LIIPAT, Institute of Pathology and Centre for Immune Regulation, University of Oslo and Oslo University Hospital, Oslo, Norway.
Thorax. 2011 Feb;66(2):151-6. doi: 10.1136/thx.2010.149591. Epub 2010 Dec 16.
Childhood represents an immunological window of vulnerability in which individuals are at increased risk for both serious infections and development of allergic diseases, particularly affecting the airways. However, little is known about how the airway mucosal immune system is organised and functions during early age. Here, the organisation of immune cells in bronchial mucosa of children was characterised.
Immunophenotyping was performed on mucosal samples obtained postmortem from nine children aged 2-15 years without any history of atopic manifestations or any signs of respiratory disease, who died from non-inflammatory causes.
In all nine cases, isolated lymphoid follicles (ILFs), interpreted as bronchus-associated lymphoid tissue (BALT), were found, constituting an average frequency of 60 ILFs/cm(2) of airway mucosal surface. Outside these ILFs, dense networks of CD11c(+) myeloid dendritic cells (DCs), CD68(+) macrophages and CD3(+)CD45RA(-) memory T cells were found. Plasmacytoid DCs occurred in low numbers. Importantly, intraepithelial antigen-presenting cells were found to extend cellular projections into the airway lumen.
The density and location of antigen-presenting cells and T cells in this age group are similar to those observed in adults. However, in contrast to adults, BALT appears to be a normal feature of the airway mucosa throughout childhood, suggesting that these structures contribute to regional immunity and homeostasis. This indicates that the local immune system in the airways of children has unique features which should be taken into account, not only when studying airway immunology and immunopathology, but also in the development of mucosal vaccines.
儿童期是一个免疫脆弱期，在此期间，个体患严重感染和过敏性疾病（尤其是呼吸道疾病）的风险增加。然而，人们对于早期气道黏膜免疫系统的组织和功能仍知之甚少。本研究旨在对儿童支气管黏膜中的免疫细胞进行组织分析。
对 9 名无特应性表现或任何呼吸道疾病迹象、因非炎症性原因死亡的 2-15 岁儿童死后获取的支气管黏膜样本进行免疫表型分析。
在所有 9 例中，均发现了孤立淋巴滤泡（ILF），其被认为是支气管相关淋巴组织（BALT），占气道黏膜表面 60 ILF/cm2 的平均频率。在这些 ILF 之外，发现了密集的 CD11c+髓样树突状细胞（DC）、CD68+巨噬细胞和 CD3+CD45RA-记忆 T 细胞网络。浆细胞样 DC 数量较少。重要的是，上皮内抗原呈递细胞的细胞突起延伸至气道腔中。
在该年龄组中，抗原呈递细胞和 T 细胞的密度和位置与成人相似。然而，与成人不同的是，BALT 似乎是儿童整个气道黏膜的一个正常特征，这表明这些结构有助于局部免疫和稳态。这表明儿童气道中的局部免疫系统具有独特的特征，不仅在研究气道免疫学和免疫病理学时需要考虑，而且在黏膜疫苗的开发中也需要考虑。
