Asthma is a chronic debilitating airway disease affecting millions of people worldwide. Although largely thought to be a disease of the first world, it is now clear that it is on the rise in many middle- and lower-income countries. The disease is complex, and its etiology is poorly understood, which explains failure of most treatment strategies. We know that in children, asthma is closely linked to poor lung function in the first 3-years of life, when the lung is still undergoing post-natal alveolarization phase. Epidemiological studies also suggest that environmental factors around that age do play a critical part in the establishment of early wheezing which persists until adulthood. Some of the factors that contribute to early development of asthma in children in Western world are clear, however, in low- to middle-income countries this is likely to differ significantly. The contribution of fungal species in the development of allergic diseases is known in adults and in experimental models. However, it is unclear whether early exposure during perinatal or post-natal lung development influences a protective or promotes allergic asthma. Host immune cells and responses will play a crucial part in early development of allergic asthma. How immune cells and their receptors may recognize fungi and promote allergic asthma or protect by tolerance among other immune mechanisms is not fully understood in this early lung development stage. The aim of this review is to discuss what fungal species are present during early exposure as well as their contribution to the development of allergic responses.We also discuss how the host has evolved to promote tolerance to limit hyper-responsiveness to innocuous fungi, and how host evasion by fungi during early development consequentially results in allergic diseases.

中文翻译：

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儿童过敏性哮喘：发育过程中真菌的影响

哮喘是一种慢性气道疾病，影响全世界数百万人。尽管在很大程度上被认为是第一世界的疾病，但现在很明显，它在许多中低收入国家呈上升趋势。这种疾病很复杂，它的病因知之甚少，这解释了大多数治疗策略的失败。我们知道，哮喘与生命最初 3 年的肺功能不佳密切相关，此时肺仍处于出生后肺泡生命阶段。流行病学研究还表明，该年龄附近的环境因素确实在早期喘息的形成中发挥了关键作用，这种早期喘息一直持续到成年。然而，一些导致西方世界儿童哮喘早期发展的因素是明确的，然而，在低收入和中等收入国家，这可能会有很大差异。在成人和实验模型中，真菌物种在过敏性疾病发展中的作用是已知的。然而，尚不清楚围产期或产后肺部发育期间的早期暴露是否会影响保护性或促进过敏性哮喘。宿主免疫细胞和反应将在过敏性哮喘的早期发展中发挥关键作用。在这个早期的肺部发育阶段，免疫细胞及其受体如何识别真菌并促进过敏性哮喘或通过耐受等免疫机制进行保护尚不完全清楚。本综述的目的是讨论早期暴露期间存在哪些真菌种类以及它们对过敏反应发展的贡献。