TLR3 essentially promotes protective class I–restricted memory CD8+ T-cell responses to Aspergillus fumigatus in hematopoietic transplanted patients

Aspergillus fumigatus is a model fungal pathogen and a common cause of severe infections and diseases. CD8+ T cells are present in the human and murine T-cell repertoire to the fungus. However, CD8+ T-cell function in infection and the molecular mechanisms that control their priming and differentiation into effector and memory cells in vivo remain elusive. In the present study, we report that both CD4+ and CD8+ T cells mediate protective memory responses to the fungus contingent on the nature of the fungal vaccine. Mechanistically, class I MHC-restricted, CD8+ memory T cells were activated through TLR3 sensing of fungal RNA by cross-presenting dendritic cells. Genetic deficiency of TLR3 was associated with susceptibility to aspergillosis and concomitant failure to activate memory-protective CD8+ T cells both in mice and in patients receiving stem-cell transplantations. Therefore, TLR3 essentially promotes antifungal memory CD8+ T-cell responses and its deficiency is a novel susceptibility factor for aspergillosis in high-risk patients.These studies were supported by the Specific Targeted Research Project ALLFUN (FP7-HEALTH-2009 contract number 260338 to L.R.), by SYBARIS (FP7-HEALTH-2009 contract number 242220 to L.R.), and by the Italian Project AIDS 2010 by the Istituto Superiore di Sanita (contract number 40H40 to L.R.). A.C. and C.C. were supported by fellowships from Fundacao para a Ciencia e Tecnologia, Portugal (contracts SFRH/BPD/46292/2008 and SFRH/BD/65962/2009, respectively)

Incidence, Risk Factors and Outcome of Pre-engraftment Gram-Negative Bacteremia after Allogeneic and Autologous Hematopoietic Stem Cell Transplantation: An Italian Prospective Multicenter Survey

Background Gram-negative bacteremia (GNB) is a major cause of illness and death after hematopoietic stem cell transplantation (HSCT), and updated epidemiological investigation is advisable. Methods We prospectively evaluated the epidemiology of pre-engraftment GNB in 1118 allogeneic HSCTs (allo-HSCTs) and 1625 autologous HSCTs (auto-HSCTs) among 54 transplant centers during 2014 (SIGNB-GITMO-AMCLI study). Using logistic regression methods. we identified risk factors for GNB and evaluated the impact of GNB on the 4-month overall-survival after transplant. Results The cumulative incidence of pre-engraftment GNB was 17.3% in allo-HSCT and 9% in auto-HSCT. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most common isolates. By multivariate analysis, variables associated with GNB were a diagnosis of acute leukemia, a transplant from a HLA-mismatched donor and from cord blood, older age, and duration of severe neutropenia in allo-HSCT, and a diagnosis of lymphoma, older age, and no antibacterial prophylaxis in auto-HSCT. A pretransplant infection by a resistant pathogen was significantly associated with an increased risk of posttransplant infection by the same microorganism in allo-HSCT. Colonization by resistant gram-negative bacteria was significantly associated with an increased rate of infection by the same pathogen in both transplant procedures. GNB was independently associated with increased mortality at 4 months both in allo-HSCT (hazard ratio, 2.13; 95% confidence interval, 1.45-3.13; P <.001) and auto-HSCT (2.43; 1.22-4.84; P =.01). Conclusions Pre-engraftment GNB is an independent factor associated with increased mortality rate at 4 months after auto-HSCT and allo-HSCT. Previous infectious history and colonization monitoring represent major indicators of GNB. Clinical Trials registration NCT02088840

Rational design, synthesis and biological evaluation of modular fluorogenic substrates with high affinity and selectivity for PTP1B

Protein-tyrosine phosphatase 1B (PTP1B) is a key regulatory enzyme in several signal transduction pathways, and its upregulation has been associated with type-2 diabetes, obesity and cancer. Selective determination of the functional significance of PTP1B remains a major challenge because the activity of this crucial enzyme is currently evaluated through the use of fluorescent probes that lack selectivity and are limited to biochemical assays. Here we describe the rational design, synthesis and biological evaluation of new modular PTP1B fluorogenic substrates. The self-immolative 4-hydroxybenzyl alcohol has been used as a key component for the design of phosphotyrosine mimics linked to a latent chromophore, which is released through an enzyme-initiated domino reaction. Preliminary biological investigations showed that, by optimising the stereoelectronic properties and the binding interactions at the enzyme active site, it is possible to achieve substrates with high affinity and promising selectivity. Due to their modular nature, the synthesised fluorogenic probes represent versatile tools; customisation of the different subunits could widen the scope of these probes to a broader range of in vitro assays. Finally, these studies elucidate the critical role played by Asp181 in the PTP1B-catalysed dephosphorylation mechanism: disruption of the native conformation of this key amino acid residue on the WDP loop yields fluorogenic inhibitors, rather than substrates. For this reason, our studies also represent a step forward for the development of improved PTP1B noncovalent inhibitors. Smart probes: The aminocoumarin latent chromophore is released through an enzyme-initiated 1,6-elimination reaction. Optimisation of the stereoelectronic properties and of the binding interactions at the enzyme active site led to substrates with high affinity and promising selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Esplorare e creare nuove anatomie dal margine: da Isabelle Eberhardt a Timberlake Wertenbaker e Divenire S/Oggette dal futuro: una rilettura di S/Oggetti immaginari. Letterature comparate al femminile

Esplorare e creare nuove anatomie dal margine: da Isabelle Eberhardt a Timberlake Wertenbaker di Sarah PerruccioDivenire S/Oggette dal futuro: una rilettura di S/Oggetti immaginari. Letterature comparate al femminile di Francesca Maffioli e Laura Marz

Posaconazole oral dose and plasma levels in pediatric hematology-oncology patients

Posaconazole is a triazole with limited pharmacokinetic information in children. This study assessed the correlation between posaconazole-oral-solution daily dosage/kg/body weight and trough plasma level

Posaconazole delayed-release tablets in paediatric haematology-oncology patients

To date, there are few studies that describe pharmacokinetics, safety and efficacy of posaconazole delayed-release tablet (DRT) formulation in the paediatric population

Retrospective study on the incidence and outcome of proven and probable invasive fungal infections in high-risk pediatric onco-hematological patients

Invasive fungal infection (IFI) is a cause of morbidity, mortality and increased health costs in children undergoing chemotherapy or hematopoietic stem cell transplant (HSCT)