Division of Immunology, Kitasato University School of Allied Health Sciences, Sagamihara, Kanagawa 252-0373, Japan.
Department of Urology, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0373, Japan.
Oncol Rep. 2018 Jan;39(1):417-424. doi: 10.3892/or.2017.6095. Epub 2017 Nov 13.
Radiotherapy (RT) is one of the most important treatments for prostate cancer. Although RT can kill cancer cells through direct and indirect effects of radiation, it occasionally induces an abscopal effect whereby localized radiation treatment is associated with elimination of metastatic cancer at a distance from the irradiated area. Thus, RT may induce an effective antitumor immune response, although the mechanism involved has remained unclear. The present was designed to evaluate this effect of RT in 36 patients with prostate cancer who provided informed consent prior to enrollment in this clinical trial. Peripheral blood samples were collected periodically after low-dose-rate (LDR) prostate brachytherapy, and lymphocyte subsets were analyzed by flow cytometry. The proportion of activated T cells (CD3+HLA-DR+, CD4+HLA-DR+ and CD8+HLA-DR+) in peripheral blood revealed a gradual and bimodal increase after LDR brachytherapy, whereas memory CD8+ T cells bimodally decreased after treatment. The ratios of activated T cells and regulatory T cells gradually increased after the treatment. Thus, LDR brachytherapy was demonstrated to induce effective immune responses in patients. This increase of activated T cells may contribute to maintenance of remission and reduction of relapse rates.
放射治疗（RT）是前列腺癌最重要的治疗方法之一。虽然 RT 可以通过辐射的直接和间接作用杀死癌细胞，但它偶尔会引起远隔效应，即局部放射治疗与照射区域外的转移性癌症的消除有关。因此，尽管涉及的机制仍不清楚，但 RT 可能会诱导有效的抗肿瘤免疫反应。本研究旨在评估 36 例前列腺癌患者的这种 RT 效应，这些患者在参加这项临床试验前均签署了知情同意书。在低剂量率（LDR）前列腺近距离放射治疗后定期采集外周血样本，并通过流式细胞术分析淋巴细胞亚群。外周血中活化 T 细胞（CD3+HLA-DR+、CD4+HLA-DR+和 CD8+HLA-DR+）的比例在 LDR 近距离放射治疗后逐渐呈双峰式增加，而治疗后记忆性 CD8+T 细胞呈双峰式减少。活化 T 细胞和调节性 T 细胞的比例在治疗后逐渐增加。因此，LDR 近距离放射治疗可诱导患者产生有效的免疫反应。这种活化 T 细胞的增加可能有助于维持缓解和降低复发率。
