Through their action on DNA replication, anticancer chemotherapies could increase the basal mutation rate in bacteria and increase the risk of selecting antibiotic resistant mutants. We investigated ...the impact of several drugs on a beta-lactamase model using KPC-type carbapenemase-producing Enterobacteriaceae. We studied the impact of anticancer chemotherapies used in pediatric hematologic malignancies on 7 clinical isolates of Enterobacteriaceae producing KPC-type carbapenemases. We compared the mutation rates from cultures with/without chemotherapy on ceftazidime-avibactam, rifampicin and ceftazidime-avibactam combined with meropenem media. Mechanisms of ceftazidime-avibactam resistance were explored on a subset of mutants. After exposure to some cytotoxic molecules, the bacterial mutation rates leading to ceftazidime-avibactam and to rifampicin resistance increased up to 10
-fold while we observed no emergence of resistant mutants (frequency of <10
) on a meropenem combined with ceftazidime-avibactam media. Compared to the parental strains, an increased susceptibility to meropenem was observed in the ceftazidime-avibactam resistant mutants. The bla
genes of ceftazidime-avibactam mutants harbored either mutations, deletions or insertions, especially in the region encoding the Ω-loop of the KPC-type carbapenemase. Anticancer chemotherapy can increase the mutation rates of bacteria accelerating the extension of KPC-type carbapenemases towards ceftazidime-avibactam, one of the last resort antimicrobial chemotherapy.
Summary
Kabuki syndrome (KS) is now listed in the Human Inborn Errors of Immunity (IEI) Classification. It is a rare disease caused by KMT2D and KDM6A variants, dominated by intellectual disability ...and characteristic facial features. Recurrently, pathogenic variants are identified in those genes in patients examined for autoimmune cytopenia (AIC), but interpretation remains challenging. This study aims to describe the genetic diagnosis and the clinical management of patients with paediatric‐onset AIC and KS. Among 11 patients with AIC and KS, all had chronic immune thrombocytopenic purpura, and seven had Evans syndrome. All had other associated immunopathological manifestations, mainly symptomatic hypogammaglobinaemia. They had a median of 8 (5–10) KS‐associated manifestations. Pathogenic variants were detected in KMT2D gene without clustering, during the immunological work‐up of AIC in three cases, and the clinical strategy to validate them is emphasized. Eight patients received second‐line treatments, mainly rituximab and mycophenolate mofetil. With a median follow‐up of 17 (2–31) years, 8/10 alive patients still needed treatment for AIC. First‐line paediatricians should be able to recognize and confirm KS in children with ITP or multiple AIC, to provide early appropriate clinical management and specific long‐term follow‐up. The epigenetic immune dysregulation in KS opens exciting new perspectives.
From a cohort of 1802 patients with paediatric‐onset autoimmune cytopenia (AIC), 11 pathogenic variants in the KMT2D gene were identified, with three cases detected during this AIC genetic work‐up. Three patients had variants of unknown significance; this underscores challenges in NGS interpretation using both genetic and clinical data integration. Recognizing KS in paediatric or adult patients with AIC is crucial for appropriate management and follow‐up. Those rare patients may benefit from rituximab, mycophenolate mofetil or rapamycin.
Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric myeloproliferative neoplasm requiring hematopoietic stem cell transplantation (HSCT) in most cases. We retrospectively analyzed 119 ...JMML patients who underwent first allogeneic HSCT between 2002 and 2021. The majority (97%) carried a RAS-pathway mutation, and 62% exhibited karyotypic alterations or additional mutations in SETBP1, ASXL1, JAK3 and/or the RAS pathway. Relapse was the primary cause of death, with a 5-year cumulative incidence of 24.6% (95%CI: 17.1-32.9). Toxic deaths occurred in 12 patients, resulting in treatmentrelated mortality (TRM) of 9.0% (95%CI: 4.6-15.3). The 5-year overall (OS) and event-free survival were 73.6% (95%CI: 65.7-82.4) and 66.4% (95%CI: 58.2-75.8), respectively. Four independent adverse prognostic factors for OS were identified: age at diagnosis >2 years, time from diagnosis to HSCT >6 months, monocyte count at diagnosis >7.2x109/L, and the presence of additional genetic alterations. Based on these factors, we proposed a predictive classifier. Patients with three or more predictors (21% of the cohort) had a 5-year OS of 34.2%, whereas those with none (7%) had a 5-year OS of 100%. Our study demonstrates improved transplant outcomes compared to prior published data, which can be attributed to the synergistic impacts of a low TRM and a reduced yet still substantial relapse incidence. By integrating genetic information with clinical and hematological features, we have devised a predictive classifier. This classifier effectively identifies a subgroup of patients who are at a heightened risk of unfavorable post-transplant outcomes who would benefit novel therapeutic agents and post-transplant strategies.
Haploidentical stem cell transplantation (haplo‐SCT) represents the main alternative for children with inherited bone marrow failure syndrome (I‐BMF) lacking a matched donor. This retrospective ...study, conducted on behalf of the EBMT SAAWP and PDWP, aims to report the current outcomes of haplo‐SCT in I‐BMFs, comparing the different in vivo and ex vivo T‐cell depletion approaches. One hundred and sixty‐two I‐BMF patients who underwent haplo‐SCT (median age 7.4 years) have been registered. Fanconi Anemia was the most represented diagnosis (70.1%). Based on different T‐cell depletion (TCD) approaches, four categories were identified: (1) TCRαβ+/CD19+‐depletion (43.8%); (2) T‐repleted with post‐transplant Cyclophosphamide (PTCy, 34.0%); (3) In‐vivo T‐depletion with ATG/alemtuzumab (14.8%); (4) CD34+ positive selection (7.4%). The cumulative incidences (CI) of neutrophil and platelet engraftment were 84% and 76% respectively, while that of primary and secondary graft failure was 10% and 8% respectively. The 100‐day CI of acute GvHD grade III‐IV(95% CI) was 13%, while the 24‐month CI of extensive chronic GvHD was 4%. After a median follow‐up of 43.4 months, the 2‐year overall survival(OS) and GvHD/Rejection‐free Survival (GRFS) probabilities are 67% and 53%, respectively. The TCR CD3+αβ+/CD19+ depletion group showed a significantly lower incidence of both acute and chronic GvHD and higher OS (79%; p0.013) and GRFS (71%; p < .001), while no significant differences in outcomes have been observed by different diagnosis and conditioning regimens. This large retrospective study supports the safety and feasibility of haplo‐SCT in I‐BMF patients. TCRαβ+/CD19+ depletion offers higher chances of patients' survival, with a significantly lower risk of severe a‐ and c‐GvHD in I‐BMFs compared to other platforms.
Juvenile myelomonocytic leukemia (JMML) is a rare, generally aggressive myeloproliferative neoplasm affecting young children. It is characterized by granulomonocytic expansion, with monocytosis ...infiltrating peripheral tissues. JMML is initiated by mutations upregulating RAS signaling. Approximately 10% of cases remain without an identified driver event. Exome sequencing of 2 unrelated cases of familial JMML of unknown genetics and analysis of the French JMML cohort identified 11 patients with variants in SH2B3, encoding LNK, a negative regulator of the JAK-STAT pathway. All variants were absent from healthy population databases, and mutation spectrum was consistent with a loss of function of the LNK protein. A stoploss variant was shown to affect both protein synthesis and stability. The other variants were either truncating or missense, the latter affecting the SH2 domain that interacts with activated JAK. Of the 11 patients, 8 from 5 families inherited pathogenic bi-allelic SH2B3 germline variants from their unaffected heterozygous parents. These children represent half of the cases with no identified causal mutation in the French cohort. They displayed typical clinical and hematological JMML features with neonatal onset and marked thrombocytopenia. They were characterized by absence of additional genetic alterations and a hypomethylated DNA profile with fetal characteristics. All patients showed partial or complete spontaneous clinical resolution. However, progression to thrombocythemia and immunity-related pathologies may be of concern later in life. Bi-allelic SH2B3 germline mutations thus define a new condition predisposing to a JMML-like disorder, suggesting that the JAK pathway deregulation is capable of initiating JMML, and opening new therapeutic options.
Summary
Congenital sideroblastic anaemia (CSA) is a rare disease caused by germline mutations of genes involved in haem and iron‐sulphur cluster formation, and mitochondrial protein biosynthesis. We ...performed a retrospective multicentre European study of a cohort of childhood‐onset CSA patients to explore genotype/phenotype correlations. We studied 23 females and 20 males with symptoms of CSA. Among the patients, the most frequently mutated genes were ALAS2 (n = 10; 23·3%) and SLC25A38 (n = 8; 18·6%), causing isolated forms of microcytic anaemia of varying severity. Five patients with SLC19A2 mutations suffered from thiamine‐responsive megaloblastic anaemia and three exhibited the ‘anaemia, deafness and diabetes’ triad. Three patients with TRNT1 mutations exhibited severe early onset microcytic anaemia associated with thrombocytosis, and two exhibited B‐cell immunodeficiency, inflammatory syndrome and psychomotor delay. The prognoses of patients with TRNT1 and SLC2A38 mutations were generally dismal because of comorbidities or severe iron overload. No molecular diagnosis could be established in 14/43 cases. This study emphasizes the frequency of ALAS2 and SLC25A38 mutations and provides the largest comprehensive analysis to date of genotype/phenotype correlations in CSA. Further studies of CSA patients with data recorded in an international registry would be helpful to improve patient management and establish standardized guidelines.
Refractory chronic immune thrombocytopenia (r‐cITP) is one of the most challenging situations in chronic immune thrombocytopenia (cITP). Pediatric r‐cITP is inconsistently defined in literature, ...contributing to the scarcity of data. Moreover, no evidence is available to guide the choice of treatment. We compared seven definitions of r‐cITP including five pediatric definitions in 886 patients with cITP (median min‐max follow‐up 5.3 1.0–29.3 years). The pediatric definitions identified overlapping groups of various sizes (4%–20%) but with similar characteristics (higher proportion of immunopathological manifestations IM and systemic lupus erythematosus SLE), suggesting that they adequately captured the population of interest. Based on the 79 patients with r‐cITP (median follow‐up 3.1 0–18.2 years) according to the CEREVANCE definition (≥3 second‐line treatments), we showed that r‐cITP occurred at a rate of 1.15% new patients per year and did not plateau over time. In multivariate analysis, older age was associated with r‐cITP. One patient (1%) experienced two grade five bleeding events after meeting r‐cITP criteria and while not receiving second‐line treatment. The cumulative incidence of continuous complete remission (CCR) at 2 years after r‐cITP diagnosis was 9%. In this analysis, splenectomy was associated with a higher cumulative incidence of CCR (hazard ratio: 5.43, 95% confidence interval: 1.48–19.84, p = 7.8 × 10−4). In sum, children with cITP may be diagnosed with r‐cITP at any time point of the follow‐up and are at increased risk of IM and SLE. Second‐line treatments seem to be effective for preventing grade 5 bleeding. Splenectomy may be considered to achieve CCR.
Pediatric chronic immune thrombocytopenia (cITP) is a heterogeneous condition in terms of bleeding severity, second‐line treatment use, association with clinical and/or biological immunopathological ...manifestations (IMs), and progression to systemic lupus erythematosus (SLE). No risk factors for these outcomes are known. Specifically, whether age at ITP diagnosis, sex, or IMs impact cITP outcomes is unknown. We report the outcomes of patients with pediatric cITP from the French nationwide prospective cohort OBS'CEREVANCE. We used multivariate analyses to investigate the effect of age at ITP diagnosis, sex, and IMs on cITP outcomes. We included 886 patients with a median (min‐max) follow‐up duration of 5.3 (1.0–29.3) years. We identified an age cutoff that dichotomized the risk of the outcomes and defined two risk groups: patients with ITP diagnosed <10 years (children) and ≥ 10 years (adolescents). Adolescents had a two to four‐fold higher risk of grade ≥3 bleeding, second‐line treatment use, clinical and biological IMs, and SLE diagnosis. Moreover, female sex and biological IMs were independently associated with higher risks of biological IMs and SLE diagnosis, second‐line treatment use, and SLE diagnosis, respectively. The combination of these three risk factors defined outcome‐specific risk groups. Finally, we showed that patients clustered in mild and severe phenotypes, more frequent in children and adolescents, respectively. In conclusion, we identified that age at ITP diagnosis, sex, and biological IMs impacted the long‐term outcomes of pediatric cITP. We defined risk groups for each outcome, which will help clinical management and further studies.
Background
A growing number of centers worldwide are preserving testicular tissue (TT) of young boys at risk of fertility loss to preserve their fertility. Data in this regard are scarce and ...experience sharing is essential to the optimization of the process.
Objectives
This report of our 10‐year activity of pediatric fertility preservation (FP) has the objective to (1) improve knowledge regarding the feasibility, acceptability, safety, and potential usefulness of the procedure; (2) analyze the impact of chemotherapy on spermatogonia in the cryopreserved TT.
Materials and methods
For this retrospective study of data prospectively recorded, we included all boys under 18 years of age referred to the FP consultation of our academic network between October 2009 and December 2019. Characteristics of patients and cryopreservation of testicular tissue (CTT) were extracted from the clinical database. Univariate and multivariate analyses were used to assess factors associated with the risk of absence of spermatogonia in the TT.
Results
Three hundred and sixty‐nine patients (7.2 years; 0.5–17.0) were referred to the FP consultation for malignant (70%) or non‐malignant (30%) disease, of whom 88% were candidates for CTT, after a previous chemotherapy exposure (78%). The rate of recorded immediate adverse events was 3.5%, with painful episodes dominating. Spermatogonia were detected in the majority of TTs: 91.1% of those exposed to chemotherapy and 92.3% of those not exposed (p = 0.962). In multivariate analysis, the risk of absence of spermatogonia was almost three‐fold higher in boys > 10 years of age (OR 2.74, 95% CI 1.09–7.26, p = 0.035) and four‐fold higher in boys exposed to alkylating agents prior to CTT (OR 4.09, 95% CI 1.32–17.94, p = 0.028).
Discussion/conclusion
This large series of pediatric FP shows that this procedure is well accepted, feasible, and safe in the short term, strengthening its place in the clinical care pathway of young patients requiring a highly gonadotoxic treatment. Our results demonstrate that CTT post‐chemotherapy does not impair the chance to preserve spermatogonia in the TT except when the treatment includes alkylating agents. More data on post‐CTT follow‐up are still required to ensure the long‐term safety and usefulness of the procedure.
Background: Acquired aplastic anemia (AA) is a rare immunological disease resulting in bone marrow failure. Patients can be treated either by immunosuppressive therapy (IST) or by allogeneic ...hematopoietic stem cell transplantation (HSCT). HSCT is the recommended treatment in patients younger than 40 years old with an available matched-related donor. IST is the recommended option for other patients: from the randomized trial published by Scheinberg in 2011, ATGAM® (horse anti-human T lymphocyte immunoglobulin) in addition to cyclosporine was the reference first-line IST for moderate to severe AA.Aims: This retrospective, multicentric study was conducted to report safety and efficacy data from ATGAM use in patients with AA utilizing surveillance data.Methods: This Temporary Use Authorization (ATU) program was initiated to collect surveillance data from the ATGAM Named Patients Program for French authorities before ATGAM was registered. This is the final report from this program. Safety and efficacy data was collected from the program and reported every 6 months. ATGAM was dosed at 40 mg/kg for 4 days in all patients that received treatment. Severity of AA was classified according to Camitta and EBMT scores. Response criteria followed the British Committee for Standards in Haematology Guidelines. For severe AA, no response: still severe; partial response: transfusion independence and the patient no longer met criteria for severe disease; complete response: hemoglobin was normal, neutrophil count >1.5x109/L, and platelet count >150x109/L. For moderate AA: no response: worse or did not meet criteria for response that included transfusion independence (if previously dependent) or doubling or normalization of at least 1 cell line or an increase of baseline hemoglobin, or an increase of baseline neutrophils or increase of baseline; complete response: the same criteria as for severe AA.Results: 634 patients (including 148 children) with moderate to very severe AA received ATGAM (n=537 first line; n=68 refractory/relapse; n=29 not classified) in addition to cyclosporine from January 2012 to August 2022. Overall hematologic response (Complete + Partial) at 6 months was 62.3% in the combined population. By severity, response rates were 84.4%, 50.8%, and 36.4% among patients with moderate, severe, and very severe AA, respectively, receiving first-line therapy (n=537; Table). By age, response rates were respectively 54.3%, 65.2%, and 64.4% in children (≤17 years), adults (≥18-<65 years), and elderly (≥65 years) patients. The overall survival rate (95% confidence interval) at 3 years was 96.9% (91.9-98.8%) in children, 83.4% (77.1-88.1%) in adults, and 79.7% (65.9-88.3%) in elderly patients. Treatment was well tolerated for the majority of patients. In total, 1087 adverse events (485 serious adverse events) were reported, with 48 fatal events.Summary/Conclusion: Reported response rate and overall survival in this real-life surveillance study are in line with a 2011 randomized controlled study comparing horse versus rabbit ATG (Scheinberg, et al 2011) and control group of the most recent study RACE (Peffault de Latour, et al 2022). The relatively large number of patients in this study compared with other similar studies in patients with AA adds to the robustness of this real-world data study. No new safety risks were identified, and this study showed that use of ATGAM remains favorable in this patient population.
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