Efficacy and Safety of Children With Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia After Anti-CD19 CAR T-Cell Therapy Without Bridging Transplantation.

BACKGROUND: Anti-CD19 chimeric antigen receptor (CAR) T-cell therapies have demonstrated significant efficacy in achieving complete remission (CR) in pediatric patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). However, a considerable number of patients experience relapse within 1 year after CAR T-cell therapy, leading to an extremely poor prognosis, particularly in patients without bridging transplantation. MATERIALS AND METHODS: In our study, we investigated 42 children with R/R B-ALL who underwent anti-CD19 CAR T-cell therapy without bridging transplantation at our center. All patients were included in the response analysis and evaluated for survival and toxicity. RESULTS: The cohort that received the CAR T-cell infusion exhibited a 100% CR rate by day 28 (d28). The overall survival (OS) at 4 years was 61.3% ± 8.5%, and the event-free survival (EFS) was 55.9% ± 7.9%, with a median follow-up duration of 50.1 months. Minimal residual disease (MRD) ≥1% was associated with inferior outcomes, resulting in lower 4-year OS (P = .033) and EFS (P = .014) compared to MRD<1%. The incidences of grade ≥3 cytokine release syndrome (CRS) and neurotoxicity were 26.8% and 23.8%, respectively. Furthermore, MRD≥1% was identified as an independent factor associated with increased severity of CRS and occurrence of neurotoxicity. CONCLUSION: These findings suggest that reducing the pre-infusion MRD could serve as an effective treatment strategy to enhance the outcomes of CAR T-cell therapy.

Outcomes and prognosis of haploidentical haematopoietic stem cell transplantation in children with FLT3-ITD mutated acute myeloid leukaemia.

The presence of internal tandem duplication mutations in the FMS-like tyrosine kinase 3 receptor (FLT3-ITD) is a poor prognostic predictor in paediatric patients with acute myeloid leukaemia (AML). We evaluated the treatment outcomes and prognostic factors of 45 paediatric patients with FLT3-ITD AML who achieved complete remission before haploidentical haematopoietic stem cell transplantation (haplo-HSCT) at our institution from 2012 to 2021. Among the 45 patients, the overall survival (OS), event­free survival (EFS), and cumulative incidence of relapse (CIR) rates were 74.9% ± 6.6%, 64.1% ± 7.2%, and 31.4% ± 7.1%, respectively, with 48.8 months of median follow-up. Univariate and multivariate analyses associated positive minimal residual disease (MRD) at pre-HSCT and non-remission (NR) after introduce 1 with inferior long-term survival. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 35.6% ± 5.2%, and that of grade III-IV aGVHD was 15.6% ± 3.0% The overall 4-year cumulative incidence of chronic graft-versus-host disease after transplantation was 35.7% ± 9.8%, respectively. In conclusion, haplo-HSCT may be a feasible strategy for paediatric patients with FLT3-ITD AML, and pre-HSCT MRD status and NR after introduce 1 significantly affected the outcomes.

SOD2 promotes the immunosuppressive function of mesenchymal stem cells at the expense of adipocyte differentiation.

The potent immunomodulatory function of mesenchymal stem/stromal cells (MSCs) elicited by proinflammatory cytokines IFN-γ and TNF-α (IT) is critical to resolve inflammation and promote tissue repair. However, little is known about how the immunomodulatory capability of MSCs is related to their differentiation competency in the inflammatory microenvironment. In this study, we demonstrate that the adipocyte differentiation and immunomodulatory function of human adipose tissue-derived MSCs (MSC(AD)s) are mutually exclusive. Mitochondrial reactive oxygen species (mtROS), which promote adipocyte differentiation, were decreased in MSC(AD)s due to IT-induced upregulation of superoxide dismutase 2 (SOD2). Furthermore, knockdown of SOD2 led to enhanced adipogenic differentiation but reduced immunosuppression capability of MSC(AD)s. Interestingly, the adipogenic differentiation was associated with increased mitochondrial biogenesis and upregulation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A/PGC-1α) expression. IT inhibited PGC-1α expression and decreased mitochondrial mass but promoted glycolysis in an SOD2-dependent manner. MSC(AD)s lacking SOD2 were compromised in their therapeutic efficacy in DSS-induced colitis in mice. Taken together, these findings indicate that the adipogenic differentiation and immunomodulation of MSC(AD)s may compete for resources in fulfilling the respective biosynthetic needs. Blocking of adipogenic differentiation by mitochondrial antioxidant may represent a novel strategy to enhance the immunosuppressive activity of MSCs in the inflammatory microenvironment.