淋巴细胞减少症现在普遍被认为是放射治疗的负面预后因素。早在本世纪初，我们就证明，高能碳离子对放疗患者淋巴细胞的损伤比 X 射线要小，即使重离子每单位剂量在诱导受辐射的血细胞中染色体畸变方面更有效。 -体内。这种解释是基于体积效应，即布拉格峰值疗法中保留了较大体积的正常组织。在这里，我们将回顾目前关于粒子疗法和光子疗法之间淋巴细胞减少症的差异及其后果的知识。当今有压倒性的证据表明，粒子疗法可显着减少几个肿瘤部位的放疗引起的淋巴细胞减少症。由于淋巴细胞减少症会降低对检查点抑制剂的免疫反应，因此可以预测，粒子疗法可能是放射治疗和免疫疗法联合治疗的理想搭配，对于 X 射线后预计出现严重淋巴细胞减少症的患者应选择粒子疗法。

Lymphopenia is now generally recognized as a negative prognostic factor in radiotherapy. Already at the beginning of the century we demonstrated that high-energy carbon ions induce less damage to the lymphocytes of radiotherapy patients than X-rays, even if heavy ions are more effective per unit dose in the induction of chromosomal aberrations in blood cells irradiated ex-vivo. The explanation was based on the volume effect, i.e. the sparing of larger volumes of normal tissue in Bragg peak therapy. Here we will review the current knowledge about the difference in lymphopenia between particle and photon therapy and the consequences.There is nowadays an overwhelming evidence that particle therapy reduces significantly the radiotherapy-induced lymphopenia in several tumor sites. Because lymphopenia turns down the immune response to checkpoint inhibitors, it can be predicted that particle therapy may be the ideal partner for combined radiation and immunotherapy treatment and should be selected for patients where severe lymphopenia is expected after X-rays.