Mycobacterium marinum (Mm) is a promiscuous pathogen infecting many vertebrates including humans, whose persistent infections are problematic for aquaculture and public health. Among unsettled aspects of host-pathogen interactions, the respective roles of conventional and innate-like (i)T cells in host defenses against Mm remain unclear. Here, we developed an infection model system in the amphibian Xenopus laevis to study host responses to Mm at two distinct life stages, tadpole and adult. Adult frogs possess efficient conventional T cell-mediated immunity, whereas tadpoles predominantly rely on innate-like (i)T cells. We hypothesized that tadpoles are more susceptible and elicit weaker immune responses to Mm than adults. However, our results show that although anti-Mm immune responses between tadpoles and adults are different, tadpoles are as resistant to Mm inoculation as adult frogs. Mm inoculation triggered a robust pro-inflammatory CD8 + T cell response in adults, whereas tadpoles elicited only a non-inflammatory CD8 negative-and iT cell-mediated response. Furthermore, adult anti-Mm responses induced active granuloma formation with abundant T cell infiltration and associated with significantly reduced Mm loads. This is reminiscent of local CD8 + T cell response in lung granulomas of human tuberculosis patients. In contrast, tadpoles rarely exhibited granulomas and tolerated persistent Mm accumulation. Gene expression profiling confirmed poor tadpole CD8 + T cell response contrasting with the marked increase in transcript levels of the anti-Mm iT cell receptor rearrangement (iVα45-Jα1.14) and of CD4. These data provide novel insights into the critical roles of iT cells in vertebrate anti-mycobacterial immune response and tolerance to pathogens.

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AimsThe aim of this study was the analysis of the risk associated with direct oral anticoagulants (DOACs) in patients undergoing non-elective operations on the proximal aorta due to aortic disease.Methods and resultsData from the department’s register of cardiac surgery was analysed retrospectively with emphasis on operative mortality. 135 non-elective operations for proximal aortic disease (October 2016 to 2018) were identified, of which 19 died during the first 90 days. DOAC use was the top-ranked risk factor in the univariate analysis with a HR of 9.6 (3.1 to 29), p=0.00007. Using a Cox proportional hazards model including the most relevant risk factors, the risk associated with DOAC use remained significant with a HR of 6.1 (1.4 to 26.3), p=0.015. We did not find increased risk associated with warfarin use.ConclusionIn patients undergoing non-elective operations on the proximal aorta due to aortic disease, the use of DOAC is associated with increased operative mortality.

BackgroundStudies evaluating peripheral patient samples show radiation can modulate immune responses, yet the biological changes in human tumors particularly at the cellular level remain largely unknown. Here, we address how radiation treatment shapes the immune compartment and interactions with cancer cells within renal cell carcinoma (RCC) patient tumors.MethodsTo identify how radiation shaped the immune compartment and potential immune interactions with tumor cells we evaluated RCC tumors from patients treated only with nephrectomy or with radiation followed by nephrectomy. Spectral flow cytometry using a 35-marker panel was performed on cell suspensions to evaluate protein expression within immune subsets. To reveal how radiation alters programming of immune populations and interactions with tumor cells, we examined transcriptional changes by single-cell RNA sequencing (scRNAseq).ResultsSpectral flow cytometry analysis revealed increased levels of early-activated as well as effector programmed cell death protein-1 (PD-1)+CD8 T-cell subsets within irradiated tumors. Following quality control, scRNAseq of tumor samples from nephrectomy-only or radiation followed by nephrectomy-treated patients generated an atlas containing 34,626 total cells. Transcriptional analysis revealed increased transition from stem-like T-cell populations to effector T cells in irradiated tumors. Interferon (IFN) pathways, that are central to radiation-induced immunogenicity, were enriched in irradiated lymphoid, myeloid, and cancer cell populations. Focused cancer cell analysis showed enhanced antigen presentation and increased predicted TRAIL-mediated and IFN-mediated interactions between tumor cells and the same effector T-cell subsets increased by radiation. TRAIL and IFN pathways enriched in irradiated tumors were associated with survival in patients treated with immunotherapy.ConclusionsThese findings identify the source of IFN enrichment within irradiated RCC and reveal heightened levels of PD-1+CD8+T-cell subsets and increased probability of interactions with tumor cells following standalone radiation treatment. This study provides a window into the irradiated tumor-immune microenvironment of patients and rationale for treatment combinations.