Liver transplantation from donors with positive blood cultures: increased risk of graft failure or opportunity to expand the donor pool?

Dendritic cells with METTL3 gene knockdown exhibit immature properties and prolong allograft survival

Maturation of dendritic cells (DCs) initiates adaptive immune responses and thereby provokes allograft rejection. Here, this study aimed to explore the effect of Methyltransferase-like protein 3 (METTL3) silencing on DC function and the role of METTL3-silencing donor DCs in the immune response after mouse heart transplantation. Bone marrow-derived DCs from donor BALB/c mice were infected with lentiviruses expressing METTL3-specific short hairpin RNA (LV-METTL3 shRNA) to silence METTL3. Then METTL3-silencing DCs were treated with lipopolysaccharide (LPS) for another 48 h to induce DC maturation. Recipient C57BL/6 mice were injected with phosphate-buffered saline (PBS), immature DCs, and METTL3 shRNA-DCs prior to the cardiac transplantation involving the transfer of hearts from donor BALB/c mice to recipient C57BL/6 mice. In vitro we demonstrated that METTL3-silencing DCs had lower expression of MHCII, costimulatory molecules (CD80, CD86), and DC-related cytokines (IFN-γ, IL-12) as well as lower ability to activate T-cell proliferation, which were consistent with the characteristics of tolerogenic DCs. In vivo we found that METTL3-silencing donor DCs induced immune tolerance after mouse heart transplantation and prolonged the allograft survival, which might be associated with Th1/Th2 immune deviation. In summary, METTL3-silencing DCs exhibit immature properties and prolong allograft survival.

Organ donor screening for carbapenem-resistant gram-negative bacteria in Italian intensive care units: the DRIn study

The 759 cases of brain death declaration (BDD [Italian law, 6 hours of observation time]) that occurred in 190 Italian intensive care units (ICUs) between May and September 2012 were studied to quantify carbapenem-resistant gram-negative bacteria (CR-GN) isolated in organ donors, to evaluate adherence to national screening guidelines, and to identify risk factors for CR-GN isolation. Mandatory blood, bronchoalveolar lavage, and urine cultures were performed on the BDD day in 99% of used donors. Because results were rarely made available before transplant, >20% of transplants were performed before obtaining any microbiological information, and organs from 15 of 22 CR-GN cases were used. Two (lung-liver) of the 37 recipients died, likely because of donor-derived early CR-GN sepsis. ICU stay >3 days (odds ratio [OR] = 7.49, P = .004), fever (OR = 3.11, P = .04), age <60 years (OR = 2.80, P = .06), and positive ICU epidemiology (OR = 8.77, P = .07) were associated with CR-GN isolation. An association between single ICU and risk of CR-GN was observed, as a result of differences across ICUs (ICC = 29%; 95% confidence interval [CI] 6.5%-72%) probably related to inadequate practices of infection control. Continuous education aimed at implementing priority actions, including stewardship programs for a rational use of antimicrobials, is a priority in healthcare systems and transplant networks. Improved awareness among ICU personnel regarding the importance of early CR-GN detection and timely alert systems might facilitate decisions regarding organ suitability and eventually save recipient lives.