[Characterization of asthma phenotypes in children of the tropics]. / Caracterización de fenotipos de asma en niños del trópico.

OBJECTIVE: Determine the main asthma phenotypes in a population of asthmatic children in Cartagena, Colombia. METHODS: 107 children (7 to 17 years old) with a previous diagnosis of asthma were recruited. Biomarkers of T2 inflammation were evaluated by measuring FeNO, eosinophil count in peripheral blood by hemocytometry, and determination of specific IgE to mite allergens by ELISA. The study was approved by the ethics committee of the University of Cartagena (SGR, Grant BPIN2020000100405). RESULTS: The average age of patients was 10,9 years. 19,6% of the children did not show elevation of any of the T2 inflammation biomarkers evaluated (FeNO<20ppb, eos<300/ul, negative specific IgE), so they were considered patients with non-allergic asthma (non-T2). 71,9% of all patients were sensitized to at least one allergen, this phenotype was considered allergic asthma. 30,8% of the patients presented the three elevated biomarkers (FeNO>20ppb + eos >300/ul + positive specific IgE), this phenotype was classified as high T2 allergic asthma. A moderate correlation (Spearman rho=0,44, p<0,0001) was found between FeNO values and eosinophil counts. CONCLUSION: In this study, the following phenotypes were found: allergic asthma, high T2 asthma, and non-allergic asthma. Most patients presented a type 2 inflammatory phenotype with allergic sensitization. In addition to the measurement of specific IgE, the use of FeNO and eosinophil count in peripheral blood help to accurately determine those patients with high T2 asthma phenotypes.

OBJETIVO: Determinar los fenotipos principales de asma en una población de niños asmáticos en Cartagena, Colombia. MÉTODOS: Se reclutaron 107 niños (entre 7 y 17 años), con diagnóstico previo de asma. Se evaluaron biomarcadores de inflamación T2 mediante la medición de FeNO, conteo de eosinófilos en sangre periférica mediante hemocitometría, y la determinación de IgE específica a alergenos de ácaros mediante ELISA. El estudio fue aprobado por el Comité de Ëtica de la Universidad de Cartagena (SGR, Grant BPIN2020000100405). RESULTADOS: La edad media de los pacientes fue de 10,9 años. El 19,6% de los niños no mostró elevación de ninguno de los biomarcadores de inflamación T2 evaluados (FeNO<20 ppb, eos<300/ul, IgE específica negativa), por lo que se consideraron como pacientes con asma no alérgica (no-T2). El 71,9% de todos los pacientes estaban sensibilizados al menos a un alergeno considerándose este fenotipo como asma alérgica. El 30,8% de los pacientes presentaron los tres biomarcadores elevados (FeNO>20 ppb + eos >300/ul + IgE específica positiva), clasificando este fenotipo como asma alérgica T2 alta. Se encontró una correlación moderada (Spearman rho=0,44, p<0,0001) entre los valores de FeNO y los conteos de eosinófilos. CONCLUSIÓN: En este estudio se encontraron los siguientes fenotipos de asma alérgica: asma T2 alta y asma no alérgica. La mayoría de los pacientes presentó un fenotipo inflamatorio tipo 2 con sensibilización alérgica. Además de la medición de la IgE específica, el uso del FeNO y los conteos de eosinófilos en sangre periférica ayudan a determinar con mayor exactitud a aquellos pacientes con fenotipos de asma T2 alto.

The Allergenic Activity of Blo t 2, a Blomia tropicalis IgE-Binding Molecule.

Only few allergens derived from house dust mite (HDM) species have been evaluated in terms of their potential to induce allergic inflammation. In this study, we aimed to evaluate different aspects of the allergenicity and allergenic activity of Blo t 2, a Blomia tropicalis allergen. Blo t 2 was produced as a recombinant protein in Escherichia coli. Its allergenic activity was tested in humans by skin prick test and basophil activation assays, and in mice, by passive cutaneous anaphylaxis and a model of allergic airway inflammation. Sensitization rate to Blo t 2 (54.3%) was similar to that found to Blo t 21 (57.2%) and higher than to Der p 2 (37.5%). Most Blo t 2-sensitized patients showed a low intensity response (99.5%). Blo t 2 elicited CD203c upregulation and allergen induced skin inflammation. Additionally, immunized animals produced anti-Blo t 2 IgE antibodies and passive transfer of their serum to non-immunized animals induced skin inflammation after allergen exposure. Immunized animals developed bronchial hyperreactivity and a strong inflammatory lung reaction (eosinophils and neutrophils). These results confirm the allergenic activity of Blo t 2 and supports its clinical relevance.

Diagnostic Performance of IgE Anti-Der p 10 to Identify Patients with Shrimp Allergy.

BACKGROUND: Patients with allergic rhinitis to house dust mites have an increased risk of shrimp allergy. Der p 10 is a candidate biomarker to predict the risk of shrimp allergy among allergic rhinitis patients. OBJECTIVES: The aim of this study was to evaluate the diagnostic performance of anti-Der p 10 IgE as a predictor of shrimp allergy. METHODS: A nested case-control study was carried out with eighty-six allergic rhinitis patients sensitized to mite (Dermatophagoides pteronyssinus) and shrimp (Litopenaeu vannamei). Cases and controls were defined by anti-Der p 10 IgE results. Oral challenge with shrimp was used as the gold standard for the evaluation of diagnostic performance. RESULTS: All shrimp oral challenge test (OCT)-positive patients were positive for IgE against Der p 10. The level of anti-Der p 10 IgE >1.2 kUA/mL had the best diagnostic performance (sensitivity 100%, specificity 65%) Conclusion: Anti-Der p 10 IgE is useful for predicting shrimp allergy diagnosis and could reduce the requirement of an OCT.

Structural and allergenic properties of the fatty acid binding protein from shrimp Litopenaeus vannamei.

BACKGROUND: The shrimp Litopenaeus vannamei is an important source of food allergens but its allergenic repertoire is poorly characterized. Cross-reactivity between crustacean and mites has been reported, with tropomyosin, the most relevant allergen involved. The aim of this study was to investigate the structural and immunological properties of a recombinant Fatty Acid Binding Protein (FABP) family from L. vannamei (LvFABP). METHODS: ELISA, skin prick test (SPT) and basophil activation assays were performed to determine IgE reactivity and allergenic activity of LvFABP. LC-MS/MS and Circular Dichroism experiments were done for structural analysis. B-cell epitope mapping with overlapping peptides, and cross-inhibition studies using human sera were done to identify antigenic regions and cross-reactivity. RESULTS: The recombinant LvFABP bound serum IgE from 27% of 36 shrimp allergic patients and showed allergenic activity when tested for basophil activation and SPT in a selected number of them. CD-spectroscopy of LvFABP revealed that the protein is folded with a secondary structure composed of mainly ß-strands and a smaller fraction of α helices. This is consistent with molecular modelling results, which exhibit a typical ß barrel fold with two α-helices and ten ß-strands. Epitope mapping identified two IgE-binding antigenic regions and inhibition assays found high cross-reactivity between LvFABP and Blo t 13, mediated by the antigenic region involving amino acids 54 to 72. CONCLUSIONS: Our results show that LvFABP is a shrimp allergen that cross reacts with the house dust mite allergen Blo t 13 and has allergenic activity, which suggest that it could be clinically relevant in case of shellfish allergy. This new allergen, named Lit v 13, will also help to understand basic mechanisms of sensitization to shrimp.

Clinical Relevance of Shrimp Sensitization in Patients with Allergic Rhinitis: Anti-Der p 10 IgE as Predictor.

INTRODUCTION: Cross-reactivity between shrimp and house dust mite (HDM) proteins has been widely documented. In tropical region, shrimp (5-15%) and mite sensitization (80-95%) is prevalent in allergic patients. However, the clinical relevance of shrimp sensitization in patients with allergic rhinitis (AR) has been poorly studied. The aim of this study was to determine the prevalence and the clinical relevance shrimp IgE sensitization in AR patients sensitized to Dermatophagoides pteronyssinus. METHODS: The study was conducted in Medellin (Colombia). A cross-sectional study in patients with AR sensitized to HDM was performed in 3 steps: (i) assessment of IgE sensitization frequency to shrimp Penaeus azteca, Litopenaeus vannamei, and tropomyosin homologous allergens rDer p 10, rPen a 1, and rLit v 1, (ii) evaluation of the clinical relevance of shrimp sensitization using oral challenge test (OCT) and (iii) identification of possible risk factors for positive-OCT results. Ethical committee approval was obtained. RESULTS: From 443 patients with AR, 86 (19.4%) were sensitized to shrimp and 23 of them (26.7%) had shrimp allergy diagnosis. Thirty-six of the patients sensitized to shrimp (41.2%) reported not previously consumed this food and eleven of them had a positive-OCT (30.5%). There was not statistically significant difference in total IgE or sIgE (D. pteronyssinus, P. azteca, L. vannamei, rPen a 1, and rLit v 1) between OCT groups (positive vs. negative results). Anti-Der p 10 IgE was associated with risk for a positive-OCT in different multivariable scenarios. DISCUSSION/CONCLUSION: Our results suggest that in patients with HDM-associated AR and shrimp IgE sensitization is necessary to evaluate the clinical relevance of shrimp IgE even if the patient has never consumed shrimp because of cross-reactivity. Anti-Der p 10 could be a possible biomarker of clinical relevance to shrimp sensitization and could reduce the need for OCTs.

Mosquitoes: Important Sources of Allergens in the Tropics.

There are more than 3,000 mosquito species. Aedes aegypti, Ae. communis, and C. quinquefasciatus are, among others, three of the most important mosquito allergen sources in the tropics, western, and industrialized countries. Several individuals are sensitized to mosquito allergens, but the epidemiological data indicates that the frequency of sensitization markedly differs depending on the geographical region. Additionally, the geographical localization of mosquito species has been affected by global warming and some mosquito species have invaded areas where they were not previously found, at the same time as other species have been displaced. This phenomenon has repercussions in the pathogenesis and the accuracy of the diagnosis of mosquito allergy. Allergic individuals are sensitized to mosquito allergens from two origins: saliva and body allergens. Exposure to saliva allergens occurs during mosquito bite and induces cutaneous allergic reactions. Experimental and clinical data suggest that body allergens mediate different manifestations of allergic reactions such as asthma and rhinitis. The most studied mosquito species is Ae. aegypti, from which four and five allergens of the saliva and body, respectively, have been reported. Many characterized allergens are homologs to arthropod-derived allergens, which cause strong cross-reactivity at the humoral and cellular level. The generalized use of whole body Ae. communis or C. quinquefasciatus extracts complicates the diagnosis of mosquito allergy because they have low concentration of saliva allergens and may result in poor diagnosis of the affected population when other species are the primary sensitizer. This review article discusses the current knowledge about mosquito allergy, allergens, cross-reactivity, and proposals of component resolved approaches based on mixtures of purified recombinant allergens to replace saliva-based or whole-body extracts, in order to perform an accurate diagnosis of allergy induced by mosquito allergen exposure.

The allergenic activity and clinical impact of individual IgE-antibody binding molecules from indoor allergen sources.

A large number of allergens have been discovered but we know little about their potential to induce inflammation (allergenic activity) and symptoms. Nowadays, the clinical importance of allergens is determined by the frequency and intensity of their IgE antibody binding (allergenicity). This is a rather limited parameter considering the development of experimental allergology in the last 20 years and the criteria that support personalized medicine. Now it is known that some allergens, in addition to their IgE antibody binding properties, can induce inflammation through non IgE mediated pathways, which can increase their allergenic activity. There are several ways to evaluate the allergenic activity, among them the provocation tests, the demonstration of non-IgE mediated pathways of inflammation, case control studies of IgE-binding frequencies, and animal models of respiratory allergy. In this review we have explored the current status of basic and clinical research on allergenic activity of indoor allergens and confirm that, for most of them, this important property has not been investigated. However, during recent years important advances have been made in the field, and we conclude that for at least the following, allergenic activity has been demonstrated: Der p 1, Der p 2, Der p 5 and Blo t 5 from HDMs; Per a 10 from P. americana; Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 from A. fumigatus; Mala s 8 and Mala s 13 from M. sympodialis; Alt a 1 from A. alternata; Pen c 13 from P. chrysogenum; Fel d 1 from cats; Can f 1, Can f 2, Can f 3, Can f 4 and Can f 5 from dogs; Mus m 1 from mice and Bos d 2 from cows. Defining the allergenic activity of other indoor IgE antibody binding molecules is necessary for a precision-medicine-oriented management of allergic diseases.

Identification of B Cell Epitopes of Blo t 13 Allergen and Cross-Reactivity with Human Adipocytes and Heart Fatty Acid Binding Proteins.

Cross-reactivity between allergens and human proteins could have a clinical impact in allergic diseases. Blo t 13 is an allergen from the mite Blomia tropicalis, which belongs to the fatty acid binding protein (FABP) family and has structural homology with human FABPs. This work aimed to map B cell epitopes on Blo t 13 and to identify epitopes involved in cross-reactivity with human heart FABP (FABP3) and adipocyte FABP (FABP4). Sera from 25 patients with house dust mite (HDM) allergy that were sensitized to Blo t 13 were used for testing the reactivity of immunoglobulin E (IgE) and IgG to FABP. The epitope mapping of Blo t 13 was performed using overlapping peptides, and cross-reactivity between Blo t 13 and human FABP was analyzed using human sera and anti-Blo t 13 monoclonal antibodies. IgE antibodies to all FABPs were detected in 14/25 serum samples, and IgG was detected in 25/25 serum samples. The cross-reactivity of Blo t 13 was 42% with FABP3 and 48% with FABP4. Two IgE-binding regions were identified in Blo t 13; one between residues 54 and 72 (the main cross-reacting region) and another between residues 111 to 129. Our results suggest that exposure to the Blo t 13 allergen could induce an auto-reactive response to endogenous FABP in allergic patients sensitized to Blo t 13.

Anticuerpos IgG4 específicos anti Aedes aegypti como factor protector en niños con dengue grave / Aedes aegypti-specifc IgG4 Antibodies as a Protection Factor in Children with Severe Dengue / Anticorpos IgG4 específicos anti-aedes aegypti como fator de proteção em crianças com dengue grave

Resumen: Introducción: La infección por el virus del dengue es un problema de salud pública mundial. El virus es transmitido por la picadura de mosquitos del género Aedes. Las proteínas de la saliva del vector Aedes aegypti inducen anticuerpos IgE e IgG4 específicos, cuya relación con la gravedad del dengue aún es desconocida. Objetivo: Evaluar la asociación entre anticuerpos IgE e IgG4 específicos anti A. aegypti con la gravedad de la infección por dengue. Método: Se realizó un estudio transversal en el que se incluyeron 16 niños con dengue grave (DG), 15 niños con dengue con signos de alarma (DCSA) y 26 niños sanos, todos menores de 15 años. Se determinaron niveles séricos de IgE e IgG4 específicas de A. aegypti; también se cuantificó VEGF, SST2 y VEGFRI por ELISA. Para las variables cualitativas se calcularon proporciones y odds ratio (OR); en las variables cuantitativas se hallaron medianas, rango intercuartílico y se utilizó la prueba U Mann Whitney. Resultados: La oportunidad de los niños de tener dg con niveles séricos de IgG4 específica mayores de 0,5 OD es 78 % menor [OR=0,22] (IC de 95 % de 0,06-0,77), comparado con la oportunidad de tener dg con niveles séricos de IgG4 específica menores de 0,5 OD. Plaquetas (p=0,0002) y VEFG (p=0,003) más elevado en los pacientes con DCSA y SST2 fue más alto en el DG (p=0,004). Conclusión: Niveles de anticuerpos de IgG4 anti A. aegypti se relacionan con menor gravedad clínica del dengue.

Abstract: Introduction: Dengue virus infection is a global public health problem. The bite of Aedes mosquitoes transmits the virus. The proteins in the saliva of the Aedes aegypti vector induce specific IgE and IgG4 antibodies, whose relationship with the severity of dengue is still unknown. Aim: To evaluate the association between A. aegypti-specific IgE and IgG4 antibodies and the severity of dengue infection. Method: A cross-sectional study was carried out involving 16 children with severe dengue (DG), 15 children with dengue and warning signs (DCSA), and 26 healthy children, all of them under 15 years of age. Serum levels of A. aegypti-specific IgE and IgG4 were determined; VEGF, SST2, and VEGFRI were also quantified by ELISA. For the qualitative variables, proportions and odds ratios (OR) were calculated; as to the quantitative variables, medians and interquartile range were found and the U Mann Whitney test was used. Results: Children's chance of having DG with specific IgG4 serum levels greater than 0.5 DO is 78 % lower [OR = 0.22] (95% CI, 0.06-0.77), compared to the possibility of having dg with specific IgG4 serum levels less than 0.5 DO. Platelets (p = 0.0002) and VEFG (p = 0.003) that are higher in patients with DCSA and SST2 were higher in DG (p = 0.004). Conclusion: A. aegypti-specific IgG4 antibody levels are related to lower clinical severity of dengue.

Resumo: Introdução: A infecção pelo vírus da dengue é um problema mundial de saúde pública. O vírus é transmitido pela picada de mosquitos do gênero Aedes. As proteínas na saliva do vetor Aedes aegypti induzem anticorpos IgE e IgG4 específicos, cuja relação com a gravidade da dengue ainda é desconhecida. Objetivo: Avaliar a associação entre anticorpos IgE e IgG4 específicos Anti-Aedes ae-gypti com a gravidade da infecção por dengue. Método: Foi realizado um estudo transversal no qual foram incluídas 16 crianças com dengue grave (DG), 15 crianças com dengue com sinais de alarme (DCSA) e 26 crianças saudáveis, todas com menos de 15 anos de idade. Os níveis séricos de IgE e IgG4 específicos para Aedes aegypti foram determinados. VEGF, SST2 e VEGFR1 também foram quantificados por ELISA. Para as variáveis qualitativas, foram calculadas proporções e odds ratio (OR). Nas variáveis quantitativas foram encontradas medianas, intervalo interquartil e utilizado o teste U de Mann Whitney. Resultados: A chance de as crianças terem dg com níveis séricos de IgG4 específica maiores que 0,5 od é 78% menor [OR=0,22] (IC 95% 0,06-0,77), em comparação com a chance delas terem dg com níveis séricos de IgG4 específica menor que 0,5 od. As plaquetas (p=0,0002) e VEFG (p=0,003) foram maiores nos pacientes com DCSA e o SST2 foi maior no DG (p=0,004). Conclusão: Os níveis de anticorpos IgG4 Anti-Aedes aegypti estão relacionados à menor gravidade clínica da dengue.

An Engineered Hybrid Protein from Dermatophagoides pteronyssinus Allergens Shows Hypoallergenicity.

The house dust mite (HDM) Dermatophagoides pteronyssinus is an important risk factor for asthma and rhinitis. Allergen specific immunotherapy that is based on recombinant proteins has been proposed for the safer and more efficient treatment of allergic diseases. The aim of this study was to design and obtain a hybrid protein (DPx4) containing antigenic regions of allergens Der p 1, Der p 2, Der p 7, and Der p 10 from this mite. DPx4 was produced in Escherichia coli and its folding was determined by circular dichroism. Non-denaturing dot-blot, ELISA, basophil activation test, dot blot with monoclonal antibodies, ELISA inhibition, and cysteine protease activity assays were performed. Mice that were immunized with DPx4 were also analyzed. We found that DPx4 had no cysteine protease activity and it showed significantly lower IgE reactivity than Der p 1, Der p 2, and D. pteronyssinus extract. DPx4 induced lower basophil activation than Der p 2 and the allergen extract. Immunized mice produced IgG antibodies that inhibited the binding of allergic patient's IgE to the allergen extract and induced comparatively higher levels of IL-10 than the extract in peripheral blood mononuclear cells (PBMC) culture. These results suggest that DPx4 has immunological properties that are useful for the development of a mite allergy vaccine.

Characterization of a hybrid protein designed with segments of allergens from Blomia tropicalis and Dermatophagoides pteronyssinus.

BACKGROUND: Sensitization to allergens of the house dust mites Dermatophagoides pteronyssinnus and Blomia tropicalis is an important risk factor for asthma and allergic diseases. Allergen-specific immunotherapy is currently based on natural allergen extracts, however, in the last years recombinant allergens with different modifications have shown promising immunological properties that may be advantageously applied for developing novel allergy vaccines. METHODS: A hybrid molecule (MAVAC-BD-2) containing epitopes of B. tropicalis (Blo t 5, Blo t 8 and Blo t 10) and D. pteronyssinus (Der p 1, Der p 2, Der p 7 and Der p 8) allergens was constructed, expressed in Escherichia coli and purified by affinity chromatography. Its folding was analyzed by circular dichroism. Antibody reactivities were evaluated by ELISA and non-denaturing dot blot assays using a battery of sera from mite allergic patients and non-allergic subjects. ELISA inhibition and dot blot assays with monoclonal antibodies were used to detect B-cell epitopes. Human basophil activation and induction of IgG-blocking antibodies in mice immunized with the hybrid protein were also evaluated. RESULTS: MAVAC-BD-2, expressed as a 22.8 kDa protein, showed a lower frequency and strength of IgE reactivity compared to Blo t 5, Der p 1, Der p 2 and the extracts of B. tropicalis and D. pteronyssinus. MAVAC-BD-2 inhibited 26% of IgE reactivity to Der p 2 and Blo t 5, reacted with anti-Der p 1 and anti-Der p 2 monoclonal antibodies and did not induce relevant basophil activation. MAVAC-BD-2 immunized mice produced specific antibodies that reacted against mite extracts and the purified allergens, as well as IgG antibodies that blocked the human IgE reactivity to mite extracts. CONCLUSION: MAVAC-BD-2 has hypoallergenic characteristics and in mice induces IgG antibodies that block the human IgE reactivity to mite extracts.

Allergens involved in the cross-reactivity of Aedes aegypti with other arthropods.

BACKGROUND: Cross-reactivity between Aedes aegypti and mites, cockroaches, and shrimp has been previously suggested, but the involved molecular components have not been fully described. OBJECTIVE: To evaluate the cross-reactivity between A aegypti and other arthropods. METHODS: Thirty-four serum samples from patients with asthma and/or allergic rhinitis were selected, and specific IgE to A aegypti, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Periplaneta americana. and Litopenaeus vannamei was measured by enzyme-linked immunosorbent assay. Cross-reactivity was investigated using pooled serum samples from allergic patients, allergenic extracts, and the recombinant tropomyosins (Aed a 10.0201, Der p 10, Blo t 10, Lit v 1, and Per a 7). Four IgE reactive bands were further characterized by matrix-assisted laser desorption/ionization tandem time of flight. RESULTS: Frequency of positive IgE reactivity was 82.35% to at least one mite species, 64.7% to A aegypti, 29.4% to P americana, and 23.5% to L vannamei. The highest IgE cross-reactivity was seen between A aegypti and D pteronyssinus (96.6%) followed by L vannamei (95.4%), B tropicalis (84.4%), and P americana (75.4%). Recombinant tropomyosins from mites, cockroach, or shrimp inhibited the IgE reactivity to the mosquito at a lower extent than the extracts from these arthropods. Several bands of A aegypti cross-reacted with arthropod extracts, and 4 of them were identified as odorant binding protein, mitochondrial cytochrome C, peptidyl-prolyl cis-trans isomerase, and protein with hypothetical magnesium ion binding function. CONCLUSION: We identified 4 novel cross-reactive allergens in A aegypti allergenic extract. These molecules could influence the manifestation of allergy to environmental allergens in the tropics.

Particularities of allergy in the Tropics.

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Identification and Characterization of IgE-Binding Tropomyosins in Aedes aegypti.

BACKGROUND: The mosquito Aedes aegypti is a potential source of important clinically relevant allergens. However, the allergenicity and cross-reactivity of most of these has not been fully described. METHODS: Natural wild-type mosquito tropomyosin was purified by size exclusion and anionic-exchange chromatography from an A. aegypti extract. Further characterization was accomplished by MALDI-TOF/TOF. Two recombinant variants of tropomyosin were obtained by expression in Escherichia coli. Specific IgE measurement by ELISA and skin tests for mosquito extract were performed in 12 patients with asthma or allergy rhinitis residing on the Caribbean island of Martinique. Cross-reactivity between natural A. aegypti tropomyosin and recombinant tropomyosins from A. aegypti, house dust mite, shrimp and Ascaris lumbricoides was analyzed by ELISA competition. RESULTS: Four variants of natural tropomyosin were purified. A band of 32 kDa in SDS-PAGE representing 2 tropomyosin variants (Aed a 10.0101 and Aed a 10.0201) reacted with specific IgE of 4 of the 12 (33%) allergic patients and with rabbit polyclonal anti-shrimp tropomyosin. A high degree of cross-reactivity (60-70%) was detected between natural mosquito tropomyosin and Blo t 10, Der p 10 and Lit v 1, and a lower degree with Asc l 3 from A. lumbricoides (<30%). rAed a 10.0101 inhibited IgE binding to natural A. aegypti tropomyosin; however, rAed a 10.0201 showed a low inhibitory capacity. CONCLUSION: Tropomyosin is a new IgE-binding protein from A. aegypti. Two of the 4 variants identified showed different degree of cross-reactivity with tropomyosins from other arthropods. The potential allergenic role of each variant should be further investigated.

Immunological aspects of the immune response induced by mosquito allergens.

Allergies caused by mosquito bites may produce local or systemic reactions. The inhalation of mosquito allergens may also cause asthma and/or allergic rhinoconjunctivitis in sensitized individuals. The mechanisms implicated in the development of these immune responses involve IgE antibodies, different subtypes of IgG and proinflammatory cytokines as well as basophils, eosinophils and mast cells. Several allergenic components have been identified in the saliva and bodies of mosquitoes and some of these are present in different mosquito species. The most common species implicated in allergic reactions belong to the genera Aedes, Culex and Anopheles. Several Aedes aegypti allergens have been cloned and sequenced. The recombinant molecules show IgE reactivity similar to that of the native allergens, making them good candidates for the diagnosis of mosquito allergies. Allergen-specific immunotherapy with mosquito extracts induces a protective response characterized by a decreased production of IgE antibodies, increased IgG levels, a reduction in the severity of cutaneous and respiratory symptoms and the need for medication. The aims of this review are to summarize the progress made in the characterization of mosquito allergens and discuss the types of immune responses induced by mosquito bites and the inhalation of mosquito allergens in atopic individuals.

El camarón como una fuente de alérgenos / Shrimp as an allergen source

La alergia a los mariscos es una de las alergias alimentarias de mayor prevalencia en muchos países, especialmente la inducida por el consumo o contacto con los camarones. A varias especies de camarón se les conoce la capacidad de inducir alergias; sin embargo, el conjunto de alérgenos que producen no se conoce y pocos de ellos se han caracterizado completamente. Este trabajo se llevó a cabo para conocer los avances recientes en la caracterización de los alérgenos del camarón y su relación con alérgenos de otros artrópodos de importancia en las alergias. Se hace énfasis en la especie Litopenaeus vannamei , la de mayor consumo en Colombia. A los alérgenos de los camarones mayormente caracterizados se les nombra según la nomenclatura oficial, aunque se les conoce más por la función biológica asociada. La tropomiosina, el alérgeno principal y más estudiado en diferentes especies de camarón, participa en la reacción cruzada entre el camarón y otros artrópodos, como los ácaros domésticos. Los otros alérgenos caracterizados parecen contribuir poco en este tipo de reacción. El potencial alergénico del camarón L. vannamei no está completamente dilucidado y unos pocos de sus alérgenos se han caracterizado, mientras que otros recientemente identificados, como la hemocianina y las proteínas de unión a ácidos grasos, se empiezan a investigar. Los resultados preliminares sugieren que participan en la reacción cruzada entre el camarón y los ácaros. La caracterización molecular e inmunológica del conjunto de alérgenos presentes en el camarón, ayudaría a conocer mejor su papel alergénico.

Allergy to shellfish is one of the most prevalent food allergies in several countries, especially the one induced by consuming or having contact with shrimp. Several shrimp species are known to induce allergy diseases. However, the whole spectrum of allergens they contain is unknown and few of them have been completely characterized. This study was done in order to know the recent advances in the characterization of shrimp allergens and its relationship with allergens from other arthropods of importance in allergic diseases. We emphasize the species Litopenaeus vannamei , the most consumed shrimp in Colombia. Well characterized shrimp allergens are named following an official classification; nevertheless, they are better known according to the biological function associated with them. Tropomiosin, the main and most studied allergen in different shrimp species, is involved in crossreactivity among shrimp and other arthropods like domestic mites. The other characterized allergens seem to have a minor participation in this cross-reactivity. The allergenic potential of L. vannamei is not well known and few of its allergens have been characterized, whilst others that were recently identified such as the hemocyanin and the fatty acid binding proteins are beginning to be studied. Preliminary results suggest that these allergens are involved in the cross-reactivity between shrimp and domestic mites, which deserves further evaluation. The molecular and immunological characterization of all allergens present in shrimp would help understanding its allergenic role.

[Shrimp as an allergen source]. / El camarón como una fuente de alérgenos.

Allergy to shellfish is one of the most prevalent food allergies in several countries, especially the one induced by consuming or having contact with shrimp. Several shrimp species are known to induce allergy diseases. However, the whole spectrum of allergens they contain is unknown and few of them have been completely characterized. This study was done in order to know the recent advances in the characterization of shrimp allergens and its relationship with allergens from other arthropods of importance in allergic diseases. We emphasize the species Litopenaeus vannamei , the most consumed shrimp in Colombia. Well characterized shrimp allergens are named following an official classification; nevertheless, they are better known according to the biological function associated with them. Tropomiosin, the main and most studied allergen in different shrimp species, is involved in crossreactivity among shrimp and other arthropods like domestic mites. The other characterized allergens seem to have a minor participation in this cross-reactivity. The allergenic potential of L. vannamei is not well known and few of its allergens have been characterized, whilst others that were recently identified such as the hemocyanin and the fatty acid binding proteins are beginning to be studied. Preliminary results suggest that these allergens are involved in the cross-reactivity between shrimp and domestic mites, which deserves further evaluation. The molecular and immunological characterization of all allergens present in shrimp would help understanding its allergenic role.

Papel de la biopelícula dental en la enfermedad periodontal / Biofilm role in periodontal disease

La biopelícula dental muestra una organización altamente compleja en relación a lo que se puede esperar de unos organismos que anteriormente se creían independientes y de poca capacidad de asociaciones. Tienen una forma de crecimiento y de sostenibilidad bastante avanzada y estructurada que facilita la supervivencia de los patógenos incluidos dentro de estas formas de asociación. El presente artículo es una revisión narrativa de mecanismos como el quórum sensing, la biopelícula dental y las acciones que pueden presentar éstas con la enfermedad periodontal que afectan a muchos seres humanos en todas las latitudes a nivel mundial. Se plantean posibles opciones de investigación y de campos futuros que faciliten aplicaciones a nivel de experimentación

Dental Biofilms are highly complex organization in relation to what you would expect some organisms previously thought and low capacity independent of associations. They have a sustainable growth and well advanced and structured to facilitate the survival of pathogens contained within these forms of association. This article is a narrative review of mechanisms such as quorum sensing, biofilm and the actions which can present these with periodontal diseases that affect many people at all latitudes worldwide. Options are proposed field research and to facilitate future experimental level applications

Nuevos esquemas de inmunoterapia específicas con alérgenos: [revisión] / New approaches for allergen-specific immunotherapy: [review]

Las enfermedades alérgicas, como el asma y la rinitis, son un problema de salud de importancia en todos los países y con una tendencia global al aumento en su prevalencia. La inmunoterapia específica con extractos alergénicos naturales es el único tratamiento con antígenos dirigido a brindar una protección duradera y que beneficia a la mayoría de la población tratada. Sin embargo, este tratamiento presenta inconvenientes porque los extractos son preparaciones de difícil estandarización y gran complejidad en sus componentes, lo que aumenta los riesgos de que se presenten reacciones adversas y nuevas sensibilizaciones a otros antígenos presentes en el extracto. Por lo tanto, se ha planteado la necesidad de desarrollar nuevos esquemas de inmunoterapia específica con el alérgeno en los que se utilicen moléculas bien caracterizadas de fácil estandarización y manejo, con las que se puedan brindar tratamientos más seguros y eficaces. Con estos nuevos esquemas se han diseñado vacunas basadas en alérgenos recombinantes y variantes o péptidos derivados de éstos, para ser administrados solos o con adyuvantes en preparaciones que favorecen la captación y presentación antigénica por las células dendríticas o tienen como blanco las células efectoras, como mastocitos y basófilos. Los estudios in vitro, en modelos animales y algunos en fase clínica en humanos, indican que estas preparaciones pueden brindar protección frente a la exposición alergénica o mejorar la sintomatología, al inducir la producción de anticuerpos bloqueadores de la actividad de la IgE, de células T reguladoras y de citocinas del perfil Th1.

Rates of allergic diseases such as asthma and rhinitis are on the rise as important health problems in every country of the world. Allergen specific immunotherapy with natural allergenic extracts is a treatment directed to changing the natural course of these diseases, and is a treatment that has reported beneficial effects in a majority of allergic patients. However, this treatment is difficult because of the complex composition of the extracts. The composition is difficult to standardize and, consequently, the risk of anaphylactic shock is increased; furthermore, sensitization can occur to other antigens present in the extract. Therefore, new allergen specific immunotherapy approaches are needed. Chemically defined and standardized antigens are more easily managed and provide a safer and more efficient treatment. Vaccines for immunotherapy have already been designed, based on recombinant allergens, variants (or peptides derived from them), that can be administrated alone or in combination with adjutants. Some of these preparations are indicated for facilitating the uptake and antigenic presentation by dendritic cells, or by targeting the mast cells and basophiles. Studies in vitro, in animal models and clinical trials in allergic patients, indicate that these preparations may provide protection against the allergen exposure and improve the symptoms by inducing the production of blocking antibodies of the IgE mediated response, production of regulator T cells and cytokines of Th1 profile.

[New approaches for allergen-specific immunotherapy]. / Nuevos esquemas de inmunoterapia específicas con alérgenos.

Rates of allergic diseases such as asthma and rhinitis are on the rise as important health problems in every country of the world. Allergen specific immunotherapy with natural allergenic extracts is a treatment directed to changing the natural course of these diseases, and is a treatment that has reported beneficial effects in a majority of allergic patients. However, this treatment is difficult because of the complex composition of the extracts. The composition is difficult to standardize and, consequently, the risk of anaphylactic shock is increased; furthermore, sensitization can occur to other antigens present in the extract. Therefore, new allergen specific immunotherapy approaches are needed. Chemically defined and standardized antigens are more easily managed and provide a safer and more efficient treatment. Vaccines for immunotherapy have already been designed, based on recombinant allergens, variants (or peptides derived from them), that can be administrated alone or in combination with adjutants. Some of these preparations are indicated for facilitating the uptake and antigenic presentation by dendritic cells, or by targeting the mast cells and basophiles. Studies in vitro, in animal models and clinical trials in allergic patients, indicate that these preparations may provide protection against the allergen exposure and improve the symptoms by inducing the production of blocking antibodies of the IgE mediated response, production of regulator T cells and cytokines of Th1 profile.