Contact allergy and sociodemographic characteristics

The aim of the study was to determine the frequency of positive patch test reaction to different contact allergens according to patients age, sex, occupation and clinical features. Between 1999 and 2003, patch testing was performed in 3,293 patients with respective clinical diagnoses. Patch testing was done by the standard technique proposed by the International Contact Dermatitis Research Group (ICDRG). Study results showed statistically significant differences in patch test response according to sex and age for three allergens (cobalt chloride, nickel sulphate and thiomersal); according to occupation for nine allergens (cobalt chloride, nickel sulphate, balsam of Peru, fragrance mix, thiuram mix, wood tars, neomycin sulphate, thiomersal and detergents), and clinical diagnosis for two allergens (nickel sulphate, and wood tars). The most common and relevant allergens were: nickel sulphate, cobalt chloride and carba mix. They were found in all examinees regardless of age, sex, occupation and diagnoses. The increased awareness of allergens and their potential sources may help to limit the usage of these chemicals in manufacture of consumer products.     

Trichloroethylene Hypersensitivity Syndrome Is Potentially Mediated through Its Metabolite Chloral Hydrate

BackgroundWe documented previously the entity of trichloroethylene (TCE) hypersensitivity syndrome (THS) in occupational workers.ObjectivesTo identify the culprit causative compound, determine the type of hypersensitivity of THS, and establish a screening test for subjects at risk of THS.MethodsTCE and its main metabolites chloral hydrate (CH), trichloroethanol (TCOH) and trichloroacetic acid (TCA) were used as allergens at different concentrations in skin patch tests. The study included 19 case subjects diagnosed with occupational THS, 22 control healthy workers exposed to TCE (exposure >12 weeks), and 20 validation new workers exposed to TCE for <12 weeks free of THS. All subjects were followed-up for 12 weeks after the patch test.ResultsThe highest patch test positive rate in subjects with THS was for CH, followed by TCOH, TCA and TCE. The CH patch test positive rate was 100% irrespective of CH concentrations (15%, 10% and 5%). The TCOH patch test positive rate was concentration-dependent (89.5%, 73.7% and 52.6% for 5%, 0.5% and 0.05%, respectively). Lower patch test positive rates were noted for TCA and TCE. All patch tests (including four allergens) were all negative in each of the 22 control subjects. None of the subjects of the validation group had a positive 15% CH patch test.ConclusionsChloral hydrate seems to be the culprit causative compound of THS and type IV seems to be the major type of hypersensitivity of THS. The CH patch test could be potentially useful for screening workers at risk of THS.     

Unmet diagnostic needs in contact oral mucosal allergies

The oral mucosa including the lips is constantly exposed to several noxious stimuli, irritants and allergens. However, oral contact pathologies are not frequently seen because of the relative resistance of the oral mucosa to irritant agents and allergens due to anatomical and physiological factors. The spectrum of signs and symptoms of oral contact allergies (OCA) is broad and a large number of condition can be the clinical expression of OCA such as allergic contact stomatitis, allergic contact cheilitis, geographic tongue, oral lichenoid reactions, burning mouth syndrome. The main etiological factors causing OCA are dental materials, food and oral hygiene products, as they contain flavouring agents and preservatives. The personal medical history of the patient is helpful to perform a diagnosis, as a positive history for recent dental procedures. Sometimes histology is mandatory. When it cannot identify a direct cause of a substance, in both acute and chronic OCA, patch tests can play a pivotal role in the diagnosis. However, patch tests might have several pitfalls. Indeed, the presence of metal ions as haptens and specifically the differences in their concentrations in oral mucosa and in standard preparation for patch testing and in the differences in pH of the medium might result in either false positive/negative reactions or non-specific irritative reactions. Another limitation of patch test results is the difficulty to assess the clinical relevance of haptens contained in dental materials and only the removal of dental materials or the avoidance of other contactant and consequent improvement of the disease may demonstrate the haptens’ responsibility. In conclusion, the wide spectrum of clinical presentations, the broad range of materials and allergens which can cause it, the difficult interpretation of patch-test results, the clinical relevance assessment of haptens found positive at patch test are the main factors that make sometimes difficult the diagnosis and the management of OCA that requires an interdisciplinary approach to the patient.     

Internal aluminum block of plant inward K(+) channels

Aluminum (Al) inhibits inward K(+) channels (K(in)) in both root hair and guard cells, which accounts for at least part of the Al toxicity in plants. To understand the mechanism of Al-induced K(in) inhibition, we performed patch clamp analyses on K(in) in guard cells and on KAT1 channels expressed in Xenopus oocytes. Our results show that Al inhibits plant K(in) by blocking the channels at the cytoplasmic side of the plasma membrane. In guard cells, single-channel recording revealed that Al inhibition of K(in) occurred only upon internal exposure. Using both "giant patch" recording and single-channel analyses, we found that Al reduced KAT1 open probability and changed its activation kinetics through an internal membrane-delimited mechanism. We also provide evidence that a Ca(2)+ channel-like pathway that is sensitive to antagonists verapamil and La(3)+ mediates Al entry across the plasma membrane. We conclude that Al enters plant cells through a Ca(2)+ channel-like pathway and inhibits K(+) uptake by internally blocking K(in).     

Reproducibility of atopy patch tests with food and inhalant allergens

Although atopy patch tests (APT) seem a valuable additional tool in the diagnostic work-up for food allergy in children with atopic eczema/dermatitis syndrome, the immunopathology and some technical aspects of testing remain controversial. Few published data are available on the reproducibility of APT with inhalants and only two studies include fresh food allergens. In this study we therefore investigated the reproducibility of duplicate APT (left versus right side of the back) with native and commercially available food (cow s milk, hen s egg, tomato, wheat flour) and with inhalant allergens (Dermatophagoides pteronyssinus and mixed grasses) in a large unselected population of children. We tested a population of 277 Italian school children with three APT allergens: fresh food (cow s milk, hen s egg, tomato and wheat flour), standardised food allergens in petrolatum (the same four foods) and standardised inhalant allergens routinely used for skin prick testing. For the four food allergens (applied in the natural form or as the standardised commercial preparation) from one- to three quarters of the APT gave positive results on one side and negative reactions on the opposite side (Cohen s K coefficient between 0.38, fresh tomato and 0.81, fresh cow s milk). Conversely, APT with inhalant allergens were invariably reproducible (Cohen s K = 1.00). The possible technical and immunologic reasons explaining why reproducibility of APT differed for the two types of allergens await an answer from extensive controlled studies.     

Use of water flow direction to provide spatial information in a small-scale orientation task

Experiments were designed to investigate whether three-spined sticklebacks Gasterosteus aculeatus can use direction of water flow as an orientation cue. The fish had to learn the location of a food patch in a channel where water flow direction was the only reliable indicator of the food patch position. Fish from two ponds and two rivers were trained and tested in the spatial task to determine whether river three-spined sticklebacks are more adept at using water flow as a spatial cue than fish from ponds. All fish were able to use water flow to locate the food patch but one of the two river groups was significantly faster at learning the patch location. When the task was reversed so that fish that had formerly been trained to swim downstream now had to learn to swim upstream and vice versa both river groups learned the reversed task faster than the two pond groups. In a second experiment, to investigate whether fish from ponds or rivers vary in the type of spatial cue that they prefer to use, fish from one pond and one river were given a choice between two different types of spatial cue: flow direction or visual landmarks. A test trial in which these two cues were put into conflict revealed that the river population showed a strong preference for flow direction whilst the pond population preferred to use visual landmarks.     

Rapid in vivo transport of proteins from digested allergen across pre-sensitized gut

Although the route of sensitization to food allergens is still the subject of debate, it is generally accepted the gut immune system plays a pivotal role. However, hitherto the transport of allergens across the normal, pre-sensitized gut epithelium remained largely unknown. Our aim was to identify the route through which protein bodies and soluble proteins from digested peanuts penetrated the pre-sensitized gut epithelium in vivo and the specific cell types involved in the transport. Digestion of peanuts released a large number of protein bodies that are exclusively transported across the epithelium by specialized antigen-sampling M cells and delivered to the lymphoid tissue of Peyer's patch. Intracellular transport of soluble protein also occurred almost exclusively via M cells and it was negligible across absorptive enterocytes. We hypothesize that these conditions which are known to favour strongly the induction of immune responses rather than oral tolerance may play a significant role in the genesis of allergic reactions.     

Prosopis juliflora pollen allergen induced hypersensitivity and anaphylaxis studies in guinea pigs

In vivo and in vitro allergenic activities of Prosopis juliflora pollen allergens were measured in guinea pigs. Intracutaneous skin test showed an early wheal flare response and a late erythema-redness, sensitized with various concentrations (100, 50, 25, 5 and 1.5 micrograms/ml) of Prosopis juliflora pollen extract after administration of a challenging dose. A 50 micrograms/ml sensitizing dose of Prosopis juliflora pollen allergen gave optimum skin response as both early and late effects. The nature of immunochemical reactivity between pollen allergens and reaginic antibodies were further characterized by histamine release test, gel diffusion test, radioallergosorbent test and passive cutaneous anaphylaxis test. These tests confirm allergenicity caused by Prosopis juliflora pollen allergens and showed the binding of allergens with reaginic antibody and its regulation in guinea pigs.     

Contact allergy caused by fragrance mix and Myroxylon pereirae (balsam of Peru)--a retrospective study

Because of their widespread use, fragrances are among the most common causes of contact allergic dermatitis, second only to nickel. During a five-year period 3,065 patients with contact dermatitis were patch tested using a specific mix of fragrances. 509 (16.6%) patients were allergic to the fragrance mix, while 258 (8.4%) patients exhibited an allergic reaction to Myroxylon pereirae (balsam of Peru). Between those 509 patients, 157 were patch tested with eight individual substances contained in the fragrance mix: cinnamal, cinnamyl alcohol, eugenol, isoeugenol, geraniol, hydroxycitronellal, alpha-amyl cinnamal and Evernia prunastri (oak moss). The most frequent allergens were isoeugenol 57.9% (91/157), eugenol 55.4% (87/157), cinnamyl alcohol 34.4% (54/157) and Evernia prunastri (oak moss) 24.2% (38/157). There were 62 patients (39.5%) who exhibited an allergic reaction to both the fragrance mix and Myroxylon pereirae (balsam of Peru). The results prove the importance of avoiding allergens in daily life, especially in industrial and cosmetic products. In order to prevent ACD, better cooperation between industry and dermatologists is needed.     

Quantitation of latex allergens

Minimizing allergen concentration in latex goods to prevent sensitization to natural rubber latex (NRL) and thereby the development of clinical allergy is acknowledged as of mutual interest for rubber manufacturers and regulatory health authorities. However, measuring total protein, the principal currently available method, cannot be deemed a satisfactory regulatory measure to control allergen content. Specific methods based on human IgE-containing reagents, such as radioallergosorbent test (RAST) inhibition, have been available in certain laboratories for demonstrating NRL allergens in rubber products but the methods lack standardization. Currently, one commercial test has become available for measuring individual NRL allergens by capture ELISA-based assays using monoclonal antibodies and purified or recombinant allergens. Such methods are specific, they can be properly standardized, and they are of sufficient sensitivity and reproducibility. Results from medical gloves collected in two national market surveys in Finland in 1995 and 1999, respectively, show that Hev b 6.02 and Hev b 5, the two major allergens for NRL-allergic adults, are the most abundant allergens regularly detectable in high- and moderate-allergen gloves. In addition, Hev b 3 and Hev b 1, the two major allergens for children with spina bifida, are also commonly found. In general, when the sum of the four allergens exceeded 1 microg/g, most NRL-allergic patients showed positive skin prick test reactions against them. Using these new methods assessment of threshold levels that could in due course become guidelines for the rubber industry and regulatory health authorities is becoming possible. Eventually, this progress is expected to lead to a declining incidence of latex allergy.     

Contact allergy to special and standard allergens in patients with venous ulcers

The aim of the study was to determine the prevalence of contact sensitivity in patients with leg ulcers, and possible difference in the rate of contact hypersensitivity to standard series of allergens used in patch testing, and to particular topical agents used in local therapy of leg ulcers in special series, patients with and without atopy. The study included 60 patients, 45 female and 15 male, aged 37-85 (mean 68.37 female and 51.13 male), 30 of them with and 30 without allergic contact dermatitis (ACD) of the leg (control group). The mean duration of leg ulceration was 5.62 years. The two groups of patients underwent testing to standard series allergens and target series allergens including mupirocin, bepanthene, silver sulfadiazine, chloramphenicol + clostridiopeptidase, betamethasone dipropionate, hydrocortisone + oxytetracycline, momethasone, alginate, hydrocolloid, lanolin, pyrogallol, Vaseline, permanganate, Rivanol, povidone-iodine, gentamicin, i.e. local agents most frequently used by the patients. Contact allergic hypersensitivity to standard series allergens was demonstrated in 25 patients with a total of 49 positive reactions and a mean of 1.6 reactions per patient. Positive reactions were most commonly recorded to balsam of Peru, fragrance mix and neomycin sulfate. There were 12 positive reactions to target series allergens, mean 0.4 reactions per patient. Forty-five positive reactions, mean 0.1 reactions per patient, were recorded in the control group. Positive reactions were most commonly demonstrated to corticosteroid ointments, lanolin and bepanthene. Study results did not confirm a statistically significantly higher rate of sensitization to particular topical agents frequently used in the treatment of patients with venous ulcers. Patch testing to standard and special series allergens should be performed in case of prolonged leg ulcer epithelization.     

Oral Mucosa Patch Test: A New Tool to Recognize and Study the Adverse Effects of Dietary Nickel Exposure

On contact with the skin, nickel may cause allergic contact dermatitis, which can be diagnosed by an epicutaneous patch test. Nickel exposure via the intestinal mucosa can induce diarrhea, abdominal pain, and swelling. The aim of the present study was to investigate the relationship between these symptoms and nickel intake by means of a novel oral mucosa patch test. Eighty-six patients with intestinal symptoms related to ingestion of nickel-containing foods were submitted to epicutaneous and oral mucosa patch tests for nickel. All patients with positive oral mucosa patch test results were subject to a low-nickel diet and monitored over time. Skin lesions were observed in 33 out of 86 (38.4%) patients evaluated by the epicutaneous patch test. Mucosal lesions were seen in 53 out of 86 (61.6%) patients given the oral mucosa patch test. After 2 months of a low-nickel diet, 52 out of 53 (98.1%) patients showed an improvement of their symptoms. There is a significant correlation between response time of the oral mucosa patch test and the latency of symptoms after ingestion of nickel-containing foods. Consequently, the oral mucosa patch test can be used to recognize and study the adverse effects of dietary nickel exposure that could be defined as allergic contact mucositis. A low-nickel diet is also shown to be an effective treatment for this condition.     

Fractional composition of the allergens from cereals

The composition of cereal allergens was studied and the specific activity of the fractions isolated from these allergens was determined. Four protein fractions were obtained from wheat flour by the method of salting out. None of the fractions thus obtained exceeded the whole wheat allergen in specific activity as determined in the indirect mast-cell degranulation (IMCD) test. Three fractions were isolated by fractionation through Sephadex G-75. Of these, the first fraction possessed better physical properties, and its specific activity exceeded that of the initial allergen in the IMCD test.     

Cytokine gene polymorphisms and atopic disease in two European cohorts. (ECRHS-Basel and SAPALDIA)

Background

Avoidance of allergens is still recommended as the first and best way to prevent allergic illnesses and their comorbid diseases. Despite a variety of attempts there has been very limited success in the area of environmental control of allergic disease. Our objective was to identify a non-invasive, non-pharmacological method to reduce indoor allergen loads in atopic persons' homes and public environments. We employed a novel in vivo approach to examine the possibility of using aluminum sulfate to control environmental allergens.

Methods

Fifty skin test reactive patients were simultaneously skin tested with conventional test materials and the actions of the protein/glycoprotein modifier, aluminum sulfate. Common allergens, dog, cat, dust mite, Alternaria, and cockroach were used in the study.

Results

Skin test reactivity was significantly reduced by the modifier aluminum sulfate. Our studies demonstrate that the effects of histamine were not affected by the presence of aluminum sulfate. In fact, skin test reactivity was reduced independent of whether aluminum sulfate was present in the allergen test material or removed prior to testing, indicating that the allergens had in some way been inactivated.

Conclusion

Aluminum sulfate was found to reduce the in vivo allergic reaction cascade induced by skin testing with common allergens. The exact mechanism is not clear but appears to involve the alteration of IgE-binding epitopes on the allergen. Our results indicate that it may be possible to diminish the allergenicity of an environment by application of the active agent aluminum sulfate, thus producing environmental control without complete removal of the allergen.     

Microarrayed allergens for IgE profiling

Diagnosis of type I allergy is based on anamnesis, provocation testing, and serological determination of total and specific IgE. Currently, in vivo and in vitro diagnostic tests employ allergen extracts prepared from various allergen sources (e.g., pollen, mites, animal dander, moulds, foods, venoms, etc.). The application of recombinant DNA technology to the field of allergen characterization has allowed to reveal the molecular nature of the most common allergens. To date a continuously increasing number of allergen sequences has become available and panels of recombinant allergens-assembling the epitope complexity of natural allergens sources-can be produced. The use of recombinant allergens instead of crude, natural extracts for allergy diagnosis allows us to determine the individual IgE reactivity profile of each patient. To enable a comprehensive analysis of the patient's IgE binding pattern to a large number of individual allergens, a new type of serological test is required. In this paper, we applied microarray technology to create a multi-allergen test system, based on microarrayed recombinant allergens.     

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.     

A comparative evaluation of the biological action of allergens and allergoids prepared from plant pollen by the double radial immunodiffusion method

Antisera to allergens and allergoids prepared from timothy, orchard grass, birch and wormwood pollen have been obtained and used in the double radial immunodiffusion test. The preparations of the allergoid row have been found capable of inducing immune response in laboratory animals (rabbits). Both forms of pollen preparations, allergens and allergoids, have been shown to possess common antigenic determinants reacting with antibodies present in antisera to allergens and allergoids. The absence of identity in the ratio of manifestations of gel precipitation reactions for allergoid with respect to the initial forms of allergens of individual pollen preparation has been noted.     

Identification and biochemical characterization of Asp t 36, a new fungal allergen from Aspergillus terreus

Aspergillus terreus is an allergenic fungus, in addition to causing infections in both humans and plants. However, the allergens in this fungus are still unknown, limiting the development of diagnostic and therapeutic strategies. We used a proteomic approach to search for allergens, identifying 16 allergens based on two-dimensional immunoblotting with A. terreus susceptible patient sera. We further characterized triose-phosphate isomerase (Asp t 36), one of the dominant IgE (IgE)-reactive proteins. The gene was cloned and expressed in Escherichia coli. Phylogenetic analysis showed Asp t 36 to be highly conserved with close similarity to the triose-phosphate isomerase protein sequence from Dermatophagoides farinae, an allergenic dust mite. We identified four immunodominant epitopes using synthetic peptides, and mapped them on a homology-based model of the tertiary structure of Asp t 36. Among these, two were found to create a continuous surface patch on the 3D structure, rendering it an IgE-binding hotspot. Biophysical analysis indicated that Asp t 36 shows similar secondary structure content and temperature sensitivity with other reported triose-phosphate isomerase allergens. In vivo studies using a murine model displayed that the recombinant Asp t 36 was able to stimulate airway inflammation, as demonstrated by an influx of eosinophils, goblet cell hyperplasia, elevated serum Igs, and induction of Th2 cytokines. Collectively, our results reveal the immunogenic property of Asp t 36, a major allergen from A. terreus, and define a new fungal allergen more broadly. This allergen could serve as a potent candidate for investigating component resolved diagnosis and immunotherapy.     

西安地区儿童支气管哮喘吸入性过敏原的调查分析

目的:探讨西安地区儿童支气管哮喘吸入性过敏原的分布情况。方法:选择950例来自西安地区的支气管哮喘患儿为研究对象,采用过敏原皮肤点刺试验检测,以组胺作为阳性对照,生理盐水为阴性对照,分析不同年龄和性别的患儿过敏原的分布情况。结果:950例支气管哮喘患儿中,384例皮肤点刺过敏原检测呈阳性,占40.4%,男女患儿过敏原检测阳性分布无明显差异(P0.05);尘螨为主要的过敏原,其次为艾蒿和霉菌类;随着患儿年龄的增加,其过敏原检测的阳性率明显升高(P0.05),且大多数过敏原检测阳性患儿至少合并2-3种过敏原阳性。结论:西安地区支气管哮喘患儿吸入性过敏原阳性率与其性别无关,但与其年龄有关,过敏原以尘螨类为主,大多数检测阳性的患儿对至少一种以上的过敏原阳性。     

Evaluation of specific activity of preparations of allergens from synanthropic insects

Physical, chemical and immunobiological characteristics of allergens from synanthropic insects were studied by tests for anaphylaxis, indirect degranulation of mast cells test and ELISA. Sera from 20 patients with severe and intermediate atopic asthma with sensiblization to common allergens have been studied. All extracts of allergens from synanthropic insects (german cockroach, oriental cockroach, american cockroach, speckled feeder cockroach, cricket, common house fly, brown house moth, confused flour beetle, rice weevil, grain weevil) have specific activity. Extracts of allergens from common house fly, brown house moth, german cockroach and oriental cockroach had the strongest allergenic activity as measured by ELISA. Obtained allergens can be used for insect allergy diagnostics.