Genotypic and Phenotypic Analysis of Dairy Lactococcus lactis Biodiversity in Milk: Volatile Organic Compounds as Discriminating Markers

The diversity of nine dairy strains of Lactococcus lactis subsp. lactis in fermented milk was investigated by both genotypic and phenotypic analyses. Pulsed-field gel electrophoresis and multilocus sequence typing were used to establish an integrated genotypic classification. This classification was coherent with discrimination of the L. lactis subsp. lactis bv. diacetylactis lineage and reflected clonal complex phylogeny and the uniqueness of the genomes of these strains. To assess phenotypic diversity, 82 variables were selected as important dairy features; they included physiological descriptors and the production of metabolites and volatile organic compounds (VOCs). Principal-component analysis (PCA) demonstrated the phenotypic uniqueness of each of these genetically closely related strains, allowing strain discrimination. A method of variable selection was developed to reduce the time-consuming experimentation. We therefore identified 20 variables, all associated with VOCs, as phenotypic markers allowing discrimination between strain groups. These markers are representative of the three metabolic pathways involved in flavor: lipolysis, proteolysis, and glycolysis. Despite great phenotypic diversity, the strains could be divided into four robust phenotypic clusters based on their metabolic orientations. Inclusion of genotypic diversity in addition to phenotypic characters in the classification led to five clusters rather than four being defined. However, genotypic characters make a smaller contribution than phenotypic variables (no genetic distances selected among the most contributory variables). This work proposes an original method for the phenotypic differentiation of closely related strains in milk and may be the first step toward a predictive classification for the manufacture of starters

Post‐transplant cyclophosphamide as sole GHVD prophylaxis after matched reduced‐intensity conditioning allotransplant

Abstract Background Post‐transplant cyclophosphamide (PTCY) alone as graft‐versus‐host disease (GVHD) prophylaxis may avoid/reduce short‐ and mid‐term toxicities of drugs commonly used for GVHD prophylaxis, accelerate immune reconstitution after the graft to decrease infections and facilitate the early integration of adjunct maintenance therapies to prevent relapse. Objective A prospective phase 2 study was designed in order to assess the feasibility and safety of PTCY as a sole GVHD prophylaxis in adult patients receiving a Baltimore‐based reduced‐intensity conditioning (RIC) peripheral blood (PB) allogeneic hematopoietic stem cell transplantation (Allo‐HSCT) with a matched donor. Study design Patients were planned to be included stepwise up to 59 evaluable PTCY recipients, in order to be able to stop the protocol in case of excessive corticosteroid resistant grade 3–4 severe acute GVHD (aGVHD). Because a high incidence of grade 2–4 aGVHD was observed after analysis of the first 27 patients, the protocol was amended to test the addition of 1 day of anti‐thymoglobulin to PTCY. In spite of this, the trial had to be stopped after 38 treated patients, because of an unacceptable rate of grade 3–4 aGVHD. Donors were matched related to 12 patients and unrelated to 26. Results With a median follow‐up of 29.6 months, 2‐year overall, disease‐free and GVHD‐free relapse‐free (GRFS) survivals were respectively 65.4%, 62.1% and 46.9%. Cumulative incidences of grade 2–4 and 3–4 aGVHD at day 100 were 52.6% and 21.1%, respectively, while that of moderate/severe chronic(c) GVHD was 15.7% at 2 years. Addition of ATG to PTCY did influence neither aGVHD, cGVHD nor GRFS. Conclusion Despite paradoxically good survivals, especially GRFS, this study failed to demonstrate that PTCY (± ATG) alone can be used for Baltimore‐based RIC PB Allo‐HSCT with matched donors. Other combinations should be tested to try and avoid long‐term use of immunosuppressive drugs following Allo‐HSCT in this setting

Impact du lait humain et d'une préparation pour les nourrissons sur l'axe microbiote-intestin chez le nourrisson, étude pré clinique.

International audienceThème : 12-Pédiatrie et néonatalogie Introduction et but de l’étude : L’alimentation du nourrisson est cruciale pour son développement. Un impact physiologique différent entre lait humain (LH) et préparations pour nourrisson (PPN) est démontré sans que les mécanismes d’actions, en particulier sur le rôle de l’axe microbiote-intestin-cerveau, ne soient réellement connus. L’objectif de cette étude a été de préciser son rôle chez le mini-porcelet Yucatan utilisé comme modèle du nourrisson. Matériel et méthodes : Deux groupes de 9 porcelets âgés de 19 jours ont été nourris avec un pool de LH (provenant de 50 mères) ou une PPN pendant 6 jours puis ont été sacrifiés. Le microbiote (séquençage ARNr 16S) et la digestibilité iléale standardisée (DIS) du tryptophane (Trp) ont été analysés. La perméabilité iléale et colique a été mesurée en chambre d’Ussing. L’expression de gènes impliqués dans les fonctions barrière et immunitaire, le métabolisme, ou codant les récepteurs de nutriments, de neurotransmetteurs et d’hormones a été analysée par PCR (SmartChip) dans le cerveau (69 gènes) et l’intestin (106 gènes). Résultats et analyse statistique : Une baisse de l’α-diversité associée à une plus faible abondance des phyla Bacteroidetes, Fusobacteria et Deferribacteres ont été observées dans le colon des porcelets LH. Le nombre de gènes différemment exprimés entre LH et PPN était variable selon les tissus : 35% dans le colon, 10% dans l’iléon, 16% dans hypothalamus, 14% dans le cortex préfrontal, 10% dans l’hippocampe et seulement 3% dans le striatum. Dans les colons du groupe LH, les gènes impliqués dans la réponse immunitaire pro- et anti-inflammatoire (BAFF, IL10, IL10Rα, TNFαR1 et TLR2) étaient significativement plus exprimés (+28% à +70%, P0,05). Dans le cerveau, les gènes impliqués dans les fonctions barrière hémato-encéphalique (Cdh2 et Marveld2) et endocrine (NPY et GLP1r) et de la neuro-/synaptogenèse (BDNF, SHH, CYPFIP2) étaient moins exprimés chez les porcelets LH (-52% à -211%, P<0,05). Conclusion : L’alimentation du nourrisson, LH vs. PPN, affecte de manière spécifique l’axe microbiote-intestin-cerveau. Ces résultats suggèrent un rôle du microbiote dans ce phénomène et montrent que l’optimisation des PPNs pour mimer au mieux le LH est encore à poursuivre

Higher Early Monocyte and Total Lymphocyte Counts Are Associated with Better Overall Survival after Standard Total Body Irradiation, Cyclophosphamide, and Fludarabine Reduced-Intensity Conditioning Double Umbilical Cord Blood Allogeneic Stem Cell Transplantation in Adults

International audienceThis single-center retrospective study aimed to report the impact of early hematopoietic and immune recoveries after a standard total body irradiation, cyclophosphamide, and fludarabine (TCF) reduced-intensity conditioning (RIC) regimen for double umbilical cord blood (dUCB) allogeneic stem cell transplantation (allo-SCT) in adults. We analyzed 47 consecutive patients older than 17 years who engrafted after a dUCB TCF allo-SCT performed between January 2006 and April 2013 in our department. Median times for neutrophil and platelet recoveries were 17 (range, 6 to 59) and 37 days (range, 0 to 164), respectively. The 3-year overall (OS) and disease-free survivals, relapse incidence, and nonrelapse mortality were 65.7%, 57.2%, 27.1%, and 19%, respectively. In multivariate analysis, higher day þ30 monocyte (!615/mm 3 ; hazard ratio [HR], .04; 95% confidence interval [CI], .004 to .36; P < .01) and day þ42 lymphocyte (!395/mm 3 ; HR, .16; 95% CI, .03 to .78; P ¼ .02) counts were independently associated with better OS. These results suggest that early higher he-matopoietic and immune recovery is predictive of survival after dUCB TCF RIC allo-SCT in adults. Factors other than granulocyte colonyestimulating factor, which was used in all cases, favoring expansion of monocytes or lymphocytes, should be tested in the future as part of the UCB transplantation procedure

SARS-CoV-2 T-cell responses after one or two COVID-19 vaccine boosters in allogeneic transplant recipients

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Tocilizumab in combination with a standard induction chemotherapy in acute myeloid leukaemia patients (TOCILAM study): a single-centre, single-arm, phase 1 trialResearch in context

Summary: Background: In acute myeloid leukaemia (AML), interleukin-6 (IL-6) promotes chemo-resistance and its levels correlate with poor prognosis. IL-6 blockade may represent a promising therapeutic strategy. We aimed to test, tocilizumab, an anti-IL-6 receptor (R) monoclonal antibody in combination with standard intensive AML induction chemotherapy. Methods: This investigator-initiated single-centre phase 1 trial was conducted at Nantes University Hospital in France. According to a continual reassessment method, three escalating doses were tested of intravenous (IV) tocilizumab (4, 6, and 8 mg/kg) administered at day (d) 8 of a standard AML induction chemotherapy (IV idarubicine 8 mg/m2 d1 to d5 + IV cytarabine 100 mg/m2 d1 to d7). All adults (aged ≥ 18 years) with an Eastern Cooperative Oncology Group performance status of 0–2 and with a newly diagnosed (excluding patients with a favourable risk according to ELN-2017 classification if <60 year-old) or a relapsed/refractory AML were eligible. The primary objective was to determine the maximum tolerated dose of tocilizumab to administrate with a standard intensive AML induction. Safety outcomes were continuously monitored for at each participant contact. This trial is registered with ClinicalTrials.gov, NCT04547062. Findings: Between Dec 29, 2020 and Dec 1, 2022, 12 patients were enrolled, of whom 75% had an ELN-2017 high-risk profile, and were treated with tocilizumab— two patients at 4 mg/kg, two at 6 mg/kg and eight at 8 mg/kg of tocilizumab. No dose-limiting toxicity related to tocilizumab was documented. There were nine serious adverse events, none of which were related to tocilizumab, and there was no treatment-related deaths. MTD was thus not reached. Two deaths occurred during induction. In the remaining ten evaluable patients, nine responded to treatment. Interpretation: The combination of tocilizumab with standard AML intensive induction appears to be safe and resulting responses are encouraging. A dose of 8 mg/kg of tocilizumab given at day 8 of induction could be used for further phase 2/3 studies. Funding: The Leucémie Espoir Atlantique Famille (LEAF)—“Tous avec Fabien” association

Strong SARS-CoV-2 T-Cell Responses after One or Two COVID-19 Vaccine Boosters in Allogeneic Hematopoietic Stem Cell Recipients

International audienceA full exploration of immune responses is deserved after anti-SARS-CoV-2 vaccination and boosters, especially in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although several reports indicate successful humoral responses in such patients, the literature is scarce on cellular specific immunity. Here, both B- (antibodies) and T-cell responses were explored after one (V3 n = 40) or two (V4 n = 12) BNT162b2 mRNA vaccine boosters in 52 allo-HSCT recipients at a median of 755 days post-transplant (250 BAU/mL) and anti-spike T-cell responses. Similarly, 81% of the patients developed protective antibody levels, without difference between V3 and V4 (82.5% vs. 75%, p = 0.63), and 85% displayed T-cell responses. The median frequency of anti-spike T cells did not differ either between controls or the whole cohort of patients, although it was significantly lower for V3 (but not V4) patients. COVID-19 infections were solely observed in individuals having received only one booster. These results indicate that four vaccine injections help to achieve a satisfactory level of both humoral and cellular immune protection in allo-HSCT patients