Firestone Institute of Respiratory Health, Michael G DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada.
Clin Exp Allergy. 2014 Jul;44(7):921-9. doi: 10.1111/cea.12297.
Dendritic cells (DCs) are professional antigen-presenting cells that mediate the response to inhaled allergen. A major division in DC ontogeny exists between myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). A subtype of mDC expressing thrombomodulin, termed myeloid DCs type 2 (mDC2s), has been identified in both the circulation and lung and has recently been suggested to have a role in allergic asthma.
To investigate changes in circulating and sputum mDC2s after allergen inhalation in subjects with asthma.
Peripheral blood and induced sputum were obtained before and 3, 7, and 24 h after inhalation of diluent and allergen from allergic asthmatic subjects who develop both allergen-induced early- and late-phase responses. mDC2s were measured by flow cytometry. Soluble BDCA-3 (thrombomodulin) was measured in sputum by ELISA.
The number of sputum mDC2s significantly increased 24 h after allergen challenge compared with diluent. The expression of BDCA-3 on sputum mDCs also increased, albeit non-significantly, at 7 and 24 h after allergen. Soluble BDCA-3 in sputum and the number of circulating mDC2s were not different between allergen and diluent.
Myeloid DCs type 2 (mDC2s) increase in the sputum of subjects with asthma after allergen challenge, suggesting this subtype of mDC is involved in the regulation of allergen responses in the lung.
树突状细胞（DCs）是专业的抗原呈递细胞，介导对吸入变应原的反应。DC 个体发生中存在髓样 DC（mDCs）和浆细胞样 DC（pDCs）之间的主要分支。在循环和肺部均发现了表达血栓调节蛋白的 mDC 的一个亚型，称为 mDC2，最近有研究提示其在变应性哮喘中具有作用。
研究哮喘患者吸入变应原后循环和痰中 mDC2 的变化。
从发生变应原诱导的早相和晚相反应的过敏性哮喘患者中，在吸入稀释剂和变应原前及吸入后 3、7 和 24 h 时，分别采集外周血和诱导痰，通过流式细胞术检测 mDC2，通过 ELISA 法检测痰中可溶性 BDCA-3（血栓调节蛋白）。
与稀释剂相比，变应原吸入后 24 h 时痰中 mDC2 的数量显著增加。尽管在 7 和 24 h 时痰 mDC 上的 BDCA-3 表达也增加，但并不显著。痰中可溶性 BDCA-3 和循环 mDC2 的数量在变应原和稀释剂之间无差异。
变应原激发后哮喘患者痰中 mDC2 增加，提示 mDC2 亚型参与了肺内变应原反应的调节。
