Long-term outcome after allogeneic stem cell transplantation for GATA2 deficiency: An analysis of 67 adults and children from France and Belgium.

Modalities and timing of haematopoietic stem cell transplant (HSCT) in patients with GATA2 deficiency are still subject to debate. On June 2022, 67 patients (median age 20.6 years) underwent a first allogeneic HSCT among 21 centres. Indications for HSCT were myelodysplastic syndrome (MDS) ≤5% blasts ± immunodeficiency (66%), MDS >5% blasts (15%), acute myeloid leukaemia (19%). Conditioning regimen was myeloablative in 85% and anti-thymocyte globulins were used in 67%. The cumulative incidence (CInc) of acute graft versus host disease (GvHD) grade II-IV and III-IV at day 100 were 42% and 13%, and CInc of chronic and extensive chronic GvHD at 2 years were 42% and 23%. CInc of relapses was 3% and 11% at 1 and 5 years. Overall survival (OS) at 1 and 5 years was 83% and 72% (median follow-up 5.6 years). The factors associated with worse OS in multivariable analysis were the year of HSCT, a history of excess blasts before transplant and peripheral blood stem cell (PBSC) grafts. Age at HSCT, non-myeloablative conditioning and PBSC grafts were associated with increased non-relapse mortality. In conclusion, bone marrow monitoring to identify clonal evolution and perform HSCT before the appearance of excess blast is mandatory.

[Preventive and therapeutic strategies for relapse after hematopoietic stem cell transplant for pediatric AML (SFGM-TC)]. / Stratégies préventives et thérapeutiques de la rechute après allogreffe de cellules souches hématopoïétiques pour les LAM pédiatriques (SFGM-TC).

Treatment of pediatric high-risk acute myeloid leukemia (AML), defined either on molecular or cytogenetic features, relies on bone marrow transplant after cytologic remission. However, relapse remains the first post-transplant cause of mortality. In this 13th session of practice harmonization of the francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), our group worked on recommendations regarding the management of post-transplant relapse in AML pediatric patients based on international literature, national survey and expert opinion. Overall, immunomodulation strategy relying on both measurable residual disease (MRD) and chimerism evaluation should be used for high-risk AML. In very high-risk (VHR) AML with a 5-year overall survival ≤30 %, a post-transplant maintenance should be proposed using either hypomethylating agents, combined with DLI whenever possible, or FLT3 tyrosine kinase inhibitors if this target is present on leukemia cells. In the pre-emptive or early relapse settings (< 6 months post-transplant), treatments combining DLI, Azacytidine and Venetoclax should be considered. Access to phase I/II trails for targeted therapies (menin, IDH or JAK inhibitors) should be discussed in each patient according to the underlying molecular abnormalities of the disease.

Pediatric refractory chronic immune thrombocytopenia: Identification, patients' characteristics, and outcome.

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.

Autoimmune cytopenia and Kabuki syndrome in paediatrics: Insights in 11 patients.

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.

HLA-haploidentical stem cell transplantation in children with inherited bone marrow failure syndromes: A retrospective analysis on behalf of EBMT severe aplastic Anemia and pediatric diseases working parties.

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) TCRαß+/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+αß+/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. TCRαß+/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.

A predictive classifier of poor prognosis in transplanted patients with juvenile myelomonocytic leukemia: a study on behalf of the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire.

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 treatment-related 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 3 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 hematologic 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 from novel therapeutic agents and post-transplant strategies.

Ovarian tissue cryopreservation for fertility preservation before hematopoietic stem cell transplantation in patients with sickle cell disease: safety, ovarian function follow-up, and results of ovarian tissue transplantation.

PURPOSE: To describe the experience of performing ovarian tissue cryopreservation (OTC) before hematopoietic stem cell transplantation (HSCT), among girls/women with severe sickle cell disease (SCD)(SS or S/ß0-thalassemia) who are, besides the usual surgical risk, at risk of SCD-related complications during the fertility preservation procedure for improving their counseling and management. METHODS: This retrospective study included 75 patients (girls/women) with SCD who have had OTC before myeloablative conditioning regimen (MAC) for HSCT. Characteristics of patients and data on OTC, ovarian status follow-up, and results of ovarian tissue transplantation (OTT) were collected in medical records. RESULTS: At OTC, the median (IQR 25-75; range) age of the patients was 9.6 (6.9-14.1; 3.6-28.3) years, 56/75 were prepubertal, and no SCD or surgery-related complications occurred. The median follow-up post-HSCT was > 9 years. At the last follow-up, among prepubertal patients at HSCT, 26/56 were ≥ 15 years old and presented with a premature ovarian insufficiency (POI), except 2, including the patient who had received an OTT to induce puberty. Eight were 13-15 years old and presented for POI. The remaining 22 patients were under 13. Among the 19 patients who were menarche at HSCT, 2 died 6 months post-HSCT and we do not have ovarian function follow-up for the other 2 patients. All the remaining patients (n = 15) had POI. Five patients had OTT. All had a return of ovarian function. One patient gave birth to a healthy baby. CONCLUSION: OTC is a safe fertility preservation technique and could be offered before MAC independent of the patient's age.

Antinuclear antibody-associated autoimmune cytopenia in childhood is a risk factor for systemic lupus erythematosus.

ABSTRACT: Autoimmune cytopenia (AIC) in children may be associated with positive antinuclear antibodies (ANA) and may progress to systemic lupus erythematosus (SLE). We evaluated the risk of progression to SLE of childhood-onset ANA-associated AIC. In the French national prospective OBS'CEREVANCE cohort, the long-term outcome of children with ANA-associated AIC (ANA titer ≥1/160) and a subgroup of children who developed SLE were described. ANA were positive in 355 of 1803 (20%) children with AIC. With a median follow-up of 5.8 (range, 0.1-29.6) years, 79 of 355 (22%) patients developed SLE at a median age of 14.5 (1.1-21.4) years; 20% of chronic immune thrombocytopenic purpura, 19% of autoimmune hemolytic anemia, and 45% of Evans syndrome. None of the patients with ANA-negative test developed SLE. Severe manifestations of SLE were observed in 21 patients, and 2 patients died. In multivariate analysis including patients with positive ANA within the first 3 months after AIC diagnosis, age >10 years at AIC diagnosis (relative risk [RR], 3.67; 95% confidence interval [CI], 1.18-11.4; P = .024) and ANA titer >1/160 (RR, 5.28; 95% CI, 1.20-23.17; P = .027) were associated with the occurrence of SLE after AIC diagnosis. ANA-associated AIC is a risk factor for progression to SLE, especially in children with an initial ANA titer >1/160 and an age >10 years at AIC diagnosis. ANA screening should be recommended in children with AIC, and patients with ANA should be monitored long-term for SLE, with special attention to the transition period. This trial was registered at www.ClinicalTrials.gov as #NCT05937828.

A 10-year experience in testicular tissue cryopreservation for boys under 18 years of age: What can be learned from 350 cases?

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.

Germline bi-allelic SH2B3/LNK alteration predisposes to a neonatal juvenile myelomonocytic leukemia-like disorder.

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.

Impact of age at diagnosis, sex, and immunopathological manifestations in 886 patients with pediatric chronic immune thrombocytopenia.

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.

Determinants of long-term outcomes of splenectomy in pediatric autoimmune cytopenias.

Splenectomy is effective in ∼70% to 80% of pediatric chronic immune thrombocytopenia (cITP) cases, and few data exist about it in autoimmune hemolytic anemia (AIHA) and Evans syndrome (ES). Because of the irreversibility of the procedure and the lack of predictions regarding long-term outcomes, the decision to undertake splenectomy is difficult in children. We report here factors associated with splenectomy outcomes from the OBS'CEREVANCE cohort, which prospectively includes French children with autoimmune cytopenia (AIC) since 2004. The primary outcome was failure-free survival (FFS), defined as the time from splenectomy to the initiation of a second-line treatment (other than steroids and intravenous immunoglobulins) or death. We included 161 patients (cITP, n = 120; AIHA, n = 19; ES, n = 22) with a median (minimum-maximum) follow-up of 6.8 years (1.0-33.3) after splenectomy. AIC subtype was not associated with FFS. We found that immunopathological manifestations (IMs) were strongly associated with unfavorable outcomes. Diagnosis of an IM before splenectomy was associated with a lower FFS (hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.21-0.72, P = .003, adjusted for AIC subtype). Diagnosis of an IM at any timepoint during follow-up was associated with an even lower FFS (HR, 0.22; 95% CI, 0.12-0.39; P = 2.8 × 10-7, adjusted for AIC subtype) as well as with higher risk of recurrent or severe bacterial infections and thrombosis. In conclusion, our results support the search for associated IMs when considering a splenectomy to refine the risk-benefit ratio. After the procedure, monitoring IMs helps to identify patients with higher risk of unfavorable outcomes.

Outcomes of pediatric patients with therapy-related myeloid neoplasms.

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs.

Impact of anticancer chemotherapy on the extension of beta-lactamase spectrum: an example with KPC-type carbapenemase activity towards ceftazidime-avibactam.

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 104-fold while we observed no emergence of resistant mutants (frequency of <10-10) 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 blaKPC 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.

Genotype/phenotype correlations of childhood-onset congenital sideroblastic anaemia in a European cohort.

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.