Objective and design

This systematic review aims to establish the role of CD8 + T lymphocytes in COPD.

Methods

Forty-eight papers published in the last 15 years were identified for inclusion.

Results

CD8 + T-cells are increased in the lungs of patients with COPD (17 studies, 16 positive) whereas in the circulation, findings were inconclusive. Activation of CD8 + T-cells was enhanced in lungs (four studies, three positive) but cell phenotype was unclear. There was substantial evidence of a higher proportion of type 1 CD8 + (Tc1) cells in COPD (11 studies, 9 positive), though the population of type 2 (Tc2) cells was also increased (5 studies, 4 positive). CD8 + T-cells in COPD exhibited greater expression of cytotoxic proteins (five studies, five positive). Studies assessed a variety of questions so evidence was insufficient to draw firm conclusions. The role of CD8 + T-cells at acute exacerbation of COPD and also their contribution to alveolar destruction can only be hypothesised at this stage.

Conclusions

Not only is the number of CD8 + T-cells increased in COPD, these cells have increased capacity to exert effector functions and are likely to contribute to disease pathogenesis. Several mechanisms highlighted show promise for future investigation to consolidate current knowledge.

中文翻译：

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CD8+T淋巴细胞在慢性阻塞性肺疾病中的作用：系统评价

目标和设计

本系统评价旨在确定 CD8 + T 淋巴细胞在 COPD 中的作用。

方法

在过去 15 年中发表的 48 篇论文被确定纳入。

结果

CD8 + T 细胞在 COPD 患者的肺中增加（17 项研究，16 项阳性），而在循环中，结果尚无定论。CD8 + T 细胞的活化在肺中增强（四项研究，三项阳性），但细胞表型尚不清楚。有大量证据表明 COPD 中 1 型 CD8 + (Tc1) 细胞比例较高（11 项研究，9 项阳性），尽管 2 型 (Tc2) 细胞的数量也有所增加（5 项研究，4 项阳性）。COPD 中的 CD8 + T 细胞表现出更高的细胞毒性蛋白表达（五项研究，五项阳性）。研究评估了各种问题，因此证据不足以得出确切的结论。CD8 + T 细胞在 COPD 急性加重中的作用及其对肺泡破坏的贡献只能在现阶段假设。

结论

不仅在 COPD 中 CD8 + T 细胞的数量增加，这些细胞发挥效应功能的能力也增加了，并且可能有助于疾病的发病机制。突出显示的几种机制显示了未来调查巩固当前知识的希望。