Black race and Hispanic ethnicity are associated with higher mortality in severe combined immunodeficiency (SCID) following hematopoietic cell transplantation (HCT), though mechanisms remain unclear. We evaluated 796 children with SCID who received nonsibling HCT between 1982 and 2020 using data from the Primary Immune Deficiency Treatment Consortium. Overall survival for Black (aHR 2.47, 95%CI 1.64, 3.71) and Asian/Pacific Islander patients (aHR 1.82, 95%CI 1.00, 3.30) was significantly lower compared with non-Hispanic White patients, while Hispanic patients had lower event-free survival (aHR 1.83, 95%CI 1.27, 2.63) compared with non-Hispanic White patients. Even after adjusting for age and infection, Black patients with SCID had more than twofold hazard of death compared with non-Hispanic White patients. NBS was associated with earlier diagnosis, reduced infection at HCT, and elimination of survival disparities between Black and non-Hispanic White patients. These findings suggest that universal, system-level interventions such as NBS can mitigate disparities in outcomes for children with SCID.

BackgroundSevere leukocyte adhesion deficiency-I (LAD-I) results from biallelic deleterious ITGB2 variants leading to deficient/defective CD18 leukocyte expression and impaired endothelial adhesion and extravasation.Children with <2% of normal CD18 neutrophil expression experience recurrent, life-threatening bacterial and fungal infections, and extensive mortality. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is potentially curative but limited by donor availability, graft-versus-host disease (GvHD), and graft failure (GF).AimsTo evaluate the long-term safety and efficacy of RP-L201 (marnetegragene autotemcel), an autologous CD34+ hematopoietic stem cell gene therapy utilizing the Chim-CD18-WPRE lentiviral vector carrying ITGB2, including restoration of peripheral blood (PB) polymorphonuclear cell (PMN) CD18 and CD11 expression.MethodsPatients ≥3 months old with severe LAD-I enrolled in the pivotal phase I/II study (NCT03812263), underwent G-CSF/plerixafor mobilization, apheresis, ex vivo transduction of CD34+ cells with RP-L201, and myeloablative busulfan (cAUC 71.6mg/L*h) conditioning, including therapeutic drug monitoring prior to infusion. Assessments included alloHSCT-free survival, PB PMN CD18 expression, PB vector copy number (VCN) and integration site analysis (ISA), leukocytosis normalization, and infection-related hospitalization annualized events. All patients subsequently entered the long-term follow-up (LTFU) study (NCT06282432).ResultsAs of June 18, 2025, nine patients (age at infusion 9.8–117.4 months) were treated and followed for a median (range) of 50.92 (42.6–67.9) months. AlloHSCT-free survival is 100% with no GF. VCN was 0.42–2.4 at 3 months post-infusion and remained durable thereafter with a mean VCN of 1.73 at M12, sustained through M24 and beyond with concomitant sustained PMN CD18 expression. There were no new skin or oral lesions from the end of the parent study to the data-cut date in the LTFU study.Significant infections (either requiring IV antimicrobials or hospitalization) were markedly (90.7%) reduced from pre-infusion through the following 91 days post-engraftment up to the end of the study. RP-L201 was well-tolerated with no discontinuations or RP-L201-related adverse events. ISA demonstrated highly polyclonal integration patterns without evidence of predominant clones.Summary/ConclusionTreatment with RP-L201 results in durable phenotypic correction across all relevant clinical and laboratory parameters of severe LAD-I patients. The long-term benefit-risk profile for RP-L201 remains favorable, with no RP-L201-related adverse events and 100% alloHSCT-free survival.

RATIONALE:Lung injury after hematopoietic stem cell transplantation (HCT) occurs due to infection, chemotherapy toxicity, and alloreactive inflammation. Analyses of bronchoalveolar lavage (BAL) fluid have revealed dominant pathobiologic signatures, but minimally-invasive diagnostics are needed. OBJECTIVES:To determine whether microbiome and gene expression perturbations are shared along the respiratory tract or isolated to the alveoli in pediatric HCT patients with lung injury. METHODS:We performed bulk RNA sequencing on 206 paired nasal and BAL samples from 160 HCT patients and 17 healthy controls enrolled at 28 children's hospitals (2016-2025). Microbial and human transcripts were compared using multivariable models accounting for age, sex, and paired sampling. MEASUREMENTS AND MAIN RESULTS:HCT BAL and nasal transcriptomes differed across 13,698 genes, 48 cellular components, and network interactions linking inflammation, reactive oxygen species, and immunometabolism. Minimal BAL-nasal correlation was observed in gene expression levels (median ρ = 0.03, IQR -0.03 to 0.08) or fractional abundance of key cells such as neutrophils and CD8 + T-cells. BAL microbiomes harbored fewer commensal bacteria and more fungi and DNA viruses. BAL bacterial RNA was associated with diminished immune signaling whereas nasal bacterial RNA aligned with inflammatory gene expression. Further, only BAL microbial RNA was linked to transcriptional shifts in epithelial injury response, keratinization, and collagen deposition. Finally, BAL commensal microbiome depletion, epithelial injury, and immune dysregulation signatures were associated with death or prolonged mechanical ventilation, whereas nasal samples provided minimal prognostic information. CONCLUSIONS:These data support alveolar compartmentalization in pediatric HCT and emphasize the ongoing need for minimally-invasive but informative diagnostics.

Abstract Sickle cell disease (SCD) is characterized by chronic hemolysis, and painful vaso-occlusive episodes (VOE). High levels of fetal hemoglobin (HbF) attenuate the disease phenotype. We used a lentivirus vector (LVV) expressing a short hairpin RNA embedded in a microRNA (shmiR) that targets BCL11A in erythrocytes to induce HbF in a first-in-human study in SCD. The purpose of the study was to assess hematopoietic stem/progenitor cells collection, transduction parameters, safety, HbF induction, and durability. Eleven eligible patients with SCD underwent hematopoietic stem cell (HSC) collection. Plerixafor-mobilized peripheral blood HSCs required for manufacturing were obtained in 1 mobilization cycle for 10 of 11 participants, and 11 of 11 patient products were successfully manufactured with a median time to release of product of 39 days. Ten patients were infused with HSCs transduced with the shmiR vector. Engraftment occurred in all 10 patients. At a median follow-up of 58 months (range, 35-82) after infusion, there were no adverse events attributed to the vector. The transduction efficiency was 93.1%. One patient demonstrated low engraftment of the transduced cells and had suboptimal HbF induction. In the remaining 9 patients, at 2 years after treatment, the peripheral blood demonstrated 71% F cells with 11.9 pg HbF per F cells, and both parameters remained stable in 9 patients with ≥48 months follow-up. All patients who had VOEs before gene therapy demonstrated sustained mitigation of pain events. These data demonstrate excellent manufacturing efficiency, efficacy and safety of targeting BCL11A using a shmiR LVV, and long-term durability of the shmiR vector, leading to a pivotal, multisite, phase 2 trial that is currently underway (NCT05353647). This trial was registered at www.clinicaltrials.gov as NCT03282656.

Wiskott-Aldrich syndrome (WAS), an X-linked disorder characterized by immunodeficiency, thrombocytopenia, autoimmunity, and malignancy, can be effectively treated with allogeneic hematopoietic cell transplantation (HCT). Older age at HCT and mismatched donors are known to impact overall survival (OS). The influence of specific clinical manifestations or WAS variant class on OS and factors associated with event-free survival (EFS) remain incompletely defined. We analyzed outcomes of 308 patients with WAS who underwent HCT at 37 institutions of the Primary Immune Deficiency Treatment Consortium (PIDTC) from 1990-2018. With a median follow-up of 5.3 years, the 5-year OS and EFS were 87.2% and 79.7%, respectively. Age ≥5 years, donor type, and a pre-HCT history of severe infection had a negative impact on OS and EFS, whereas pre-HCT autoimmunity had no impact. Reduced intensity regimens were associated with lower T cell and myeloid donor chimerism, particularly when non-busulfan-based regimens were used. Low myeloid donor chimerism was associated with lower platelet counts. Mixed chimerism was not consistently associated with post-HCT autoimmunity. Patients with class I (exon 1-2 missense and intron 5 hotspot variants) and class II variants (all others) had similar pre-HCT clinical symptom severity and no difference in OS, EFS or platelet recovery post-HCT. In conclusion, our study showed excellent long-term OS and EFS following HCT for WAS, highlighting the importance of early HCT, before the development of severe infections. We confirmed that HCT using busulfan-based conditioning was associated with improved donor chimerism and platelet recovery. This study was registered at www.clinicaltrials.gov as #NCT02064933.

Abstract Sickle cell disease (SCD) is a monogenic disorder in which autologous gene therapy may offer a safer curative alternative to allogeneic transplantation. We report outcomes from a phase 1/2 study using the Lenti/G-βAS3-FB lentiviral vector, which encodes an antisickling β-globin. This single-site study treated 4 adults with severe SCD. The first patient was treated using the original Lenti/βAS3-FB and initial protocol, which resulted in suboptimal clinical response. Subsequent protocol refinements included improved hematopoietic stem and progenitor cell (HSPC) collection, using plerixafor-mobilized peripheral blood apheresis with precollection erythrocytapheresis, and the use of an optimized lentiviral vector with a transduction enhancer. All patients received myeloablative busulfan conditioning followed by infusion of gene-modified autologous HSPCs. Primary end points were safety and feasibility; secondary end points included gene marking, therapeutic hemoglobin expression, and clinical outcomes. All patients achieved hematopoietic recovery without rescue transplantation. The first patient demonstrated low gene marking (peak vector copy number [VCN], 0.035) and undetectable HbAS3 expression, with minimal clinical benefit. In contrast, the 3 patients treated with the optimized protocol achieved higher and sustained gene marking (peak granulocyte VCNs, ∼0.5-2.0) and persistent HbAS3 expression. These patients experienced some reductions in vaso-occlusive crises and transfusion requirements, with 2 becoming transfusion independent. No insertional oncogenesis was observed. This trial highlights the necessity of optimized vector design and transduction protocols to achieve durable gene expression. Although this specific vector will not be pursued further, the study provides crucial insights into gene therapy protocol development. This trial was registered at www.clinicaltrials.gov as #NCT02247843.

Correlation between ICANS, CRS, and various electrolyte derangements with categories of neurological adverse events reported in CAR T-cell recipients.

Figure S4. Association of hypophosphatemia incidence by ICANS grade.

Range and interquartile range of nadir serum electrolyte values in patients with and without ICANS.

Figure S2. Trends in serum electrolyte concentrations following CAR T-cell infusion grouped by patient ICANS status.

Figure S7. Coincidence of serum hypocalcemia with hypophosphatemia.

Incidence of hypophosphatemia and AKI following CAR-T cell infusion.

BACKGROUND:Allogeneic hematopoietic cell transplantation corrects the phagocytic defect in patients with chronic granulomatous disease (CGD) and resolves infection risk and immune dysregulation. Umbilical cord blood transplantation (UCBT) is an option for patients lacking suitable HLA-matched bone marrow or peripheral blood stem cell donors. However, information related to UCBT for CGD is limited to a few small case series and limited subsets of larger cohorts where detailed information is lacking. OBJECTIVES:To describe UCBT procedures and outcomes in patients with CGD. STUDY DESIGN:Thirty-nine patients with CGD who underwent UCBT at Primary Immune Deficiency Treatment Consortium (PIDTC) centers between 2001 and 2019 were included. RESULTS:All patients were male, and most (97%) had X-linked CGD due to pathogenic variants in CYBB. High infection burden (1.72/person years) and inflammatory disease (38%) were common in the year pre-UCBT. Median age at receipt of UCBT was 2.1 (range 0.3-14.0) years. Most (87%) patients received UCB from unrelated donors, and most (72%) patients received busulfan and cyclophosphamide-based conditioning. All but two (95%) patients received serotherapy with anti-thymocyte globulin or alemtuzumab. Neutrophil and platelet recovery occurred at a median of 18 (range 12-46) and 38 (range 21-186) days, respectively. Nine patients experienced early graft failure [donor myeloid chimerism <10% or receipt of second hematopoietic cell transplantation (HCT) within 100 days] for a cumulative incidence of 23.1% (95% CI 11.3-37.3). There were no cases of late graft failure (after 100 days), and median whole blood and myeloid donor chimerism of engrafted patients were >95% at all time points. One of the nine patients with early graft failure had autologous reconstitution. The remaining 8 patients underwent repeat HCT; six of the patients survived and achieved durable myeloid engraftment on long-term follow-up. Twenty-eight patients were alive at a median follow-up of 4.28 (IQR 2.66-6.08) years. Estimated 3-year overall and event-free survival were 73.7% (95% CI 56.5-84.9) and 56.2% (95% CI 39.3-70.1), respectively. No identifiable factors, including history of infection or inflammatory disease in the year prior to UCBT, year of UCBT, age at UCBT, conditioning regimen, cell dose, and recipient and donor HLA match, were associated with graft failure or survival. Infections decreased with time post-UCBT and pre-existing inflammatory disease resolved in all surviving patients CONCLUSIONS: UCBT for CGD is associated with high rates of early graft failure. Nevertheless, UCBT can provide an effective alternative for CGD patients when HLA-matched donors are not available with resolution of disease. Strategies to overcome high rates of early graft failure while optimizing conditioning regimens to minimize toxicity are needed.

Neurological adverse events included within each neurological adverse event category for CAR T-cell recipients.

BACKGROUND:Severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) deficiency (ADA-SCID) is a life-threatening inborn error of immunity for which lentiviral gene therapy has been investigated in clinical trials. METHODS:Between 2012 and 2019, we treated patients who had ADA-SCID with busulfan nonmyeloablative conditioning followed by transplantation with autologous CD34+ hematopoietic stem cells transduced ex vivo with a lentiviral vector encoding human ADA. The primary efficacy end points were overall survival and event-free survival (defined as survival free from rescue allogeneic hematopoietic stem-cell transplantation, reinitiation of enzyme-replacement therapy, and additional gene therapy). Secondary end points included no receipt of immunoglobulin-replacement therapy, the presence of protective titers to tetanus or pneumococcal vaccines, and sustained discontinuation of fungal or viral prophylaxis. We now report the long-term results from this cohort representing 474 patient-years of follow-up, with a median follow-up of 7.5 years. RESULTS:We treated 62 patients with ADA-SCID in the United States (33 patients) and the United Kingdom (29 patients). Overall survival was 100%, and event-free survival was 95% (59 of 62 patients). All 59 patients who had successful gene-marked engraftment at 6 months have continued not to receive enzyme-replacement therapy and have had stable gene marking, ADA enzyme activity, metabolic detoxification, and immune reconstitution through the last follow-up; 58 of these patients (98%) discontinued IgG replacement therapy and have evidence of a robust response to vaccinations. None of the patients had a leukoproliferative event or clonal expansion. CONCLUSIONS:These long-term findings in a large patient cohort show the sustained clinical efficacy and safety of autologous CD34+ hematopoietic stem-cell lentiviral gene therapy for ADA-SCID, indicating that it is a curative treatment. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT04049084.).

Background:Pediatric hematopoietic stem cell transplant (pHSCT) patients are at risk for many life-threatening post-transplant complications, notably relapse, graft-versus-host disease (GvHD), and infection. Methods:This retrospective study reviewed 10 years of pHSCT at a single institution, assessing for risk factors for post-transplantation viral infections (herpes simplex virus (HSV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpes virus 6 (HHV6), adenovirus (ADNV), and human polyoma virus 1 (BK virus)), and characterizing adverse infectious outcomes. Results:Overall, 139 patients received 151 transplants. With respect to graft source: 73 (48.3%) were bone marrow, 67 (44.4%) umbilical cord blood (UCB), and 11 (7.2%) peripheral blood stem cells (PBSCs). Forty-one deaths occurred, for an overall mortality rate of 29.5%. The overall incidence of post-transplant viral infections was 47.7% (n = 72). Incidence of post-transplant infection varied by virus type: 3.97% HSV, 0.67% VZV, 3.97% EBV, 24.5% CMV, 14.5% HHV6, 12.6% ADNV, and 12.6% BK virus. Viral encephalitis, though relatively uncommon, was primarily caused by HHV6 and more common in UCB transplants. Overall, cell source and donor source were identified with statistically significant correlation to both risk of infection and mortality. Conclusions:Post-transplant viral infection remains as a serious adverse event in pediatric patients, and thus prospective studies should be performed to implement early intervention and more aggressive treatment in select high-risk patients. More studies specifically addressing infection risks in cord blood transplants and risk factors for post-transplant viral encephalitis are warranted.

Telomere Biology Disorders (TBD) are a group of heritable disorders characterized by short telomeres. We report two patients that presented with bone marrow failure (BMF), who were identified to have low telomere length (TL) and variants of uncertain significance (VUS) in two different telomere genes inherited from their parents. At age 6, Patient 1 had stage 4 neuroblastoma. He was treated with chemotherapy, surgery, immunotherapy, and autologous stem cell rescue. At age 10, he developed pancytopenia. Bone marrow biopsy revealed hypocellular marrow and der (1; 7), associated with myelodysplastic syndrome. Germline genetic evaluation showed a pathogenic variant in DNAJC21 (from father) and VUS in NAF1 (c.1375C > T) (from father) and RTEL1 (c.533T > C) (from mother). The patient was found to have very low TL (VLTL) (< 1st percentile) in 4/6 white blood cell subsets. The patient’s mother was found to have borderline low TL (VLTL) ( 1 and < 10th percentiles) in 4/6 subsets and VLTL in 1/6 subsets. Father had VLTL in 1/6 but normal TL in other subsets. Neither parent reported any symptoms of TBD. Patient 2 presented with a depressed skull fracture at age 15. He was found incidentally to have pancytopenia. Bone marrow biopsy showed hypocellular marrow and no cytogenetic abnormalities. The patient had VLTL in all 6/6 subsets. Genetic evaluation showed VUSs in TERT (c.3158-80G > A) (from mother), TINF2 (c.814T > C) (from mother) and SRP72 (c.1928C > T) (from father). Mother was also found to have VLTL in all 6 subsets but has reported good health except for premature graying of hair. These two patients presented with BMF, identified to have VUSs in more than one TBD-associated gene with functional evidence of shortened telomeres, highlighting the potential for a digenic mode of inheritance. Synergy between two VUSs could contribute to a penetrant phenotype and resulting in earlier or more severe onset of disease.

Hematopoietic stem cell transplantation (HCT) is a potentially life-saving therapy but can lead to lung injury due to chemoradiation toxicity, infection, and immune dysregulation. We previously showed that bronchoalveolar lavage (BAL) transcriptomes representing pulmonary inflammation and cellular injury can phenotype post-HCT lung injury and predict mortality. To test whether peripheral blood might be a suitable surrogate for BAL, we compared 210 paired BAL and blood transcriptomes obtained from 166 pediatric patients with HCT at 27 hospitals. BAL and blood RNA abundance showed minimal correlation at the level of individual genes, gene set enrichment scores, imputed cell fractions, and T and B cell receptor clonotypes. Instead, we identified significant site-specific transcriptional programs. In BAL, pathways related to immunity, hypoxia, and epithelial mesenchymal transition were tightly coexpressed and linked to mortality. In contrast, in blood, expression of endothelial injury, DNA repair, and cellular metabolism pathways was associated with mortality. Integration of paired BAL and blood transcriptomes dichotomized patients into 2 groups with significantly different rates of hypoxia and clinical outcomes within 1 week of BAL. These findings reveal a compartmentalized injury response, where BAL and blood transcriptomes provide distinct but complementary insights into local and systemic mechanisms of post-HCT lung injury.