Distinct Host–Mycobacterial Pathogen Interactions between Resistant Adult and Tolerant Tadpole Life Stages of Xenopus laevis

Mycobacterium marinum 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 T (iT) cells in host defenses against M. marinum remain unclear. In this study, we developed an infection model system in the amphibian Xenopus laevis to study host responses to M. marinum at two distinct life stages, tadpole and adult. Adult frogs possess efficient conventional T cell–mediated immunity, whereas tadpoles predominantly rely on iT cells. We hypothesized that tadpoles are more susceptible and elicit weaker immune responses to M. marinum than adults. However, our results show that, although anti–M. marinum immune responses between tadpoles and adults are different, tadpoles are as resistant to M. marinum inoculation as adult frogs. M. marinum inoculation triggered a robust proinflammatory CD8+ T cell response in adults, whereas tadpoles elicited only a noninflammatory CD8 negative- and iT cell–mediated response. Furthermore, adult anti–M. marinum responses induced active granuloma formation with abundant T cell infiltration and were associated with significantly reduced M. marinum 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 M. marinum accumulation. Gene expression profiling confirmed poor tadpole CD8+ T cell response, contrasting with the marked increase in transcript levels of the anti–M. marinum invariant TCR rearrangement (iVα45-Jα1.14) and of CD4. These data provide novel insights into the critical roles of iT cells in vertebrate antimycobacterial immune response and tolerance to pathogens

Operative survival in patients with acute aortic disease in the era of newer oral anticoagulants

The 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.In patients undergoing non-elective operations on the proximal aorta due to aortic disease, the use of DOAC is associated with increased operative mortality