[Radiation-induced lymphopenia: Lymphocytes as a new organ at risk]

Taking the immune system into account in the fight against tumors has upset the cancer treatment paradigm in the 21st century. Combination treatment strategies associating radiotherapy with immunotherapy are being increasingly implemented in clinical practice. In this context, lymphocytes, whether lymphocytes infiltrating the tumour, circulating blood lymphocytes or lymphocytes residing within the lymph nodes, are key players in cellular and humoral anti-tumor immunity. The significant radiosensitivity of lymphocytes was demonstrated in the early 1990s. Along with the cells of the digestive mucosa, lymphocytes are thus among the most radiosensitive cell types in the body. Compared to the old practices of external radiotherapy, current intensity modulated treatments have allowed a considerable improvement in acute and late toxicity, at the cost of a significant increase in the volume irradiated at low doses. This is not without consequence on the incidence of radiation-induced lymphopenia, with prognostic implications for many tumor types. Thus, in order not to hinder the action of antitumor immunity and the efficacy of immunotherapy, it is essential to consider lymphocytes as a new organ at risk in its own right. In this development, based on current data from the literature, we will begin by justifying the necessary prevention of radiation-induced lymphopenia, before providing the tools currently known to apprehend lymphocytes as a new multicompartments. Finally, we will broaden the perspective by outlining ways to develop research in this area.

Radiotherapy for primary tumor in lung cancer with synchronous metastases: Overview from the past and proposal for the future

The management of metastatic lung cancers, either of the small-cell (SCLC) or the non-small cell (NSCLC) subtype, largely based on systemic treatments so far, has been the subject of breakthrough advances over the past few years, with notably the wide use of immunotherapy changing the landscape of these harmful prognosis diseases. In parallel with this major progress, the increasing use of radiotherapy (RT) for the treatment of the primary thoracic lesion±the distant lesions, may contribute to improving the condition of these metastatic patients, both in terms of progression-free survival (PFS) and overall survival (OS). This review proposes to summarize and explain the findings provided by the different studies published in the last years experiencing RT of the primary tumor in metastatic lung cancers, either associated or not with the local ablative treatment of a low number of distant lesions. It will also expose the respective limits encountered in these studies and, in the light of all these elements, suggests various promising issues and fields of research for the future.

Inactivation of alpha 1-antitrypsin by aqueous coal solutions: possible relation to the emphysema of coal workers

Increasing evidence demonstrates that emphysema in coal workers may be related to their exposure to coal dusts. The hypothesis that emphysema could be related to the production of reactive oxygen species (ROS) generated by inhaled coal dusts was examined in the present study. Using ESR, we investigated whether the interaction of different coals with dissolved oxygen in aqueous medium could generate ROS. Indeed, we found that one of the five examined French coal samples, Vouters coal, was effective in oxidizing formate anions or ethanol by a radical pathway. Inactivation of alpha 1-antitrypsin (alpha 1-AT) in vitro was then examined for all five coal filtrates. The Vouters coal filtrate, which exhibits oxidative activity, can also inactivate alpha 1-AT. When this coal filtrate was crystallized and redissolved, its oxidative activity was found to be conserved. By use of various analytical techniques, the active component of this coal filtrate was identified to be primarily ferrous sulfate. We confirmed that pure ferrous sulfate can effectively reduce oxygen to produce ROS in aqueous medium in vitro and can also inactivate alpha 1-AT. In this report, the nature of the coal-generated oxidative species, the origin of ferrous sulfate, and the stability of ferrous sulfate in the different coal samples are discussed. These results offer evidence that some inhaled coal dusts are capable of producing ROS, which may play an important role in the development of coal workers' emphysema.