IgY antialérgenos específicos del grupo 1 de ácaros del polvo doméstico inducidos por oligopéptidos sintéticos no glicosilados / Specific IgY anti-group 1 dust mite allergens induced by unglycosylated synthetic oligopeptides

Resumen Introducción. La obtención de anticuerpos específicos capaces de detectar alérgenos del grupo 1 de ácaros del polvo doméstico representa una estrategia potencial de salud pública para reducir la exposición y la sintomatología clínica asociada con el asma y la rinitis alérgica. Objetivo. Producir y purificar anticuerpos aviares antialérgenos específicos del grupo 1 de los ácaros Dermatophagoides sp.y Blomia tropicalis utilizando la tecnología IgY. Materiales y métodos. Se diseñaron y sintetizaron oligopéptidos que evidenciaran epítopes inmunogénicos de los alérgenos Der p1, Der f1 y Blo t1 empleados posteriormente para producir anticuerpos IgY policlonales en gallinas Hy Line Brown. Las IgY presentes en las yemas de los huevos se purificaron mediante cromatografía tiofílica. Su inmunorreactividad y especificidad se determinaron mediante un inmunoensayo ELISA indirecto y Dot Blot. Resultados. Se obtuvo una reactividad elevada de las IgY contra epítopes de alérgenos presentes en extractos de cuerpo entero de D. farinae, D. pteronyssinus y B. tropicalis. Los niveles más altos de IgY se produjeron entre los días 32 y 40 de inmunización. Los anticuerpos mostraron mayor inmunorreactividad y especificidad en el reconocimiento de proteínas de D. farinae, con un límite de detección mayor de 0,03 µg de proteína total delcaroajo las condiciones experimentales analizadas. Las IgY purificadas no mostraron reactividad significativa frente al extracto de Periplaneta americana. Conclusión. La tecnología IgY permitió la producción de anticuerpos específicos contra alérgenos del grupo 1 de los ácaros del polvo al utilizar oligopéptidos sintéticos no glicosilados. Hasta donde se sabe, esta es la primera vez que se usan estos reactivos inmunológicos para la detección de ácaros de importancia médica.

Abstract Introduction: The use of specific antibodies capable of detecting allergens of the group 1 of house dust mites represents a potential strategy to reduce exposure and clinical symptomatology associated with asthma and allergic rhinitis. Objective: To produce and purify chicken antibodies specific for the dust mites Dermatophagoides sp. and B. tropicalis using the IgY technology. Materials and methods: We designed and synthesized oligopeptides showing immunogenic epitopes of Der p1, Der f1, and Blo t1. These were used to produce IgY antibodies in Hy Line Brown chickens. IgY were extracted from egg yolk using thiophilic chromatography. The immunogenicity and specificity were assayed by indirect ELISA and Dot Blot. Results: We obtained high reactivity of IgY antibodies against epitopes of allergens present in whole body mites extracts of D. farinae, D. pteronyssinus, and B. tropicalis. The highest IgY levels were registered between days 32 and 40 after immunization. The antibodies showed high immunoreactivity and specificity towards D. farinae proteins with detection limits above 0.03 µg of mite proteins under the experimental conditions used. Purified IgY did not show significant reactivity when binding to Periplaneta americana extract. Conclusion: The IgY technology allowed the production of specific antibodies against house dust mites group 1 allergens using non-glycosylated synthetic peptides. To our knowledge, this is the first time that this immunochemicals are used in the detection of mites of medical relevance.

Sublingual immunotherapy in the treatment of allergic asthma: a systematic review with meta-analysis

Introduction: The guidelines for the management of allergic respiratory diseases oriented towards control from medical treatment combined with measures of environmental hygiene. Immunotherapy is one of several types of treatment, applied in combination with prophylactic drugs and environmental care. The aim of the study is to evaluate the efficacy of sublingual immunotherapy (SLIT) for house dust mites (HDM) in people with allergic asthma. Methods: The study is based on a systematic review with meta-analysis of randomized clinical trials, associating sublingual immunotherapy with the treatment of allergic patients with HDM. Results: The searches were applied in PubMed, ScienceDirect and Scielo databases. Initially, 98 articles were recovered, of which only nine were eligible. Of these, eight (88.9%) were conducted in Europe and only one (11.1%) in Asia. Comparing the outcomes expiratory volume in the first minute (FEV1 ) and sensitivity to allergens (HDM) between SLIT and placebo groups before and after intervention, no differences were observed between the groups. Conclusions: SLIT is not evidenced significantly by meta-analysis for the treatment of allergic asthma (AU)

Revisão sistemática sobre modelos experimentais de asma aguda e crônica induzidos com extrato de ácaro da poeira doméstica / Systematic review on experimental models of acute and chronic asthma induced with house dust mite extract

Introdução: Asma é uma doença crônica das vias aéreas inferiores com elevada prevalência. Pesquisadores no mundo todo têm desenvolvido vários estudos experimentais em camundongos com o objetivo de entender melhor os mecanismos da doença e testar novas terapias. Ácaros estão presentes de forma abundante na poeira doméstica, sendo considerados os alérgenos mais comuns desencadeantes de asma alérgica. Este estudo objetiva apresentar e discutir desfechos inflamatórios no tecido pulmonar dos camundongos, verificar a diferença entre os modelos agudo e crônico de asma alérgica, tempo de exposição ao alérgeno, dose administrada e seu impacto nas pesquisas em modelos experimentais com asma. Métodos: A revisão da literatura foi realizada em quatro bancos de dados (PubMed, Scielo, Scopus e ScienceDirect). Os artigos selecionados foram avaliados primeiramente por dois pesquisadores de forma independente, de acordo com os critérios de inclusão. Resultados: Foram separados 126 artigos. Aplicados os critérios de inclusão e exclusão, somente 15 foram selecionados. São artigos que apresentaram diferentes protocolos de exposição ao HDM. A dose de HDM mais encontrada foi 100µg seguida por 25µg, e o tipo de modelo foi agudo. Conclusão: No modelo agudo, observa-se um elevado nível de inflamação das vias aéreas. Já o modelo crônico reproduz melhor as características da asma em humanos, hiper-responsividade brônquica e remodelamento das vias aéreas (AU)

Introduction: Asthma is a chronic disease of the lower airways with a high prevalence. Researchers worldwide have developed several experimental studies in mice with the goal of better understanding the mechanisms of the disease and testing new therapies. Mites are abundantly present in household dust, being considered the most common allergens triggering allergic asthma. This study aims to present and discuss inflammatory outcomes in the lung tissue of the mice, verify the difference between acute and chronic models of allergic asthma, time of exposure to the allergen, dose administered and its impact on research in experimental models with asthma. Methods: Literature review was performed in four databases (PubMed, Scielo, Scopus and ScienceDirect). The selected articles were first evaluated by two researchers independently, according to the inclusion criteria. Results: A total of 126 articles were separated. When the inclusion and exclusion criteria were applied, only 15 were selected. They are articles that presented different protocols of exposure to HDM. The most commonly found HDM dose was 100µg followed by 25µg, and the model type was acute. Conclusion: In the acute model, a high level of airway inflammation is observed. However, the chronic model better reproduces the characteristics of asthma in humans, bronchial hyperresponsiveness, and airway remodeling (AU)

Retrospective Analysis on the Effects of House Dust Mite Specific Immunotherapy for More Than 3 Years in Atopic Dermatitis

PURPOSE: In extrinsic atopic dermatitis (AD), house dust mites (HDM) play a role in eliciting or aggravating allergic lesions. The nature of skin inflammation in AD has raised a growing interest in allergen-specific immunotherapy (SIT). Thus, we assessed clinical improvement and laboratory parameters for evaluation of the benefit of long-term SIT. MATERIALS AND METHODS: A total of 217 AD patients who were treated with SIT for at least 3 years were retrospectively assessed, by using their investigator global assessment, pruritus scores, loss of sleep (LOS), total serum IgE, and eosinophil counts collected. Patients were additionally classified into subgroups according to age, initial AD severity and mono- or multi-sensitization to include different individual factors in the evaluation of SIT efficacy. Lastly, we compared laboratory data of good responders to SIT with that of poor responders to SIT. RESULTS: Improvement after SIT therapy was observed in 192 out of 217 patients (88.4%). Among these patients, 138 (63.5%) achieved excellent, near-complete or complete clinical remission. Significant reduction of pruritus, LOS, and the mean value of total serum IgE were observed (p0.05). CONCLUSION: We emphasize the usefulness of long-term HDM SIT as a disease-modifying therapy for AD.

Sensitization study of dogs with atopic dermatitis in the central region of Rio Grande do Sul / Estudo da sensibilização de cães com dermatite atópica na região central do Rio Grande do Sul

Canine atopic dermatitis (CAD) is a common dermatosis, defined as a genetic-related disease which predisposes to skin inflammation and pruritus, associated to a IgE-specific response in most of cases. Clinical diagnosis may be later complemented by skin allergy and/or serological tests. The aim of these tests is to identify possible allergens in order to enable the clinicians to select candidate antigens for allergen specific immunotherapy. In the present study 58 CAD positive animals were tested. All were submitted to the intradermal test (IDT) and screened for the presence of antibodies against different antigens using ELISA. The obtained results show a high prevalence of sensitization among the tested dogs to house dust mites and to pollen ofC. dactylon. With this work it was possible to identify the main allergens involved in immunological response of dogs with CAD living in central area of Rio Grande do Sul.

A dermatite atópica canina (DAC) é uma dermatose comum, definida como doença de cunho genético que predispõe à inflamação e ao prurido cutâneo, associados à resposta IgE específica na maior parte dos casos. O diagnóstico da DAC é clínico e pode ser posteriormente complementado por testes alérgicos cutâneos e/ou sorológicos. O objetivo desses testes é identificar possíveis alérgenos e, com isso, possibilitar ao clínico a seleção de antígenos candidatos para a imunoterapia alérgeno-específica. No presente estudo, foram testados 58 animais diagnosticados para DAC. Todos os animais foram submetidos ao teste cutâneo intradérmico (TID), e amostras de sangue foram coletadas para a realização de testes sorológicos. Os resultados obtidos demonstraram elevada prevalência de sensibilização aos ácaros domiciliares e ao pólen da gramínea C. dactylon nos cães testados. Com este trabalho, foi possível identificar os principais alérgenos envolvidos na resposta imunológica de cães atópicos residentes na região central do Rio Grande do Sul.

Production of Egg Yolk Antibodies Specific to House Dust Mite Proteins

PURPOSE: House dust mites (HDMs) are an important source of indoor allergens associated with asthma, rhinitis and atopic dermatitis. Chicken immunoglobulin (Ig) Y is known to be a good alternative to mice and rabbit antibody production. In this study, we produced IgYs specific to HDMs and investigated their IgE immunoreactivities. MATERIALS AND METHODS: Total IgYs were isolated from the yolks of White Leghorn hens immunized with either Dermatophagoides pteronyssinus or D. farinae protein extract. Control antibodies were separated from the yolks of immunized hens with phosphate buffered saline. IgYs specific to HDMs were analyzed using enzyme-linked immunosorbent assay and Western blotting analysis. RESULTS: The concentration of egg IgY specific to D. farinae in an immunized hen increased and the highest achieved was 661.3 ug/mg (per an egg) on day 47, compared with 760 ug/mg IgY specific to D. pteronyssinus on day 16. The D. pteronyssinus or D. farinae-specific IgY was detected by binding of each mite proteins, and their immunoreactivities were elevated dependent of the specific IgY concentration. CONCLUSION: IgY specific to HDMs may be a promising antibody for immunological diagnosis as well as identification of possible resistance relating to HDM allergy.

Sensibilización a ácaros domésticos en niños asmáticos severos / Sensitization to domestic mites identified in severe asthmatic patients

Introducción: las enfermedades alérgicas y el asma incrementan su prevalencia en Cuba y a nivel mundial. Los ácaros del polvo se encuentran entre los alérgenos perennes más prevalentes en todo el mundo. Objetivo: determinar la sensibilización a 3 especies de ácaros domésticos en los niños asmáticos severos de la Escuela Especial Celia Sánchez Manduley, de Tarará, provincia La Habana. Métodos: se realizó un estudio descriptivo transversal en 91 alumnos, durante el curso escolar 2011-2012, y a toda la muestra se le realizaron pruebas cutáneas por punción (prick test), utilizando extractos Vallergen-BT (Blomia tropicalis), Vallergen-DS (Dermatophagoides siboney) y Vallergen-DP (Dermatophagoides pteronyssinus) confeccionados por el Centro de Biopreparados, en Cuba; además se determinó IgE sérica total. Resultados: la rinitis alérgica resultó la comorbilidad alérgica más frecuente. El total de los pacientes presentó reactividad cutánea positiva a los ácaros, así como IgE sérica total elevada. La sensibilización frente al D. pteronyssinus se reportó en el 93,4 por ciento de los pacientes. No existió diferencia estadísticamente significativa en el diámetro del habón. Existió correlación entre la positividad de la IgE sérica total y la sensibilización cutánea a los 3 ácaros del polvo estudiado. Conclusiones: existe una estrecha relación entre el asma bronquial y la sensibilización a ácaros, con predominio de la especie D. Pteronyssinus

Introduction: the prevalence of allergic diseases and asthma grows in Cuba and worldwide. Dust mites are one of the most prevailing perennial allergens throughout the world. Objective: to determine the sensitization to 3 domestic mite species of severe asmathic children from Celia Sanchez Manduley special school located in Tarara, Havana province. Methods: a cross-sectional descriptive study was carried out in 91 students during the 2011-2012 academic year. The whole sample was performed prick tests using Vallergen-BT (Blomia tropicalis), Vallergen-DS (Dermatophagoides siboney) and Vallergen-DP (Dermatophagoides pteronyssinus) extracts prepared by the National Center of Biopreparations and their total serum IgE were additionally estimated. Results: allergic rhinitis proved to be the most frequent comorbidity. All the patients showed positive skin reactivity to mites as well as increased total serum IgE. Sensitization to D. pteronyssinus was reported in 93.4 percent of patients. There was no statistically significant difference in the habon diameter, but total serum IgE positivity and skin sensitization to the three dust mites under study were correlated. Conclusions: there is close association between bronchial asthma and sensitization to mites, being D. Pteronyssinus predominant

Skin reactivity to allergens in Rabigh area, Kingdom of Saudi Arabia

This study determined the pattern of skin prick test reactivity to allergens in patients with airway allergy residing in Rabigh Area, based on data analysis of skin prick test results. Skin prick tests of 160 Saudi attended Al Nakheel Polyclinic between July, 2012 and April, 2013. Allergen extracts set was used to test them. Out 160 patients, 114 [71%] reacted to one or more allergens, who were 73 [64%] adults and 41 [36%] children. The majority of adults [17.8%] reacted to six allergens and children [19.5%] reacted to five ones. The most frequently reacting allergen was house dust mites followed by Candida albicans then Cladosporium spp. The maximum number of positive tests per patients was 13 in adults, compared to 10 in children. A significantly higher proportion of adults were reacting to house dust mites, Aspergillus and Penicillium. Sensitivity to allergens was common in patients with airway allergy residing in Rabigh area

Avaliação do teste de contato com aeroalérgenos em pacientes com dermatite atópica / Evaluation of patch test with airbone allergic agents in patients with atopic dermatitis

FUNDAMENTOS: a dermatite atópica é uma doença inflamatória cutânea que apresenta múltiplos fatores desencadeantes. Há vários relatos de autores que confirmaram os aeroalérgenos como fatores agravantes ou desencadeantes. O teste de contato com aeroalérgenos ou teste de contato atópico foi proposto para avaliar a participação destes alérgenos na dermatite atópica. OBJETIVO: objetivo deste estudo foi avaliar a positividade do teste de contato atópico em pacientes com dermatite atópica. MÉTODOS: Avaliamos 50 pacientes com dermatite atópica e 45 do grupo com rinite alérgica, nos quais realizamos teste de contato atópico com extratos de Dermatophagoides pteronissynus, Dermatophagoides farinae e Blomia tropicalis, além de testes cutâneos de leitura imediata para os mesmos alérgenos, acrescidos de epitélio de cão e gato e fungos. RESULTADOS: verificamos que o teste de contato atópico com ácaros apresentou maior positividade nos indivíduos do grupo de dermatite atópica quando comparado ao grupo de rinite alérgica. CONCLUSÕES: o teste de contato atópico apresenta resultados estatisticamente significativos quando realizado com ácaros, em pacientes com dermatite atópica, com p=0,035, OR (odds ratio) = 3,35 e IC(95 por cento) = [ 1,18; 9,47].

BACKGROUND: Atopic dermatitis is an inflammatory skin disease that can be triggered by many factors. Several reports confirm the role of airborne allergic agents as aggravating or triggering factors. The patch test with airborne allergic agents or the atopy patch test was suggested to evaluate the role of these allergens in atopic dermatitis. OBJECTIVE: This study aimed at evaluating the positivity of the atopy patch test in patients with atopic dermatitis. METHODS: We evaluated 50 patients with atopic dermatitis and 45 with allergic rhinitis, the atopy patch test was performed in these patiennts with extracts of Dermatophagoides pteronissynus, Dermatophagoides farinae and Blomia tropicalis, as well as immediate skin prick tests for the same allergens with cat and dog epithelia and fungi. RESULTS: It was found that the atopy patch test with dust mites showed higher positivity in individuals with atopic dermatitis when compared to those with allergic rhinitis. CONCLUSIONS: The atopy patch test shows statistically significant results when performed with dust mites in patients with atopic dermatitis, p = 0.035, odds ratio (OR) = 3.35 and CI (95 percent) = [1.18, 9, 47].

Safety of Accelerated Schedules of Subcutaneous Allergen Immunotherapy with House Dust Mite Extract in Patients with Atopic Dermatitis

The safety of accelerated schedules of allergen immunotherapy (ASAI) in patients with bronchial asthma (BA) has been reported but there are little data on the safety of ASAI for patients with atopic dermatitis (AD). In this study, we investigated the safety of ASAI in patients with AD. Sixty patients with AD and 18 patients with BA sensitized to house dust mites (HDM) were studied. A maximum maintenance dose of HDM extract, adsorbed to aluminum hydroxide, was administered to patients by subcutaneous injection with either a 3-day protocol (rush immunotherapy) or 1-day protocol (ultra-rush immunotherapy). Systemic reactions were observed 4 of 15 patients (26.7%) with AD during rush immunotherapy, 13 of 45 patients (28.9%) with AD during ultra-rush immunotherapy, and 4 of 18 patients (22.2%) with BA during rush immunotherapy (P > 0.05). No severe or near fatal systemic reactions occurred in 78 subjects of this study. Systemic reactions developed within 4 hr after administration of the maximum allergen dose in 20 of 21 patients (95.2%) with AD and BA who showed systemic reactions during rush or ultra-rush immunotherapy. In conclusion, ASAI was safe and well tolerated in patients with AD. ASAI can be a useful therapeutic option for AD.

Sensitization to Aeroallergens in Korean Children: A Population-based Study in 2010

We performed this study to assess the prevalence of sensitization to aeroallergens and to analyze the difference between prevalence rates according to children's ages and residential areas. In this nationwide cross-sectional study, first grade students of 45 elementary schools and 40 middle schools were randomly selected, and skin prick tests were performed for 18 inhalant allergens between October and November 2010. Of 7,829 analyzed subjects, 3,753 (47.9%) were sensitized to at least one aeroallergen. Sensitization to Dermatophagoides farinae was found to be the most prevalent in elementary schoolchildren (32.4%), followed by Dermatophagoides pteronyssinus, Tyrophagus putrescentiae, Japanese hop, and oak. In middle schoolchildren, D. pteronyssinus yielded the highest prevalence (42.7%), followed by D. farinae, T. putrescentiae, Japanese hop, and cat. In middle schoolchildren, the sensitization rate to aeroallergens in metropolitan, urban, and rural areas was 57.2%, 54.3%, and 49.8%, respectively (P = 0.019). In this age group, the sensitization rate in low, middle, high, and very high income groups was 53.8%, 51.8%, 59.0%, and 59.6%, respectively (P = 0.002). In conclusion, the sensitization rate is 47.9% and house dust mite is the most prevalent allergen in the pediatric population in Korea. The rate is higher in metropolitan areas and the highest income group than in rural areas and low income groups.

Common allergens of atopic dermatitis in dogs: comparative findings based on intradermal tests

Intradermal tests were performed on 58 dogs diagnosed with atopic dermatitis from 2004~2008 at the Veterinary Medical Teaching Hospital of Konkuk University, Korea. To compare the allergen distribution observed in the present investigation to the results from other studies conducted in Korea and elsewhere, the allergens were grouped according to their kinds. There was no significant difference in gender distribution among the dogs. The most common breeds among the 58 dogs were Maltese (n = 11) and Shih-tzu (n = 11). The average age was 4.8 years. The most frequently produced a positive reaction on the intradermal tests was mold (67.3%) followed by house dust (54.5%) and house dust mites (49.1%). The present study found a low distribution of dogs allergic to various outdoor allergens compared to studies performed in other countries; this may reflect differences in living conditions for dogs living in Korea.

Potential Adjuvant Effects of Nigella sativa Seeds to Improve Specific Immunotherapy in Allergic Rhinitis Patients

To investigate the effects of Nigella sativa seed supplementation on symptom levels, polymorphonuclear leukocyte [PMN] functions, lymphocyte subsets and hematological parameters of allergic rhinitis. Twenty-four patients randomly selected from an experimental group of 31 [mean age 34 years] sensitive to house dust mites with allergic rhinitis and a control group of 8 healthy volunteers [mean age 23 years] were treated with allergen-specific immunotherapy in conventional doses for 30 days. After a month of immunotherapy, 12 of the 24 patients and the 8 healthy volunteers were given N. sativa seed supplementation [2 g/day orally] for 30 days. The remaining 12 patients continued only on immunotherapy during the same period. The other 7 patients were given 0.1 ml saline solution subcutaneously once a week as a placebo. The symptom scores, PMN functions, lymphocyte subsets and other hematological parameters were evaluated before and after all treatment periods. There was a statistically significant increase in the phagocytic and intracellular killing activities of PMNs of patients receiving specific immunotherapy, especially after the addition of N. sativa seed. The CDS counts of patients receiving specific immunotherapy plus N. sativa seed supplementation significantly increased compared to patients receiving only specific immunotherapy. PMN functions of healthy volunteers significantly increased after N. sativa seed supplementation compared to baseline. N. sativa seed supplementation during specific immunotherapy of allergic rhinitis may be considered a potential adjuvant therapy

The Effect of Rush Immunotherapy with House Dust Mite in the Production of IL-5 and IFN-gamma from the Peripheral Blood T Cells of Asthmatic Children

Although the mechanisms are unclear, rush immunotherapy (RIT) may be effective to treat allergic diseases. We investigated the long-term modifications of cellular immunity as a mechanism of RIT. The RIT group, included 15 house dust mite (HDM)-sensitized asthmatic children, received RIT only with Dermatophagoides farinae (Der f) and Dermatophagoides pteronyssinus (Der p), whereas the control group, consisted of 10 HDM-sensitized asthmatic children, did not receive RIT. The asthma symptom scores and the skin reactivities to Der f were measured. The cellular proliferative responses and intracellular interleukin (IL)-5 and interferon (IFN)-gamma productions from peripheral blood T cells were also measured before, 8 weeks and 1 yr after RIT. The symptom scores, skin reactivity to Der f and cellular proliferative responses to Der f were decreased significantly after 8 weeks and maintained until 1 yr of RIT. The IFN-gamma/IL-5 ratio of the CD3(+) and CD4(+) cells were increased significantly after 8 weeks and maintained until 1 yr of RIT, while there were no changes in the control group. These data indicate that the continuous functional modification from Th2 to Th1 phenotype of the CD4(+) T cells are developed after RIT in the asthmatic children sensitized with HDM.

Anaphylaxis following the ingestion of flour contaminated by house dust mites--a report of two cases from Singapore.

This study presents two patients who developed anaphylaxis after eating mite-contaminated food, and also contains a survey of dust-mites contamination in flour samples from Singapore households. The clinical records of each patient was studied. Patient A developed anaphylaxis twenty minutes following the ingestion of home-made fried fish coated with Japanese flour, while Patient B developed similar life-threatening symptoms one hour after the ingestion of home baked scones. Both patients were NSAID-intolerant and had a history of allergic rhinitis. Skin prick tests showed a strong positive result for dust-mites and for extracts prepared from the ingested flour. Flour samples were also examined microscopically which revealed large numbers of live Dermatophagoides farinae dust-mites. A survey of 57 flour samples showed that 4 samples (7%) were contaminated with dust mites. The findings in the present study confirm that mite-contamination of flour exists in Singaporean households, and it may trigger anaphylaxis in susceptible individuals.

Analysis of cross-reactivity between group 1 allergens from mites

Mite allergen exposure can lead to sensitization in genetically predisposed individuals, and the development of asthma in previously sensitized individuals. The major allergens of mites belong to Dermatophagoides spp. and Blomia tropicalis (Bt). Various allergens of Bt have been cloned and sequenced. Some of them show homology sequence with purified allergens from Dermatophagoides pteronissynus (Dp). Recently, the allergen group 1 from Bt, Blo t 1, was cloned and sequenced at our laboratory. Recombinant Blo t 1 showed 35 % of identity and 50% of similarity with group 1 allergens as Der p 1 (from Dp), Der f 1 (from D. farinae) and Eur m 1 (from Euroglyphus maynei) at amino acid level. This would suggest that cross-reactivity between allergens of different mite species could exist. Here, we analyzed the crossreactivity between group 1 allergens from mites using recombinant proteins and monoclonal antibodies against them. ELISA inhibition assay showed that crossreactivity between homologous allergens from Dermatophagoides spp. is high, but it is low to moderate between mites from different species. IgE-reactivity analysis using serum samples from allergic individuals revealed a strong reactivity of rBlo t 1 for serum samples from subjects with highly positive reaction to Bt extract in skin test, but lack of reactivity of this protein with serum samples from individuals with highly positive reaction to house dust mite extract in the skin test. These results suggest that it is important to include Bt allergens in routine skin test in order to improve the diagnostic accuracy and precision of allergies.

House Dust Mite Allergens in Domestic Homes in Cheonan, Korea

House dust mites produce inhalant allergens of importance to allergic patients. We measured the major group 1 allergens, Der p 1 and Der f 1, from the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farina, respectively in 100 randomly selected domestic homes from Cheonan, Korea. Dust samples were collected by vacuuming from the living room floor and 1 mattress in each home. Der p 1 and Der f 1 were measured by double monoclonal ELISA. Der p 1 levels were very low, with geometric mean levels for floors and mattresses being 0.11 microgram/g (range: 0.01-4.05) and 0.14 microgram/g (range: 0.01-30.0), respectively. Corresponding levels of Der f 1 were higher, 7.46 microgram/g (range: 0.01-262.9) and 10.2 microgram/g (range: 0.01-230.9) for floors and mattresses, respectively. D. farinae appears to be the dominant house dust mite in Cheonan.

Native troponin-T of the American cockroach (CR), Periplaneta americana, binds to IgE in sera of CR allergic Thais.

The American cockroach, Periplaneta americana, is the predominant cockroach (CR) species in Thailand and a major source of indoor allergens second only to the house dust mite. The incidence of CR allergy among allergic Thai patients is increasing but basic information on the allergenic components is scarce. In this study a recombinant troponin-T was produced by using cDNA prepared from RNA of the P. americana as a template and PCR primers designed from the P. americana troponin-T sequence deposited in the GenBank database. The recombinant protein (Mr approximately 50) did not bind to IgE in the sera of 18 skin prick test positive CR allergic patients. Rabbit polyclonal antiserum (PAb) against the recombinant troponin-T was produced and used in preparing an affinity column for the purification of native troponin-T from the crude P. americana extract (Mr approximately 47). IgE-immunoblotting revealed that the native protein bound to IgE in 3 of the 18 (16.7%) patients. Our results imply that native P. americana troponin-T, but not its recombinant counterpart, is a minor allergen among the CR allergic Thais.