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

Laboratory animals and respiratory allergies: The prevalence of allergies among laboratory animal workers and the need for prophylaxis

OBJECTIVE: Subjects exposed to laboratory animals are at a heightened risk of developing respiratory and allergic diseases. These diseases can be prevented by simple measures such as the use of personal protective equipment. We report here the primary findings of the Laboratory Animals and Respiratory Allergies Study regarding the prevalence of allergic diseases among laboratory animal workers, the routine use of preventive measures in laboratories and animal facilities, and the need for prevention programs. METHODS: Animal handlers and non-animal handlers from 2 Brazilian universities (University of São Paulo and State University of Campinas) answered specific questionnaires to assess work conditions and symptoms. These subjects also underwent spirometry, a bronchial challenge test with mannitol, and skin prick tests for 11 common allergens and 5 occupational allergens (rat, mouse, guinea pig, hamster, and rabbit). RESULTS: Four hundred fifty-five animal handlers (32±10 years old [mean±SD], 209 men) and 387 non-animal handlers (33±11 years old, 121 men) were evaluated. Sensitization to occupational allergens was higher among animal handlers (16%) than non-animal handlers (3%, p<0.01). Accessibility to personal protective equipment was measured at 85% (median, considering 73 workplaces of the animal handler group). Nineteen percent of the animal handlers indicated that they wear a respirator at all times while handling animals or working in the animal room, and only 25% of the animal handlers had received an orientation about animal-induced allergies, asthma, or rhinitis. CONCLUSION: In conclusion, our data indicate that preventive programs are necessary. We suggest providing individual advice to workers associated with institutional programs to promote a safer work environment. .

Effect of ozone on response to ovalbumin & its modulation by vitamins C & E in sensitized guinea pigs.

Background & objectives: Exposure to ozone and asthma are both associated with increased oxidative stress. Exposure to ozone therefore, may potentiate the airway response to allergens. We undertook this study to investigate the effect of ozone exposure on airway response to ovalbumin in sensitized guinea pigs and its modulation by dietary supplementation with antioxidant vitamins C and E. Methods: After in vivo measurements of specific airways conductance (SGaw) and airway hyperresponsiveness (AHR) to inhaled histamine, guinea pigs were sensitized to ovalbumin and divided into three groups: (i) sensitized; (ii) sensitized and exposed daily to ozone; and (iii) sensitized, exposed daily to ozone and given dietary supplementation with vitamin C, 2 mg/kg body wt and E, 7 IU/kg body wt. A control group of nonsensitized animals was included. After 4 wk, AHR was measured again and animals were challenged with inhaled ovalbumin. Changes in SGaw were followed for early and late airway bronchoconstrictive responses. The following measurements were obtained: (i) parameters of oxidative stress - plasma malonaldehyde (MDA) as marker of lipid peroxidation and superoxide anion generation by leukocytes and bronchoalveolar lavage (BAL) cells; (ii) antioxidant status: red cell superoxide dismutase (SOD); and (iii) glutathione peroxidase (GPx). BAL cytology was studied. Results: Ozone exposure resulted in an increase in AHR and early and late bronchoconstrictive responses after ovalbumin challenge, greater superoxide anion generation in BAL cells, higher plasma MDA levels and decrease in red cell SOD activity. Dietary supplementation with vitamin C and E prevented or ameliorated these responses. Interpretation & conclusions: Exposure to ozone at concentrations of 0.12 ppm for 2 h daily for 4 wk enhances the airway response to allergens in sensitized guinea pigs. Dietary supplementation with antioxidant vitamins E and C, affords variable degree of protection against this enhancement.

Allergy to house dust mites and asthma

House dust mites have been shown to be important sources of indoor allergens associated with asthma and other allergic conditions. Asthma is a chronic respiratory disease that affects millions of people worldwide, and numerous scientific studies have shown that the prevalence of asthma is increasing. The most common dust mite species around the world include Dermatophagoides pteronyssinus (Dp), Dermatophagoides farinae (Df), Euroglyphus maynei (Em) and Blomia tropicalis (Bt). Over the past three decades, many important allergens from these species have been identified and characterized at the molecular level. The biological function of several house dust mite allergens has been elucidated, with many of them showing enzymatic activity. However, Bt allergens remain the least studied, even though this mite is very common in tropical and subtropical regions of the world, including Puerto Rico. Therefore, it is very important to include Bt in diagnostic and therapeutic strategies for house dust mite induced allergy and asthma, particularly in areas where Bt exposure and sensitization is high. Recombinant DNA technology, as well as other molecular biology and immunological techniques, have played a fundamental role in advances towards a better understanding of the biology of house dust mites and their role in allergic diseases. This kind of study also contributes to the understanding of the complex immunologic mechanisms involved in allergic reactions. The development of effective diagnostic and therapeutic approaches depends on the continuity of research of house dust mite allergens. The objectives of this review are to describe the most important aspects of house dust mite allergy and to acquaint the scientific community with the latest findings pertaining to house dust mite allergens, particularly those derived from Bt.