Department of Surgery, University of Chicago, Chicago, Illinois, USA.
Office of Shared Research Facilities, University of Chicago, Chicago, Illinois, USA.
Clin Transplant. 2022 Jul;36(7):e14670. doi: 10.1111/ctr.14670. Epub 2022 Apr 18.
Ex vivo lung perfusion (EVLP) is used to assess and preserve lungs prior to transplantation. However, its inherent immunomodulatory effects are not completely understood. We examine perfusate and tissue compartments to determine the change in immune cell composition in human lungs maintained on EVLP.
Six human lungs unsuitable for transplantation underwent EVLP. Tissue and perfusate samples were obtained during cold storage and at 1-, 3- and 6-h during perfusion. Flow cytometry, immunohistochemistry, and bead-based immunoassays were used to measure leukocyte composition and cytokines. Mean values between baseline and time points were compared by Student's t test.
During the 1st hour of perfusion, perfusate neutrophils increased (+22.2 ± 13.5%, p < 0.05), monocytes decreased (-77.5 ± 8.6%, p < 0.01) and NK cells decreased (-61.5 ± 22.6%, p < 0.01) compared to cold storage. In contrast, tissue neutrophils decreased (-22.1 ± 12.2%, p < 0.05) with no change in monocytes and NK cells. By 6 h, perfusate neutrophils, NK cells, and tissue neutrophils were similar to baseline. Perfusate monocytes remained decreased, while tissue monocytes remained unchanged. There was no significant change in B cells or T cell subsets. Pro-inflammatory cytokines (IL-1b, G-CSF, IFN-gamma, CXCL2, CXCL1 granzyme A, and granzyme B) and lymphocyte activating cytokines (IL-2, IL-4, IL-6, IL-8) increased during perfusion.
Early mobilization of innate immune cells occurs in both perfusate and tissue compartments during EVLP, with neutrophils and NK cells returning to baseline and monocytes remaining depleted after 6 h. The immunomodulatory effect of EVLP may provide a therapeutic window to decrease the immunogenicity of lungs prior to transplantation.
体外肺灌注 (EVLP) 用于在移植前评估和保存肺。然而，其内在的免疫调节作用尚不完全清楚。我们检查灌流液和组织腔室，以确定在 EVLP 中维持的人肺中的免疫细胞组成的变化。
6 个不适合移植的人肺进行 EVLP。在冷藏期间以及灌注的 1、3 和 6 小时时获得组织和灌流液样本。使用流式细胞术、免疫组织化学和基于珠子的免疫测定法测量白细胞组成和细胞因子。通过 Student's t 检验比较基线和时间点之间的平均值。
在灌注的第 1 小时，与冷藏相比，灌流液中的中性粒细胞增加（+22.2 ± 13.5%，p < 0.05），单核细胞减少（-77.5 ± 8.6%，p < 0.01），NK 细胞减少（-61.5 ± 22.6%，p < 0.01）。相比之下，组织中的中性粒细胞减少（-22.1 ± 12.2%，p < 0.05），单核细胞和 NK 细胞没有变化。到 6 小时时，灌流液中的中性粒细胞、NK 细胞和组织中的中性粒细胞与基线相似。灌流液中的单核细胞仍然减少，而组织中的单核细胞保持不变。B 细胞或 T 细胞亚群没有明显变化。促炎细胞因子（IL-1b、G-CSF、IFN-γ、CXCL2、CXCL1 颗粒酶 A 和颗粒酶 B）和淋巴细胞激活细胞因子（IL-2、IL-4、IL-6、IL-8）在灌注过程中增加。
在 EVLP 过程中，固有免疫细胞在灌流液和组织腔室中都发生早期动员，中性粒细胞和 NK 细胞在 6 小时后恢复到基线，而单核细胞仍然耗竭。EVLP 的免疫调节作用可能为在移植前降低肺的免疫原性提供一个治疗窗口。
