Hematopoietic stem cell transplantation for B-thalassemia major with alemtuzumab.

While matched related donor (MRD) allogeneic hematopoietic stem cell transplantation (HSCT) is a curative option for transfusion-dependent beta-thalassemia (TDT), the use of alternative sources has increased, resulting in the exploration of novel transplant-conditioning regimens to reduce the contribution of graft-versus-host disease (GVHD) and graft failure (GF) to transplant-related morbidity and mortality. Alemtuzumab is a CD52 monoclonal antibody that has been successfully incorporated into myeloablative conditioning regimens for other hematologic conditions, yet there have been limited studies regarding the use of alemtuzumab in HSCT for TDT. The purpose of this study was to evaluate engraftment, incidence of GVHD, and transplant related morbidity and mortality in patients with TDT who received alemtuzumab in addition to standard busulfan-based conditioning. The primary endpoint was severe GVHD-free, event-free survival (GEFS). Our cohort included 24 patients with a median age of 6.8 years (range 1.5-14.9). Eleven patients received a 10/10 MRD HSCT, eleven 10/10 unrelated donor (UD), and two mismatched UD. All patients achieved primary engraftment. For all patients, 5-year GEFS was 77.4% and 5-year overall survival (OS) was 91%. The 5-year cumulative incidence of GF (attributed to poor graft function) without loss of donor chimerism was 13.8% (95% CI: 4.5, 35.3). We report low rates of significant acute GVHD grade II-IV (12.5%) and chronic GVHD (4.4%). Younger age and MRD were associated with significantly improved GEFS, OS and EFS. Our results show that the use of alemtuzumab promotes stable engraftment, may reduce rates of severe GVHD, and results in acceptable GEFS, OS, and EFS.

Sickle cell disease: an international survey of results of HLA-identical sibling hematopoietic stem cell transplantation.

Despite advances in supportive therapy to prevent complications of sickle cell disease (SCD), access to care is not universal. Hematopoietic cell transplantation is, to date, the only curative therapy for SCD, but its application is limited by availability of a suitable HLA-matched donor and lack of awareness of the benefits of transplant. Included in this study are 1000 recipients of HLA-identical sibling transplants performed between 1986 and 2013 and reported to the European Society for Blood and Marrow Transplantation, Eurocord, and the Center for International Blood and Marrow Transplant Research. The primary endpoint was event-free survival, defined as being alive without graft failure; risk factors were studied using a Cox regression models. The median age at transplantation was 9 years, and the median follow-up was longer than 5 years. Most patients received a myeloablative conditioning regimen (n = 873; 87%); the remainder received reduced-intensity conditioning regimens (n = 125; 13%). Bone marrow was the predominant stem cell source (n = 839; 84%); peripheral blood and cord blood progenitors were used in 73 (7%) and 88 (9%) patients, respectively. The 5-year event-free survival and overall survival were 91.4% (95% confidence interval, 89.6%-93.3%) and 92.9% (95% confidence interval, 91.1%-94.6%), respectively. Event-free survival was lower with increasing age at transplantation (hazard ratio [HR], 1.09; P < .001) and higher for transplantations performed after 2006 (HR, 0.95; P = .013). Twenty-three patients experienced graft failure, and 70 patients (7%) died, with the most common cause of death being infection. The excellent outcome of a cohort transplanted over the course of 3 decades confirms the role of HLA-identical sibling transplantation for children and adults with SCD.

Current Allogeneic Hematopoietic Stem Cell Transplantation for Pediatric Acute Lymphocytic Leukemia: Success, Failure and Future Perspectives-A Single-Center Experience, 2008 to 2016.

Hematopoietic stem cell transplantation (HSCT) is the only curative option for a subset of patients with high-risk or relapsed acute lymphoblastic leukemia (ALL). Given evolving practices, it is important to continually evaluate outcomes for pediatric ALL following HSCT. Outcomes after HSCT are influenced by the type of donor used as this determines the degree and method of T cell depletion used and, consequently, specific transplant-related morbidities. We retrospectively analyzed HSCT data from our center for transplants performed between January 2008 and May 2016, comparing outcomes among different donor types. One hundred and twenty-four pediatric patients underwent HSCT from a matched sibling donor (MSD; n = 48), an unrelated matched donor (UMD; n = 56), or a haploidentical donor (n = 20). We observed a similar 3-year event-free survival (EFS) for MSD recipients (of .64) and for UMD recipients (.62), but a significantly lower EFS for recipients of haploidentical transplants (.35; P = .01). Relapse was the main cause of HSCT failure and was significantly higher in the haploidentical donor group (.47 versus .19 for MSD and .24 for UMD; P = .02). Treatment-related mortality was evenly distributed among the donor groups (.17, .16, and .15 for the MSD, UMD, and haploidentical groups, respectively). Rates of infection-related mortality were lower than previously reported. Relapse is the main obstacle for successful HSCT in the contemporary era, and this effect is most evident in recipients of haploidentical donor grafts. Newer methods to improve graft-versus-leukemia effect are being evaluated and will need to be incorporated into the management of high-risk patients.

Outcomes after Allogeneic Transplant in Patients with Wiskott-Aldrich Syndrome.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterized by a triad of immunodeficiency, eczema, and thrombocytopenia. Currently, hematopoietic stem cell transplantation (HSCT) is the most reliable curative treatment with excellent results for patients with HLA-matched family or unrelated donors. However, even after fully myeloablative preparative regimens, mixed donor chimerism is a potential concern. We performed a retrospective chart review of 12 children who underwent allogeneic HSCT for WAS to report our experience. The median age at transplant was 10.5 months (range, 3 to 39). The median nucleated cell dose from the marrow was 4.55 × 109/kg (range, .3 to 7.9). The median times to neutrophil and platelet engraftment were 19 days (range, 13 to 27) and 18.5 days (range, 12 to 31), respectively. The rate of overall survival was 92% with median follow-up of 67 months (range, 3 to 146). Two patients developed grade IV acute graft-versus-host disease, and 1 died on day +99. Five of 12 patient's (42%) had mixed donor chimerism (range, 12% to 85%) at day +180. None of the pretransplant patient parameters was predictive of mixed chimerism. Nonetheless, of these 5 patients, 2 had normalization of the platelet count despite the mixed chimerism, 2 had full donor chimerism after receiving a second transplant with the same donor, and 1 remains transfusion dependent awaiting a second transplant. Hence, even with a significant rate of mixed chimerism, HSCT provides substantial benefit to WAS patients, with excellent overall survival.

High Incidence of Autoimmune Disease after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease.

There is a lack of consensus regarding the role and method of hematopoietic stem cell transplantation (HSCT) on patients with chronic granulomatous disease (CGD). Long-term follow-up after HSCT in these patient population is essential to know its potential complications and decide who will benefit the most from HSCT. We report the outcome of HSCT and long-term follow-up in 24 patients with CGD, transplanted in our center from either related (n = 6) or unrelated (n = 18) donors, over a 12-year period (2003 to 2015), using high-dose alemtuzumab in the preparative regimen. We evaluated the incidence and timing of adverse events and potential risk factors. We described in detailed the novel finding of increased autoimmunity after HSCT in patients with CGD. At a median follow-up of 1460 days, 22 patients were full donor chimeras, and 2 patients had stable mixed chimerism. All assessable patients showed normalization of their neutrophil oxidative burst test. None of the patients developed grades II to IV acute graft-versus-host disease, and no patient had chronic graft-versus-host disease. Twelve of 24 patients developed 17 autoimmune diseases (ADs). Severe ADs (cytopenia and neuropathy) occurred exclusively in the unrelated donor setting and mainly in the first year after HSCT, whereas thyroid AD occurred in the related donor setting as well and more than 3 years after HSCT. Two patients died due to infectious complications after developing autoimmune cytopenias. One additional patient suffered severe brain injury. The remaining 21 patients have long-term Lansky scores ≥ 80. The outcome of HSCT from unrelated donors is comparable with related donors but might carry an increased risk of developing severe AD. A lower dose of alemtuzumab may reduce this risk and should be tested in further studies.

A trial of unrelated donor marrow transplantation for children with severe sickle cell disease.

Children with sickle cell disease experience organ damage, impaired quality of life, and premature mortality. Allogeneic bone marrow transplant from an HLA-matched sibling can halt disease progression but is limited by donor availability. A Blood and Marrow Transplant Clinical Trials Network (BMT CTN) phase 2 trial conducted from 2008 to 2014 enrolled 30 children aged 4 to 19 years; 29 were eligible for evaluation. The primary objective was 1-year event-free survival (EFS) after HLA allele-matched (at HLA-A, -B, -C, and -DRB1 loci) unrelated donor transplant. The conditioning regimen included alemtuzumab, fludarabine, and melphalan. Graft-versus-host disease (GVHD) prophylaxis included calcineurin inhibitor, short-course methotrexate, and methylprednisolone. Transplant indications included stroke (n = 12), transcranial Doppler velocity >200 cm/s (n = 2), ≥3 vaso-occlusive pain crises per year (n = 12), or ≥2 acute chest syndrome episodes (n = 4) in the 2 years preceding enrollment. Median follow-up was 26 months (range, 12-62 months); graft rejection was 10%. The 1- and 2-year EFS rates were 76% and 69%, respectively. The corresponding rates for overall survival were 86% and 79%. The day 100 incidence rate of grade II-IV acute GVHD was 28%, and the 1-year incidence rate of chronic GVHD was 62%; 38% classified as extensive. There were 7 GVHD-related deaths. A 34% incidence of posterior reversible encephalopathy syndrome was noted in the first 6 months. Although the 1-year EFS met the prespecified target of ≥75%, this regimen cannot be considered sufficiently safe for widespread adoption without modifications to achieve more effective GVHD prophylaxis. The BMT CTN #0601 trial was registered at www.clinicaltrials.gov as #NCT00745420.

Allogeneic hematopoietic cell transplant following crizotinib monotherapy for relapsed/refractory anaplastic large cell lymphoma.

Relapsed ALK-positive ALCL often is responsive to CRZ monotherapy. The subsequent role of allogeneic HCT after achieving second remission is poorly understood. We report 6 children who underwent allogeneic HCT for relapsed ALCL after CRZ. Age at transplant ranged from 10.7 to 22.6 years. Follow-up ranged from 0.9 to 4.5 years. All patients engrafted. Three of 4 patients that received a reduced-toxicity conditioning regimen containing fludarabine, alemtuzumab, and low-dose irradiation showed progressive mixed chimerism. Five patients remain in remission. One patient developed isolated CNS relapse 3.6 years after HCT despite a lack of previous CNS involvement. No acute transplant-related complications were experienced. One patient developed chronic renal disease secondary to transplant-associated microangiopathy and one patient chronic GVHD secondary to DLI. Ultimately, allogeneic HCT appears safe and potentially curative after remission induction with CRZ. The role of conditioning therapy, ablative or reduced intensity, remains uncertain for patients' post-CRZ monotherapy, and further studies may be warranted.

Long-term outcome after haploidentical stem cell transplant and infusion of T cells expressing the inducible caspase 9 safety transgene.

Adoptive transfer of donor-derived T lymphocytes expressing a safety switch may promote immune reconstitution in patients undergoing haploidentical hematopoietic stem cell transplant (haplo-HSCT) without the risk for uncontrolled graft versus host disease (GvHD). Thus, patients who develop GvHD after infusion of allodepleted donor-derived T cells expressing an inducible human caspase 9 (iC9) had their disease effectively controlled by a single administration of a small-molecule drug (AP1903) that dimerizes and activates the iC9 transgene. We now report the long-term follow-up of 10 patients infused with such safety switch-modified T cells. We find long-term persistence of iC9-modified (iC9-T) T cells in vivo in the absence of emerging oligoclonality and a robust immunologic benefit, mediated initially by the infused cells themselves and subsequently by an apparently accelerated reconstitution of endogenous naive T lymphocytes. As a consequence, these patients have immediate and sustained protection from major pathogens, including cytomegalovirus, adenovirus, BK virus, and Epstein-Barr virus in the absence of acute or chronic GvHD, supporting the beneficial effects of this approach to immune reconstitution after haplo-HSCT. This study was registered at www.clinicaltrials.gov as #NCT00710892.

Outcomes after Second Hematopoietic Stem Cell Transplantations in Pediatric Patients with Relapsed Hematological Malignancies.

Relapse of hematological malignancies after hematopoietic stem cell transplantation (HCT) is associated with poor prognosis. A second HCT represents one of the few therapeutic options for these high-risk patients. For children undergoing second HCT, the outcome data are particularly limited. We, therefore, conducted a retrospective single-institution study and report the outcomes and prognostic variables associated with overall survival (OS) and relapse in 43 pediatric patients who underwent a second HCT between 2000 and 2013. Eleven of the 43 patients who underwent transplantation remain alive and disease-free at a median follow-up of 49 months (range, 5 to 127 months). The 5-year probability of OS for the entire cohort was 24%. Patients who had early relapse (<6 months) after first HCT had significantly worse OS than those who relapsed late (>6 months), with 5-year OS at 11% versus 34%, respectively (hazard ratio [HR], 2.24; 95% confidence interval [CI], 1.21 to 4.93; P = .013). Active disease at time of second HCT was also associated with a significantly increased risk of relapse (subdistribution hazard ratio [SHR], 2.36; P = .049) for the entire cohort and relapse was the most frequent cause of death (23 of 32; 72%). On subgroup analysis for the 34 patients with leukemia alone, presence of active disease was associated both with a significant decrease in OS (SHR, 2.28; 95% CI, 1.02 to 5.09; P = .044) and significant increase in the rate of relapse (SHR, 2.46; P = .046). By contrast, underlying disease, donor source, conditioning regimen, or development of GVHD did not modify OS or rate of relapse. Hence, a second HCT appears to be a useful therapeutic option in children with relapsed hematological malignancies that is most likely to benefit those individuals with late onset of relapse and with low disease burden at the time of transplantation.

Safety and clinical efficacy of rapidly-generated trivirus-directed T cells as treatment for adenovirus, EBV, and CMV infections after allogeneic hematopoietic stem cell transplant.

Adoptive transfer of virus-specific T cells can prevent and treat serious infections with Epstein-Barr virus (EBV), cytomegalovirus (CMV), and adenovirus (Adv) after allogeneic hematopoietic stem cell transplant. It has, however, proved difficult to make this approach widely available since infectious virus and viral vectors are required for T cell activation, followed by an intensive and prolonged culture period extending over several months. We now show that T cells targeting a range of viral antigens derived from EBV, CMV, and Adv can be reproducibly generated in a single culture over a 2-3-week period, using methods that exclude all viral components and employ a much-simplified culture technology. When administered to recipients of haploidentical (n = 5), matched unrelated (n = 3), mismatched unrelated (n = 1) or matched related (n = 1) transplants with active CMV (n = 3), Adv (n = 1), EBV (n = 2), EBV+Adv (n = 2) or CMV+Adv (n = 2) infections, the cells produced complete virological responses in 80%, including all patients with dual infections. In each case, a decrease in viral load correlated with an increase in the frequency of T cells directed against the infecting virus(es); both immediate and delayed toxicities were absent. This approach should increase both the feasibility and applicability of T cell therapy. The trial was registered at www.clinicaltrials.gov as NCT01070797.

Monoculture-derived T lymphocytes specific for multiple viruses expand and produce clinically relevant effects in immunocompromised individuals.

Immunocompromised individuals are at high risk for life-threatening diseases, especially those caused by cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus. Conventional therapeutics are primarily active only against CMV, and resistance is frequent. Adoptive transfer of polyclonal cytotoxic T lymphocytes (CTLs) specific for CMV or EBV seems promising, but it is unclear whether this strategy can be extended to adenovirus, which comprises many serotypes. In addition, the preparation of a specific CTL line for each virus in every eligible individual would be impractical. Here we describe genetic modification of antigen-presenting cell lines to facilitate the production of CD4(+) and CD8(+) T lymphocytes specific for CMV, EBV and several serotypes of adenovirus from a single cell culture. When administered to immunocompromised individuals, the single T lymphocyte line expands into multiple discrete virus-specific populations that supply clinically measurable antiviral activity. Monoculture-derived multispecific CTL infusion could provide a safe and efficient means to restore virus-specific immunity in the immunocompromised host.

Excellent survival after sibling or unrelated donor stem cell transplantation for chronic granulomatous disease.

BACKGROUND: Matched related donor (MRD) hematopoietic stem cell transplantation (HSCT) is a successful treatment for chronic granulomatous disease (CGD), but the safety and efficacy of HSCT from unrelated donors is less certain. OBJECTIVE: We evaluated the outcomes and overall survival in patients with CGD after HSCT. METHODS: We report the outcomes for 11 children undergoing HSCT from an MRD (n = 4) or an HLA-matched unrelated donor (MUD) (n = 7); 9 children were boys, and the median age was 3.8 years (range, 1-13 years). We treated both X-linked (n = 9) and autosomal recessive (n = 2) disease. Nine children had serious clinical infections before transplantation. The conditioning regimens contained busulfan, cyclophosphamide, cytarabine, or fludarabine according to the donor used. All patients received alemtuzumab (anti-CD52 antibody). Additional graft-versus-host disease (GvHD) prophylaxis included cyclosporine and methotrexate for MUD recipients and cyclosporine and prednisone for MRD recipients. RESULTS: Neutrophil recovery took a median of 16 days (range, 12-40 days) and 18 days (range, 13-24 days) for MRD and MUD recipients, respectively. Full donor neutrophil engraftment occurred in 9 patients, and 2 had stable mixed chimerism; all patients had sustained correction of neutrophil oxidative burst defect. Four patients had grade I skin acute GVHD responding to topical treatment. No patient had grade II to IV acute GvHD or chronic GvHD. All patients are alive between 1 and 8 years after HSCT. CONCLUSION: For CGD, equivalent outcomes can be obtained with MRD or MUD stem cells, and HSCT should be considered an early treatment option.

Abatacept GVHD prophylaxis in unrelated hematopoietic cell transplantation for pediatric bone marrow failure.

Hematopoietic cell transplantation (HCT) is the only readily available cure for many life-threatening pediatric nonmalignant diseases (NMD), but most patients lack a matched related donor and are at higher risk for graft-versus-host disease (GVHD). Use of abatacept (Aba) to target donor T-cell activation has been safe and effective in preventing GVHD after unrelated donor (URD) HCT for malignant diseases (Aba2 trial). Our primary objective was to evaluate the tolerability of Aba added to standard GVHD prophylaxis (cyclosporine and mycophenolate mofetil) in pediatric patients with NMD undergoing URD HCT. In this single-arm, single-center phase 1 trial, 10 patients receiving reduced intensity or nonmyeloablative conditioning underwent URD HCT. Immune reconstitution was assessed longitudinally via flow cytometry and compared to pediatric patients on Aba2. Nine patients successfully engrafted, with 1 primary graft rejection in the setting of inadequate cell dose; secondary graft rejection occurred in 1 patient with concurrent cytomegalovirus viremia. Two deaths occurred, both unrelated to Aba. One patient developed probable posttransplant lymphoproliferative disease, responsive to rituximab and immune suppression withdrawal. No patients developed severe acute or chronic GVHD, and 8 patients were off systemic immunosuppression at 1 year. Immune reconstitution did not appear to be impacted by Aba, and preservation of naïve relative to effector memory CD4+ T cells was seen akin to Aba2. Thus, 4 doses of Aba were deemed tolerable in pediatric patients with NMD following URD HCT, with encouraging preliminary efficacy and supportive immune correlatives in this NMD cohort.

Short-Course Empiric Antibiotics in Children Undergoing Allogeneic Hematopoietic Cell Transplantation.

Fever is common in children undergoing hematopoietic cell transplantation (HCT). Empiric antibiotic (EA) therapy is initiated and often continued until neutrophil engraftment. Prolonged antibiotic exposure reduces microbiome diversity and causes overgrowth of pathogenic organisms, leading to such complications as infections from antibiotic-resistant organisms and Clostridium difficile colitis. Shorter courses of EA therapy have been studied in adults undergoing HCT without significant safety concerns, but data in children are lacking. We instituted a single-center preintervention/ postintervention quality improvement (QI) project to assess the feasibility of short-course EA therapy for first fever in patients undergoing HCT. We aimed to reduce the median duration of broad-spectrum antibiotic use in eligible patients from 20 days in 2020 to 10 days in 2021. Patients were eligible for the intervention, limiting EAs to 7 days for first fever, if they were admitted for their first allogeneic HCT, were afebrile for >24 hours, had no infection requiring systemic treatment, and were hemodynamically stable. Outcome measures included days of EA therapy for first fever and total broad-spectrum antibiotic use during the period of hospitalization, defined as the time from the start of conditioning to 30 days after HCT or hospital discharge, whichever occurred first. Balancing measures included bloodstream infection (BSI), fever, and intensive care (ICU) admission within 3 days of stopping EA therapy. Project criteria were applied retrospectively to patients who underwent HCT in 2020 to construct a preintervention short-course-eligible cohort. During the intervention period, 41 patients underwent allogeneic HCT, of whom 17 (41%) were eligible for short-course EA therapy. Among eligible patients, the median age was 5.3 years, 47% had an underlying malignancy, and 88% received myeloablative conditioning. There were no differences in demographic or HCT characteristics between patients eligible for short-course EA during the intervention and preintervention period (n = 24). The short-course EA schedule was adhered to by 14 of the 17 eligible patients (82%). The duration of EA for first fever and total broad-spectrum antibiotic use was significantly decreased in the short-course EA-eligible patients compared to the preintervention cohort, from a median of 17 days to 8 days and from 20 days to 10 days, respectively (P < .01). Of the 14 patients adhering to short-course EA, 2 experienced a balancing measure of recurrent fever requiring resumption of EA, but no infection was identified. There were no BSIs, ICU admissions, or deaths during the hospitalization period in patients who received short-course EA. In this single-center QI project, short-course EA for initial fever was successfully applied to children undergoing allogeneic HCT using strict criteria and led to a significant decrease in broad-spectrum antibiotic use during hospitalization. These results should be validated in a prospective clinical trial to include the impact of short-course EA on antibiotic-resistant organisms, the intestinal microbiome, and HCT outcomes.

BCMA CAR-T induces complete and durable remission in refractory plasmablastic lymphoma.

Plasmablastic lymphoma (PBL) is a rare subtype of aggressive large B-cell lymphoma, with a dismal prognosis despite aggressive therapies. New approaches are needed for those with refractory disease. PBL expresses antigens similar to multiple myeloma (MM), including B-cell maturation antigen (BCMA). Chimeric antigen receptor T-cell (CAR-T) therapy directed against BCMA has shown efficacy for the treatment of heavily pretreated MM with low rates of grades 3 and 4 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in a phase Ib/II trial (A Study of JNJ-68284528, a CAR-T Directed Against BCMA in Participants With Relapsed or Refractory Multiple Myeloma (CARTITUDE-1), NCT03548207). However, data for the use of BCMA CAR-T for treating PBL are lacking.We report a challenging case of multiple refractory PBL that emerged from B-cell acute lymphoblastic leukemia in an adolescent who failed to respond to an allogeneic hematopoietic cell transplant. The patient developed rapidly advancing disease despite withdrawal of immunosuppression, treatment with etoposide, ibrutinib, and daratumumab, prompting consideration of BCMA CAR-T (under emergency investigational new drug (eIND)). The patient achieved a complete remission (CR), without recurrent acute graft versus host disease (GVHD), CRS or ICANS after BCMA CAR-T therapy. BCMA CAR-T expansion was detected in vivo, peaking on day 15. The patient remains in CR for more than a year post CAR-T therapy, supporting consideration of immunotherapy for future patients with refractory PBL, a disease with few treatment options.

Cytotoxic T lymphocyte therapy with donor T cells prevents and treats adenovirus and Epstein-Barr virus infections after haploidentical and matched unrelated stem cell transplantation.

Viral infection or reactivation remains a major cause of morbidity and mortality after allogeneic stem cell transplantation. We now show that infusions of single cytotoxic T lymphocyte (CTL) lines (5 x 10(6)-1.35 x 10(8) cells/m(2)) with specificity for 2 commonly detected viruses, Epstein-Barr virus (EBV) and adenovirus, can be safely administered to pediatric transplantation recipients receiving partially human leukocyte antigen-matched and haploidentical stem cell grafts (n = 13), without inducing graft-versus-host disease. The EBV-specific component of the CTLs expanded in vivo and persisted for more than 12 weeks, but the adenovirus-specific component only expanded in vivo in the presence of concomitant adenoviral infection. Nevertheless, adenovirus-specific T cells could be detected for at least 8 weeks in peripheral blood, even in CTL recipients without viral infection, provided the adenovirus-specific component of their circulating lymphocytes was first expanded by exposure to adenoviral antigens ex vivo. After infusion, none of these 13 high-risk recipients developed EBV-associated lymphoproliferative disease, while 2 of the subjects had resolution of their adenoviral disease. Hence, bispecific CTLs containing both EBV- and adenovirus-specific T cells can safely reconstitute an antigen responsive "memory" population of CTLs after human leukocyte antigen-mismatched stem cell transplantation and may provide antiviral activity. This trial was registered at www.clinicaltrials.gov as #NCT00590083.

Defective mitochondrial peroxiredoxin-3 results in sensitivity to oxidative stress in Fanconi anemia.

Cells from patients with Fanconi anemia (FA), an inherited disorder that includes bone marrow failure and cancer predisposition, have increased sensitivity to oxidative stress through an unknown mechanism. We demonstrate that the FA group G (FANCG) protein is found in mitochondria. Wild-type but not G546R mutant FANCG physically interacts with the mitochondrial peroxidase peroxiredoxin-3 (PRDX3). PRDX3 is deregulated in FA cells, including cleavage by a calpainlike cysteine protease and mislocalization. FA-G cells demonstrate distorted mitochondrial structures, and mitochondrial extracts have a sevenfold decrease in thioredoxin-dependent peroxidase activity. Transient overexpression of PRDX3 suppresses the sensitivity of FA-G cells to H2O2, and decreased PRDX3 expression increases sensitivity to mitomycin C. Cells from the FA-A and -C subtypes also have PRDX3 cleavage and decreased peroxidase activity. This study demonstrates a role for the FA proteins in mitochondria witsh sensitivity to oxidative stress resulting from diminished peroxidase activity. These defects may lead to apoptosis and the accumulation of oxidative DNA damage in bone marrow precursors.

Children with acute leukemia: a comparison of outcomes from allogeneic blood stem cell and bone marrow transplantation.

BACKGROUND: The relative merits of peripheral blood stem-cell transplantation (PBSCT) versus bone marrow transplantation (BMT) for children with standard and high-risk hematologic malignancies remain unclear. In a retrospective study, we compared allogeneic PBSCT (n = 30) with BMT (n = 110) in children with acute leukemia between January 2001 and September 2006. PROCEDURE: Median age for PBSCT was 9 years versus 8 years for BMT. Descriptive statistics were used to summarize the demographic and medical variables. The unadjusted probabilities of disease-free survival were estimated using the Kaplan-Meier method. The association of graft-source and time to each of the study endpoints was estimated by Cox's regression model and the occurrence of graft-versus-host disease (GvHD) was included as a time-dependent covariate. RESULTS: Time to neutrophil engraftment and platelet independence was faster after PBSCT than BMT (neutrophils 15.0 days vs. 17.0 days, P < 0.001; platelets, 21.0 days vs. 27.0 days, P = 0.034). The cumulative incidence of grades II-IV acute GvHD at 100 days was 10.4% (SE 5.6%) after PBSCT and 15.1% (SE 3.5%) after BMT (P = NS). The cumulative incidence of chronic GvHD was 13.8% (SE 6.3%) after PBSCT and 11.3% (SE 3.1%) after BMT (P = NS). One-year disease-free survival was 37.9% (SE 9.0%) for PBSCT recipients versus 65.1% (SE 4.6%) after BMT (P = 0.005) but this difference was not sustained in multivariate analysis. Thus, only disease risk and pre-transplant CMV seropositivity were significant predictors of disease-free survival. CONCLUSIONS: We conclude that PBSCT for children produces faster engraftment without increased risk of acute or chronic GvHD.

Matched related hematopoietic cell transplant for sickle cell disease with alemtuzumab: the Texas Children's Hospital experience.

Serotherapeutic agents facilitate engraftment and prevent graft-versus-host disease (GVHD) following hematopoietic stem cell transplant. Anti-thymocyte globulin is generally added to conditioning chemotherapy for matched related donor transplant (MRD-HCT) for sickle cell disease (SCD). Alemtuzumab, however, is appealing due to its broad lymphocyte killing that may achieve very low rejection and GVHD rates. To assess the impact of alemtuzumab in MRD-HCT for SCD, we retrospectively reviewed transplant-related outcomes and markers of immunity in 38 consecutive patients at Texas Children's Hospital having received myeloablative conditioning with alemtuzumab. Median follow-up was 4.8 years (range: 0.2-17). All patients engrafted. Donor chimerism was mixed in 47.1% of patients at ≥2-years. Donor chimerism <50% was uncommon (n = 2). One patient with low myeloid chimerism (19%) had sickle-related hemolysis at 10-years. Incidence of acute GVHD grade II-IV (5.3%) and extensive chronic GVHD (2.8%) was very low. Five-year event-free survival (EFS) and composite chronic GVHD-EFS were excellent at 94.7% (95% CI: 80.3, 98.6) and 89.2% (95% CI: 73.7, 95.8), respectively. Infections did not contribute to mortality although cytomegalovirus reactivation occurred commonly in the first 3 months after transplant. Our data suggest potential for alemtuzumab in myeloablative transplant for children with SCD although further evaluation in older patients and with unrelated donors is warranted.