Safety and efficacy of peripheral blood stem cells collection in healthy children and pediatric patients with thalassemia major weighing 20 kg or less.

BACKGROUND: Peripheral blood stem cell (PBSC) collection in children poses challenges due to their small size, low body weight (BW), and unique pediatric physiology, especially among children weighing 20 kg (kg) or less. METHODS: PBSC collection data of both healthy children and patients with thalassemia major (TM) weighing 20 kg or less between January 2013 and December 2020 were reviewed. Moreover, PBSCs characteristics along with various aspects of efficiency and safety between healthy donors and patients with TM were compared. RESULTS: A total of 262 PBSC procedures were performed on 255 children. Of these, 91 procedures were carried out on 85 allogeneic healthy donors, and 171 auto-backup collections were performed on 170 patients with TM to ensure PBSC availability and prevent transplantation failure. A minimum pre-apheresis hemoglobin (HGB) level of 60 g/L was discovered to be safe and feasible in patients with TM. The median CD34+ cell dose in the PBSC product during the initial apheresis procedure was higher in healthy donors compared to patients with TM (7.29 ± 5.28 × 106 cells/kg vs5.88 ± 4.23 × 106 cells/kg, P = .043). The total CD34+ cells/kg recipient weight exhibited a positive correlation with pre-apheresis monocyte counts, but a negative correlation with donor weight. Apheresis significantly reduced hematocrit and platelet counts in the allogeneic group compared to the autologous group. Patients with TM experienced a higher occurrence of bone pain related to granulocyte colony-stimulating factor treatment. Notably, no serious complications related to PBSCs mobilization, central venous catheter placement, or the apheresis procedure were observed in either group. CONCLUSIONS: PBSCs collection was both safe and effective in healthy children and pediatric patients with TM weighing 20 kg or less.

Vincristine and dexamethasone pulses in addition to maintenance therapy among pediatric acute lymphoblastic leukemia (GD-ALL-2008): An open-label, multicentre, randomized, phase III clinical trial.

The efficacy and safety on the addition of vincristine (VCR) and dexamethasone (DEX) pulses to maintenance therapy among childhood acute lymphoblastic leukemia (ALL) remain uncertain. Herein, we perform an open-label, multicentre, randomized, phase III clinical trial that was conducted at nine major medical centers in Guangdong Province, China. Patients were randomly assigned either the conventional maintenance therapy (control group, n = 384) or the VCR/DEX pulse (treatment group, n = 375). When limited to the SR cohort, 10-year EFS was 82.6% (95% CI: 75.9-89.9) in the control group and 80.7% (95% CI: 74-88.1) in the treatment group (pnon-inferiority  = .0002). Similarly, patients with IR also demonstrated non-inferiority of the treatment group to the control group in terms of 10-year EFS (73.6% [95% CI: 67.6-80] vs. 77.6% [95% CI: 71.8-83.9]; pnon-inferiority  = .005). Among the HR cohort, compared with the control group, patients in the treatment group experienced a significant benefit in terms of 10-year EFS (61.1% [95% CI: 47.7-78.2] vs. 72.6% [95% CI: 55.6-94.7], p = .026) and a trend toward higher 10-year OS (73.8% [95% CI: 61.6-88.4] vs. 87.9% [95% CI: 579.2-97.5], p = .068). In the HR cohort, the total rate of drug-induced liver injury and Grade 3 chemotherapy-induced anemia were both lower for patients in the treatment group than in the control group (55.6% vs. 100%, p = .033; 37.5% vs. 60%, p = .036). Conversely, the total prevalence of chemotherapy-induced thrombocytopenia was higher for patients in the treatment group than in the control group (88.9% vs. 40%, p = .027). Pediatric acute lymphoblastic leukemia with high risk is suitable to VCR/DEX pulse during maintenance phase for the excellent outcome, while the standard-to-intermediate-risk patients could eliminate the pulses.

The Effect of Iron Overload on the Mobilization of Peripheral Blood Hematopoietic Stem Cells in Pediatric Patients with Thalassemia Major.

INTRODUCTION: The purpose of this study was to examine the effect of iron overload on the mobilization of peripheral blood stem cells (PBSCs) in pediatric patients with ß-thalassemia major (TM). METHODS: We retrospectively reviewed the records of 226 patients with TM from whom PBSCs were collected. Iron overload was based on serum ferritin level, and liver and cardiac iron overload was measured by magnetic resonance imaging (MRI) T2*. RESULTS: The mean age of the TM patients was 7.35 ± 3.41 years. Of the patients, only 171 received MRI. Of the 171 patients, 35 had normal liver iron levels, 39 mild liver iron overload, 90 intermediate liver iron overload, and 7 severe liver iron overload. The intermediate + severe group was associated with significantly higher age and BMI and lower leukapheresis product white blood cell count and CD34+ cell levels (all, p < 0.05). CONCLUSION: Leukapheresis indices were similar between patients with different degrees of iron overload according to the ferritin level and cardiac iron overload, in which the later might be due to the small number of patients with cardiac overload. In patients with TM, the intermediate and severe liver iron overload was associated with poorer mobilization of PBSCs.

Hematopoietic stem cell transplantation for CYBB heterozygous mutation resulting in very early onset inflammatory bowel disease in children: a case report.

BACKGROUND: Inflammatory bowel disease (IBD) is a heterogeneous group of disorders associated with environmental triggers and dysregulated immune responses resulting in chronic, recurrent intestinal inflammation. Very early-onset IBD (VEO-IBD) refers to patients with symptoms or diagnosis before the age of 6 years and is widely thought to be associated with monogenic mutations. Traditional drug therapy is often ineffective in this patient population, while hematopoietic stem cell transplantation (HSCT) represents the definitive cure for patients with gene mutations. CASE PRESENTATION: We report a case of VEO-IBD associated with a monogenic mutation in a 2-year-old girl presenting mainly with gastrointestinal symptoms, including recurrent hematochezia and abdominal pain for more than 3 months. A gastroscopy revealed erosive gastritis and bulbar duodenitis, while a colonoscopy indicated erosive colitis. Abnormal results were obtained from the dihydrohodamine (DHR) assay and immunoglobulin testing. Whole-exome sequencing identified a heterozygous and de novo nonsense mutation (c.388 C > T; p.R130X) in the CYBB gene leading to deficiency of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) (encoded by CYBB), a critical component of phagocytes. HSCT was performed successfully, and the DHR assay showed that normal neutrophil function was restored. Six months after HSCT, clinical remission was observed, and a repeat colonoscopy revealed intestinal mucosal healing was attained. CONCLUSIONS: Patients with CYBB mutations often develop recurrent or severe bacterial or fungal infections, mostly in the lungs, skin, lymph nodes, and liver. Here, we report on a young female child with CYBB mutations presenting predominantly with gastrointestinal symptoms. This study explores the mechanisms of inflammatory bowel disease caused by a monogenic mutation in CYBB to improve early diagnosis and effective treatment rates of this patient population.

Integrin α6 mediates the drug resistance of acute lymphoblastic B-cell leukemia.

Resistance to multimodal chemotherapy continues to limit the prognosis of acute lymphoblastic leukemia (ALL). This occurs in part through a process called adhesion-mediated drug resistance, which depends on ALL cell adhesion to the stroma through adhesion molecules, including integrins. Integrin α6 has been implicated in minimal residual disease in ALL and in the migration of ALL cells to the central nervous system. However, it has not been evaluated in the context of chemotherapeutic resistance. Here, we show that the anti-human α6-blocking Ab P5G10 induces apoptosis in primary ALL cells in vitro and sensitizes primary ALL cells to chemotherapy or tyrosine kinase inhibition in vitro and in vivo. We further analyzed the underlying mechanism of α6-associated apoptosis using a conditional knockout model of α6 in murine BCR-ABL1+ B-cell ALL cells and showed that α6-deficient ALL cells underwent apoptosis. In vivo deletion of α6 in combination with tyrosine kinase inhibitor (TKI) treatment was more effective in eradicating ALL than treatment with a TKI (nilotinib) alone. Proteomic analysis revealed that α6 deletion in murine ALL was associated with changes in Src signaling, including the upregulation of phosphorylated Lyn (pTyr507) and Fyn (pTyr530). Thus, our data support α6 as a novel therapeutic target for ALL.

Wnt Signaling in the Tumor Microenvironment.

Dysregulated Wnt signaling plays a central role in initiation, progression, and metastasis in many types of human cancers. Cancer development and resistance to conventional cancer therapies are highly associated with the tumor microenvironment (TME), which is composed of numerous stable non-cancer cells, including immune cells, extracellular matrix (ECM), fibroblasts, endothelial cells (ECs), and stromal cells. Recently, increasing evidence suggests that the relationship between Wnt signaling and the TME promotes the proliferation and maintenance of tumor cells, including leukemia. Here, we review the Wnt pathway, the role of Wnt signaling in different components of the TME, and therapeutic strategies for targeting Wnt signaling.

Wnt Signaling in Leukemia and Its Bone Marrow Microenvironment.

Leukemia is an aggressive hematologic neoplastic disease. Therapy-resistant leukemic stem cells (LSCs) may contribute to the relapse of the disease. LSCs are thought to be protected in the leukemia microenvironment, mainly consisting of mesenchymal stem/stromal cells (MSC), endothelial cells, and osteoblasts. Canonical and noncanonical Wnt pathways play a critical role in the maintenance of normal hematopoietic stem cells (HSC) and LSCs. In this review, we summarize recent findings on the role of Wnt signaling in leukemia and its microenvironment and provide information on the currently available strategies for targeting Wnt signaling.

Minimal Residual Disease Detection in Acute Lymphoblastic Leukemia.

Minimal residual disease (MRD) refers to a chemotherapy/radiotherapy-surviving leukemia cell population that gives rise to relapse of the disease. The detection of MRD is critical for predicting the outcome and for selecting the intensity of further treatment strategies. The development of various new diagnostic platforms, including next-generation sequencing (NGS), has introduced significant advances in the sensitivity of MRD diagnostics. Here, we review current methods to diagnose MRD through phenotypic marker patterns or differential gene patterns through analysis by flow cytometry (FCM), polymerase chain reaction (PCR), real-time quantitative polymerase chain reaction (RQ-PCR), reverse transcription polymerase chain reaction (RT-PCR) or NGS. Future advances in clinical procedures will be molded by practical feasibility and patient needs regarding greater diagnostic sensitivity.

Transplant Outcomes in Beta-Thalassemia Major Patients Receiving Combined Granulocyte Colony-Stimulating Factor-Primed Bone Marrow and Cord Blood Graft Compared to Granulocyte Colony-Stimulating Factor-Primed Bone Marrow Alone.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for thalassemia majorTM. Graft rejection (GR) and graft-versus-host disease (GVHD) are the primary obstacles to a successful outcome. METHODS: We conducted a retrospective study of HSCT in 29 children (median age at transplantation: 6 years) with Beta-thalassemia (ß-TM) after the combined infusion of granulocyte colony-stimulating factor-primed bone marrow (G-BM) and cord blood (CB) from the human leukocyte antigen (HLA)-identical sibling donors. We also compared the outcomes of the co-transplanted children with those of children with ß-TM who received G-BM alone from an HLA-identical sibling donor (n = 26). RESULTS: Compared to the G-BM transplant (G-BMT) recipients, those who received a co-transplant had a lower incidence of grade ≥II acute (17.24 vs. 30.7%, p = 0.047) and limited chronic (0 vs.15.4%, p = 0.022) GVHD as well as a lower incidence of GR (0 vs. 7.7%, p = 0.132). Neutrophil recovery time was faster in the co-transplant group (18.5 vs. 21 days, p = 0.04). All the patients were monitored until December 31, 2016; the median follow-up time was 74 months, and the 5-year thalassemia-free survival rate was 89.7% in the co-transplant group and 84.6% in the G-BMT-alone group (p = 0.590). CONCLUSIONS: A combined CB and G-BM graft from an HLA-identical sibling donor is an effective treatment option for TM in children, with less acute and chronic GVHD.

[Outcome of childhood high-risk acute lymphoblastic leukemia treated with the ALL-BFM 95 protocol].

OBJECTIVE: To evaluate the effectiveness and the practicability of the Acute Lymphoblastic Leukemia Berlin-Frankfurt-Münster 95 (ALL-BFM 95) protocol in treating childhood high-risk acute lymphoblastic leukemia (HR-ALL). METHODS: A retrospective analysis of 47 children with newly diagnosed HR-ALL between July 2003 and August 2013 was performed. These children were treated by the ALL-BFM 95 protocol. Survival was evaluated by Kaplan Meier analysis and Log-Rank test. RESULTS: Relapse-related death occurred in 12 of 47 patients (26%), and 5 of 47 patients (11%) were treatment-related mortality. Five-year probability of event-free-survival (pEFS) was 62%. Children with hematopoietic stem cell transplantation (HSCT) after chemotherapy achieved significantly better pEFS than those with chemotherapy alone (77% vs 52%; P=0.035). The patients who were only poor responders to prednisone had a better outcome (5-year pEFS 80%) than the Days 15 and 33 bone marrow M3 subgroups (5-year pEFS 60% and 0 respectively). CONCLUSIONS: ALL-BFM 95 protocol can improve the outcome of children with high-risk ALL. The major cause of death is attributed to relapse. Chemotherapy plus HSCT can produce a better outcome than chemotherapy alone. The Days 15 and 33 bone marrow M3 subgroups have a poor prognosis.