髓系来源的免疫抑制性细胞在人酒精性肝病中的免疫调控机制的研究

It is important to find immunological factors that can drive the immune pathogenesis in human alcoholic liver disease (ALD). Recent studies showed that myeloid derived suppressor cells (MDSCs) is closely associated with liver diseases. However, the association between MDSCs and ALD has not been reported and the immune regulatory pathogenesis underlying disease progression remains unknown. Our recent study found that the MDSC frequency in patients with ALD was significantly higher than that in health controls and the MDSC frequency in patients with ALD was gradually increased compared that at baseline when they was given 5μg/kg/d G-CSF subcutaneously therapy. As such, we hypothesize that abnormal activation of immune system duo to long-time drinking could be negatively regulated by MDSC via the alleviation of inflammation and fibrosis in patients with ALD. Therefore, we design the study to test the hypothesis in order to explore MDSCs on immune regulatory mechanisms during human alcoholic liver diseases.

阐明酒精性肝病（alcoholic liver diseases,ALD）免疫致病机制对于了解此病具有重要意义。近来研究提示，人髓系来源的免疫抑制性细胞（myeloid derived suppressor cells, MDSCs）与肝脏疾病密切相关。然而，MDSC与ALD的关系目前未见相关报道，其参与调节的免疫学致病机制更不清楚。我们前期研究显示ALD患者gMDSC的频率明显升高（p < 0.01），同时接受重组人粒细胞集落刺激因子（G-CSF）治疗后重症酒精性肝炎患者的gMDSC频率较基线水平不断升高。因此，我们推测长期大量饮酒虽造成免疫系统异常活化，但gMDSC作为负向免疫调节细胞可以减轻肝脏炎症损伤进展。本项目拟扩大病例队列研究，同时设计功能实验和重症酒精性肝炎患者随机对照G-CSF临床试验，用于证实上述推测，以阐明gMDSC在酒精性肝病患者疾病进程中的作用及参与的免疫调控机制。

目的：髓系来源免疫抑制细胞（Myeloid derived suppressor cells, MDSCs）是最近鉴定的一种新型免疫调节细胞，但其在酒精性肝病（Alcoholic liver disease, ALD）中的特点及其与疾病进展的关系目前还不清楚。本研究首先探讨ALD患者外周血及肝内单核细胞型髓系来源抑制细胞（Monocytic myeloid derived suppressor cell,mMDSC）和粒细胞型髓系来源抑制细胞（Granulocytic myeloid derived suppressor cell,gMDSC）频率与差异以及它们与疾病进展的关系。.方法：本研究入组15例酒精性肝炎（Alcoholic hepatitis,AH）、89例酒精性肝硬化(Alcoholic cirrhosis,ALC)为研究对象，同时入组24例健康人作为对照。检测研究对象外周血gMDSCs和mMDSCs的频率和表型特点并分析与临床指标的相关性；通过免疫组化及共聚焦染色等技术观察研究对象肝脏组织gMDSCs的表达及分布特点；通过gMDSCs与自然杀伤细胞（Natural killer cell,NK）共培养观察gMDSCs的免疫调节功能。.结果：（1）与健康对照相比，ALD患者外周血gMDSCs与mMDSCs频率均显著升高；（2）与健康对照相比，ALD患者精氨酸酶阳性的gMDSCs与mMDSCs频率均显著升高；（3）免疫组化显示：ALC患者肝组织gMDSCs表达较健康对照及AH患者均显著增高；（4）在体外gMDSCs与NK细胞共培养发现，gMDSCs可抑制自体及NK细胞系产生TRAIL、IFN-γ和CD107a的能力。.结论：ALD患者外周血gMDSCs及mMDSCs频率升高，高表达精氨酸酶；ALC患者肝组织gMDSCs表达数量增多；gMDSCs可能通过精氨酸酶耗竭精氨酸，抑制NK细胞的活化。该研究揭示了gMDSCs与ALD患者疾病进展的关系，为深入研究酒精性肝病患者的免疫调节机制，寻找合适的治疗靶点提供了思路。