Outcomes after Second Hematopoietic Cell Transplantation in Children and Young Adults with Relapsed Acute Leukemia

Children with acute leukemia who relapse after hematopoietic cell transplantation (HCT) have few therapeutic options. We studied 251 children and young adults with acute myelogenous or lymphoblastic leukemia who underwent a second HCT for relapse after their first HCT. The median age at second HCT was 11 years, and the median interval between first and second HCT was 17 months. Most of the patients (n = 187; 75%) were in remission, received a myeloablative conditioning regimen (n = 157; 63%), and underwent unrelated donor HCT (n = 230; 92%). The 2-year probability of leukemia-free survival (LFS) was 33% after transplantation in patients in remission, compared with 19% after transplantation in patients not in remission (P = .02). The corresponding 8-year probabilities were 24% and 10% (P = .003). A higher rate of relapse contributed to the difference in LFS. The 2-year probability of relapse after transplantation was 42% in patients in remission and 56% in those in relapse (P = .05). The corresponding 8-year probabilities were 49% and 64% (P = .04). These data extend the findings of others showing that patients with a low disease burden are more likely to benefit from a second transplantation. Late relapse led to a 10% decrement in LFS beyond the second year after second HCT. This differs from first HCT, in which most relapses occur within 2 years after HCT.

Filtered sunlight versus intensive electric powered phototherapy in moderate-to-severe neonatal hyperbilirubinaemia: a randomised controlled non-inferiority trial

BACKGROUND

Kernicterus resulting from severe neonatal hyperbilirubinaemia is a leading cause of preventable deaths and disabilities in low-income and middle-income countries, partly because high-quality intensive phototherapy is unavailable. Previously, we showed that filtered-sunlight phototherapy (FSPT) was efficacious and safe for treatment of mild-to-moderate neonatal hyperbilirubinaemia. We aimed to extend these studies to infants with moderate-to-severe hyperbilirubinaemia.

METHODS

We did a prospective, randomised controlled non-inferiority trial in Ogbomoso, Nigeria-a simulated rural setting. Near-term or term infants aged 14 days or younger who were of 35 weeks or more gestational age and with total serum bilirubin concentrations at or above the recommended age-dependent treatment levels for high-risk neonates were randomly assigned (1:1) to either FSPT or intensive electric phototherapy (IEPT). Randomisation was computer-generated, and neither clinicians nor the parents or guardians of participants were masked to group allocation. FSPT was delivered in a transparent polycarbonate room lined with commercial tinting films that transmitted effective phototherapeutic light, blocked ultraviolet light, and reduced infrared radiation. The primary outcome was efficacy, which was based on assessable treatment days only (ie, those on which at least 4 h of phototherapy was delivered) and defined as a rate of increase in total serum bilirubin concentrations of less than 3·4 μmol/L/h in infants aged 72 h or younger, or a decrease in total serum bilirubin concentrations in those older than 72 h. Safety was defined as no sustained hypothermia, hyperthermia, dehydration, or sunburn and was based on all treatment days. Analysis was by intention to treat with a non-inferiority margin of 10%.

FINDINGS

Between July 31, 2015, and April 30, 2017, 174 neonates were enrolled and randomly assigned: 87 to FSPT and 87 to IEPT. Neonates in the FSPT group received 215 days of phototherapy, 82 (38%) of which were not assessable. Neonates in the IEPT group received 219 treatment days of phototherapy, 67 (31%) of which were not assessable. Median irradiance was 37·3 μW/cm²/nm (IQR 21·4-56·4) in the FSPT group and 50·4 μW/cm²/nm (44·5-66·2) in the IEPT group. FSPT was efficacious on 116 (87·2%) of 133 treatment days; IEPT was efficacious on 135 (88·8%) of 152 treatment days (mean difference -1·6%, 95% CI -9·9 to 6·7; p=0·8165). Because the CI did not extend below -10%, we concluded that FSPT was not inferior to IEPT. Treatment was safe for all neonates.

INTERPRETATION

FSPT is safe and no less efficacious than IEPT for treatment of moderate-to-severe neonatal hyperbilirubinaemia in near-term and term infants.

FUNDING

Thrasher Research Fund and National Center for Advancing Translational Sciences.

Assessment of blood levels of heavy metals including lead and manganese in healthy children living in the Katanga settlement of Kampala, Uganda

Background

Exposure to environmental heavy metals is common among African children. Although many of these metals are known neurotoxicants, to date, monitoring of this exposure is limited, even in countries such as Uganda that are undergoing rapid industrialization. An assessment of the burden and potential causes of metal exposure is a critical first step in gauging the public health burden of metal exposure and in guiding its elimination.

Methods

In May 2016, we enrolled 100 children between the ages of 6 and 59 months living in the Katanga urban settlement of Kampala, Uganda. We measured whole blood concentrations of antimony, arsenic, barium, cadmium, cesium, chromium, cobalt, copper, lead, manganese, nickel, selenium, and zinc. Applying reference cutoffs, we identified metals whose prevalence of elevated blood concentrations was > 10%. We also administered an environmental questionnaire to each child’s caregiver to assess potential exposures, including source of drinking water, cooking location and fuel, materials used for roof, walls, and floor, and proximity to potential pollution sources such as main roads, garbage landfills, and fuel stations. We compared log-transformed blood metal concentrations by exposure category, using t-test for dichotomous comparisons and ANOVA for comparisons of three categories, using Tukeys test to adjust for multiple comparisons.

Results

The prevalence of high blood levels was elevated for six of the metals: antimony (99%), copper (12%), cadmium (17%), cobalt (19.2%), lead (97%), and manganese (36.4%). Higher blood manganese was significantly associated with having cement walls (p = 0.04) or floors (p = 0.04). Cadmium was greater among children who attended school (< 0.01), and cobalt was higher among children who lived near a garbage landfill (p = 0.01).

Conclusions

Heavy metal exposure is prevalent in the Katanga settlement and may limit neurodevelopment of children living there. Future studies are needed to definitively identify the sources of exposure and to correct potential nutritional deficiencies that may worsen metal absorption.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5589-0) contains supplementary material, which is available to authorized users.

Abnormal polyamine metabolism is unique to the neuropathic forms of MPS: potential for biomarker development and insight into pathogenesis

The mucopolysaccharidoses (MPS) are rare genetic disorders marked by severe somatic and neurological symptoms. Development of treatments for the neurological manifestations of MPS has been hindered by the lack of objective measures of central nervous system disease burden. Identification of biomarkers for central nervous system disease in MPS patients would facilitate the evaluation of new agents in clinical trials. High throughput metabolite screening of cerebrospinal fluid (CSF) samples from a canine model of MPS I revealed a marked elevation of the polyamine, spermine, in affected animals, and gene therapy studies demonstrated that reduction of CSF spermine reflects correction of brain lesions in these animals. In humans, CSF spermine was elevated in neuropathic subtypes of MPS (MPS I, II, IIIA, IIIB), but not in subtypes in which cognitive function is preserved (MPS IVA, VI). In MPS I patients, elevated CSF spermine was restricted to patients with genotypes associated with CNS disease and was reduced following hematopoietic stem cell transplantation, which is the only therapy currently capable of improving cognitive outcomes. Additional studies in cultured neurons from MPS I mice showed that elevated spermine was essential for the abnormal neurite overgrowth exhibited by MPS neurons. These findings offer new insights into the pathogenesis of CNS disease in MPS patients, and support the use of spermine as a new biomarker to facilitate the development of next generation therapeutics for MPS.

Post-transplant adaptive function in childhood cerebral adrenoleukodystrophy

Objective

Hematopoietic stem cell transplantation (HSCT) is the only treatment known to slow or halt inflammatory demyelination among boys with the cerebral form of X‐linked adrenoleukodystrophy (cALD), a devastating childhood condition affecting the central nervous system. HSCT can lead to a range of adverse outcomes including fatality. Previous studies have examined the potential predictors of post‐HSCT survival and neurologic functioning. However, little is known about patients' daily‐life adaptive functional outcomes (i.e., ability to communicate, maintain social relationships, and independently execute tasks of daily living). The purpose of this retrospective cohort study was to identify which patient characteristics and treatment‐related variables predict long‐term adaptive function among the survivors of HSCT for cALD.

Methods

We obtained caregiver ratings of adaptive functioning of 65 transplant survivors at an average of 4.6 years (range: 1.0–24.1 years) post‐HSCT. Using linear regression with penalized maximum likelihood estimation, we modeled the relative contribution of pre‐transplant neurocognitive test performance, MRI severity, transplant regimen, and length of time since transplant on patient adaptive functioning outcomes.

Results

Higher radiographic disease severity and poorer performance on baseline neurocognitive tests requiring fine motor skills and visual perception were associated with inferior adaptive functioning after HSCT. Use of radiation during the transplant preparative regimen also predicted poorer adaptive outcomes.

Interpretation

In addition to radiological disease severity, baseline neurocognitive test performance is associated with post‐transplant adaptive functional outcomes. Neurocognitive measures may play an important role in prognostic counseling and post‐transplant treatment planning for patients considering HSCT for cALD.

Hematopoietic Stem-Cell Gene Therapy for Cerebral Adrenoleukodystrophy

BACKGROUND

In X-linked adrenoleukodystrophy, mutations in ABCD1 lead to loss of function of the ALD protein. Cerebral adrenoleukodystrophy is characterized by demyelination and neurodegeneration. Disease progression, which leads to loss of neurologic function and death, can be halted only with allogeneic hematopoietic stem-cell transplantation.

METHODS

We enrolled boys with cerebral adrenoleukodystrophy in a single-group, open-label, phase 2-3 safety and efficacy study. Patients were required to have early-stage disease and gadolinium enhancement on magnetic resonance imaging (MRI) at screening. The investigational therapy involved infusion of autologous CD34+ cells transduced with the elivaldogene tavalentivec (Lenti-D) lentiviral vector. In this interim analysis, patients were assessed for the occurrence of graft-versus-host disease, death, and major functional disabilities, as well as changes in neurologic function and in the extent of lesions on MRI. The primary end point was being alive and having no major functional disability at 24 months after infusion.

RESULTS

A total of 17 boys received Lenti-D gene therapy. At the time of the interim analysis, the median follow-up was 29.4 months (range, 21.6 to 42.0). All the patients had gene-marked cells after engraftment, with no evidence of preferential integration near known oncogenes or clonal outgrowth. Measurable ALD protein was observed in all the patients. No treatment-related death or graft-versus-host disease had been reported; 15 of the 17 patients (88%) were alive and free of major functional disability, with minimal clinical symptoms. One patient, who had had rapid neurologic deterioration, had died from disease progression. Another patient, who had had evidence of disease progression on MRI, had withdrawn from the study to undergo allogeneic stem-cell transplantation and later died from transplantation-related complications.

CONCLUSIONS

Early results of this study suggest that Lenti-D gene therapy may be a safe and effective alternative to allogeneic stem-cell transplantation in boys with early-stage cerebral adrenoleukodystrophy. Additional follow-up is needed to fully assess the duration of response and long-term safety. (Funded by Bluebird Bio and others; STARBEAM ClinicalTrials.gov number, NCT01896102 ; ClinicalTrialsRegister.eu number, 2011-001953-10 .).

Dermatopontin in Bone Marrow Extracellular Matrix Regulates Adherence but Is Dispensable for Murine Hematopoietic Cell Maintenance

The hematopoietic marrow microenvironment is composed of multiple cell types embedded in an extracellular matrix (ECM). We have explored marrow ECM using mass spectrometry and found dermatopontin (DPT), a small non-collagenous ECM protein, to be present. We found that DPT cooperates with other ECM proteins to promote hematopoietic cell adherence in vitro on plastic as well as OP9 stromal cells. We generated constitutional DPT^−/− mice that were viable and had no peripheral lympho-hematopoietic abnormalities. The composition of the marrow of wild-type and DPT^−/− mice was equivalent in terms of cellularity, CFU-C, LSK (Lineage⁻, SCA-1⁺, KIT⁺), and LSK-SLAM (LSK, CD48⁻, CD150⁺) frequencies. These data suggest that DPT fosters adherence but is not required for steady-state hematopoiesis in vivo. There are likely overlapping cellular adhesion mechanisms that can compensate to maintain the hematopoietic niche in the absence of DPT.

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Murine marrow can be decellularized to reveal the ECM

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Dermatopontin is a component of the marrow ECM

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DPT can promote HSPC adherence in vitro

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DPT is dispensable for native hematopoiesis

TP53 Modulates Oxidative Stress in Gata1+ Erythroid Cells

Metabolism of oxidative stress is necessary for cellular survival. We have previously utilized the zebrafish as a model of the oxidative stress response. In this study, we found that gata1-expressing erythroid cells contributed to a significant proportion of total-body oxidative stress when animals were exposed to a strong pro-oxidant. RNA-seq of zebrafish under oxidative stress revealed the induction of tp53. Zebrafish carrying tp53 with a mutation in its DNA-binding domain were acutely sensitive to pro-oxidant exposure and displayed significant reactive oxygen species (ROS) and tp53-independent erythroid cell death resulting in an edematous phenotype. We found that a major contributing factor to ROS was increased basal mitochondrial respiratory rate without reserve. These data add to the concept that tp53, while classically a tumor suppressor and cell-cycle regulator, has additional roles in controlling cellular oxidative stress.

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Erythroid precursors contribute significantly to total ROS after oxidative challenge

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Tp53 is induced after pro-oxidant challenge

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Mutated tp53 is associated with an increased mitochondrial oxygen consumption rate

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Decreased mitochondrial reserve leads to overwhelming ROS and erythroid cell death

A Functional Bioluminescent Zebrafish Screen for Enhancing Hematopoietic Cell Homing

To discover small molecules that modulate hematopoietic cell homing after adoptive transfer, we created a transgenic zebrafish expressing firefly luciferase downstream of the ubiquitin promoter (ubi:luc) to serve as a hematopoietic donor. Bioluminescence imaging (BLI) was used to detect and follow ubi:luc hematopoietic cells that homed to the marrow as early as 1 day post-transplant. BLI was able to detect the biological effect of prostaglandin E₂ on early homing/engraftment of donor hematopoietic cells. This system was utilized in a functional screen of small molecules to enhance homing/engraftment. We discovered a phytosterol, ergosterol, that could increase hematopoietic cell homing in zebrafish and mice. In addition, ergosterol increased CXCR4 expression and promoted expansion of Lin⁻SCA-1⁺KIT⁺ cells in vitro. We have demonstrated the utility of in vivo BLI to non-invasively monitor donor hematopoietic cell activity in adult zebrafish as a functional screen for mediators of cellular homing.

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Bioluminescent imaging (BLI) can track engrafting hematopoietic cells

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BLI can be used for screening of enhancers of hematopoietic cell homing

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Using BLI, ergosterol was found to increase hematopoietic cell homing

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Ergosterol affects hematopoietic progenitor migration, growth, and viability in vitro

Elevated cerebral spinal fluid biomarkers in children with mucopolysaccharidosis I-H

Mucopolysaccharidosis (MPS) type-IH is a lysosomal storage disease that results from mutations in the IDUA gene causing the accumulation of glycosaminoglycans (GAGs). Historically, children with the severe phenotype, MPS-IH (Hurler syndrome) develop progressive neurodegeneration with death in the first decade due to cardio-pulmonary complications. New data suggest that inflammation may play a role in MPS pathophysiology. To date there is almost no information on the pathophysiologic changes within the cerebral spinal fluid (CSF) of these patients. We evaluated the CSF of 25 consecutive patients with MPS-IH. While CSF glucose and total protein were within the normal range, we found a significantly mean elevated CSF opening pressure at 24 cm H₂O (range 14–37 cm H₂O). We observed a 3-fold elevation in CSF heparan sulfate and a 3–8 fold increase in MPS-IH specific non-reducing ends, I0S0 and I0S6. Cytokine analyses in CSF of children with MPS-IH showed significantly elevated inflammatory markers including: MCP-1 SDF-1a, IL-Ra, MIP-1b, IL-8, and VEGF in comparison to unaffected children. This is the largest report of CSF characteristics in children with MPS-IH. Identification of key biomarkers may provide further insight into the inflammatory-mediated mechanisms related to MPS diseases and perhaps lead to improved targeted therapies.

Allele-Level HLA Matching Impacts Key Outcomes Following Umbilical Cord Blood Transplantation for Inherited Metabolic Disorders

Allogeneic hematopoietic stem cell transplantation has demonstrated efficacy for numerous inherited metabolic disorders (IMDs). Umbilical cord blood transplant (UCBT) is increasingly used as a graft source in IMDs, but little is known of the impact of cord blood unit (CBU)/recipient HLA allelic disparity on key outcomes following UCBT for IMD. We reviewed outcomes of 106 consecutive first, single UCBTs for IMD at the University of Minnesota with regard to CBU/recipient HLA allelic matching (HLA-A, -B, -C, and -DRB1). The median age at UCBT was 1 year, and 87 patients (82%) received myeloablative conditioning. Primary diagnoses were Hurler syndrome (41%), cerebral adrenoleukodystrophy (35%), metachromatic leukodystrophy/globoid cell leukodystrophy (9%), and other (16%). The 5-year overall survival (OS) for the entire cohort was 70% (95% confidence interval, 59% to 79%). Rates of severe acute and chronic graft-versus-host disease were low (6% for each). CBU/recipient HLA conventional matching was based on antigen-level matching at HLA-A and -B, and on allele-level matching at HLA-DRB1. Of 46 conventional matched UCBTs, 20 (43%) were mismatched at 1 or more alleles. Of 49 conventional 5/6 UCBTs, 30 (61%) were mismatched at ≥2 alleles and 19 (39%) were mismatched at ≥3 alleles. Within the 6/6 conventional match stratum, comparisons of key outcomes between allele-matched and allele-mismatched UCBT were as follows: 5-year OS, 88% versus 42% (P < .01); 1-year engrafted survival (ES) with ≥90% donor chimerism, 73% versus 60% (P = .33); graft failure, 8% versus 30% (P = .05); and transplantation-related mortality (TRM), 8% versus 30% (P = .04). For patients undergoing conventional 5/6 HLA-matched UCBT, better allelic matching was associated with similar outcomes: 5-year OS, 77% versus 74% (P = .72); 1-year ES, 73% versus 47% (P = .06); graft failure, 17% versus 42% (P = .05); and TRM, 10% versus 16% (P = .54). On multivariable analyses, fewer allele-level mismatches within each conventional match stratum continued to predict more favorable outcomes following UCBT. These data provide evidence that allele-level HLA matching considerations within a conventional HLA match stratum may better predict outcomes of interest after UCBT for IMD. Larger studies are warranted to confirm these findings and explore other allele-level HLA match dynamics.

CD4+ T Cells Coexpressing CD134 (OX40) Harbor Significantly Increased Levels of Human Herpesvirus 6B DNA Following Umbilical Cord Blood Transplantation

Human herpesvirus 6B (HHV-6B) commonly reactivates after umbilical cord blood transplantation (UCBT) and is associated with delayed engraftment, fever, rash, and central nervous system dysfunction. Recently, CD134 (OX40) has been implicated as a potential viral entry receptor. We evaluated CD4⁺CD134⁺/^neg-lo and CD8⁺CD134⁺/^neg-lo cells at day 28 after UCBT in 20 subjects with previously documented HHV-6 reactivation and persistent viremia. Analysis of CD4⁺CD134⁺ cells as compared to CD4⁺CD134^neg-lo cells showed 0.308 versus 0.129 copies of HHV-6B/cell (P = .0002). CD8⁺CD134^+/neg-lo cells contained little to no HHV-6B copies. Following UCBT, CD4⁺CD134⁺ cells harbor significantly increased levels of HHV-6B, suggesting that CD134 (OX40) may facilitate viral entry.

Cerebral Spinal Fluid levels of Cytokines are elevated in Patients with Metachromatic Leukodystrophy

Metachromatic leukodystrophy (MLD) is a lysosomal storage disease resulting from a deficiency of arylsulfatase A causing an accumulation of cerebroside sulfate, a lipid normally abundant in myelin. Sulfatide accumulation is associated with progressive demyelination and a clinical presentation in severe disease forms that is dominated by motor manifestations. Cerebral inflammation may contribute to the pathophysiology of MLD. To date, cytokine levels in the cerebral spinal fluid of MLD patients have not previously been reported. The objective of this study was to evaluate the concentration of inflammatory cytokines in the CSF of patients with MLD and to compare these levels to unaffected controls. Of 22 cytokines evaluated, we documented significant elevations of MCP-1, IL-1Ra, IL-8, MIP-1b and VEGF in the MLD patients compared to unaffected controls. The elevated cytokines identified in this study may play a significant role in the pathophysiology of MLD. Better understanding of the inflammatory and neurodegenerative process of MLD may lead to improved targeted therapies.

Progression of Hip Dysplasia in Mucopolysaccharidosis Type I Hurler After Successful Hematopoietic Stem Cell Transplantation

BACKGROUND

Dysostosis multiplex contributes substantially to morbidity in patients with Hurler syndrome (mucopolysaccharidosis type I Hurler phenotype [MPS I-H]), even after successful hematopoietic stem cell transplantation (HSCT). One of the hallmarks of dysostosis multiplex in MPS I-H is hip dysplasia, which often requires surgical intervention. We sought to describe in detail the course of hip dysplasia in this group of patients, as assessed by radiographic analysis, and to identify potential outcome predictors.

METHODS

Longitudinal data were obtained from digitally scored pelvic radiographs of patients with MPS I-H using OrthoGon software for parameters including, but not limited to, the acetabular index, migration percentage, Smith ratio, and neck-shaft angle. Scoring was performed independently by two blinded observers. Additional information on genotype, enzyme replacement therapy pre-HSCT, donor chimerism, and enzyme activity post-HSCT were obtained. General trends and potential correlations were calculated with mixed-model statistics.

RESULTS

Fifty-two patients (192 radiographs) were included in this analysis. Intraobserver and interobserver variation analysis showed an intraclass correlation coefficient ranging from 0.78 to 1.00. Among the twenty-one patients with follow-up beyond the age of five years, the acetabular index was in the range of severe hip dysplasia in up to 86% of the patients. Severe coxa valga was seen in 91% of the patients. Lateral and superior femoral displacement were highly prevalent, with the migration percentage outside the reference range in up to 96% of the patients. Finally, anterior pelvic tilt increased with age (p = 0.001). No correlations were identified between clinical parameters and radiographic findings.

CONCLUSIONS

Our study shows that progressive acetabular dysplasia as well as coxa valga and hip displacement are highly prevalent and progressive over time in patients with MPS I-H, despite successful HSCT. These data may provide essential natural history determinations for the assessment of efficacy of new therapeutic strategies aimed at improving skeletal outcomes in patients with MPS I-H.

Quantitative Proteomics of Vestibular Schwannoma Cerebrospinal Fluid

This pilot study aimed to identify candidate proteins for future study that are differentially expressed in vestibular schwannoma (VS) cerebrospinal fluid (CSF) and to compare such proteins with those previously identified in perilymph and specimen secretions. CSF was collected intraoperatively prior to removal of untreated sporadic VS (3 translabyrinthine, 3 middle cranial fossa approaches) and compared with reference CSF samples. After proteolytic digestion and iTRAQ labeling, tandem mass spectrometry with ProteinPilot was used to identify candidate proteins. Of the 237 proteins detected, 13 were dysregulated in ≥3 of the 6 VS patients versus controls, and 13 were dysregulated (12 up, 1 down) in samples from patients with class D versus class B hearing. Four perilymph proteins of interest were dysregulated in ≥1 VS CSF samples. Thus, 26 candidate VS CSF biomarkers were identified that should be considered in future VS biomarker and tumor pathophysiology investigations.

Fatal Myocarditis Associated With HHV-6 Following Immunosuppression in Two Children

Fatal myocarditis is a rare complication in immunosuppressed children. Recent reports have linked human herpesvirus 6 (HHV-6) infection, typically a benign infection in childhood, with myocarditis. HHV-6 can reactivate during periods of immunosuppression. Here, we report 2 cases in which children were immunosuppressed, one for treatment of Evans syndrome and the other post hematopoietic stem cell transplantation, who developed rapid and fatal HHV-6-associated myocarditis. These cases suggest that HHV-6 infection should be considered as an etiology of myocarditis in immunosuppressed patients regardless of correlating blood levels. Early treatment of HHV-6 in patients with myocarditis could improve morbidity and mortality.

Evaluation of TCR Gene Editing Achieved by TALENs, CRISPR/Cas9, and megaTAL Nucleases

Present adoptive immunotherapy strategies are based on the re-targeting of autologous T-cells to recognize tumor antigens. As T-cell properties may vary significantly between patients, this approach can result in significant variability in cell potency that may affect therapeutic outcome. More consistent results could be achieved by generating allogeneic cells from healthy donors. An impediment to such an approach is the endogenous T-cell receptors present on T-cells, which have the potential to direct dangerous off-tumor antihost reactivity. To address these limitations, we assessed the ability of three different TCR-α-targeted nucleases to disrupt T-cell receptor expression in primary human T-cells. We optimized the conditions for the delivery of each reagent and assessed off-target cleavage. The megaTAL and CRISPR/Cas9 reagents exhibited the highest disruption efficiency combined with low levels of toxicity and off-target cleavage, and we used them for a translatable manufacturing process to produce safe cellular substrates for next-generation immunotherapies.

Second allogeneic hematopoietic cell transplantation for graft failure: poor outcomes for neutropenic graft failure

Graft failure (GF) after hematopoietic cell transplant (HCT) occurs in 5-30% of patients. GF can be accompanied by neutropenia (NGF) or can result with adequate neutrophils, but loss of donor chimerism (non-neutropenic graft failure, NNGF). In this report, we describe the outcomes of 95 patients treated with a second HCT for GF at the University of Minnesota; 62 with NGF and 33 with NNGF. The cumulative incidence of neutrophil recovery at 42 days after second HCT was 45% for NGF and 88% for NNGF. A second GF occurred in 34 NGF (55%) and in 9 NNGF (27%) patients. The incidence of Grade III-IV acute graft versus host disease (GVHD) was 8% (95% confidence interval (CI), 1-16%) and 12% (95% CI, 1-23%) for NGF and NNGF, respectively. From the 2nd HCT, 1-year overall survival (OS) was 44% (95% CI, 34-54%), [NNGF: 76% (95% CI, 57-87%) and NGF: 27% (95% CI, 17-39%)]. The most common cause of death after second HCT was infection (52%). In summary, the outcomes of second HCT after NGF and NNGF are different with much worse outcomes for NGF necessitating new approaches for this complication.

Second Allogeneic Hematopoietic Cell Transplantation for Patients with Fanconi Anemia and Bone Marrow Failure

A second allogeneic hematopoietic cell transplantation (HCT) is the sole salvage option for individuals who develop graft failure after their first HCT. Data on outcomes after second HCT in patients with Fanconi anemia (FA) are scarce. Here we report outcomes after second allogeneic HCT for FA (n = 81). The indication for second HCT was graft failure after the first HCT. Transplantations were performed between 1990 and 2012. The timing of the second HCT predicted subsequent graft failure and survival. Graft failure was high when the second HCT was performed less than 3 months from the first. The 3-month probability of graft failure was 69% when the interval between the first HCT and second HCT was less than 3 months, compared with 23% when the interval was longer (P < .001). Consequently, the 1-year survival rate was substantially lower when the interval between the first and second HCTs was less than 3 months compared with longer (23% vs 58%; P = .001). The corresponding 5-year probability of survival was 16% and 45%, respectively (P = .006). Taken together, these data suggest that fewer than one-half of patients with FA undergoing a second HCT for graft failure are long-term survivors. There is an urgent need to develop strategies to reduce the rate of graft failure after first HCT.