Effects of early allergen exposure on airway inflammation responses and airway hyper-reactivity in an asthma mouse model / 中华微生物学和免疫学杂志

Objective:To investigate the effects of early allergen exposure on airway inflammation responses and airway hyper-reactivity in a mouse model of asthma and the possible mechanism.Methods:Neonate BALB/c mice were randomly divided into three groups of normal control group, asthma group and early exposure group with eight in each group. The mice in the early exposure group were subcutaneously injected with 0.1 ml of ovalbumin (OVA) once a day for 10 consecutive days on the third day after birth and the other two groups were treated with 0.1 ml of PBS. Six weeks after birth, the mice in the asthma group and the early exposure group were sensitized with 0.2 ml of OVA allergen once a day for five consecutive days and then challenged with OVA 7 d after sensitization. The normal group was sensitized and challenged with PBS. Pathological changes in 1ung tissues were detected by HE or PAS staining. Flow cytometry was performed to quantify T cell subsets in bronchoalveolar lavage fluid (BALF). Th2-related cytokines (IL-4, IL-5 and IL-13) in BALF and the levels of OVA-specific IgE and IgG in serum were measured by ELISA. The percentages of CD4 + IFN-γ + T(Th1), CD4 + IL-4 + T(Th2) and CD4 + CD25 + Foxp3 + Treg cells in lung tissues were detected by flow cytometry. The airway resistance was detected using a small animal lung function testing system. Results:The pathological changes in lung tissues were less severe in the early exposure group than in the asthma group. However, PAS staining results showed no significant difference in cell metaplasia was found between the two groups. Compared with the asthma group, early exposure to OVA allergen significantly reduced the percentage of Th2 cells [(16.2±2.4)% vs (19.4±3.4)%, P<0.05] and increased the proportion of Treg cells [(3.7±0.4)% vs (2.1±1.4)%, P<0.05]. Moreover, the levels of IL-4 [(65.3±17.1) pg/ml vs (144.4±23.1) pg/ml] and IL-5 [(103.3±21.1) pg/ml vs (198.3±23.1) pg/ml] in BALF were significantly down-regulated in the early exposure group. A reduced production of OVA-specific IgE but not IgG in serum and an inhibited airway hyper-reactivity following OVA challenge were observed in the early exposure group. Conclusions:Early exposure to OVA allergen could offer a protective effect against OVA re-exposure-induced pathological changes, inflammatory responses and airway hyper-reactivity in grown-up mice.

Diversidade da exposição alergênica: implicações na obtenção da eficácia do controle ambiental: [revisão] / Diversity of allergen exposure: implications for the efficacy of environmental control: [review]

As doenças alérgicas, como a asma, rinite, conjuntivite alérgica e a dermatite atópica têm apresentado um aumento na sua prevalência nas últimas décadas. A relação entre exposição alergênica, sensibilização atópica e desenvolvimento de doenças alérgicas são amplamente descrita na literatura. OBJETIVO: Discutir a dificuldade no controle ambiental da exposição alergênica como parte do tratamento das doenças alérgicas. MÉTODOS: Analisar trabalhos de exposição alergênica realizados com metodologia similar na região central do Brasil, incluindo casas, hotéis, cinemas, carros, táxis, ônibus e transporte escolar. RESULTADOS: Níveis elevados dos alérgenos do grupo 1 de Dermatophagoides pteronyssinus (Der p 1) e de D. farinae (Der f 1), capazes de causar sensibilização e exacerbação de sintomas foram encontrados na maioria dos ambientes estudados em uma larga proporção das amostras, enquanto os alérgenos de animais domésticos atingiram maiores níveis em carros e veículos de transporte escolar. CONCLUSÃO: A diversidade da exposição alergênica mostra a necessidade de uma compreensão da doença alérgica pelos pacientes e familiares, e que as medidas de controle do ambiente doméstico fazem parte de uma estratégia global do tratamento das doenças alérgicas, uma vez que os indivíduos vivem em uma sociedade e não isoladas no interior de seus domicílios.

The prevalence of allergic diseases such as asthma, rhinitis, allergic conjunctivitis and atopic dermatitis has increased in the last decades. The relationship between allergen exposure, atopic sensitization and development of allergic diseases is widely described in the literature. AIM: To evaluate measures for reducing allergen exposure as part of the treatment of allergic diseases. METHODS: An analysis was made of previous studies on allergen exposure done with a similar methodology in the central region of Brazil; the study included homes, hotels, cinemas, cars, taxis, buses and scholar transportation. RESULTS: High levels of Der p 1 and Der f 1 mite allergens were found in a large proportion of the sample in most of the environments included in those studies; there were higher levels of pet allergens in cars and school transportation vehicles. CONCLUSION: The diversity of allergen exposure demonstrates the need for education about allergic diseases for patients and their families, as well as measures of reducing allergens in homes. This should be part of a global strategy of the management of allergic diseases, given that individuals live in society, not only in their houses.

Health Promotion and Prevention of Allergic Disease

The prevalence of allergic diseases have been increasing over the last few decades. These diseases have become a global public health problem and a burden to health care resources. Allergen exposure in the high risk group is one of the numerous factors contributing to the developing and worsening allergic diseases. Thus, prevention is a very important strategy in treating allergic diseases. This review focuses on environmental risk factors and possible preventive methods in combating allergic diseases.