哮喘联盟

   摘要
   背景：前期研究发现，儿童期医疗条件改善和感染发生率下降可影响过敏性疾病的进展。卫生学相关的机制尚未完全清楚，但两个明显矛盾的免疫学指标支持这一点：Th1和Th2细胞因子和IL-10介导的Th2细胞因子调节。
   目的：本试验采用潜类分析定义免疫学表型，在拉丁美洲人群中研究这些表型与环境因素、过敏症和哮喘标志物的关系。
   方法：居住在巴西城市的1127名儿童入选本研究。采用标准的问卷调查收集有关喘息和环境暴露相关的信息。特应性通过检测血清空气过敏原特异性IgE和皮肤针刺试验进行评价。体外有丝分裂原刺激外周血白细胞后，检测培养液中的细胞因子水平。病原体感染通过血液学和粪便检查进行来评价。儿童分为感染高负担和低负担组。基于细胞因子产生，采用潜类分析鉴别免疫表型。采用Logistic回归评价校正后的环境和感染负担对免疫表型的影响以及表型对特应性和哮喘的影响。
   结果：共找到3个表型，分别为低反应性、中等反应性和高反应性。母亲教育水平较高、居住地环境得到改善以及较低感染负担的儿童，更有可能出现高反应性表型。高反应表型与特应性（非哮喘）患病率增加显著相关。
   结论：研究结果有助于更好的了解拉丁美洲城市人群中免疫机制在卫生学假设中的作用。
 

                                                                (林江涛 审校)
JAllergyClinImmunol. 2013Feb13.pii:S0091-6749(13)00153-X.doi:10.1016/j.jaci.2013.01.016. [Epub ahead of print]
 

Environmental conditions, immunologic phenotypes, atopy, and asthma: New evidence of how hygiene hypothesis operates in Latin America.
 
Figueiredo CA, Amorim LD, Alcantara-Neves NM, Matos SM, Cooper PJ, Rodrigues LC, Barreto ML.

Source
Instituto de Ciências da Saúde, Universidade Federal de Bahia, Salvador, Brazil.

Abstract
BACKGROUND: It has been proposed that improved hygiene and reduced experience of infections in childhood influences the development of allergic diseases. The mechanisms by which the hygiene operates are not well established but are underpinned by two apparently incompatible immunologic paradigms, the balance of T(H)1 versus T(H)2 cytokines and IL-10-mediated regulation of T(H)2 cytokines.
OBJECTIVE: This study defined immunologic phenotypes with the use of latent class analysis and investigated their associations with environmental factors, markers of allergy and asthma, in a Latin American population.
METHODS: We studied 1127 children living in urban Brazil. Data on wheeze and environmental exposures were collected with standardized questionnaires. Atopy was measured by specific IgE in serum and skin prick test reactivity to aeroallergens. Cytokines were measured in culture after the stimulation of peripheral blood leukocytes with mitogen. Infections with pathogens were assessed by serology and stool examinations. Children were classified as having high or low burden of infection. Latent class analysis was used to identify immune phenotypes on the basis of cytokine production. Logistic regression was used to evaluate the adjusted effects of environment and burden of infection on the immunologic phenotypes and the effect of the phenotypes on atopy and asthma.
RESULTS: Three phenotypes were identified, labeled underresponsive, intermediate, and responsive. Children of more educated mothers, living in improved environmental conditions, and with a low burden of infection were significantly more likely to have the responsive phenotype. The responsive phenotype was significantly associated with an increased prevalence of atopy but not asthma.
CONCLUSION: Our findings contribute to a better understanding of the immune mechanisms by which the hygiene hypothesis operates in urban Latin America.
 

JAllergyClinImmunol.2013Feb13.pii:S0091-6749(13)00153-X.doi:10.1016/j.jaci.2013.01.016. [Epub ahead of print]