Table_1_Intrapleural Injection of Anti-PD1 Antibody: A Novel Management of Malignant Pleural Effusion.docx

BackgroundMalignant tumors accompanied with malignant pleural effusion (MPE) often indicate poor prognosis. The therapeutic effect and mechanism of intrapleural injection of anti-programmed cell death protein 1 (PD1) on MPE need to be explored.
MethodsA preclinical MPE mouse model and a small clinical study were used to evaluate the effect of intrapleural injection of anti-PD1 antibody. The role of immune cells was observed via flow cytometry, RNA-sequencing, quantitative PCR, western blot, immunohistochemistry, and other experimental methods.
ResultsIntrathoracic injection of anti-PD1 monoclonal antibody (mAb) has significantly prolonged the survival time of mice (P = 0.0098) and reduced the amount of effusion (P = 0.003) and the number of cancer nodules (P = 0.0043). Local CD8+ T cells participated in intrapleural administration of anti-PD1 mAb. The proportion of CD69+, IFN-γ+, and granzyme B+ CD8+ T cells in the pleural cavity was increased, and the expression of TNF-α and IL-1β in MPE also developed significantly after injection. Local injection promoted activation of the CCL20/CCR6 pathway in the tumor microenvironment and further elevated the expression of several molecules related to lymphocyte activation. Clinically, the control rate of intrathoracic injection of sintilimab (a human anti-PD1 mAb) for 10 weeks in NSCLC patients with MPE was 66.7%. Local injection improved the activity and function of patients’ local cytotoxic T cells (CTLs).
ConclusionsIntrapleural injection of anti-PD1 mAb could control malignant pleural effusion and the growth of cancer, which may be achieved by enhancing local CTL activity and cytotoxicity.

背景：伴随恶性胸腔积液（malignant pleural effusion, MPE）的恶性肿瘤往往预后不良。胸膜腔内注射抗程序性死亡蛋白1（programmed cell death protein 1, PD1）治疗MPE的疗效及作用机制尚待探索。
方法：本研究采用临床前MPE小鼠模型与小型临床研究，评估胸膜腔内注射抗PD1抗体的疗效。通过流式细胞术（flow cytometry）、RNA测序（RNA-sequencing）、定量聚合酶链反应（quantitative PCR, qPCR）、蛋白质印迹（western blot）、免疫组织化学（immunohistochemistry）等实验方法，观察免疫细胞的作用。
结果：抗PD1单克隆抗体（monoclonal antibody, mAb）胸腔内注射可显著延长小鼠生存期（P=0.0098），减少胸腔积液量（P=0.003）并降低癌结节数量（P=0.0043）。局部CD8+ T细胞参与胸膜腔内注射抗PD1 mAb的治疗过程。注射后，胸腔积液中CD69阳性、干扰素γ（IFN-γ）阳性及颗粒酶B（granzyme B）阳性的CD8+ T细胞比例升高，恶性胸腔积液中肿瘤坏死因子α（TNF-α）与白细胞介素1β（IL-1β）的表达亦显著上调。局部注射可激活肿瘤微环境中的CCL20/CCR6通路，并进一步提升多种与淋巴细胞活化相关分子的表达。临床研究显示，针对伴MPE的非小细胞肺癌（non-small cell lung cancer, NSCLC）患者，胸腔内注射信迪利单抗（sintilimab，人源抗PD1 mAb）治疗10周的疾病控制率达66.7%。局部注射可改善患者局部细胞毒性T淋巴细胞（cytotoxic T lymphocytes, CTLs）的活性与功能。
结论：胸膜腔内注射抗PD1 mAb可控制恶性胸腔积液与肿瘤生长，其机制可能通过增强局部CTL的活性与细胞毒性作用实现。