Background. Sarcoidosis and hypersensitivity pneumonitis (HP) are immunologically mediated processes caused by hypersensitivity reaction accompanied by similar features including lymphocytic alveolitis and granuloma formation. Recent studies describe the role of TREM receptors in T cell activation, differentiation, and granuloma formation. Alveolar macrophages activation via TREM receptors may be the key factor mediating subsequent immune response. The aim of the study was to analyse TREM-1 and TREM-2 expression to identify further molecular mechanisms participating in the immunopathogenesis of sarcoidosis and HP. Methods. Flow cytometry was performed to analyse TREM-1 and TREM-2 expression on CD14⁺ cells in bronchoalveolar lavage fluid from patients having sarcoidosis or HP and a control group. Results. The study proved increased TREM-1 expression on alveolar macrophages in pulmonary sarcoidosis and diminished TREM-1 expression in HP-Sarcoidosis: median: 76.7; HP: median: 29.9; control: median: 53.3, (sarcoidosis versus HP: ; sarcoidosis versus control: ). TREM-2 expression was increased in both, sarcoidosis and HP-sarcoidosis: median: 34.79; HP: median: 36.00; control: median: 12.98, (sarcoidosis versus control: ; HP versus control: ). Correlation analysis showed negative correlation between TREM-1 and total number of CD8⁺ cytotoxic T cells. In sarcoidosis TREM-1 expression decreased with changes of HRCT image, decrease in CD4/CD8 ratio and decrease in DLCO. Conclusions. Differences in TREM receptor expression in sarcoidosis (increase in TREM-1 and TREM-2) and HP (increase in TREM-2) and correlation analysis suggests that activation via TREM may participate in typical immunological characteristics of sarcoidosis and HP.

中文翻译：

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在 T 细胞免疫反应的背景下，肺结节病和过敏性肺炎中支气管肺泡灌洗液中 CD14+ 细胞的 TREM-1 和 TREM-2 表达。

背景。结节病和过敏性肺炎 (HP) 是由过敏反应引起的免疫介导过程，伴有类似特征，包括淋巴细胞性肺泡炎和肉芽肿形成。最近的研究描述了 TREM 受体在 T 细胞活化、分化和肉芽肿形成中的作用。通过 TREM 受体激活肺泡巨噬细胞可能是介导后续免疫反应的关键因素。该研究的目的是分析 TREM-1 和 TREM-2 的表达，以确定参与结节病和 HP 免疫发病机制的进一步分子机制。方法。进行流式细胞术以分析 CD14 ^{+上 TREM-1 和 TREM-2 的表达}来自患有结节病或HP的患者和对照组的支气管肺泡灌洗液中的细胞。结果。研究证明肺结节病肺泡巨噬细胞 TREM-1 表达增加，HP-结节病 TREM-1 表达减少：中位数：76.7；HP：中位数：29.9；对照：中位数：53.3，（结节病与 HP：; 结节病与对照：）。TREM-2 在结节病和 HP 结节病中的表达均增加：中位数：34.79；HP：中位数：36.00；对照：中位数：12.98，（结节病与对照：; HP 与控制：）。^{相关分析显示TREM-1与CD8 +}细胞毒性T细胞总数呈负相关在结节病中，TREM-1 表达随着 HRCT 图像的变化、CD4/CD8 比值的降低和 DLCO 的降低而降低。结论。结节病（TREM-1 和 TREM-2 增加）和 HP（TREM-2 增加）中 TREM 受体表达的差异和相关性分析表明，通过 TREM 激活可能参与结节病和 HP 的典型免疫学特征。