Dynamic changes in the T cell receptor repertoire during treatment with radiotherapy combined with an immune checkpoint inhibitor.

Previous studies have indicated a synergistic effect between radiotherapy and immunotherapy. A better understanding of how this combination affects the immune system can help to clarify its role in the treatment of metastatic cancer. We performed T cell receptor (TCR) sequencing on 46 sequentially collected samples from 15 patients with stage IV non-small cell lung cancer, receiving stereotactic body radiotherapy combined with a programmed cell death ligand-1 (PD-L1) inhibitor. TCR repertoire diversity was assessed using Rényi diversity curves and the Shannon diversity index. TCR clones were tracked over time. We found decreasing or stable diversity in the best responders, and an increase in diversity at progression in patients with an initial response. Expansion of TCR clones was more often seen in responders. Several patients also developed new clones of high abundance. This seemed to be more related to radiotherapy than to immune checkpoint blockade. In summary, we observed similar dynamics in the TCR repertoire as have been described with immunotherapy alone. In addition, the occurrence of new unique clones of high abundance after radiotherapy may indicate that radiotherapy functions as a personalized cancer vaccine.

[Healthcare providers' experience with multi-dose packaged medicines]. / Helsepersonells oppfatninger om multidosepakkede legemidler.

BACKGROUND: To prevent medication errors, community homecare services (CHS) increasingly use multi-dose packaged medicines (MDPM) for their clients. More knowledge is needed on how MDPM affects routines and quality of medication handling in the CHS. MATERIAL AND METHODS: Four CHS districts in a Norwegian community (27 GPs, 121 nurses) participated in the study. Structured questionnaires with some open-ended questions were used during interviews. The questionnaire focused on experience and satisfaction with MDPM as compared to the old system, and on how the MDPM had influenced collaboration between different categories of health personnel. RESULTS: With the MDP-system most nurses and GPs felt that medication control had become easier (CHS 76%, GPs 56%; p = 0.03) and that routines had improved (CHS 84%, GPs 52%; p < 0.001) with the MDP-system. Three of four GPs felt more confident than before about patients receiving the medication they had prescribed (CHS 73%, GPs 78%; p = 0.7). 44% of the GPs felt that they spent more time on prescribing medication with MDPM. INTERPRETATION: MDPM was generally found to improve routines, the quality of medication handling and medication safety. GPs were less content with the arrangement than nurses, probably because they had to collaborate with more CHS districts with different routines for exchanging information. When introducing MDPM in the CHS, explicit and definite orders of responsibility should be established as well as uniform collaboration routines between the GPs, the CHS and the MDPM-providers.

Photochemically enhanced gene transfection increases the cytotoxicity of the herpes simplex virus thymidine kinase gene combined with ganciclovir.

Tumor targeting is an important issue in cancer gene therapy. We have developed a gene transfection method, based on light-inducible photochemical internalization (PCI) of a transgene, to improve gene delivery and expression selectively in illuminated areas, for example, in tumors. In the present work, we demonstrate that PCI improved the nonviral vector polyethylenimine (PEI)-mediated transfection of a therapeutic gene, the 'suicide' gene encoding herpes simplex virus thymidine kinase (HSVtk). In U87MG glioblastoma cells in vitro, the photochemical treatment stimulated expression of the HSVtk transgene, and, consequently, enhanced cell killing by the subsequent treatment with the prodrug ganciclovir (GCV). When relatively low doses of DNA (1 microg/ml) and the PEI vector (N/P 4) were used, HSVtk gene transfection followed by the GCV treatment did not have an effect on cell survival unless the photochemical treatment was performed, which potentiated the cytotoxicity to 90%. These findings indicate that photochemical transfection allows: (i) selective enhancement in gene expression and gene-mediated biological effects (cell killing by the Hsvtk/GCV approach) in response to illumination; (ii) the use of low, suboptimal for the nonviral transfection methods without PCI, doses of both DNA and the vector, which may be relevant and advantageous for therapeutic gene transfer in vivo.

Photochemical transfection: a technology for efficient light-directed gene delivery.

Most synthetic gene delivery vectors are taken up in the cell by endocytosis, and inefficient escape of the transgene from endocytic vesicles often is a major barrier for gene transfer by such vectors. To improve endosomal release we have developed a new technology, named photochemical internalization (PCI). PCI is based on photochemical reactions initiated by photosensitizing compounds localized in endocytic vesicles, inducing rupture of these vesicles upon light exposure. PCI constitutes an efficient light-inducible gene transfer method in vitro, which potentially can be developed into a site-specific method for gene delivery in in vivo gene therapy. In this paper the principle behind the PCI technology and the effect of PCI on transfection with different synthetic gene delivery vectors are reviewed. PCI treatment by the photosensitizer aluminum phthalocyanine (AlPcS2a) strongly improves transfection mediated by cationic polymers (e.g., poly-L-lysine and polyethylenimine), while the effect on transfection with cationic lipids is more variable. The timing of the light treatment relative to the transfection period was also important, indicating that release of the DNA from early endosomes is important for the outcome of PCI-induced transfection. The possibilities of using PCI as a technology for efficient, site-specific gene delivery in in vivo gene therapy is discussed.