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Objective:Central-line–associated bloodstream infections (CLABSIs) are associated with significant morbidity among pediatric oncology-hematology patients, and risk factors remain largely unknown in the setting of hospital at home (HAH). Children in HAH receive intensive treatment (eg, chemotherapy and parenteral nutrition), with frequent central-line handling; thus, they may be at higher risk for CLABSI.Methods:We conducted a monocentric retrospective study of patients with a central line included in our HAH program from January 1 to December 31, 2016. HAH patient characteristics for children developing CLABSIs were compared to those who did not, based on blood cultures positive for infection and clinical data of all patients included.Results:Overall, 492 HAH stays were analyzed, with 144 patients. The overall CLABSI rate in these patients was 2.6 per 1,000 central-line days. Children who developed CLABSIs were younger (median age, 2.5 vs 8.8 years; P < .001), suffered more from hematological pathologies (malignant or nonmalignant, 75% vs 52%; P = .02), and had more frequently undergone hematopoietic stem-cell transplantation (30.8% vs 6.5%; P = .01). In addition, these patients often had a tunneled externalized catheter as the central line and were more frequently given parenteral nutrition at home (46% vs 8%; P < .001).Conclusions:CLABSI rates for children in HAH were more similar to those of inpatients than to rates previously reported for ambulatory patients. The factors associated with infection identified herein should be further validated in multicentric studies and considered to improve HAH practices, parallel to prevention measures used in the inpatient setting.

Background: Allogenic hematopoietic stem cell transplantation (a-HCT) remains a therapeutic treatment for many pediatric hematological diseases. The occurrence of invasive fungal infections (IFIs) is a complication for which ECIL-8 recommends primary antifungal prophylaxis. In this study, we evaluated the impact of our local strategy of not systematically administering primary antifungal prophylaxis in children undergoing a-HCT on the occurrence and mortality of IFIs. Methods: We performed a retrospective monocentric study from 2010 to 2020. We retained all proven and probable IFIs diagnosed during the first year post a-HCT. Results: 308 patients were included. Eighteen patients developed twenty IFIs (thirteen proven, seven probable) (6.5%) among which aspergillosis (n = 10, 50%) and candidosis (n = 7, 35%) were the most frequently diagnosed infections. Only 2% of children died because of an IFI, which represents 14% of all deaths. Multivariate analysis found that age > 10 years (OR: 0.29), the use of a therapeutic antiviral treatment (OR: 2.71) and a low neutrophil count reconstitution (OR: 0.93) were significantly associated with the risk of IFI occurrence. There was also a trend of malignant underlying disease and status ≥ CR2 but it was not retained in multivariate analysis. Conclusions: IFI occurrence was not higher in our cohort than what is reported in the literature with the use of systematic antifungal prophylaxis, with a good survival rate nonetheless. Thus, a prophylaxis could be considered for children with a high risk of IFI such as those aged over 10 years.

Ten to fifteen percent of children with acute lymphoblastic leukemia (ALL) relapse following treatment. Of these, less than 2% display ophthalmic relapses, which owing to their scarcity, are largely undocumented, leaving clinicians with few diagnostic and therapeutic recommendations, despite serious functional sequelae. We conducted a French multicenter retrospective study to collect all clinical, radiological, biological, and therapeutic data, and outcomes for children with ALL ophthalmic relapses. From 2000 to 2020, 20 ophthalmic relapses occurring after first-line therapy performed before January 1

International audience; Fanconi anemia (FA) patients experience chromosome instability, yielding hematopoietic stem/progenitor cell (HSPC) exhaustion and predisposition to poor-prognosis myeloid leukemia. Based on a longitudinal cohort of 335 patients, we performed clinical, genomic, and functional studies in 62 patients with clonal evolution. We found a unique pattern of somatic structural variants and mutations that shares features of BRCA-related cancers, the FA-hallmark being unbalanced, microhomology-mediated translocations driving copy-number alterations. Half the patients developed chromosome 1q gain, driving clonal hematopoiesis through MDM4 trisomy downmodulating p53 signaling later followed by secondary acute myeloid lukemia genomic alterations. Functionally, MDM4 triplication conferred greater fitness to murine and human primary FA HSPCs, rescued inflammation-mediated bone marrow failure, and drove clonal dominance in FA mouse models, while targeting MDM4 impaired leukemia cells in vitro and in vivo. Our results identify a linear route toward secondary leukemogenesis whereby early MDM4-driven downregulation of basal p53 activation plays a pivotal role, opening monitoring and therapeutic prospects.

Allogenic hematopoietic stem cell transplantation (aHSCT) remains the treatment of choice for some malignant hemopathies in children, albeit with the risk of long-term consequences, including chronic kidney disease (CKD). In our single tertiary referral center, we retrospectively assessed the long-term renal outcome in a cohort of children and adolescents who had undergone aHSCT for malignant hemopathies between 2003 and 2017. We distinguished glomerular and tubular dysfunctions and assessed the accuracy of the most common formula(s) to estimate glomerular filtration rate (GFR) during standard clinical follow-up. Among the 166 patients who had received aHSCT, 61 underwent kidney functional assessment 1 to 10 years post-transplantation. Twenty-seven patients (44.3%) had a CKD with glomerular impairment, including 20 patients with a GFR

To obtain a national overview of the epidemiology and management of invasive fungal infections (IFIs) in France for severely immunocompromised children who were treated for acute leukemia or had undergone allogeneic hematopoietic stem cell transplantation (a-HSCT).We performed a national multicenter retrospective study to collect epidemiologic data for proven and probable IFIs in children with acute leukemia under first- line or relapse treatment or who had undergone a-HSCT. We also conducted a prospective practice survey to provide a national overview of IFI management in pediatric hematology units.From January 2014 to December 2017, 144 cases of IFI were diagnosed (5.3%) in 2721 patients, including 61 cases of candidiasis, 60 cases of aspergillosis, and 23 cases of infection with "emergent" fungi, including 10 cases of mucormycosis and 6 cases of fusariosis. The IFI rate was higher in patients with acute myelogenous leukemia (12.9%) (OR, 3.24; 95% CI, 2.15-4.81; P.0001) compared with the rest of the cohort. Patients undergoing a-HSCT had an IFI rate of only 4.3%. In these patients, the use of primary antifungal prophylaxis (principally fluconazole) was associated with a lower IFI rate (OR, 0.28; 95% CI, 0.14-0.60; P = 4.90 ×10The emerging fungi and new antifungal resistance profiles uncovered in this study should be considered in IFI management in immunocompromised children.

To date, invasive fungal infections (IFIs) are still responsible for a high mortality rate in children managed for haematological malignancy. Although Candida and Aspergillus infections remain in the majority, emerging fungal infections are increasingly common. Children differ from adults in their pathology and treatment, as well as in their prior fungal colonisation and unique pharmacokinetics. Therefore, we propose here specific paediatric management recommendations for IFIs in haematology.We based our recommendations on a review of the literature, including the latest ECIL recommendations, an analysis of practices and a collection of expert opinions.In France, approximately 5% of children treated for haematological malignancy or who have received a bone marrow allograft present an IFI. These IFIs are equally divided between yeast infections (mainly due to Candida albicans) and filamentous infections (mainly aspergillosis) and 16% are IFIs due to emerging fungi, half of which are due to Mucorales. In these recommendations, we recall the diagnostic criteria for proven or probable IFI according to the Donnelly classification, then we propose strategies for screening, diagnosing, evaluating the extension and treating these three types of IFI. We also detail the diagnostic and therapeutic management of chronic disseminated candidiasis. We also discuss prophylactic measures, including environmental measures which are of primary importance in children.

Background. Osteonecrosis (ON) is a long-known complication of acute leukemia (AL) management affecting 1 to 10% of young patients, leading to long-term morbidity. Widespread access to Magnetic Resonance Imagery (MRI) over the past ten years has allowed earlier detection and more accurate assessment. This study investigated clinical and radiological features of ON, among the large French cohort L.E.A (Leucémie Enfant Adolescent) Procedure. Patients with ON were retrospectively enrolled and risk factors for the onset, the multifocal involvement and severe damage were analyzed. Quality of life (QoL) was also evaluated. A sub-study described radiological features. Results. 129/4973 patients developed ON (2.5%) and were preferentially aged over 10 years at time of AL diagnosis (OR 22.46, p

Documenting bacteremia at the onset of fever in immunosuppressed children is challenging; therefore, it leads to the early administration of broad-spectrum antibiotics. We aimed to analyse the evolution of antibiotic resistance profiles of bacterial bloodstream infections (BSI) and gut colonisations in a large cohort of immunocompromised children carrying a central venous catheter, in comparison with a prior, similar study conducted in our centre from 2014 to 2017. A retrospective, observational cohort study was conducted from January 2018 to December 2021, in a tertiary centre for paediatric immuno-haematology and oncology. Empirical antibiotic therapy was adapted to the immunosuppression risk group and prior bacterial colonisation. There was a mean of 6.9 BSI/1000 patient bed days. Multidrug-resistant bacteria (MDRB) associated BSI accounted for 35/273 (12.8%). The incidence of MDRB gum/gut colonisation and MDRB associated BSI increased annually and correlated with the level of immunosuppression (p = 0.024). One third (34.7%) of the BSI episodes were not associated with neutropenia. As compared to the previous study, an alarming emergence of MDRB responsible for gut colonisations and BSI in immunosuppressed children was reported over the last four years. The degree of immunosuppression directly correlates with the risk of having an MDRB gut colonisation or MDRB BSI.

International audience; Context A negative association between a history of allergy and childhood acute lymphoblastic leukaemia (ALL) has been reported in previous studies, but remains debated. This work aimed to investigate this association accounting for genetic polymorphisms of the Th2 pathway cytokines (IL4, IL10, IL13 and IL4-receptor (IL4R)). Methods Analyses were based on the French case-control study ESTELLE (2010-2011). The complete sample included 629 ALL cases and 1,421 population-based controls frequency-matched on age and gender. The child's medical history was collected through standardised maternal interview. Biological samples were collected, and genotyping data were available for 411 cases and 704 controls of European origin. Odds ratios (OR) were estimated using unconditional regression models adjusted for potential confounders. Results In the complete sample, a significant inverse association was observed between ALL and reported history of allergic rhinitis or sinusitis (OR=0.65 [0.42-0.98]; p= 0.04), but there was no obvious association with allergies overall. There was an interaction between genetic polymorphisms in IL4 and IL4R (pinteraction=0.003), as well as a gene-environment interaction between IL4R-rs1801275 and a reported history of asthma (IOR=0.23; pint=0.008) and eczema (IOR= 0.47; pint=0.06). We observed no interaction with the candidate polymorphisms in IL4 and IL13. Conclusion These results suggest that the association between allergic symptoms and childhood ALL could be modified by IL4R-rs1801275, and that this variant could also interact with a functional variant in IL4 gene. While they warrant confirmation, these results could help understand the pathological mechanisms under the reported inverse association between allergy and childhood ALL.

Allogenic hematopoietic stem cell transplantation (aHSCT) remains the treatment of choice for some malignant hemopathies in children, albeit with the risk of long-term consequences, including chronic kidney disease (CKD).In our single tertiary referral center, we retrospectively assessed the long-term renal outcome in a cohort of children and adolescents who had undergone aHSCT for malignant hemopathies between 2003 and 2017. We distinguished glomerular and tubular dysfunctions and assessed the accuracy of the most common formula(s) to estimate glomerular filtration rate (GFR) during standard clinical follow-up.Among the 166 patients who had received aHSCT, 61 underwent kidney functional assessment 1 to 10 years post-transplantation. Twenty-seven patients (44.3%) had a CKD with glomerular impairment, including 20 patients with a GFR 90 mL/min/1.73 mIn conclusion, our study shows that CKD represents an important long-term sequela for children and adolescents who undergo aHSCT for malignant hemopathies, either with glomerular dysfunction or with the more insidious tubular dysfunction which could potentially impact growth. These patients could benefit from specialized long-term nephrology follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

We report the case of a 14-year-old boy with a completely normal medical and social background (good student and handball practice). A dentist monthly followed this patient for an orthodontic treatment. Facing with symptoms associating purpura, pancytopenia, and limbs pain, the first diagnosis that came to mind to emergency pediatricians was acute leukemia and the patient was addressed to a hematology department. However, additional psychiatry investigations revealed an avoiding restrictive food intake disorder (ARFID) associated with serious vitamin deficiencies (Vitamins B9 and D) and responsible for scurvy, mimicking acute leukemia onset. Strikingly, this young patient has been undergoing a close medical follow-up since infancy because of a selective diet. Since growth, education, and development were normal, the risk of pursuing this unbalanced diet has been neglected and this child was admitted at diagnosis in a life-threatening condition.

Genotypic diagnosis of HSV drug resistance can be performed routinely in a clinically relevant time. Nevertheless, data about HSV mutations (polymorphism or resistance) is not exhaustive which hinders the interpretation of such tests. The UL23, UL30, and UL5 genes are of greatest interest as these encode, respectively, thymidine kinase, DNA polymerase, and helicase, which, if mutated may affect the effectiveness of acyclovir, foscarnet, cidofovir, and helicase-primase inhibitors. The present study aimed to extensively characterize UL23, UL30, and UL5 genes. A total of 239 clinical HSV1 recovered from patients admitted to the hematology departments of the Lyon teaching hospitals were included in this single-center retrospective study. Drug resistance was evaluated using the neutral red dye-uptake assay, and sequencing using the Sanger method. Additional information on HSV1 natural polymorphism and resistance is now available. Twenty-two amino acid substitutions related to polymorphism were described on UL23 (E43A, L50M, L68R, Q109K, A133V, A136N, S150L, D258N, S263L, P280S, N301S, A316S, M322L, I326V, D330A, D338H, Q342H, T344I, Q349R, V352L, R370W, E371D), and 6 amino acid substitutions on UL30 (G641R, G645D, E649G, G679D, R681L, I966M). Moreover, the UL23 substitution L242P was added to ACV resistance-related mutations. There were 12 substitutions on UL23 (A37S, V70M, S74L, H151N, P154S, P155Q, L159R, E225L, Y248H, Q270R, N303Y, M372I), and 8 on UL5 (L49I, L138V, S173L, A280T, A575V, V600A, A602T, D862N) that remain of unclear significance with regards to drug resistance. The mean (±standard deviation, SD) number of natural polymorphisms in UL23 was 2.53 (±2.55), in UL30 it was 0.83 (±1.02), and in UL5 it was 5.00 (±1.59) There was no association between HSV1 phenotype and the frequency of substitutions. The results reported herein provide valuable new information concerning HSV1 mutations that will assist the interpretation of genotypic assays.

International audience

International audience; Over the years, the prognosis of adolescents treated for acute lymphoblastic leukemia (ALL) has improved. However, this age group still represents a challenge with an overall survival (OS) of 60% compared to 85% in younger children. Herein, we report the outcome of adolescents treated in the European Organisation for Research and Treatment of Cancer (EORTC) 58951 clinical trial. EORTC 58951 clinical trial included patients with de novo ALL between 1998 and 2008. For this study, we analyzed data of all adolescents between 15 and under 18. Data from 97 adolescents were analyzed, 70 had B-lineage and 27 had T-lineage ALL. The 8-year event-free survival (EFS) and OS for the B-cell precursor ALL cases were 72.3% (59.4%-81.7%) and 80.8% (67.4%-89.1%), respectively. For the T-lineage, the 8-year EFS and OS were 57.4% (36.1%-74.0%) and 59.0% (36.1%-76.2%), respectively. "B-other" ALL, defined as BCP-ALL lacking any known recurrent genetic abnormalities were more frequent in our adolescent population (52.8%) than in younger children (27.1%). Outcome of adolescents in the EORTC 58951 study is supporting the findings that adolescents have better outcome in pediatric compared to adults' trials. Nevertheless, in pediatric studies, adolescents still have a worse prognosis than younger children. Despite the fact that specific unfavorable characteristics may be linked to the adolescent population, a careful study and characterization of adolescents "B-other" genetic abnormalities in ALL is critical to improve the outcome of this population.

Bacterial infections remain a major cause of morbidity and mortality in immunocompromised children. From the onset of fever, an early administration of broad-spectrum antibiotics is begun; this strategy could induce emergence of multi-drug resistant bacteria (MDR). We describe the incidence and microbiological spectrum, including MDR bacteria of bacterial documented blood-stream infections (BSI) in immunocompromised children. A retrospective, descriptive study was conducted in a tertiary referral centre in France from January 2014 to December 2017. Our cohort included a large scale of patients with febrile neutropenia: haematological and oncological malignancies, haematopoietic stem cell transplantations, severe combined immunodeficiency syndromes. BSI were defined by positive blood culture samples associated with fever. Among 760 febrile neutropenia episodes in 7301 admitted patients, we identified 310 documented BSI with a mean of 7.4 BSI/1000 patient bed days. Only 2.9% BSIs were caused by MDR bacteria, none vancomycin resistant. Coagulase-negative staphylococci were identified in 49.7% BSI and Staphylococcus aureus caused 6.5% infections. Gram-negative bacilli accounted for 21.6% of isolated bacteria, Pseudomonas for 4.8%. The incidence of BSI annually decreased by 0.75% (p = 0.002).Conclusion: With a step-down strategy at 48 h of initial broad-spectrum antibiotic therapy, we reported a low number of MDR bacteria, no deaths related to BSI. What is Known: • Bacterial bloodstream infections are a leading cause of morbidity and mortality in immunocompromised children • Multi-drug resistant bacteria are emerging worldwide. What is New: • Initial broad-spectrum antibiotic therapy with a step-down strategy at 48 h: no deaths related to bloodstream infections with a low number of resistant bacteria. • Parental and nurse stewardship to decrease bloodstream infections incidence with a drop of staphylococcal infections.

We report the case of a 14-year-old boy with a completely normal medical and social background (good student and handball practice). A dentist monthly followed this patient for an orthodontic treatment. Facing with symptoms associating purpura, pancytopenia, and limbs pain, the first diagnosis that came to mind to emergency pediatricians was acute leukemia and the patient was addressed to a hematology department. However, additional psychiatry investigations revealed an avoiding restrictive food intake disorder (ARFID) associated with serious vitamin deficiencies (Vitamins B9 and D) and responsible for scurvy, mimicking acute leukemia onset. Strikingly, this young patient has been undergoing a close medical follow-up since infancy because of a selective diet. Since growth, education, and development were normal, the risk of pursuing this unbalanced diet has been neglected and this child was admitted at diagnosis in a life-threatening condition.

International audience

Summary Fanconi anemia (FA) causes bone marrow failure early during childhood, and recent studies indicate that a hematopoietic defect could begin in utero. We performed a unique kinetics study of hematopoiesis in Fancg−/− mouse embryos, between the early embryonic day 11.5 (E11.5) to E12.5 developmental window (when the highest level of hematopoietic stem cells [HSC] amplification takes place) and E14.5. This study reveals a deep HSC defect with exhaustion of proliferative and self-renewal capacities very early during development, together with severe FA clinical and biological manifestations, which are mitigated at E14.5 due to compensatory mechanisms that help to ensure survival of Fancg−/− embryos. It also reports that a deep HSC defect is also observed during human FA development, and that human FA fetal liver (FL) HSCs present a transcriptome profile similar to that of mouse E12.5 Fancg−/− FL HSCs. Altogether, our results highlight that early mouse FL could represent a good alternative model for studying Fanconi pathology., Highlights • Deep HSC defect in FL and Pl very early during Fancg−/− development • Functional and molecular compensation in Fancg−/− FL HSCs at E14.5 • Deep HSC defect also observed during human FA development • E12.5 Fancg−/− FL could represent a good model for studying Fanconi pathology, A deep HSC defect is present very early during Fancg−/− mouse embryonic development, and is also reported for the first time during human Fanconi anemia development. At E14.5, functional and molecular compensation in Fancg−/− FL HSCs help ensure the survival of Fancg−/− embryos. Altogether E12.5 Fancg−/− FL could represent a good model for studying Fanconi pathology.

International audience; Bone marrow (BM) failure (BMF) in children and young adults is often suspected to be inherited, but in many cases diagnosis remains uncertain. We studied a cohort of 179 patients (from 173 families) with BMF of suspected inherited origin but unresolved diagnosis after medical evaluation and Fanconi anemia exclusion. All patients had cytopenias, and 12.0% presented ≥5% BM blast cells. Median age at genetic evaluation was 11 years; 20.7% of patients were aged ≤2 years and 36.9% were ≥18 years. We analyzed genomic DNA from skin fibroblasts using whole-exome sequencing, and were able to assign a causal or likely causal germ line mutation in 86 patients (48.0%), involving a total of 28 genes. These included genes in familial hematopoietic disorders (GATA2, RUNX1), telomeropathies (TERC, TERT, RTEL1), ribosome disorders (SBDS, DNAJC21, RPL5), and DNA repair deficiency (LIG4). Many patients had an atypical presentation, and the mutated gene was often not clinically suspected. We also found mutations in genes seldom reported in inherited BMF (IBMF), such as SAMD9 and SAMD9L (N = 16 of the 86 patients, 18.6%), MECOM/EVI1 (N = 6, 7.0%), and ERCC6L2 (N = 7, 8.1%), each of which was associated with a distinct natural history; SAMD9 and SAMD9L patients often experienced transient aplasia and monosomy 7, whereas MECOM patients presented early-onset severe aplastic anemia, and ERCC6L2 patients, mild pancytopenia with myelodysplasia. This study broadens the molecular and clinical portrait of IBMF syndromes and sheds light on newly recognized disease entities. Using a high-throughput sequencing screen to implement precision medicine at diagnosis can improve patient management and family counseling.

Dexamethasone could be more effective than prednisolone at similar anti-inflammatory doses in the treatment of childhood acute lymphoblastic leukemia. In order to check if this "superiority" of dexamethasone might be dose-dependent, we conducted a randomized phase III trial comparing dexamethasone (6 mg/m(2)/day) to prednisolone (60 mg/m(2)/day) in induction therapy. All newly diagnosed children and adolescents with acute lymphoblastic leukemia in the 58951 EORTC trial were randomized on prephase day 1 or day 8. The main endpoint was event-free survival; secondary endpoints were overall survival and toxicity. A total of 1947 patients with acute lymphoblastic leukemia were randomized. At a median follow-up of 6.9 years, the 8-year event-free survival rate was 81.5% in the dexamethasone arm and 81.2% in the prednisolone arm; the 8-year overall survival rates were 87.2% and 89.0% respectively. The 8-year incidences of isolated or combined central nervous system relapse were 2.9% and 4.5% in the dexamethasone and prednisolone arms, respectively. The incidence of grade 3-4 toxicities during induction and the frequency of osteonecrosis were similar in the two arms. In conclusion, dexamethasone and prednisolone, used respectively at the doses of 6 and 60 mg/m(2)/day during induction, were equally effective and had a similar toxicity profile. Dexamethasone decreased the 8-year central nervous system relapse incidence by 1.6%. This trial was registered at www.clinicaltrials.gov as #NCT00003728.

Background Blood stream infections (BSI) remain a major cause of morbidity and mortality in immunocompromised children and increase the length of hospitalisation as well as the cost of treatment. The difficulty of documenting bacteremia at the onset of fever in neutropenic patients led to an early administration of broad-spectrum antibiotics, without waiting for further clinical or microbiological evidence of infection. Furthermore, gut decontamination is performed in children with a high-risk of BSI. Does this practice trigger the emergence of multidrug resistant bacteria? Methods We performed a monocentric, retrospective and descriptive study between January 2014 and December 2017, using a large cohort of pediatric patients with hematological and oncological diseases in a tertiary care pediatric center in France, the Institute of Hematology and Oncology Pediatric (IHOPe) in Lyon. This includes patients with acute leukemia, lymphoma, children who underwent hematopoietic stem cell transplantation (HSCT) (allogenic and autogenic), children with severe combined immunodeficiency syndromes as well as children suffering from solid tumors. A bacteremia was defined by a positive blood culture sample, associated with fever. For coagulase-negative staphylococci (CoNS), two distinct positive blood cultures within 48 h were mandatory. The children were divided into 4 infectious risk groups regarding their immunosuppression level. Groups 3 and 4 received non-absorbable antibiotics for gut and oral decontamination. The empirical antibacterial therapy was adjusted to the risk group, as well as a prior identified bacteria colonisation: all patients with a central venous access received vancomycin (stopped after 48 hours in the absence of bacterial identification), amikacin and a broad-spectrum penicillin. Results During these 4 years, our institution recorded more than 8000 hospitalisations distributed within 3 units: 2 conventional hospitalisation wards and the HSCT unit. Our protected unit is equipped with spacious positive air pressure rooms, for child and parent, with high-efficiency particulate air (HEPA) filters where only a clean non-sterile outfit (gown and mask) are required. We identified 350 cases of BSI, thus an overall incidence of 4,5%. Fifteen to twenty per cent of these children suffered from a second or more re-infection. The incidence of BSI was stable throughout the four years of our study. Gram-positive bacteria represented more than 50% of BSI and CoNS was the most frequent pathogen agent found. Among the others gram-positive isolates, we counted around 5 to 6 cases/year of Streptococcus and Staphylococcus aureus. Among Gram-negative bacteria, enterobacteries accounted for 14 to 20 BSI per year and Pseudomonas aeruginosa for 2 to 4 cases per year. Among the identified bacteria, only 6.5% were multidrug resistant for all our study time. Three highly resistant bacteria were identified in 2 children priorly treated in Romania and Tunisia: 2 Klebsiella pneumoniae producing Carbapenemase (KPC), 1 Enterococcus faecium resistant to glycopeptides. Interestingly, 35% of the BSI occurred in the less immunocompromised group. The other cases were evenly distributed between the 3 more severely immunocompromised groups. Conclusion Our empirical initial broad-spectrum antimicrobial coverage is well adapted to the epidemiology of our bacterial agents and shortens hospitalisations. Furthermore, it is not associated with the emergence of antibiotic resistance patterns. The microbiological spectrum of incriminated bacteria is relatively stable over time and we do not observe the emergence of multidrug resistant gram-negative bacteria as well as the absence of vancomycin-resistant enterococci (VRE) in our tertiary center.

International audience; Noonan syndrome is associated with a range of malignancies including acute lymphoblastic leukemia (ALL). However, little information is available regarding the frequency, natural history, characteristics and prognosis of ALL in Noonan syndrome or RASopathies in general. Cross-referencing data from a large prospective cohort of 1176 patients having a molecularly confirmed RASopathy with data from the French childhood cancer registry allowed us to identify ALL in 6 (0.5%) patients including 4/778 (0.5%) with a germline PTPN11 mutation and 2/94 (2.1%) with a germline SOS1 mutation. None of the patients of our series with CFC syndrome (with germline BRAF or MAP2K1/MAP2K2 mutation - n = 121) or Costello syndrome (with HRAS mutation - n = 35) had an ALL. A total of 19 Noonan-ALL were gathered by adding our patients to those of the International Berlin-Munster-Frankfurt (I-BFM) study group and previously reported patients. Strikingly, all Noonan-associated ALL were B-cell precursor ALL, and high hyperdiploidy with more than 50 chromosomes was found in the leukemia cells of 13/17 (76%) patients with available genetics data. Our data suggest that children with Noonan syndrome are at higher risk to develop ALL. Like what is observed for somatic PTPN11 mutations, NS is preferentially associated with the development of hyperdiploid ALL that will usually respond well to chemotherapy. However, Noonan syndrome patients seem to have a propensity to develop post therapy myelodysplasia that can eventually be fatal. Hence, one should be particularly cautious when treating these patients.

Fanconi anemia (FA) is a genetic disorder due to mutations in one of the sixteen FANC genes involved in DNA repair. Many FA patients develop bone marrow failure (BMF) during childhood, and FA strongly predisposes to myelodysplasia syndrome and/or acute myeloid leukaemia. The pathogenesis of the BMF remains uncompletely understood. Low hematopoietic progenitor cell (HPCs) counts observed early in life and preceeding the onset of blood cytopenia in patients led we, and other, to hypothesize that the hematopoietic development might be abnormal in the FA embryo. Indeed, unlike adult hematopoietic stem cells (HSCs) which are quiescent in the BM niche, during embryonic life HSCs are in active proliferation in sites of expansion such as fetal liver and placenta, where they get amplified and acquire properties of adult HSC .We hypothesized that in FA, the FA defect in response to the replicative stress could impair the expension of the HSC pool.In order to investigate this hypothesis, we carried out studies in Fancg-/- knock out mice and in human FA fetuses obtained with informed consent from medical abortion. In Fancg-/- mice, FACS analysis revealed a 1,5- to 3-fold deficiency in hematopoietic stem and progenitor cells (HSPC) very early during embryonic development (i.e 11.5 days of gestation - E11.5) in fetal liver (FL) and placenta (Pl) (p In vivo long-term hematopoietic reconstitution (LTR) assays confirmed a deficit of the HSC enriched LSA population of E14.5 Fancg-/- FL. Indeed, although the percentage of mice reconstituted was as good as that obtained with the same number of WT LSA, the CD45 Ly5.2 chimerism was reduced (49±20% vs 84±4% for 1000 LSA injected, and 56±12% vs 87±2% for 5000 LSA). Interestingly, bone marrow analysis of mice reconstituted with Fancg-/- LSA 22 weeks after injection showed a level of CD45 Ly5.2 chimerism 3-fold lower than that found in blood, spleen and thymus, as well as a very low chimerism for myeloid GEM lineages, contrasting with a high chimerism for B and T lymphoid lineages. Moreover, we were able to demonstrate that this deficit is already present at E12.5, both in Fancg-/- FL and Pl. Indeed, no mice reconstituted with 3.105 total Fancg-/- fetal liver cells, while 100% injected with the same number of WT FL cells got reconstituted with a chimerism of 59,5±5%. For Pl, when 500 000 cells were injected, reconstitution was observed in only 1 out of 3 mice for Fancg-/- (29% chimerism), and in 3 out of 3 mice for WT (88±4% chimerism). In human FA FL of 14 weeks of gestation, we also observed a 4-fold defect of HSPC with a total lack of in vitro amplification compared to control, in agreement with the mice data. Taken together, these data demonstrate that a profound deficit of HSCs and progenitors cells is present since the earlier stages of embryonic development in FA. In addition, using organotypic cultures of E11 aortas, we could show that this defect of amplification is already present in HSCs emerging from Fancg-/- aorta, which showed a 2-fold lower rate of amplification compared to WT. More importantly, our results show for the first time exhaustion in myeloid lineage of FA, in agreement with what is observed in children with FA disease. Altogether, our work suggests a role of the FA pathway during the development of the hematopoietic system leading to a deficit of amplification of HSC. Comparison of FA HSC transcriptome with that of control HSC in FL and Pl is in progress. It should allow to identify the key pathways involved in the embryonic HSC amplification that are deregulated in FA, and hopefully getting more insights in the pathogenesis of the BMF and leukemogenesis in FA patients. Disclosures No relevant conflicts of interest to declare.

Cytogenetic, molecular and phenotyping features of malignant hematologic diseases succeeded in improving their management by a more accurate stratification of patients according to several groups of risk and by providing a rational for targeted therapy. Three major types of treatment (excluding cellular therapy) are currently available in onco-hematology: conventional chemotherapy, small molecules for targeted therapy and monoclonal antibodies. Conventional chemotherapy with optimization of doses and multidrug-based regimens allowed to substantially improve survival of patients and keeps a place of choice in treatment of these diseases. Targeted treatments came from the cytogenetic and molecular characterization of hemopathies. Thus, the kinase Bcr-Abl, as a result of the translocation t(9;22)(q34;q11), has been successfully targeted by tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia. Molecular abnormalities like internal-tandem duplication/point activating mutations in FLT3 in some acute myeloblastic leukemia or epigenetic dysregulations in some blood malignancies can also be targeted by small molecules. Hematopoietic malignant cells are phenotypically characterized by expression of cluster of differentiation (CD) on their surface. These CD are detected by flow cytometry using specific antibodies. Monoclonal antibodies targeting different CD have been developed for treatment. Rituximab, an anti-CD20 antibody, was the first monoclonal antibody successfully developed for treatment of malignant hematologic diseases. Since rituximab, many other monoclonal antibodies are being developed. Trends in malignant hematologic diseases presented here will include treatments, which have at least entered phase I/II clinical trials in adult or childhood leukemia. They include some novel drugs of conventional chemotherapy like second-generation nucleoside analogues. We will give an overview of the small molecules targeting the different cellular pathways and we will highlight those appearing as the most promising like novel TKIs. The large field of monoclonal antibodies will be also approached focusing on antibodies developed in leukemias.

l-asparaginase encapsulated within erythrocytes (GRASPA(®) ) should allow serum asparagine depletion over a longer period than the native form of the enzyme, using lower doses and allowing better tolerance. The GRASPALL 2005-01 study, a multicentre randomized controlled trial, investigated three doses of GRASPA(®) for the duration of asparagine depletion in a phase I/II study in adults and children with acute lymphoblastic leukaemia (ALL) in first relapse. Between February 2006 and April 2008, 18 patients received GRASPA(®) (50 iu/kg: n = 6,100 iu/kg: n = 6, 150 iu/kg: n = 6) after randomization, and six patients were assigned to the Escherichia coli native l-asparaginase (E. colil-ASNase) control group. GRASPA(®) was effective at depleting l-asparagine. One single injection of 150 iu/kg of GRASPA(®) provided similar results to 8 × 10,000 iu/m(2) intravenous injections of E. colil-ASNase. The safety profile of GRASPA(®) showed a reduction in the number and severity of allergic reactions and a trend towards less coagulation disorders. Other expected adverse events were comparable to those observed with E. colil-ASNase and there was also no difference between the three doses of GRASPA(®) .

BACKGROUND Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a procedure with a high infection risk. Strict isolation of patients is the rule to prevent such condition. OBJECTIVE We compared the occurrence of severe infections (bacteremia and invasive fungal infection, IFI) in children undergoing alloHSCT before and after the move to a new protected unit with decreases in isolation methods. METHODS The study was conducted over a 10-year period. Unit 1 (2002-2007) consisted of laminar airflow rooms where caregivers were required to wear a sterile outfit (gown, gloves, hat, and mask). Unit 2 (2008-2012) included spacious positive air pressure rooms with HEPA filters where only a clean gown and mask were required to be worn. RESULTS Two hundred eighty-six alloHSCTs were performed (144 in Unit 1 and 142 in Unit 2). We reported a total incidence of 4.78 infections/1000 hospital-days including 4.4 episodes of bacteremia and 0.38 episodes of IFI. There was no statistical difference in the incidence of infections: n = 4.98/1000 hospital-days in Unit 1 vs. n = 4.6/1000 in Unit 2 (P = 0.63). CONCLUSION The lack of difference in the occurrence of severe infection supports our decision to decrease unnecessary high protection in alloHSCT units to improve children's daily life.

BACKGROUND Invasive aspergillosis (IA) is associated with a high mortality rate despite the introduction of new antifungal agents. Several therapeutic strategies have been proposed to improve mortality rates in IA, including combination of drugs. METHODS Here, we report the outcome of treatments based on a combination of antifungal agents on IA, including voriconazole and liposomal amphotericin B, in a pediatric population from 2001 to 2010. Our population included children with diverse hematological diseases or with bone marrow transplantation. RESULTS Over a 10-year period, we diagnosed 19 cases (2,8%) of invasive pulmonary aspergillosis with an overall survival rate of 58%. CONCLUSION Compared with the previous study conducted from 1986 to 2000, the overall survival rate (bone marrow transplantation excluded) greatly improved (12.5% to 58%), especially for patients treated for acute leukemia.

International audience; Cytogenetic, molecular and phenotyping features of malignant hematologic diseases succeeded in improving their management by a more accurate stratification of patients according to several groups of risk and by providing a rational for targeted therapy. Three major types of treatment (excluding cellular therapy) are currently available in onco-hematology: conventional chemotherapy, small molecules for targeted therapy and monoclonal antibodies. Conventional chemotherapy with optimization of doses and multidrug-based regimens allowed to substantially improve survival of patients and keeps a place of choice in treatment of these diseases. Targeted treatments came from the cytogenetic and molecular characterization of hemopathies. Thus, the kinase Bcr-Abl, as a result of the translocation t(9;22)(q34;q11), has been successfully targeted by tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia. Molecular abnormalities like internal-tandem duplication/point activating mutations in FLT3 in some acute myeloblastic leukemia or epigenetic dysregulations in some blood malignancies can also be targeted by small molecules. Hematopoietic malignant cells are phenotypically characterized by expression of cluster of differentiation (CD) on their surface. These CD are detected by flow cytometry using specific antibodies. Monoclonal antibodies targeting different CD have been developed for treatment. Rituximab, an anti-CD20 antibody, was the first monoclonal antibody successfully developed for treatment of malignant hematologic diseases. Since rituximab, many other monoclonal antibodies are being developed. Trends in malignant hematologic diseases presented here will include treatments, which have at least entered phase I/II clinical trials in adult or childhood leukemia. They include some novel drugs of conventional chemotherapy like second-generation nucleoside analogues. We will give an overview of the small molecules targeting the different cellular pathways and we will highlight those appearing as the most promising like novel TKIs. The large field of monoclonal antibodies will be also approached focusing on antibodies developed in leukemias.

International audience; l-asparaginase encapsulated within erythrocytes (GRASPA(®) ) should allow serum asparagine depletion over a longer period than the native form of the enzyme, using lower doses and allowing better tolerance. The GRASPALL 2005-01 study, a multicentre randomized controlled trial, investigated three doses of GRASPA(®) for the duration of asparagine depletion in a phase I/II study in adults and children with acute lymphoblastic leukaemia (ALL) in first relapse. Between February 2006 and April 2008, 18 patients received GRASPA(®) (50 iu/kg: n = 6,100 iu/kg: n = 6, 150 iu/kg: n = 6) after randomization, and six patients were assigned to the Escherichia coli native l-asparaginase (E. colil-ASNase) control group. GRASPA(®) was effective at depleting l-asparagine. One single injection of 150 iu/kg of GRASPA(®) provided similar results to 8 × 10,000 iu/m(2) intravenous injections of E. colil-ASNase. The safety profile of GRASPA(®) showed a reduction in the number and severity of allergic reactions and a trend towards less coagulation disorders. Other expected adverse events were comparable to those observed with E. colil-ASNase and there was also no difference between the three doses of GRASPA(®) .

Cryptosporidium is recognized as a cause of diarrhea associated with a high mortality in immunocompromised patients. We report on 2 pediatric cases of cryptosporidiosis during maintenance chemotherapy of acute lymphoblastic leukemia. The patients presented severe diarrheas, 1 of them was complicated by a cholangitis. Withdrawal of immunosuppressive treatments and adjunction of an adequate antiparasitic treatment cured the Cryptosporidium infection in both cases.

Indirubin-3'-monoxime (IO) is a derivative of indirubin, an active compound of a traditional Chinese medicinal recipe used to treat various inflammatory and malignant diseases. The main in vitro targets of IO (i.e. cyclin dependent kinases, glycogen synthase kinase-3beta, Stat 3 and Aryl hydrocarbon receptor) are regulators of lymphocyte activation. We investigated the interest of IO and its derivative 6-bromo-indirubin-3'oxime (6BIO) for inhibiting the growth of malignant lymphoid cells. IO (1-20 microM) induced cell cycle inhibition and cell death in malignant B- (IM9, Reh6) and T- (Jurkat, CEM-T) lymphoid cell lines depending to cell type, doses, and duration of treatment. IO and 6BIO (10 microM) treatment for 24 and 48 h were compared: 6BIO treatment resulted in a stronger cytotoxicity and more profound inhibition of cell proliferation. Taken together, these results showed that IO and, moreover, its derivative 6BIO may be potent antiproliferative agents in malignant lymphoid cells.

International audience; We report on the efficiency of treatment of first isolated extramedullary relapse of B-cell precursor acute lymphoblastic leukaemia. Sixty-eight children and adolescents were included in the trial COPRALL-97. Stratification criteria were time to relapse: first complete remission duration of less than 24 months for group G3A (n=35), relapse beyond 24 months for group G3B (n=33). Treatment consisted of risk-adapted alternating short course multiagent systemic and intrathecal chemotherapy and irradiation (18Gy). Event free survival (EFS) and overall survival (OS) for all registered patients at 6 years were 43% and 55%, respectively. EFS at 4 years for patients of group G3A and G3B were, respectively, 31% and 61% (p=0.0071) while OS at 4 years were, respectively, 40% and 76% (p=0.065). Our analyses highlighted two independent risks factors predictive of decreased EFS: early relapse and age at the initial diagnosis above 6 years. Early central nervous system relapses have a bad prognosis, and new therapeutic strategies are needed.

Dans le traitement des leucemies aigues lymphoblastiques (LAL) de l’enfant, la Dexamethasone (DEXA) serait plus efficace que la prednisolone (PRED) a des doses anti-inflammatoires equivalentes. Afin de verifier que cette superiorite puisse etre dose-dependante, nous avons conduit un essai randomise de phase III comparant la DEXA (6 mg/m2/j) a la PRED (60 mg/m2/j). Tous les nouveaux patients avec une LAL, enregistres dans l’essai EORTC 58951, etaient randomises soit a J1 de la prephase, soit a J8. L’objectif principal etait l’etude de la survie sans evenement (EFS); les objectifs secondaires etaient la survie totale (OS) et la toxicite. Un total de 1947 patients ont ete randomises. L’EFS a 8 ans etait de 81.5% dans le bras DEXA et 81.2% dans le bras PRED; les OS a 8 ans etaient respectivement de 87.2% et 89.0%. L’incidence de rechute du systeme nerveux central (SNC) a 8 ans etait de 2.9% (DEXA) v 4.5% (PRED). L’incidence des toxicites de grade 3–4 durant la phase d’induction et la frequence des osteonecroses etaient similaires dans les 2 bras. En conclusion, la DEXA et la PRED, utilisees aux doses de 6 et 60 mg/m2/j durant la phase d’induction, avaient une efficacite et un profil de toxicite similaires. De plus, la DEXA diminuait l’incidence de rechute du SNC a 8 ans de 1.6%.

Isolated extramedullary relapse is diagnosed in 2 to 6% of children with acute lymphoblastic leukemia (ALL). It usually occurs in the CNS or the testis. Because the prophylaxis of extramedullary leukemia has increasingly become an important part of the first line treatment, the ability to achieve a sustained second remission is now complicated by drugs toxicities and resistances. It is already known that prognosis depends on duration of first complete remission (CR1).Here, we report on the efficiency of a combination of chemotherapy and radiotherapy for the treatment of extramedullary relapses. Furthermore, we specifically searched for prognosis factors of the Event Free Survival (EFS). Between May 1997 and December 2002, 68 children and adolescents up to 20 year-old with first isolated extramedullary relapse (group G3) of B-cell (non Burkitt) ALL were included in the prospective, stratified, and multicentric trial COPRALL-97 This trial had been designed for patients pretreated with an intensive frontline therapy (EORTC or FRALLE) without cranial radiotherapy except for 5 patients. Stratification criteria was time to relapse: CR1 of less than 24 months for group G3A (n=35), relapse beyond 24 months for group G3B (n=33). Treatment consisted of risk-adapted alternating short course multiagent chemotherapy through systemic (with good CSF penetration) and intrathecal ways and conventional maintenance therapy and irradiation (18 Gy). Stem cell transplantation (SCT) was performed if an HLA identical related donor was avalaible in group G3A. Sixty four of 68 eligible patients achieved a second complete remission. There were 45 CNS relapses, 22 testis relapses and one ovary relapse. In group G3A (33 CNS, 2 testis), 20 patients received chemotherapy only and 15 had SCT (12 HLA-identical sibling donor, 2 HLA-identical unrelated donor and one autologous. In group G3B, (12 CNS, 20 testis, 1 ovary), all patients but one (SCT not indicated) were treated by chemotherapy. EFS and overall survival (OS) for all registered patients at 8 years were 40% and 53% respectively. EFS at 8 years for patients of group G3A and G3B were respectively 26% and 51% (p=0,0071) while OS at 8 years were respectively 40% and 68% (p=0,065). Our analyses highlighted two independant risks factors predictive of decreased EFS: early relapse and age at the initial diagnosis above 6 years. All other factors studied (sex, site of relapse, immunophenotype, SCT) did not predicted outcome. Most of the second relapses involved bone marrow (n=11), CNS (n=6) or were combined (n=6). There were 6 toxic deaths.We conclude that more than half of the patients who were treated with COPRALL-97 therapy had long term survival. Time of relapse and age at initial diagnosis represent important factors that should be considered when adapting treatment intensity to individuals in future trials. Furthermore, as already reported by others, early CNS relapses have a bad prognosis and new therapeutic strategies are needed.