cages appears to reduce general exposure, but filter changing and/or cleaning can lead to high exposures. In some facilities, animal receipt can cause significant exposures, as well as activities such as bleeding, culling and dosing; all activities involving the handling of animals outside of cages. We believe that the data presented may help those using air measurements in such facilities to improve their control of exposure to such aeroallergens, and thus reduce the risk of both sensitisation and subsequent allergic health problems, including the development of allergic asthma.

Clinical relevance of molecular diagnosis in pet allergy.

We describe the pattern of sensitisation to pet IgE components and its association with clinical symptoms. Hundred and fifty nine consecutive patients with rhinitis/asthma sensitised to dog, cat, and horse were recruited. Specific IgE to whole extracts and to pet recombinant allergens were performed. Only 5% of patients were monosensitised to animal allergens. Specific IgE to Can f 1 was significantly associated with persistent rhinitis, Can f 2 with asthma diagnosis, Can f 3 with moderate/severe rhinitis (M/S-R) and asthma diagnosis (AD), and Can f 5 with persistent and M/S-R. Positive IgE to Fel d 2 was significantly associated with M/S-R and AD, Equ c 1 with M/S-R and Equ c 3 with persistent rhinitis, AD and severe asthma. Sensitisation to ≥2 molecules or to pet albumins was associated with more severe respiratory symptoms. Molecular diagnosis in patients with pet allergy may also help clinicians to predict clinical symptoms and their severity.

Human memory CD4+ T cell response to the major dog allergen Can f 5, prostatic kallikrein.

Human CD4+ T cell responses to important animal allergens are still insufficiently understood. To comprehensively characterize invitro and exvivo the peripheral blood memory CD4+ T cell responses of subjects with and without allergy to the major dog allergen Can f 5, the only known animal allergen in the kallikrein family of proteins. Can f 5-specific memory CD4+ T cell lines (TCLs) were established from the peripheral blood of 12 subjects with and 12 subjects without allergy to Can f 5 and characterized for their functional and phenotypic properties. The results were evaluated with those obtained exvivo with a novel CD154 enrichment method. The epitopes recognized by the Can f 5-specific TCLs were determined with 72 overlapping 16-mer peptides covering the sequence of the allergen. Can f 5-specific TCLs were obtained at about tenfold higher frequency from allergic than from non-allergic subjects. Functionally, the TCLs of allergic subjects displayed a Th2-biased cytokine phenotype and increased T cell receptor avidity, whereas the TCLs of non-allergic subjects displayed a Th1-/Th0-biased cytokine phenotype and lower TCR avidity. The higher frequency and the Th2 phenotype of Can f 5-specific memory CD4+ T cells in allergic subjects were confirmed by the CD154 enrichment method exvivo. Six distinct T cell epitope regions of Can f 5 were predominantly recognized by the TCLs from allergic subjects. Can f 5-specific memory CD4+ T cell responses differ considerably between subjects with and without allergy, as assessed by both invitro and exvivo approaches. Peptides containing the dominant T cell epitopes of Can f 5 can be employed for developing peptide-based immunotherapy for dog allergy.

Allergen component analysis as a tool in the diagnosis of occupational allergy.

Rapid developments have been seen in molecular allergy diagnosis, based on the detection and quantification of specific IgE to single allergens. This review summarizes and discusses studies on allergen component analysis as a tool in the diagnosis of occupational allergy. More than 400 agents are identified as sensitizers of occupational asthma, but only very few are characterized on the molecular level and available for routine diagnosis. Baker's asthma is one of the most frequently occurring forms of occupational asthma caused by workplace-related inhalation of cereal flour mainly wheat. Wheat sensitization profiles of bakers show great interindividual variability and no wheat allergen could be classified as the major allergen. Component-resolved diagnosis is a useful tool for diagnosing natural rubber latex (NRL) allergy. In cases with unexpected high-latex IgE but without clinical symptoms application of crossreactive carbohydrate determinants are helpful to clarify the cause of IgE binding. Latex is an excellent model for component-resolved diagnosis and demonstrates well how to improve the diagnosis by using single allergens. For diagnosis of baker's asthma, a whole wheat extract is still the best option for specific IgE determination, but single wheat allergens might help to discriminate between wheat-induced food allergy, grass-pollen allergy, and baker's asthma. New diagnostic tools and platforms are promising, but further knowledge of molecules relevant for occupational asthma (as in wood dust allergens, enzymes, laboratory animal allergens, etc.) and for occupational hypersensitivity pneumonitis is necessary to improve and standardize the diagnostic tools.

Molecular Reference Materials for Standardization of Allergen Measurements

Allergen measurements are widely used for determination of the potency of allergy vaccines, for environmental exposure assessments, and for validation of IgE molecular diagnostics. With the exception of Bet v 1 and Phl p 5a, few purified allergen standards have been developed. The aim of this study was to produce purified allergen standards, with defined specifications, that could serve as Molecular Reference Materials (MRM) for use in allergy diagnostics, enzyme- or fluorescent immunoassays, and multiplex arrays. Natural and recombinant food, dust mite, pollen and animal allergens (n = 11) were purified by affinity and/or gel-filtration chromatography and analyzed by SDS-PAGE, LC-MS/MS, ELISA, and FEIA or chimeric IgE ELISA. Natural allergens from peanut, dust mite and animal were lyophilized using different buffer conditions. Real time stability data are collected from frozen liquid allergens and lyophilized allergens. Allergen purity, assessed by LC-MS/MS after Trypsin digest and /or silver-stained SDS-PAGE, was >95%. Real time stability tests of frozen liquid allergens (up to 24 months) and frozen lyophilized allergens, showed comparable potency in allergen-specific ELISA and no signs of degradation on SDS-PAGE. Monoclonal antibody ELISA and IgE reactivity of recombinant allergens showed excellent correlations with natural allergens. Optimized, ISO 9001 compliant, bioprocessing pathways have been established to yield pure, immune-reactive natural and recombinant allergens. These MRM are stable and will improve the standardization of allergy diagnostics and vaccines used for immunotherapy.

Sensitization to animal allergens and allergic symptoms during exposure to them in Korean veterinary researchers

Purpose: Veterinary researchers are exposed to variable animal allergens. However, sensitization to them and allergic symptoms during exposure to them in this group are not sufficiently evaluated worldwide, especially in Korea. The objective of this study is to evaluate sensitization to animal allergens and allergic symptoms during exposure to them in Korean veterinary researchers. Methods: Thirty-two veterinary researchers who participated in the 2016 annual symposium of the Korean Society of Veterinary Sci ence were asked to answer questionnaires regarding allergic symptoms during animal exposure and underwent skin prick tests for animal allergens. Animal allergens consisted of chicken feather and 10 mammals, epithelia as well as cow`s milk, hen`s egg, and 7 an imal types of meat. Results: There were 13 subjects who complained of allergic symptoms during exposure to certain animal epithelia and 19 who did not. Between the 2 groups, there were no differences in age, sex, underlying allergic disease, family history of allergy, current occu pation and its duration, numbers and specie of contact animals, or daily contact time. Meanwhile, the sensitization rates to mouse, horse, rabbit, and guinea pig were significantly higher in the symptomatic group. Rhinoconjunctivitis symptoms were the most common allergic symptoms related to animal exposure were most common followed by dermatologic symptom, and symptom of lower respiratory tract. Conclusion: We found that sensitizations to some animal epithelia were more frequent in Korean veterinary researchers with aller gic symptoms during exposure to animal compared to those without it, and their most common symptoms were rhinoconjunctivi tis symptoms. (Allergy Asthma Respir Dis 2016:4:406-414)

Specific IgE Antibodies in Young Children with Atopic Dermatitis--Correlation of Multiple Allergen Simultaneous Immunoblot Test and ImmunoCap System.

Sensitization to food allergens is a common condition in pediatric atopic dermatitis (AD). Recently, the multiple allergen simultaneous test (MAST) allowing for a comprehensive assessment of atopy has been developed, but the usefulness in young AD children is not known. The aim of this study was to determine IgE specificity in AD children using MAST and to compare the results for selected food allergens with the reference ImmunoCap system. The study enrolled 50 children up to 2 years old with a diagnosis of AD. IgE antibodies were measured with the MAST-immunoblots. Children with specific IgE levels ≥ 0.35 kU/L were identified as sensitized to allergens. Most often children were sensitized to food allergens (egg white and yolk, hazelnuts, potato, cow's milk proteins, wheat flour, codfish, and soybean), but a high percentage of them also had IgE antibodies against house dust mites (12%), grass (10%), and birch (10%). Eight percent of children were sensitized to domestic animals (cats and dogs). Almost perfect (kappa index 0.8 - 1.0) and substantial (kappa index 0.6 - 0.8) agreement between MAST and ImmunoCap was found for food allergens except codfish. Pearson's analysis of antibody classes showed a very strong correlation between two methods (r = 0.8 - 1.0) for egg white, hazelnuts, potato, cow's milk proteins, wheat flour, and soybean, and a strong correlation (r = 0.6 - 0.79) was observed for peanut, egg yolk, and codfish. The study showed the frequent occurrence of IgE antibodies against food and airborne and animal allergens in young AD children and confirmed the usefulness of MAST-immunoblots for screening of sensitization in pediatric patients.

The correlation of serum eosinophil cationic protein level with eosinophil count, and total IgE level in Korean adult allergic rhinitis patients

Background: Eosinophil cationic protein (ECP) is present in eosinophil granules. It has been associated with eosinophil-associated disorders. Objective: We compared serum ECP levels in allergic and non-allergic rhinitis patients and evaluated the association with the eosinophil count and the total IgE level. Method: We retrospectively reviewed medical records and categorized enrolled patients into the allergic (AR) and non-allergic rhinitis (NAR) groups. ECP, eosinophil count, and total IgE levels were reviewed in both groups. The association between ECP and the eosinophil count and total IgE level was further evaluated according to commonly detected specific antigens. Results: Six hundred and ten adults were included in the study. In the AR group (n=349), the median age was 27.0 (23.0-42.0) years and the female:male ratio was 0.26:1. In the NAR group (n=261), the median age was 32.0(24.0-45.5) years and the female:male ratio was 0.33:1. We found that ECP (AR: 18.8(9.9-31.4), NAR: 14.8(8.2-24.9), p=0.003), eosinophil count (AR: 191.0(112.0-308.5), NAR: 149.0(91.0-249.0), p=0.002) and total IgE (AR: 166.0(58.4-422.5), NAR: 68.8(24.5-141.0), p<0.001) were higher in AR than in NAR patients. The ECP level was associated with the eosinophil count in both the AR (p<0.001) and NAR groups (p<0.001). A significant correlation between the ECP level and eosinophil count was demonstrated in AR patients who were skin test positive against house dust mite, animal and pollen allergens. Conclusions: We suggest that ECP could be an important mediator in the pathogenesis of AR. The level of serum ECP was positively correlated with eosinophilia in AR patients regardless of the type of allergen sensitization. However, further study is warranted to verify the role of ECP in the clinical management of allergic rhinitis. Key words: eosinophil cationic protein, immunoglobulin E, eosinophil count, allergic rhinitis, MAST DOI 10.12932/AP0739

Study of risk factors for atopic sensitization, asthma, and bronchial hyperresponsiveness in animal laboratory workers.

The aim of this estudy was to investigate the influence of allergen exposure levels and other risk factors for allergic sensitization, asthma, and bronchial hyperresponsiveness (BHR) in workers exposed to laboratory animals. This was a cross-sectional study performed at two universities, 123 workplaces with 737 subjects. Dust samples were collected from laboratories and animal facilities housing rats, mice, guinea pigs, rabbits, or hamsters and analyzed by enzyme-linked immunosorbent assay (ELISA) to measure allergen concentrations. We also sampled workplaces without animals. Asthma was defined by both symptoms and BHR to mannitol. The concentrations of allergens were tested for association with a skin prick test, respiratory symptoms, spirometry data, and BHR. This multivariate analysis was performed by using Poisson regression to estimate the relative risk (RR) for the exposed group. Our sample comprised students and workers, with 336 subjects in the nonexposed group and 401 subjects in the exposed group. Sixty-nine subjects (17%) had positive results in the skin prick test for animal allergens in the exposed group; in the nonexposed group, 10 subjects had positive results (3%) (p<0.001). Exposure to laboratory animals over 2.8 years was associated with atopic sensitization (RR=1.85; 95% confidence interval: 1.09-3.15; p=0.02). Allergen concentration was not associated with sensitization, asthma, or BHR. Exposure to laboratory animals was associated with atopic sensitization. However, we did not find a cutoff allergen concentration that increased the risk for sensitization. Duration of exposure seems to be more relevant to sensitization than concentration of allergens in dust.

IgE-AB to animals molecular allergens in patients with respiratory allergy

Background. The purpose of this study was to identify IgE-antibodies to the major and minor allergenic components of pets in the blood serum of patients with bronchial asthma and/or allergic rhinitis (BA/AR). Methods. The study included 327 patients from Moscow and St. Petersburg. All of them were detected for specific IgE-antibodies (IgE-AB) to the animal allergens by ImmunoCAP® (ThermoFisherScientific, Sweden). 105 patients wanted to detect IgE-AB to the main animal allergens molecules ImmunoCAP ISAC® (ThermoFisherScientific, Sweden). Results. In the sera of 327 patients IgE-AB to cat’s (62%) allergen dominated. IgE-antibodies to dog’s, house dust mites (D.pteronyssinus, D. farinae), mold fungi, horses and rodents allergens were found in 2,6-31 times less. IgE-AB to uteroglobin (rFel d 1), major cat allergen, was detected in 80% of patients (84/105). The detection rate of IgE-AB to other cat allergens was 4,2-8 times lower (rFel d 2 - 10%, nFel d 4 - 19%). IgE-AB to major dog allergen rCan f 1 was detected in 39% of patients (41/105). Positive level of IgE-AB to other dog allergens was detected in 2,2-4,9 times lower (rCan f 2 - 8%, nCan f 3 - 9%, rCan f 5 - 18%). Positive level of IgE-AB to lipocalin was assayed in 6% of patients, to serum albumin - in 7%. Conclusion. Prevalence of IgE-AB to cat and dog allergens was almost 3 times higher than the frequency of detection of IgE-AB to house dust mite allergens in citizens of Moscow and S. Petersburg. The frequency of IgE-AB to rFel d 1 was dominated and detected 2 and 4-11 times often than to rCan f 1 and other animal allergens consequently.

New data analysis in a population study raises the hypothesis that particle size contributes to the pro-asthmatic potential of small pet animal allergens

Background: The size of inhaled particles influences where they deposit and theoretically should be important for the development of airway inflammation and responsiveness. Our aim was to assess if sensitization to smaller-sized aeroallergens relates to higher prevalence of treated asthma, increased airway responsiveness, and airway and systemic inflammation.Methods: Molecular-based IgE antibody determination was done in 467 subjects. Sensitized subjects were grouped based on the particle size of the aeroallergen: (1) Large particles only (mainly pollen); (2) Medium-sized particles (sensitized to mainly mite and mold and possibly to large particles); and 3) Small particles (sensitized to pet allergens and possibly to medium- and/or large-sized particles). Airway responsiveness to methacholine, exhaled nitric oxide (FENO), and serum eosinophil cationic protein (S-ECP) were measured. Asthma and rhinitis were questionnaire-assessed.Results: Subjects sensitized to small particles had higher prevalence of treated asthma (35% versus 10%, P < 0.001), higher FENO50 (32 versus 17 ppb, P < 0.001), higher S-ECP (10 versus 7.5 ng/mL, P = 0.04), and increased bronchial responsiveness (dose-response slope, 5.6 versus 7.5, P < 0.001) compared with non-atopics. This was consistent after adjusting for potential confounders. Sensitization to only large or to medium and possibly also large aeroallergen particles was not related to any of these outcomes after adjustments.Conclusions: Sensitization to smaller particles was associated with a higher prevalence of asthma under treatment, higher airway responsiveness, and airway and systemic inflammation. Mapping of IgE sensitization to small particles might help to detect subjects having increased airway and systemic inflammation and bronchial responsiveness, indicating increased risk of developing asthma.

Structural similarities of human and mammalian lipocalins, and their function in innate immunity and allergy.

Owners and their domestic animals via skin shedding and secretions, mutually exchange microbiomes, potential pathogens and innate immune molecules. Among the latter especially lipocalins are multifaceted: they may have an immunomodulatory function and, furthermore, they represent one of the most important animal allergen families. The amino acid identities, as well as their structures by superposition modeling were compared among human lipocalins, hLCN1 and hLCN2, and most important animal lipocalin allergens, such as Can f 1, Can f 2 and Can f 4 from dog, Fel d 4 from cats, Bos d 5 from cow's milk, Equ c 1 from horses, and Mus m 1 from mice, all of them representing major allergens. The β‐barrel fold with a central molecular pocket is similar among human and animal lipocalins. Thereby, lipocalins are able to transport a variety of biological ligands in their highly conserved calyx‐like cavity, among them siderophores with the strongest known capability to complex iron (Fe3+). Levels of human lipocalins are elevated in nonallergic inflammation and cancer, associated with innate immunoregulatory functions that critically depend on ligand load. Accordingly, deficient loading of lipocalin allergens establishes their capacity to induce Th2 hypersensitivity. Our similarity analysis of human and mammalian lipocalins highlights their function in innate immunity and allergy.

Laboratory Animal Allergy in the Modern Era

Laboratory animal workers face a high risk of developing laboratory animal allergy as a consequence of inhaling animal proteins at work; this has serious consequences for their health and future employment. Exposure to animal allergen remains to be the greatest risk factor although the relationship is complex, with attenuation at high allergen exposure. Recent evidence suggests that this may be due to a form of natural immunotolerance. Furthermore, the pattern of exposure to allergen may also be important in determining whether an allergic or a tolerant immune response is initiated. Risk associated with specific tasks in the laboratory need to be determined to provide evidence to devise a code of best practice for working within modern laboratory animal facilities. Recent evidence suggests that members of lipocalin allergens, such as Mus m 1, may act as immunomodulatory proteins, triggering innate immune receptors through toll-like receptors and promoting airway laboratory animal allergy. This highlights the need to understand the relationship between endotoxin, animal allergen and development of laboratory animal allergy to provide a safe working environment for all laboratory animal workers.

Allergen-induced early and late asthmatic responses to inhaled seasonal and perennial allergens.

The allergen bronchoprovocation (ABP) test is a validated model to study asthma pathophysiology and response to treatments. The inhibitory effect of agents on the allergen-induced late asthmatic response (LAR) is a predictor of their efficacy in asthma treatment. However, it is difficult to predict the magnitude of a LAR, which may vary according to immune responsiveness and the type of allergen used for ABP. To determine the relationship between the magnitudes of early asthmatic response (EAR) and LAR in mild asthmatic subjects according to the type of allergen inhaled and its determinants. This is a retrospective analysis of a large database of ABPs, all performed with a common standardized methodology. Patients were either challenged with house dust mites (HDMs), animals or pollens allergens. EAR was defined as a ≥20% fall in forced expiratory volume in 1s (FEV1 ) <3h following ABP and LAR as a ≥15% fall in FEV1 between 3 and 7h post-ABP. The ratio of EAR % fall in FEV1 /LAR % fall in FEV1 was compared between the groups of subjects according to the allergen used for ABP. Data from 290 subjects were analysed: 87 had an isolated EAR and 203 had a dual response (EAR+LAR). Dual responders had a significantly lower baseline PC20 , a more marked fall in FEV1 at EAR, and a trend towards higher baseline sputum eosinophil percentages. The ratio of EAR over LAR was significantly lower in HDM compared with pollen ABP, indicating a larger LAR for a similar EAR. No correlations were observed between the ratio of EAR over LAR and the various parameters recorded in the different groups analysed. Different mechanisms may be involved in modulating the magnitude of the LAR, according to the type of allergen. HDM seems to induce a stronger LAR than pollens, animal allergens being intermediary in this regard.

Dimerization of lipocalin allergens.

Lipocalins are one of the most important groups of inhalant animal allergens. The analysis of structural features of these proteins is important to get insights into their allergenicity. We have determined two different dimeric crystal structures for bovine dander lipocalin Bos d 2, which was earlier described as a monomeric allergen. The crystal structure analysis of all other determined lipocalin allergens also revealed oligomeric structures which broadly utilize inherent structural features of the β-sheet in dimer formation. According to the moderate size of monomer-monomer interfaces, most of these dimers would be transient in solution. Native mass spectrometry was employed to characterize quantitatively transient dimerization of two lipocalin allergens, Bos d 2 and Bos d 5, in solution.

Increased risk of horse sensitization in southwestern Iranian horse riders.

The aim of this study has been to investigate the frequency of sensitization to horse allergens and clinical symptoms in horse riders. A total of 42 horse riders and 50 healthy individuals were examined by means of skin prick tests for a panel of horse and common animal allergens, and pulmonary function tests were done by spirometry. The rate of sensitization to horse allergens was 31% as proven by the skin prick test in horse riders whereas horse sensitization was not seen in the control group. Occupational allergy symptoms were reported by 19 horse riders. Two horse riders with no history of clinical symptoms showed positive skin reactions to horse allergens. To decrease the high risk of occupational sensitization among horse riders, workplace conditions should be improved to reduce the load of airborne horse allergens.