Department of Hematology, Oncology and Tumor Immunology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
Department of Congenital Heart Surgery, Pediatric Heart Surgery, Deutsches Herzzentrum Berlin, Berlin, Germany.
Transplantation. 2019 Nov;103(11):2234-2244. doi: 10.1097/TP.0000000000002799.
Graft-versus-host disease (GvHD) presents a major cause for morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Rabbit-derived antithymocyte globulin (rATG) treatment reduces the incidence of GvHD after allogeneic hematopoietic stem cell transplantation. However, delayed immune reconstitution following rATG treatment, partly caused by hampered thymic function, is being discussed. The present study aims at elucidating possible cytotoxic effects of 2 commonly used rATG preparations on cultured human thymic stroma, especially thymic epithelial cells (TECs).
A primary TEC culture was established and the binding and cytotoxicity of 2 rATG preparations to the aforementioned cells were assessed by flow cytometry and immunofluorescence analyses. The release of several cytokines by cultured thymic stroma cells in response to rATG was analyzed via multiplex enzyme-linked immunosorbent assays.
Both preparations showed a comparable dose-dependent binding to TECs and exerted a similar complement-independent, dose-dependent cytotoxicity. rATG exposure further resulted in hampered secretion of interleukin (IL)-7, IL-15, and IL-6, cytokines being involved in thymic T cell development and proliferation. Pretreatment with keratinocyte growth factor diminished rATG-induced cytotoxicity of TECs and restored their IL-7 and IL-15 secretion.
Cytotoxic effects on TECs link the rATG-induced thymic damage to the delayed T cell reconstitution, witnessed after rATG treatment. Our data support a combination treatment of rATG and thymus-protective strategies such as keratinocyte growth factor to simultaneously offer sufficient GvHD prophylaxis and overcome delayed T cell reconstitution caused by thymic damage.
移植物抗宿主病（GvHD）是异基因造血干细胞移植后发病率和死亡率的主要原因。兔源性抗胸腺细胞球蛋白（rATG）治疗可降低异基因造血干细胞移植后 GvHD 的发生率。然而，rATG 治疗后免疫重建延迟，部分原因是胸腺功能受阻，这一点正在讨论中。本研究旨在阐明两种常用 rATG 制剂对培养的人胸腺基质，特别是胸腺上皮细胞（TEC）的可能细胞毒性作用。
建立原代 TEC 培养物，并通过流式细胞术和免疫荧光分析评估两种 rATG 制剂与上述细胞的结合和细胞毒性。通过多重酶联免疫吸附试验分析培养的胸腺基质细胞对 rATG 的反应中几种细胞因子的释放。
两种制剂均显示出与 TEC 相似的剂量依赖性结合，并发挥出相似的补体非依赖性、剂量依赖性细胞毒性。rATG 暴露进一步导致白细胞介素（IL）-7、IL-15 和 IL-6 的分泌减少，这些细胞因子参与胸腺 T 细胞发育和增殖。角质细胞生长因子预处理可减少 rATG 对 TEC 的细胞毒性，并恢复其 IL-7 和 IL-15 的分泌。
rATG 诱导的 TEC 细胞毒性将 rATG 诱导的胸腺损伤与 rATG 治疗后观察到的 T 细胞重建延迟联系起来。我们的数据支持 rATG 和胸腺保护策略的联合治疗，例如角质细胞生长因子，以同时提供充分的 GvHD 预防，并克服由胸腺损伤引起的 T 细胞重建延迟。
