Liu Shu-Zheng
Radiobiology Research Unit, Ministry of Health, PRC, Jilin University Norman Bethune Medical Center 8 Xinmin Street, Changchun 130021, China Phone number: +86-431-564-4597. Fax number: +86-431-563-3025. email:
Nonlinearity Biol Toxicol Med. 2003 Jan;1(1):71-92. doi: 10.1080/15401420390844483.
The health effects of low-dose radiation (LDR) have been the concern of the academic spheres, regulatory bodies, governments, and the public. Among these effects, the most important is carcinogenesis. In view of the importance of immune surveillance in cancer control, the dose-response relationship of the changes in different cell types of the immune system after whole-body irradiation is analyzed on the basis of systemic data from the author's laboratory in combination with recent reports in the literature. For T lymphocytes J- or inverted J-shaped curves are usually demonstrated after irradiation, while for macrophages dose-response curves of chiefly stimulation with irregular patterns are often observed. The intercellular reactions between the antigen presenting cell (APC) and T lymphocyte (TLC) in the immunologic synapse via expression of surface molecules and secretion of cytokines by the two cell types after different doses of radiation are illustrated. The different pathways of signal transduction thus facilitated in the T lymphocyte by different doses of radiation are analyzed to explain the mechanism of the phenomenon of low-dose stimulation and high-dose suppression of immunity. Experimental and clinical data are cited to show that LDR retards tumor growth, reduces metastasis, increases the efficacy of conventional radiotherapy and chemotherapy as well as alleviates the suppression of immunity due to tumor burden. The incidence of thymic lymphoma after high-dose radiation is lowered by preexposure to low-dose radiation, and its mechanism is supposed to be related to the stimulation of anticancer immunity induced by low-dose radiation. Recent reports on lowering of standardized cancer mortality rate and all cause death rate of cohorts occupationally exposed to low-dose radiation from the US, UK, and Canada are cited.
低剂量辐射（LDR）对健康的影响一直是学术界、监管机构、政府和公众关注的问题。在这些影响中，最重要的是致癌作用。鉴于免疫监视在癌症控制中的重要性，基于作者实验室的系统数据并结合文献中的最新报道，分析了全身照射后免疫系统不同细胞类型变化的剂量反应关系。对于T淋巴细胞，照射后通常呈现J形或倒J形曲线，而对于巨噬细胞，常观察到主要是刺激的不规则模式的剂量反应曲线。阐述了不同剂量辐射后，抗原呈递细胞（APC）和T淋巴细胞（TLC）在免疫突触中通过两种细胞类型表面分子的表达和细胞因子的分泌所发生的细胞间反应。分析了不同剂量辐射在T淋巴细胞中促进的不同信号转导途径，以解释低剂量刺激和高剂量免疫抑制现象的机制。引用实验和临床数据表明，低剂量辐射可延缓肿瘤生长、减少转移、提高传统放疗和化疗的疗效，并减轻肿瘤负荷引起的免疫抑制。高剂量辐射前预先暴露于低剂量辐射可降低胸腺淋巴瘤的发生率，其机制被认为与低剂量辐射诱导的抗癌免疫刺激有关。引用了美国、英国和加拿大关于职业性暴露于低剂量辐射的队列标准化癌症死亡率和全因死亡率降低的最新报道。
