Case Series of First Microinvasive Fully Endoscopic Use of a New Mitral Prosthesis.

The use of bioprostheses is increasing in younger patients, but it is associated with the risk of later valve deterioration, especially in the mitral position. A new bioprosthesis for mitral valve replacement offers possible longer-term durability and improved hemodynamics. Objectives: Here, we report the implantation of the novel Edwards MITRIS RESILIA mitral valve (Edwards Lifesciences Inc., Irvine, CA, USA) through microinvasive fully endoscopic access as an innovative surgical approach based on a series of twelve patients. Methods: Contrast-based ECG gated CT was preoperatively performed in all patients to determine the intravascular calcifications and vascular parameters, as well as to assess noticeable problems during the operation. CT software for cardiac interventions (3Mensio Medical Imaging BV) was used to simulate surgical prostheses digitally inside the native annulus. With this, a digital LVOT and neo LVOT was created, and the difference between the valve prostheses was measured. Implantation of the MITRIS RESILIA valve was performed in 12 patients according to the instructions for use through microinvasive access in a fully endoscopic fashion using 3D visualization. Results: The mean patient age was 56.50 years, and 7/12 (58.33%) were redo procedures. All patients survived the first 30 days after the procedure, the mean aortic cross-clamp time was 40.17 ± 13.72 min. and mean postoperative transvalvular gradient was 4.45 ± 1.74 mmHg. The neo LVOT in the CT-based simulation was measured with an average area of 414.98 ± 88.69 mm2. The average difference between the LVOT and neo LVOT area was 65.35 ± 34.99 mm2. There was no case of paravalvular leakage or obstruction of the left ventricular outflow tract. Conclusions: The novel MITRIS RESILIA valve is a promising new bioprosthesis for mitral valve replacement that offers improved features as compared to other prostheses. The ease of implantation is increased by this prosthesis by the improved pliability of the sewing cuff and the inward folding of the struts, which was confirmed by short operative times in our series.

KIR3DS1 directs NK cell-mediated protection against human adenovirus infections.

Human adenoviruses (HAdVs) are a major cause for disease in children, in particular after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Currently, effective therapies for HAdV infections in immunocompromised hosts are lacking. To decipher immune recognition of HAdV infection and determine new targets for immune-mediated control, we used an HAdV infection 3D organoid system, based on primary human intestinal epithelial cells. HLA-F, the functional ligand for the activating NK cell receptor KIR3DS1, was strongly up-regulated and enabled enhanced killing of HAdV5-infected cells in organoids by KIR3DS1+ NK cells. In contrast, HLA-A and HLA-B were significantly down-regulated in HAdV5-infected organoids in response to adenoviral E3/glycoprotein19K, consistent with evasion from CD8+ T cells. Immunogenetic analyses in a pediatric allo-HSCT cohort showed a reduced risk to develop severe HAdV disease and faster clearance of HAdV viremia in children receiving KIR3DS1+/HLA-Bw4+ donor cells compared with children receiving non­KIR3DS1+/HLA-Bw4+ cells. These findings identify the KIR3DS1/HLA-F axis as a new target for immunotherapeutic strategies against severe HAdV disease.

CD49a Expression Identifies a Subset of Intrahepatic Macrophages in Humans.

Macrophages play central roles in inflammatory reactions and initiation of immune responses during infections. More than 80% of total tissue macrophages are described to be located in the liver as liver-resident macrophages, also named Kupffer cells (KCs). While studies in mice have established a central role of liver-resident KCs in regulating liver inflammation, their phenotype and function are not well-characterized in humans. Comparing paired human liver and peripheral blood samples, we observed significant differences in the distribution of macrophage (Mφ) subsets, with lower frequencies of CD14hiCD16lo and higher frequencies of CD14int-hiCD16int Mφ in human livers. Intrahepatic Mφ consisted of diverse subsets with differential expression of CD49a, a liver-residency marker previously described for human and mice NK cells, and VSIG4 and/or MARCO, two recently described human tissue Mφ markers. Furthermore, intrahepatic CD49a+ Mφ expressed significantly higher levels of maturation and activation markers, exhibited higher baseline levels of TNF-α, IL-12, and IL-10 production, but responded less to additional in vitro TLR stimulation. In contrast, intrahepatic CD49a- Mφ were highly responsive to stimulation with TLR ligands, similar to what was observed for CD49a- monocytes (MOs) in peripheral blood. Taken together, these studies identified populations of CD49a+, VSIG4+, and/or MARCO+ Mφ in human livers, and demonstrated that intrahepatic CD49a+ Mφ differed in phenotype and function from intrahepatic CD49a- Mφ as well as from peripheral blood-derived monocytes.