Norton Thoracic Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
Division of General Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Clin Transplant. 2023 Oct;37(10):e15067. doi: 10.1111/ctr.15067. Epub 2023 Jul 10.
Comparison of donation after brain death (DBD) and donation after cardiac death (DCD) lung tissue before transplantation have demonstrated activation of pro-inflammatory cytokine pathway in DBD donors. The molecular and immunological properties of circulating exosomes from DBD and DCD donors were not previously described.
We collected plasma from 18 deceased donors (12 DBD and six DCD). Cytokines were analyzed by 30-Plex luminex Panels. Exosomes were analyzed for liver self-antigen (SAg), Transcription Factors and HLA class II (HLA-DR/DQ) using western blot. C57BL/6 animals were immunized with isolated exosomes to determine strength and magnitude of immune responses. Interferon (IFN)-γ and tumor necrosis factor-α producing cells were quantified by ELISPOT, specific antibodies to HLA class II antigens were measured by ELISA RESULTS: We demonstrate increased plasma levels of IFNγ, EGF, EOTAXIN, IP-10, MCP-1, RANTES, MIP-β, VEGF, and interleukins - 6/8 in DBD plasma versus DCD. MiRNA isolated from exosome of DBD donors demonstrated significant increase in miR-421, which has been reported to correlate with higher level of Interleukin-6. Higher levels of liver SAg Collagen III (p = .008), pro-inflammatory transcription factors (NF-κB, p < .05; HIF1α, p = .021), CIITA (p = .011), and HLA class II (HLA-DR, p = .0003 and HLA-DQ, p = .013) were detected in exosomes from DBD versus DCD plasma. The circulating exosomes isolated from DBD donors were immunogenic in mice and led to the development of Abs to HLA-DR/DQ.
This study provides potential new mechanisms by which DBD organs release exosomes that can activate immune pathways leading to cytokine release and allo-immune response.
在移植前比较脑死亡供体（DBD）和心脏死亡供体（DCD）肺组织发现，DBD 供体中的促炎细胞因子途径被激活。此前尚未描述 DBD 和 DCD 供体循环外泌体的分子和免疫特性。
我们从 18 名已故供体中采集血浆（12 名 DBD 和 6 名 DCD）。通过 30-Plex luminex 面板分析细胞因子。使用 Western blot 分析外泌体中的肝自身抗原（SAg）、转录因子和 HLA Ⅱ类（HLA-DR/DQ）。用分离的外泌体免疫 C57BL/6 动物，以确定免疫反应的强度和幅度。通过 ELISPOT 定量 IFN-γ 和肿瘤坏死因子-α产生细胞，通过 ELISA 测量针对 HLA Ⅱ类抗原的特异性抗体。
我们发现 DBD 血浆中的 IFNγ、EGF、EOTAXIN、IP-10、MCP-1、RANTES、MIP-β、VEGF 和白细胞介素-6/8 等细胞因子水平高于 DCD。DBD 供体外泌体中分离的 miRNA 显示 miR-421 显著增加，据报道 miR-421 与白细胞介素-6 水平升高相关。从 DBD 血浆中外泌体中检测到更高水平的肝 SAg Collagen III（p=0.008）、促炎转录因子（NF-κB，p<0.05；HIF1α，p=0.021）、CIITA（p=0.011）和 HLA Ⅱ类（HLA-DR，p=0.0003 和 HLA-DQ，p=0.013）。从 DBD 供体中分离的循环外泌体在小鼠中具有免疫原性，并导致抗 HLA-DR/DQ 抗体的产生。
本研究提供了新的机制，即 DBD 器官释放外泌体可激活免疫途径，导致细胞因子释放和同种免疫反应。
