BACKGROUND: The level of measurable residual disease (MRD) before and after transplantation is related to inferior transplant outcomes, and post-hematopoietic stem cell transplantation measurable residual disease (post-HSCT MRD) has higher prognostic value in determining risk than pre-hematopoietic stem cell transplantation measurable residual disease (pre-HSCT MRD). However, only a few work has been devoted to the risk factors for positive post-HSCT MRD in patients with acute lymphoblastic leukemia (ALL). This study evaluated the risk factors for post-HSCT MRD positivity in patients with ALL who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: A total of 1683 ALL patients from Peking University People's Hospital between January 2009 and December 2019 were enrolled to evaluate the cumulative incidence of post-HSCT MRD. Cox proportional hazard regression models were built for time-to-event outcomes. Multivariable analysis was performed to determine independent influencing factors from the univariable analysis. RESULTS: Both in total patients and in T-cell ALL or B-cell ALL, pediatric or adult, human leukocyte antigen-matched sibling donor transplantation or haploidentical SCT subgroups, positive pre-HSCT MRD was a risk factor for post-HSCT MRD positivity ( P  <0.001 for all). Disease status (complete remission 1 [CR1] vs . ≥CR2) was also a risk factor for post-HSCT MRD positivity in all patients and in the B cell-ALL, pediatric, or haploidentical SCT subgroups ( P  = 0.027; P  = 0.003; P  = 0.035; P  = 0.003, respectively). A risk score for post-HSCT MRD positivity was developed using the variables pre-HSCT MRD and disease status. The cumulative incidence of post-HSCT MRD positivity was 12.3%, 25.1%, and 38.8% for subjects with scores of 0, 1, and 2-3, respectively ( P  <0.001). Multivariable analysis confirmed the association of the risk score with the cumulative incidence of post-HSCT MRD positivity and relapse as well as leukemia-free survival and overall survival. CONCLUSION Our results indicated that positive pre-MRD and disease status were two independent risk factors for post-HSCT MRD positivity in patients with ALL who underwent allo-HSCT.
Humans ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology* ; Neoplasm, Residual ; Hematopoietic Stem Cell Transplantation/methods* ; Male ; Female ; Risk Factors ; Adolescent ; Adult ; Child ; Child, Preschool ; Young Adult ; Middle Aged ; Infant ; Transplantation, Homologous ; Proportional Hazards Models ; Retrospective Studies

Severe combined immunodeficiency (SCID) represents a group of genetically heterogeneous disorders characterized by mutations that lead to profound defects in both humoral and cellular immunity. Transplacental maternal engraftment (TME) is a frequently observed complication in SCID. While most cases of SCID with TME exhibit no substantial impact on disease progression, a subset of patients may encounter diagnostic delays or therapeutic challenges due to TME interference. Furthermore, TME may predispose these individuals to graft-versus-host disease (GVHD) prior to hematopoietic stem cell transplantation, thereby increasing diagnostic complexity and treatment risks. This review systematically examines the etiology and clinical manifestations of SCID associated with TME, analyzes its implications for disease management, and evaluates current detection methodologies. The synthesized evidence provides a theoretical foundation for future research and offers potential insights into the clinical diagnosis and management of SCID associated with TME.
Humans ; Severe Combined Immunodeficiency/diagnosis* ; Pregnancy ; Female ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Maternal-Fetal Exchange/immunology* ; Graft vs Host Disease/etiology* ; Animals ; Placenta/immunology*

To guide clinical blood transfusion practices for pediatric patients, the National Health Commission has issued the health standard "Guideline for pediatric transfusion" (WS/T 795-2022). Blood transfusion for children undergoing hematopoietic stem cell transplantation is highly complex and challenging. This guideline provides recommendations on transfusion thresholds and the selection of blood components for these children. This article presents the evidence and interpretation of the transfusion provisions for children undergoing hematopoietic stem cell transplantation, with the aim of enhancing the understanding and implementation of the "Guideline for pediatric transfusion".
Humans ; Hematopoietic Stem Cell Transplantation ; Child ; Blood Transfusion/standards* ; Practice Guidelines as Topic

This article reports the clinical characteristics and treatment processes of three cases of mucormycosis occurring after hematopoietic stem cell transplantation in children, along with a review of relevant literature. All three patients presented with chest pain as the initial symptom, and metagenomic next-generation sequencing (mNGS) confirmed the mucycete infection early in all cases. Two patients recovered after treatment, while one succumbed to disseminated infection. mNGS has facilitated early diagnosis and treatment, reducing mortality rates. Additionally, surgical intervention is an important strategy for improving the prognosis of this condition.
Humans ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Mucormycosis/etiology* ; Male ; High-Throughput Nucleotide Sequencing/methods* ; Child ; Female ; Metagenomics ; Child, Preschool

OBJECTIVES: To investigate the genomic characteristics and prognostic factors of juvenile myelomonocytic leukemia (JMML) with RAS mutations. METHODS: A retrospective analysis was conducted on the clinical data of JMML children with RAS mutations treated at the Hematology Hospital of Chinese Academy of Medical Sciences, from January 2008 to November 2022. RESULTS: A total of 34 children were included, with 17 cases (50%) having isolated NRAS mutations, 9 cases (27%) having isolated KRAS mutations, and 8 cases (24%) having compound mutations. Compared to children with isolated NRAS mutations, those with NRAS compound mutations showed statistically significant differences in age at onset, platelet count, and fetal hemoglobin proportion (P<0.05). Cox proportional hazards regression model analysis revealed that hematopoietic stem cell transplantation (HSCT) and hepatomegaly (≥2 cm below the costal margin) were factors affecting the survival rate of JMML children with RAS mutations (P<0.05); hepatomegaly was a factor affecting survival in the non-HSCT group (P<0.05). CONCLUSIONS Children with NRAS compound mutations have a later onset age compared to those with isolated NRAS mutations. At initial diagnosis, children with NRAS compound mutations have poorer peripheral platelet and fetal hemoglobin levels than those with isolated NRAS mutations. Liver size at initial diagnosis is related to the prognosis of JMML children with RAS mutations. HSCT can improve the prognosis of JMML children with RAS mutations.
Humans ; Leukemia, Myelomonocytic, Juvenile/therapy* ; Mutation ; Male ; Female ; Child, Preschool ; Retrospective Studies ; Child ; Infant ; GTP Phosphohydrolases/genetics* ; Membrane Proteins/genetics* ; Adolescent ; Hematopoietic Stem Cell Transplantation ; Proportional Hazards Models ; Proto-Oncogene Proteins p21(ras)/genetics* ; Prognosis

OBJECTIVES: To investigate the prognostic value of molecular minimal residual disease (Mol-MRD) monitored before and after allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric acute myeloid leukemia (AML). METHODS: Clinical data of 71 pediatric AML patients who underwent HSCT between August 2016 and December 2023 were analyzed. Mol-MRD levels were dynamically monitored in MRD-positive patients, and survival outcomes were evaluated. RESULTS: No significant difference in the 3-year overall survival (OS) rate was observed between patients with pre-HSCT Mol-MRD ≥0.01% and <0.01% (77.3% ± 8.9% vs 80.4% ± 7.9%, P=0.705). However, patients with pre-HSCT Mol-MRD <1.75% had a significantly higher 3-year OS rate than those with Mol-MRD ≥1.75% (86.6% ± 5.6% vs 44.4% ± 16.6%, P=0.020). The median Mol-MRD level in long-term survivors was significantly lower than in non-survivors [0.61% (range: 0.04%-51.58%)] vs 10.60% (range: 1.90%-19.75%), P=0.035]. Concurrent flow cytometry-based MRD positivity was significantly higher in non-survivors (80% vs 24%, P=0.039). There was no significant difference in the 3-year overall survival rate between patients with Mol-MRD ≥0.01% and those with <0.01% at 30 days post-HSCT (P=0.527). For children with Mol-MRD <0.22% at 30 days post-HSCT, the 3-year overall survival rate was 80.4% ± 5.9%, showing no significant difference compared to those with molecular negativity (87.0% ± 7.0%) (P=0.523). CONCLUSIONS Patients with pre-HSCT Mol-MRD <1.75% or post-HSCT Mol-MRD <0.22% may achieve long-term survival outcomes comparable to Mol-MRD-negative cases through HSCT and targeted interventions.
Humans ; Hematopoietic Stem Cell Transplantation ; Neoplasm, Residual ; Leukemia, Myeloid, Acute/genetics* ; Child ; Male ; Female ; Child, Preschool ; Prognosis ; Adolescent ; Infant ; Transplantation, Homologous

Pediatric chronic myeloid leukemia (CML) is more aggressive than adult CML, with unique molecular characteristics and a higher propensity for lymphoid blast crisis. The application of tyrosine kinase inhibitors (TKIs) has significantly improved the prognosis of pediatric CML. Based on international consensus and clinical experience, this article proposes standardized diagnosis and treatment recommendations for pediatric CML, covering initial therapy selection, efficacy evaluation, drug switching, and management of adverse effects. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recommended only for patients with disease progression or failure of multiple lines of TKI therapy. For children newly diagnosed with CML in accelerated phase, high-dose imatinib or second-generation TKIs are recommended as first-line therapy. Those achieving optimal responses should continue maintenance therapy, while non-responders require switching to alternative TKIs and consider allo-HSCT. For blast-phase CML, induction therapy requires a combination of TKIs and chemotherapy, with allo-HSCT serving as the core curative intervention. This article highlights common but challenging problems (poor response, drug intolerance, and disease progression) in pediatric CML treatment using three typical cases, aiming to optimize treatment strategies. Furthermore, the goal of achieving treatment-free remission needs to be further addressed through multi-center clinical studies.
Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy* ; Child ; Hematopoietic Stem Cell Transplantation ; Protein Kinase Inhibitors/therapeutic use* ; Male ; Female ; Adolescent

This report describes two cases of severe immune-mediated thrombocytopenia after allogeneic hematopoietic stem cell transplantation (HSCT) who were treated with umbilical cord mesenchymal stem cells (UC-MSCs). Case 1 was a child with severe aplastic anemia who underwent haploidentical bone marrow and peripheral blood HSCT, with a chimerism rate of 99.8% on day +25 and severe immune-mediated thrombocytopenia on day +60. After intravenous immunoglobulin (IVIG) pulse therapy, platelet count increased temporarily but then decreased, while cyclosporine, methylprednisolone, and rituximab had a poor therapeutic effect. Case 2 was a child with Gaucher's disease who underwent unrelated umbilical cord blood HSCT, with a chimerism rate of 96.35% on day +41 and severe immune-mediated thrombocytopenia on day +153. After three sessions of IVIG pulse therapy, the platelet count increased initially but subsequently decreased. Therapies with dexamethasone, prednisone, cyclosporine, and recombinant human thrombopoietin also yielded a poor response. Both children received three sessions of UC-MSCs infusion, and platelet counts increased and were subsequently maintained within the normal range. Case 1 has been followed up for 10 years and remains in disease-free survival. UC-MSCs infusion may be effective for severe immune-mediated thrombocytopenia that is unresponsive to first- and second-line therapies after HSCT and could potentially improve the quality of life and disease-free survival rate.
Child ; Humans ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Mesenchymal Stem Cell Transplantation ; Purpura, Thrombocytopenic, Idiopathic/etiology* ; Thrombocytopenia/therapy* ; Transplantation, Homologous ; Umbilical Cord/cytology*

OBJECTIVES: To evaluate the efficacy and safety of avatrombopag in promoting platelet engraftment after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children, compared with recombinant human thrombopoietin (rhTPO). METHODS: A retrospective analysis was conducted on 53 pediatric patients who underwent allo-HSCT at the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences from April 2023 to August 2024. Based on medications used during the periengraftment period, patients were divided into two groups: the avatrombopag group (n=15) and the rhTPO group (n=38). RESULTS: At days 14, 30, and 60 post-transplant, platelet engraftment was achieved in 20% (3/15), 60% (9/15), and 93% (14/15) of patients in the avatrombopag group, and in 39% (15/38), 82% (31/38), and 97% (37/38) in the rhTPO group, respectively. There were no significant differences between the two groups in platelet engraftment rates at each time point, cumulative incidence of platelet engraftment, overall survival, and relapse-free survival (all P>0.05). Multivariable Cox proportional hazards analysis indicated that acute graft-versus-host disease was an independent risk factor for delayed platelet engraftment (P=0.043). CONCLUSIONS In children undergoing allo-HSCT, avatrombopag effectively promotes platelet engraftment, with efficacy and safety comparable to rhTPO, and represents a viable therapeutic option.
Humans ; Retrospective Studies ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Male ; Female ; Child ; Child, Preschool ; Infant ; Adolescent ; Transplantation, Homologous ; Blood Platelets/drug effects* ; Thiazoles/therapeutic use* ; Thrombopoietin/therapeutic use* ; Thiophenes

OBJECTIVES: To evaluate the safety and efficacy of thiotepa (TT)-containing conditioning regimens for allogeneic hematopoietic stem cell transplantation (HSCT) in children with inborn errors of immunity (IEI). METHODS: Clinical data of 22 children with IEI who underwent HSCT were retrospectively reviewed. Survival after HSCT was estimated using the Kaplan-Meier method. RESULTS: Nine patients received a traditional conditioning regimen (fludarabine + busulfan + cyclophosphamide/etoposide) and underwent peripheral blood stem cell transplantation (PBSCT). Thirteen patients received a TT-containing modified conditioning regimen (TT + fludarabine + busulfan + cyclophosphamide), including seven PBSCT and six umbilical cord blood transplantation (UCBT) cases. Successful engraftment with complete donor chimerism was achieved in all patients. Acute graft-versus-host disease occurred in 12 patients (one with grade III and the remaining with grade I-II). Chronic graft-versus-host disease occurred in one patient. The incidence of EB viremia in UCBT patients was lower than that in PBSCT patients (P<0.05). Over a median follow-up of 36.0 months, one death occurred. The 3-year overall survival (OS) rate was 100% for the modified regimen and 88.9% ± 10.5% for the traditional regimen (P=0.229). When comparing transplantation types, the 3-year OS rates were 100% for UCBT and 93.8% ± 6.1% for PBSCT (P>0.05), and the 3-year event-free survival rates were 100% and 87.1% ± 8.6%, respectively (P>0.05). CONCLUSIONS TT-containing conditioning for allogeneic HSCT in children with IEI is safe and effective. Both UCBT and PBSCT may achieve high success rates.
Humans ; Retrospective Studies ; Transplantation Conditioning/methods* ; Thiotepa/therapeutic use* ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Male ; Female ; Child, Preschool ; Infant ; Child ; Transplantation, Homologous ; Graft vs Host Disease ; Adolescent