Allogeneic hematopoietic stem cell transplantation (HSCT) is indicated in various nonmalignant disorders that arise from genetic, hematopoietic, and immune system defects. Many of the disorders described here have life-threatening consequences in the absence of HSCT, a curative intervention. However, timing and approach to HSCT vary by disorder and optimum results are achieved by performing transplantation before irreversible disease-related morbidity or infectious complications. This article details the principles of HSCT in the very young, lists indications, and explores the factors that contribute to successful outcomes based on transplantation and disease-related nuances. It provides an overview into the HSCT realm from a neonatologist's perspective, describes the current status of transplantation for relevant disorders of infancy, and provides a glimpse into future efforts at improving on current success.

Background Children with sickle cell disease (SCD) and moyamoya may benefit from indirect cerebral revascularization surgery in addition to chronic blood transfusion therapy for infarct prevention. We sought to compare overt and silent infarct recurrence rates in children with SCD undergoing revascularization. Methods This was a retrospective cohort study of all children with SCD and moyamoya treated at two children’s hospitals. Clinical events and imaging studies were reviewed. Results Twenty-seven children with SCD and confirmed moyamoya receiving chronic transfusion therapy were identified, of whom 12 underwent indirect cerebral revascularization. Two subjects had post-operative transient ischemic attacks and another had a subarachnoid blood collection, none of which caused permanent consequences. Two subjects had surgical wound infections. Among these 12 children, the rate of overt and silent infarct recurrence decreased from 13.4 infarcts/100 patient-years before revascularization to 0 infarcts/100 patient-years after revascularization (p=0.0057); the post-revascularization infarct recurrence rate was also significantly lower than the overall infarct recurrence of 8.87 infarcts/100 patient-years in 15 children without cerebral revascularization (p=0.025). Conclusion The rate of overt and silent infarct recurrence was significantly lower following indirect cerebral revascularization. A prospective study of cerebral revascularization in children with SCD is needed.

Aldehyde dehydrogenases (ALDH) catalyze the conversion of various aliphatic and aromatic aldehydes to corresponding carboxylic acids.  Traditionally considered as housekeeping enzymes, new biochemical roles are being identified for members of ALDH family.  Recent work showed that AldA from the plant pathogen Pseudomonas syringae strain PtoDC3000 functions as an indole-3-acetaldehyde dehydrogenase for the synthesis of indole-3-acetic acid (IAA).  IAA produced by AldA allows the pathogen to suppress salicylic acid-mediated defenses in the model plant Arabidopsis thaliana.  Here we present a biochemical and structural analysis of the AldA indole-3-acetaldehyde dehydrogenase from PtoDC3000.  Site-directed mutants targeting the catalytic residues Cys302 and Glu267 resulted in a loss of enzymatic activity.  The x-ray crystal structure of the catalytically inactive AldA C302A mutant in complex with IAA and NAD+ showed the cofactor adopting a conformation that differs from the previously reported structure of AldA.  These structures suggest that NAD+ undergoes a conformational change during the AldA reaction mechanism similar to that reported for human ALDH.  Site-directed mutagenesis of the IAA binding site indicates that changes in the active site surface reduces AldA activity; however, substitution of Phe169 with a tryptophan altered the substrate selectivity of the mutant to prefer octanal.  This study highlights the inherent biochemical versatility of members of the ALDH enzyme superfamily in P. syringae.

Background: Tisagenlecleucel is an autologous CD19-directed T-cell immunotherapy indicated in the USA for treatment of patients up to 25 years (y) of age with B-cell ALL that is refractory or in second or later relapse. Overall response rate was 82% with 24 months' (mo) follow-up in the registrational ELIANA trial [Grupp et al. Blood 2018]; pooled data from ELIANA and ENSIGN revealed similar outcomes upon stratification by age (<18y and ≥18y) [Rives et al. HemaSphere 2018]. Early real-world data for tisagenlecleucel from the CIBMTR registry reported similar efficacy to ELIANA with no new safety signals [Pasquini et al. Blood Adv 2020]. Outcomes are reported here for patients who received tisagenlecleucel in the real-world setting, stratified by age (<18y and ≥18y). Methods: This noninterventional prospective study used data from the CIBMTR registry and included patients aged ≤25y with R/R ALL. Eligible patients received commercial tisagenlecleucel after August 30, 2017, in the USA or Canada. Age-specific analyses were conducted in patients aged <18y and ≥18y at the time of infusion. Efficacy was assessed in patients with ≥12mo follow-up at each reporting center and included best overall response (BOR) of complete remission (CR), duration of response (DOR), event-free survival (EFS), relapse-free survival (RFS) and overall survival (OS). Safety was evaluated in all patients who completed the first (100-day) assessment. Adverse events (AEs) of interest - including cytokine release syndrome (CRS) and neurotoxicity - were monitored throughout the reporting period. CRS and neurotoxicity were graded using the ASTCT criteria. Results: As of October 30, 2020, data from 451 patients were collected, all of whom received tisagenlecleucel. The median time from receipt of leukapheresis product at the manufacturing site to shipment was 27 days (interquartile range: 25-34). Patients aged ≥18y appeared to have greater disease burden at baseline than those aged <18y, indicated by lower rates of morphologic CR and minimal residual disease (MRD) negativity prior to infusion. Older patients were also more heavily pre-treated before infusion. All other patient characteristics at baseline were comparable between the two groups (Table 1). In the efficacy set (median follow-up 21.5mo; range 11.9-37.2; N=322), BOR of CR was 87.3% (95% CI 83.1-90.7); MRD status was available for 150 patients, of whom 98.7% were MRD negative. Median DOR was 23.9mo (95% CI 12.3-not estimable [NE]), median EFS was 14.0mo (9.8-24.8) and median RFS was 23.9mo (13.0-NE); 12mo EFS and RFS were 54.3% and 62.3%, respectively. For OS, the median was not reached. Efficacy outcomes were generally similar across age groups (Table 1). In the safety set (median follow-up 20.0mo; range 2.6-37.2; N=400), most AEs of interest occurred within 100 days of infusion. Any-grade CRS was observed in 58.0% of patients; Grade ≥3 in 17.8%. Treatment for CRS included tocilizumab (n=113; 28.3% of all patients) and corticosteroids (n=31; 7.8%). Neurotoxicity was observed in 27.3% of patients; Grade ≥3 in 10.0%. Treatment for neurotoxicity included tocilizumab (n=17; 4.3% of all patients) and corticosteroids (n=28; 7.0%). During the reporting period, 82 (20.5%) patients died; the most common cause of death was recurrence/persistence/progression of primary disease. CRS and chimeric antigen receptor (CAR)-T cell-related encephalopathy syndrome were the primary cause of death in 2 patients and 1 patient, respectively. Overall, safety data were similar across age groups, although more patients aged ≥18y experienced any-grade CRS or neurotoxicity and were subsequently treated (Table 1). Conclusions: Updated registry data for pediatric and young adult patients with R/R ALL treated with tisagenlecleucel revealed that patients aged ≥18y had a greater disease burden and were more heavily pre-treated at baseline than patients aged <18y. The overall efficacy and safety profiles of commercial tisagenlecleucel reflected those observed in the clinical trial setting [Grupp et al. Blood 2018; Rives et al. HemaSphere 2018] and were broadly consistent across age groups. Some important differences between the <18y and ≥18y groups were identified, which may point to challenges in timely identification and/or referral of older patients for CAR-T cell therapy. Figure 1 Figure 1. Disclosures Pulsipher: Equillium: Membership on an entity's Board of Directors or advisory committees; Adaptive: Research Funding; Jasper Therapeutics: Honoraria. Hu: Kite/Gilead: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Phillips: Novartis: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Margossian: Cue Biopharma, Inc.: Current Employment; Novartis: Other: Ad hoc Advisory Boards. Nikiforow: Kite/Gilead: Other: Ad hoc advisory boards; Novartis: Other: Ad hoc advisory boards; Iovance: Other: Ad hoc advisory boards; GlaxoSmithKline (GSK): Other: Ad hoc advisory boards. Martin: Novartis: Other: Local PI for clinical trial; Bluebird Bio: Other: Local PI for clinical trial. Rouce: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding; Pfizer: Consultancy. Tiwari: Novartis Healthcare private limited: Current Employment. Redondo: Novartis: Current Employment. Willert: Novartis: Current Employment. Agarwal: Novartis Pharmaceutical Corporation: Current Employment, Current holder of individual stocks in a privately-held company. Pasquini: Kite Pharma: Research Funding; GlaxoSmithKline: Research Funding; Novartis: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding. Grupp: Novartis, Roche, GSK, Humanigen, CBMG, Eureka, and Janssen/JnJ: Consultancy; Novartis, Kite, Vertex, and Servier: Research Funding; Novartis, Adaptimmune, TCR2, Cellectis, Juno, Vertex, Allogene and Cabaletta: Other: Study steering committees or scientific advisory boards; Jazz Pharmaceuticals: Consultancy, Other: Steering committee, Research Funding.

This case describes a patient with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome with diffuse eczematous dermatitis and severe, intractable pruritus. Despite a bone marrow transplant and immunosuppressive therapy, his skin findings and pruritus persisted. Off-label dupilumab provided significant improvement and almost complete clearance of the dermatitis and pruritus. This is the first known report of dupilumab being used in a patient with IPEX syndrome.