Outcomes of HLA-mismatched HSCT with TCRαß/CD19 depletion or post-HSCT cyclophosphamide for inborn errors of immunity.

ABSTRACT: HLA-mismatched transplants with either in vitro depletion of CD3+ T-cell receptor (TCR)αß/CD19 (TCRαß) cells or in vivo T-cell depletion using posttransplant cyclophosphamide (PTCY) have been increasingly used for patients with inborn errors of immunity (IEIs). We performed a retrospective multicenter study via the EBMT registry on 306 children with IEIs undergoing their first transplant between 2010 and 2019 from an HLA-mismatched donor using TCRαß (n = 167) or PTCY (n = 139). The median age for hematopoietic stem cell transplantation (HSCT) was 1.2 years (range, 0.03-19.6 years). The 3-year overall survival (OS) was 78% (95% confidence interval (CI), 71-84) after TCRαß and 66% (57-74) after PTCY (P = .013). Pre-HSCT morbidity score (hazard ratio [HR], 2.27; 1.07-4.80, P = .032) and non-busulfan/treosulfan conditioning (HR, 3.12; 1.98-4.92, P < .001) were the only independent predictors of unfavorable OS. The 3-year event-free survival (EFS) was 58% (50%-66%) after TCRαß and 57% (48%-66%) after PTCY (P = .804). The cumulative incidence of severe acute graft-versus-host disease (GvHD) was higher after PTCY (15%, 9%-21%) than TCRαß (6%, 2%-9%, P = .007), with no difference in chronic GvHD (PTCY, 11%, 6%-17%; TCRαß, 7%, 3%-11%, P = .173). The 3-year GvHD-free EFS was 53% (44%-61%) after TCRαß and 41% (32%-50%) after PTCY (P = .080). PTCY had significantly higher rates of veno-occlusive disease (14.4% vs TCRαß 4.9%, P = .009), acute kidney injury (12.7% vs 4.6%, P = .032), and pulmonary complications (38.2% vs 24.1%, P = .017). Adenoviremia (18.3% vs PTCY 8.0%, P = .015), primary graft failure (10% vs 5%, P = .048), and second HSCT (17.4% vs 7.9%, P = .023) were significantly higher in TCRαß. In conclusion, this study demonstrates that both approaches are suitable options in patients with IEIs, although they are characterized by different advantages and outcomes.

Haematopoietic cell transplantation for 106 infants and preschoolers with acquired and inherited bone marrow failures.

Aplastic anaemia in infants and young children presents unique challenges due to high prevalence of inherited bone marrow failure syndromes (IBMFS) in this age group. The objective of this study is assessing clinical characteristics and outcomes of haematopoietic cell transplantation in children ≤5 years with bone marrow failure syndromes. We analysied 106 patients (66% males), median age 4.6 years, including 40 with Fanconi anaemia (FA), 32 with Acquired Severe Aplastic anaemia (aSAA), 15 with Diamond-Blackfan Anaemia, 11 with Amegakaryocytic Purpura and 8 with other IBMFS. Molecular testing was limited (39%), with 25.4% confirmed genetically. Retrospective longitudinal study across three paediatric transplantation centres (1982-2020). Overall survival (OS) was 76.4% over a median 10-year follow-up. OS rates were similar between aSAA and IBMFS (FA 77.5%, other IBMFS 76.5%). Transplant-related mortality (TRM) was lower in aSAA (9.4%) compared with IBMFS (16.2%). Recent years showed improved outcomes, with TRM declining post-2010. Choice of stem cell source impacted OS, favouring bone marrow over umbilical cord, but showing encouraging results with haploidentical. Late complications were common, including endocrine-metabolic issues and delayed neuropsychomotor development. Diagnosing and managing bone marrow failures in young children pose significant challenges. Despite advancements in transplant practices, ongoing vigilance and comprehensive care are necessary to improve long-term survival rates.

Training in Transplantation and Cellular Therapy in Latin America: A Cross-Sectional Study of the LABMT.

Hematopoietic cell transplantation (HCT) is a complex and resource-intensive procedure that has become a critical treatment for certain hematologic conditions. However, in Latin America, access to HCT is limited compared to high-income countries, in part due to a lack of standardized training programs for HCT professionals. To address this gap, the Latin-American Bone Marrow Transplantation Group conducted a cross-sectional study to assess the current state of training programs in HCT and cellular therapy across the region. This study aimed to describe and analyze the availability, characteristics, and challenges of HCT training programs in Latin America, with a focus on identifying barriers and proposing solutions for improvement. A cross-sectional survey was sent to 127 recognized HCT centers across 14 Latin-American countries in December 2022. The survey collected data on institutional characteristics, training program structure, costs, and barriers to program development. Descriptive statistics were used to summarize the data, and comparative analyses were performed using Chi-square and Mann-Whitney tests. Of the 127 centers surveyed, 50 (39%) responded, with the majority located in Brazil (34%) and Mexico (30%). Among the respondents, 64% (n = 32) offered formal training programs lasting 6 months or longer. The most significant barriers reported were lack of funding (n = 21), limited number of transplant procedures (n = 15), and a shortage of qualified professors (n = 11). Proposed solutions included increasing student mobility opportunities (n = 28), enhancing program quality (n = 27), and improving access to funding (n = 15). Only 6% of programs offered exposure to CAR-T therapy, and fewer than half of the centers provided international rotations. This study highlights significant disparities in HCT training programs across Latin America, with most countries lacking access to formalized training. While Brazil and Mexico serve as regional hubs, other nations have limited or no training opportunities. Addressing these gaps through increased funding, international collaborations, and standardized curricula is essential to improving HCT training and ultimately patient care in the region.