Mold Allergens in Respiratory Allergy: From Structure to Therapy

Allergic reactions to fungi were described 300 years ago, but the importance of allergy to fungi has been underestimated for a long time. Allergens from fungi mainly cause respiratory and skin symptoms in sensitized patients. In this review, we will focus on fungi and fungal allergens involved in respiratory forms of allergy, such as allergic rhinitis and asthma. Fungi can act as indoor and outdoor respiratory allergen sources, and depending on climate conditions, the rates of sensitization in individuals attending allergy clinics range from 5% to 20%. Due to the poor quality of natural fungal allergen extracts, diagnosis of fungal allergy is hampered, and allergen-specific immunotherapy is rarely given. Several factors are responsible for the poor quality of natural fungal extracts, among which the influence of culture conditions on allergen contents. However, molecular cloning techniques have allowed us to isolate DNAs coding for fungal allergens and to produce a continuously growing panel of recombinant allergens for the diagnosis of fungal allergy. Moreover, technologies are now available for the preparation of recombinant and synthetic fungal allergen derivatives which can be used to develop safe vaccines for the treatment of fungal allergy.

Molecular Approach to Allergy Diagnosis and Therapy

Presently, allergy diagnosis and therapy procedures are undergoing a transition phase in which allergen extracts are being step-by-step replaced by molecule-based products. The new developments will allow clinicians to obtain detailed information on sensitization patterns, more accurate interpretation of allergic symptoms, and thus improved patients' management. In this respect, recombinant technology has been applied to develop this new generation of molecule-based allergy products. The use of recombinant allergens allows full validation of identity, quantity, homogeneity, structure, aggregation, solubility, stability, IgE-binding and the biologic potency of the products. In contrast, such parameters are extremely difficult to assay and standardize for extract-based products. In addition to the possibility of bulk production of wild type molecules for diagnostic purposes, recombinant technology opened the possibility of developing safer and more efficacious products for allergy therapy. A number of molecule-based hypoallergenic preparations have already been successfully evaluated in clinical trials, bringing forward the next generation of allergy vaccines. In this contribution, we review the latest developments in allergen characterization, molecule-based allergy diagnosis, and the application of recombinant allergens in therapeutic setups. A comprehensive overview of clinical trials using recombinant allergens as well as synthetic peptides is presented.

Molecular Approach to Allergy Diagnosis and Therapy

Presently, allergy diagnosis and therapy procedures are undergoing a transition phase in which allergen extracts are being step-by-step replaced by molecule-based products. The new developments will allow clinicians to obtain detailed information on sensitization patterns, more accurate interpretation of allergic symptoms, and thus improved patients' management. In this respect, recombinant technology has been applied to develop this new generation of molecule-based allergy products. The use of recombinant allergens allows full validation of identity, quantity, homogeneity, structure, aggregation, solubility, stability, IgE-binding and the biologic potency of the products. In contrast, such parameters are extremely difficult to assay and standardize for extract-based products. In addition to the possibility of bulk production of wild type molecules for diagnostic purposes, recombinant technology opened the possibility of developing safer and more efficacious products for allergy therapy. A number of molecule-based hypoallergenic preparations have already been successfully evaluated in clinical trials, bringing forward the next generation of allergy vaccines. In this contribution, we review the latest developments in allergen characterization, molecule-based allergy diagnosis, and the application of recombinant allergens in therapeutic setups. A comprehensive overview of clinical trials using recombinant allergens as well as synthetic peptides is presented.

Alérgenos recombinantes: papel no diagnóstico e na imunoterapia alérgeno-específica / Recombinant allergens: role in diagnosis and in allergen-specific immunotherapy

Nos últimos 30 anos tem havido um avanço notável na identificação, purificação e expressão recombinante de alérgenos relevantes das mais variadas fontes, incluindo ácaros, insetos, mamíferos, polens, alimentos, fungos, látex e outras fontes. Estes avanços resultaram na utilização crescente de alérgenos purificados, naturais ou recombinantes, para melhorar o diagnóstico de alergia pelos métodos que dispomos, incluindo os testes cutâneos de hipersensibilidade imediata, e os métodos in vitro para medida de anticorpos IgE específicos, como ImmunoCAP, ImmunoCAP-ISAC, ELISA e MARIA. Mais recentemente, o uso de alérgenos recombinantes de pólen de bétula (rBet v 1) e de gramas (coquetel de 5 alérgenos) em imunoterapia foi relatado como seguro e eficaz, com resultados comparáveis aos obtidos usando extratos naturais, em pacientes com rinoconjuntivite alérgicos a polens. No presente artigo, apresentamos revisão atualizada do uso de alérgenos recombinantes em diagnóstico de alergia e em imunoterapia alérgeno-específica, incluindo novas estratégias de imunoterapia. Focalizamos na avaliação crítica de estudos que investigaram sensibilidade, especificidade, reatividade cruzada e valor prognóstico de métodos diagnósticos com uso de alérgenos recombinantes versus extratos naturais; nas recomendações atuais para o uso destes novos métodos na prática clínica; e na revisão de estudos clínicos com imunoterapia usando alérgenos recombinantes realizados até o momento.

Over the past 30 years, a great deal of progress has been made in the identification, purification,and recombinant expression of relevant allergens from various sources, including mites, insects,mammals, pollens, foods, fungi, latex, and other sources. These new developments have resultedin an increasing use of purified allergens, either natural or recombinant, to improve the diagnosisof allergy via the methods currently available, including skin tests and in vitro tests for measuringspecific IgE antibodies, e.g., ImmunoCAP, ImmunoCAP-ISAC, ELISA, and MARIA. More recently,the use of recombinant allergens from birch pollen (rBet v 1) and from grass pollen (a cocktailof five allergens) in immunotherapy has been reported to be safe and effective, with resultscomparable to those obtained with natural extracts in patients with rhino-conjunctivitis due topollen allergy. In the present article, we present an up-to-date review on the use of recombinantallergens in the diagnosis of allergy and in allergen-specific immunotherapy, including newstrategies for immunotherapy. We focus on the critical analysis of studies that have investigatedsensitivity, specificity, cross-reactivity, and the prognostic value of diagnostic methods that includerecombinant allergens versus natural extracts; on current recommendations for the use of thesenew methods in clinical practice; and on the review of clinical studies using immunotherapy withrecombinant allergens performed to date.

Alérgenos recombinantes na prática da imunoterapia / Recombinant allergens in immunotherapy practice

Objetivo: Avaliar a associação das variaveis ambientais temperatura e velocidade dos ventos com o perfil de atendimento de crianças asmáticas. Métodos: Por intermédio de estudo retrospectivo dos arquivos públicos do Hospital e Pronto Socorro Municipal de cuiaba/ MT(HPSMC) foram separados 25.803 prontuários de crianças menores de cinco anos, realizando-se, posteriormente, análises das associações entre as com diagnóstico de asma nos atendimentos ambulatoriais e internações com as variáveis ambientais temperatura e velocidade dos ventos. Para mensuração do desfecho foram empregadas análises de regressão linear simples e múltipla. Resultados: A variável ambiental temperatura apresentou-se como preditora (p

Objective: To evaluate the association of environmental variety temperature and wind velocity whit profile on asthmatic children. Methods: Across the public files at Cuiaba' s Hospital and First-Aid Clinic, 25803 promptbooks about 0-5-year-old children were taken apart, accomplishing, afterwards, analysis of association among those children who has gotten asthma diagnosis on outpatient service and admission with environmental variants, temperature and wind velocity. For analysis of outcome were utilized linear regression sim pie and multiple. Results: The environmental variety temperature has presented as a predictor (p

Cloning, sequence analysis, and expression of cDNA coding for the major house dust mite allergen, Der f 1, in Escherichia coli

Our objective was to clone, express and characterize adult Dermatophagoides farinae group 1 (Der f 1) allergens to further produce recombinant allergens for future clinical applications in order to eliminate side reactions from crude extracts of mites. Based on GenBank data, we designed primers and amplified the cDNA fragment coding for Der f 1 by nested-PCR. After purification and recovery, the cDNA fragment was cloned into the pMD19-T vector. The fragment was then sequenced, subcloned into the plasmid pET28a(+), expressed in Escherichia coli BL21 and identified by Western blotting. The cDNA coding for Der f 1 was cloned, sequenced and expressed successfully. Sequence analysis showed the presence of an open reading frame containing 966 bp that encodes a protein of 321 amino acids. Interestingly, homology analysis showed that the Der p 1 shared more than 87 percent identity in amino acid sequence with Eur m 1 but only 80 percent with Der f 1. Furthermore, phylogenetic analyses suggested that D. pteronyssinus was evolutionarily closer to Euroglyphus maynei than to D. farinae, even though D. pteronyssinus and D. farinae belong to the same Dermatophagoides genus. A total of three cysteine peptidase active sites were found in the predicted amino acid sequence, including 127-138 (QGGCGSCWAFSG), 267-277 (NYHAVNIVGYG) and 284-303 (YWIVRNSWDTTWGDSGYGYF). Moreover, secondary structure analysis revealed that Der f 1 contained an a helix (33.96 percent), an extended strand (17.13 percent), a ß turn (5.61 percent), and a random coil (43.30 percent). A simple three-dimensional model of this protein was constructed using a Swiss-model server. The cDNA coding for Der f 1 was cloned, sequenced and expressed successfully. Alignment and phylogenetic analysis suggests that D. pteronyssinus is evolutionarily more similar to E. maynei than to D. farinae.