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Delirium is common among adults undergoing hematopoietic stem cell transplantation (HCT), although the clinical and neuroimaging correlates of post-HCT delirium have not been adequately delineated. We therefore examined the frequency of delirium and neuroimaging correlates of post-transplant delirium in a retrospective cohort of 115 adults undergoing neuroimaging after allogeneic HCT. Delirium was established using previously validated methods for retrospective identification of chart-assessed postprocedural delirium. Chart reviews were independently conducted by a multidisciplinary team with expertise in HCT, psychiatry, and psychology on consecutive allogeneic HCT patients who underwent neuroimaging assessments and transplantation at a single center between January 2009 and December 2016. Neuroimaging markers of white matter damage and brain volume loss were also recorded. In total, 115 patients were included, ranging in age from 20 to 74 years (mean [SD] age, 49 [13]). Fifty-three patients (46%) developed post-HCT delirium. In an adjusted model, delirium incidence was associated with older age (odds ratio [OR], 1.92 [1.28, 2.87] per decade, P = .002), greater severity of white matter hyperintensities (OR, 1.95 [1.06, 3.57], P = .031), and conditioning intensity (OR, 6.37 [2.20, 18.45], P < .001) but was unrelated to cortical atrophy (P = .777). Delirium was associated with fewer hospital-free days (P = .023) but was not associated with overall survival (hazard ratio, 0.95 [0.56, 1.61], P = .844). Greater incidence of delirium following HCT was associated with greater age, microvascular burden, and conditioning intensity. Pre-HCT consideration of microvascular burden and other neuroimaging biomarkers of risk may be warranted., (Copyright © 2020. Published by Elsevier Inc.)

Allogeneic hematopoietic stem cell transplantation (HCT) remains the only potentially curative option for myelodysplastic syndromes (MDS). Mortality after HCT is high, with deaths related to relapse or transplant-related complications. Thus, identifying patients who may or may not benefit from HCT is clinically important. We identified 1514 patients with MDS enrolled in the Center for International Blood and Marrow Transplant Research Registry and had their peripheral blood samples sequenced for the presence of 129 commonly mutated genes in myeloid malignancies. A random survival forest algorithm was used to build the model, and the accuracy of the proposed model was assessed by concordance index. The median age of the entire cohort was 59 years. The most commonly mutated genes were ASXL1(20%), TP53 (19%), DNMT3A (15%), and TET2 (12%). The algorithm identified the following variables prior to HCT that impacted overall survival: age, TP53 mutations, absolute neutrophils count, cytogenetics per International Prognostic Scoring System-Revised, Karnofsky performance status, conditioning regimen, donor age, WBC count, hemoglobin, diagnosis of therapy-related MDS, peripheral blast percentage, mutations in RAS pathway, JAK2 mutation, number of mutations/sample, ZRSR2, and CUX1 mutations. Different variables impacted the risk of relapse post-transplant. The new model can provide survival probability at different time points that are specific (personalized) for a given patient based on the clinical and mutational variables that are listed above. The outcomes' probability at different time points may aid physicians and patients in their decision regarding HCT., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. All rights reserved.)

Although hematopoietic cell transplantation from an HLA-matched unrelated donor is potentially curative for hematologic malignancies, survival is lower for African Americans compared with Caucasians. Because only approximately 20% of African Americans will have an HLA-matched unrelated donor, many of these patients undergo HLA-haploidentical relative or umbilical cord blood transplantation. In this study, we analyzed outcomes after HLA-haploidentical related donor (n = 249) and umbilical cord blood (n = 118) transplantations in African American patients with hematologic malignancy between 2008 and 2016. The predominant disease was acute myelogenous leukemia for recipients of both types of donor grafts. The incidences of grade II-IV and III-IV acute graft-versus-host disease were higher after umbilical cord blood transplantation compared with HLA-haploidentical relative transplantation (56% and 29%, respectively, versus 33% and 11%, respectively; P < .0001). The 2-year incidence of transplantation-related mortality adjusted for age and conditioning regimen intensity was higher after umbilical cord blood transplantation compared with HLA-haploidentical related donor transplantation (31% versus 18%; P = .008); however, there were no between-group differences in the 2-year adjusted incidence of relapse (30% versus 34%; P = .51), overall survival (54% versus 57%; P = .66), or disease-free survival (43% versus 47%; P = .46). Our findings show that the use of HLA-haploidentical and umbilical cord blood transplants expands the access to transplantation with comparable leukemia-free and overall survival for African Americans with hematologic malignancies., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic stem cell transplantation (alloHCT) may be associated with significant morbidity and mortality, resulting in increased healthcare utilization (HCU). To date, no multicenter comparative cost analyses have specifically evaluated alloHCT in children with acute leukemia. In this retrospective cohort study, we examined the relationship between survival and HCU while investigating the hypothesis that matched sibling donor (MSD) alloHCT has significantly lower inpatient HCU with unrelated donor (URD) alloHCT, and that among URDs, umbilical cord blood (UCB) alloHCT will have higher initial utilization but lower long-term utilization. Clinical and transplantation outcomes data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were merged with inpatient cost data from the Pediatric Health Information System (PHIS) database using a probabilistic merge methodology. The merged dataset comprised US patients age 1 to 21 years who underwent alloHCT for acute leukemia between 2004 and 2011 with comprehensive CIBMTR data at a PHIS hospital. AlloHCT was analyzed by donor type, with specific analysis of utilization and costs using PHIS claims data. The primary outcomes of overall survival (OS), leukemia-free survival (LFS), and inpatient costs were evaluated using Kaplan-Meier curves and Cox and Poisson models. A total of 632 patients were identified in both the CIBMTR and PHIS data. The 5-year LFS was 60% for MSD alloHCT, 47% for well-matched matched unrelated donor bone marrow (MUD) alloHCT, 48% for mismatched unrelated donor alloHCT, and 45% for UCB alloHCT (P = .09). Total adjusted costs were significantly lower for MSD alloHCT versus MUD alloHCT by day 100 (adjusted cost ratio [ACR], .73; 95% confidence interval [CI], .62 to .86; P < .001), and higher for UCB alloHCT versus MUD alloHCT (ACR, 1.27; 95% CI, 1.11 to 1.45; P < .001). By 2 years, total adjusted costs remained significantly lower for MSD alloHCT compared with MUD alloHCT (ACR, .67; 95% CI, .56 to .81; P < .001) and higher for UCB alloHCT compared with MUD alloHCT (ACR, 1.25; 95% CI, 1.02 to 1.52; P = .0280). Our data show that UCB and MUD alloHCT provide similar survival outcomes; however, MUD alloHCT has a significant advantage in cost by day 100 and 2 years. More research is needed to determine whether the cost difference among URD alloHCT approaches remains significant with a larger sample size and/or beyond 2 years post-alloHCT., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Patients with follicular lymphoma (FL) experiencing early therapy failure (ETF) within 2 years of frontline chemoimmunotherapy have poor overall survival (OS). We analyzed data from the Center for International Blood and Marrow Transplant Research (CIBMTR) and the National LymphoCare Study (NLCS) to determine whether autologous hematopoietic cell transplant (autoHCT) can improve outcomes in this high-risk FL subgroup. ETF was defined as failure to achieve at least partial response after frontline chemoimmunotherapy or lymphoma progression within 2 years of frontline chemoimmunotherapy. We identified 2 groups: the non-autoHCT cohort (patients from the NLCS with ETF not undergoing autoHCT) and the autoHCT cohort (CIBMTR patients with ETF undergoing autoHCT). All patients received rituximab-based chemotherapy as frontline treatment; 174 non-autoHCT patients and 175 autoHCT patients were identified and analyzed. There was no difference in 5-year OS between the 2 groups (60% versus 67%, respectively; P = .16). A planned subgroup analysis showed that patients with ETF receiving autoHCT soon after treatment failure (≤1 year of ETF; n = 123) had higher 5-year OS than those without autoHCT (73% versus 60%, P = .05). On multivariate analysis, early use of autoHCT was associated with significantly reduced mortality (hazard ratio, .63; 95% confidence interval, .42 to .94; P = .02). Patients with FL experiencing ETF after frontline chemoimmunotherapy lack optimal therapy. We demonstrate improved OS when receiving autoHCT within 1 year of treatment failure. Results from this unique collaboration between the NLCS and CIBMTR support consideration of early consolidation with autoHCT in select FL patients experiencing ETF., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Treatment-related mortality (TRM) remains elevated in adult patients undergoing umbilical cord blood transplantation (UCBT), including an early rise in TRM suggestive of excessive toxicity associated with the standard myeloablative total body irradiation (TBI), fludarabine, and cyclophosphamide regimen. In an attempt to reduce regimen-related toxicity, we previously studied a modified myeloablative regimen with TBI (1350 cGy) and fludarabine (160 mg/m 2 ); TRM was decreased, but neutrophil engraftment was suboptimal. Therefore, to improve engraftment while still minimizing regimen-related toxicity, we piloted a myeloablative regimen with the addition of thiotepa (10 mg/kg) to TBI and fludarabine conditioning. Thirty-one adult patients (median age, 46 years; range, 19 to 65) with hematologic malignancies (acute leukemia/myelodysplastic syndrome, 77%; lymphoid malignancy, 23%) underwent single (n = 1) or double (n = 30) UCBT from 2010 to 2015 at our institution. The cumulative incidence of neutrophil engraftment was 90% (95% confidence interval [CI], 70% to 97%) by 60 days, with a median time to engraftment of 21 days (95% CI, 19 to 26). The cumulative incidence of platelet engraftment was 77% (95% CI, 57% to 89%) by 100 days, with a median time to engraftment of 47 days (95% CI, 37 to 73). Cumulative incidences of grades II to IV and grades III to IV acute graft-versus-host disease (GVHD) at day 100 were 45% (95% CI, 27% to 62%) and 10% (95% CI, 2% to 23%), respectively. The overall incidence of chronic GVHD at 2 years was 40% (95% CI, 22% to 57%), with 17% of patients (95% CI, 6% to 33%) experiencing moderate to severe chronic GVHD by 2 years. TRM at 180 days was 13% (95% CI, 4% to 27%), at 1 year 24% (95% CI, 10% to 41%), and at 3 years 30% (95% CI, 13% to 49%). Relapse at 1 year was 13% (95% CI, 4% to 27%) and at 3 years 19% (95% CI, 6% to 38%). With a median follow-up of 35.5 months (95% CI, 12.7 to 52.2), disease-free and overall survival at 3 years were 51% (95% CI, 29% to 69%) and 57% (95% CI, 36% to 73%), respectively. This regimen represents a reasonable alternative to myeloablative conditioning with TBI, fludarabine, and cyclophosphamide and warrants further study., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Delayed hematopoietic recovery contributes to increased infection risk following umbilical cord blood (UCB) transplantation. In a Phase 1 study, adult recipients of UCB stem cells cultured ex vivo for 3 weeks with nicotinamide (NiCord) had earlier median neutrophil recovery compared with historical controls. To evaluate the impact of faster neutrophil recovery on clinically relevant early outcomes, we reviewed infection episodes and hospitalization during the first 100 days in an enlarged cohort of 18 NiCord recipients compared with 86 standard UCB recipients at our institution. The median time to neutrophil engraftment was shorter in NiCord recipients compared with standard UCB recipients (12.5 days versus 26 days; P < .001). Compared with standard UCB recipients, NiCord recipients had a significantly reduced risk for total infection (RR, 0.69; P = .01), grade 2-3 (moderate to severe) infection (RR, 0.36; P < .001), bacterial infection (RR, 0.39; P = .003), and grade 2-3 bacterial infection (RR, 0.21; P = .003) by Poisson regression analysis; this effect persisted after adjustment for age, disease stage, and grade II-IV acute GVHD. NiCord recipients also had significantly more time out of the hospital in the first 100 days post-transplantation after adjustment for age and Karnofsky Performance Status (69.9 days versus 49.7 days; P = .005). Overall, transplantation of NiCord was associated with faster neutrophil engraftment, fewer total and bacterial infections, and shorter hospitalization in the first 100 days compared with standard UCB transplantation. In conclusion, rapid hematopoietic recovery from an ex vivo expanded UCB transplantation approach is associated with early clinical benefit., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic cell transplantation (HCT) is potentially curative for patients with chronic myelomonocytic leukemia (CMML); however, few data exist regarding prognostic factors and transplantation outcomes. We performed this retrospective study to identify prognostic factors for post-transplantation outcomes. The CMML-specific prognostic scoring system (CPSS) has been validated in subjects receiving nontransplantation therapy and was included in our study. From 2001 to 2012, 209 adult subjects who received HCT for CMML were reported to the Center for International Blood and Marrow Transplant Research. The median age at transplantation was 57 years (range, 23 to 74). Median follow-up was 51 months (range, 3 to 122). On multivariate analyses, CPSS scores, Karnofsky performance status (KPS), and graft source were significant predictors of survival (P = .004, P = .01, P = .01, respectively). Higher CPSS scores were not associated with disease-free survival, relapse, or transplantation-related mortality. In a restricted analysis of subjects with relapse after HCT, those with intermediate-2/high risk had a nearly 2-fold increased risk of death after relapse compared to those with low/intermediate-1 CPSS scores. Respective 1-year, 3-year, and 5-year survival rates for low/intermediate-1 risk subjects were 61% (95% confidence interval [CI], 52% to 72%), 48% (95% CI, 37% to 59%), and 44% (95% CI, 33% to 55%), and for intermediate-2/high risk subjects were 38% (95% CI, 28% to 49%), 32% (95% CI, 21% to 42%), and 19% (95% CI, 8% to 29%). We conclude that higher CPSS score at time of transplantation, lower KPS, and a bone marrow graft are associated with inferior survival after HCT. Further investigation of CMML disease-related biology may provide insights into other risk factors predictive of post-transplantation outcomes., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Comprehensive recommendations for maintenance therapy after autologous stem cell transplantation (ASCT) for patients with multiple myeloma (MM) have yet to be defined. Bortezomib has been utilized as maintenance therapy after ASCT, but data attesting to the safety and efficacy of this agent compared with lenalidomide in the post-ASCT setting are limited. Therefore, we retrospectively analyzed the outcomes of 102 patients with MM who received maintenance therapy with bortezomib after ASCT at Duke University's adult bone marrow transplant clinic between 2005 and 2015. Maintenance with bortezomib was initiated between 60 and 90 days after ASCT as a single agent 1.3 mg/m 2 once every 2 weeks (n = 92) or in combination with lenalidomide (10 mg/day) (n = 10). The median age at ASCT was 64 (range, 31 to 78). Of the 99 patients with molecular data available, 42% had high-risk cytogenetics (including d17p, t(4;14), +1q, and t(14;16) by fluorescein in situ hybridization). Overall, 46% of patients experienced side effects from maintenance therapy, with 31% of all patients experiencing peripheral neuropathy. In total, 2% of patients required discontinuation of bortezomib maintenance because of adverse events. No secondary malignancies were reported from the therapy. The median progression-free survival (PFS) for patients receiving maintenance therapy with bortezomib after ASCT was 36.5 months (95% confidence interval [CI], 21.3 to not available) and median overall survival was 72.7 months (95% CI, 63.9 to not available). The PFS of patients with high-risk cytogenetics was not statistically significantly different from those with standard-risk cytogenetics, suggesting that maintenance with bortezomib may help overcome the impact of high-risk cytogenetics on early progression. These results indicate that maintenance therapy with bortezomib represents a safe, well-tolerated, and efficacious option for patients with high-risk cytogenetics, renal insufficiency, an inability to tolerate lenalidomide, or a previous history of another cancer., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to analyze the impact of graft-versus-host disease (GVHD) on the relapse rate of different lymphoma subtypes after allogeneic hematopoietic cell transplantation (allo-HCT). Adult patients with a diagnosis of Hodgkin lymphoma, diffuse large B cell lymphoma, follicular lymphoma (FL), peripheral T cell lymphoma, or mantle cell lymphoma (MCL) undergoing HLA-identical sibling or unrelated donor hematopoietic cell transplantation between 1997 and 2009 were included. Two thousand six hundred eleven cases were included. A reduced-intensity conditioning (RIC) regimen was used in 62.8% of the transplantations. In a multivariate analysis of myeloablative cases (n = 970), neither acute (aGVHD) nor chronic GVHD (cGVHD) were significantly associated with a lower incidence of relapse/progression in any lymphoma subtype. In contrast, the analysis of RIC cases (n = 1641) showed that cGVHD was associated with a lower incidence of relapse/progression in FL (risk ratio [RR], .51; P = .049) and in MCL (RR, .41; P = .019). Patients with FL or MCL developing both aGVHD and cGVHD had the lowest risk of relapse (RR, .14; P = .007; and RR, .15; P = .0019, respectively). Of interest, the effect of GVHD on decreasing relapse was similar in patients with sensitive disease and chemoresistant disease. Unfortunately, both aGVHD and cGVHD had a deleterious effect on treatment-related mortality and overall survival (OS) in FL cases but did not affect treatment-related mortality, OS or PFS in MCL. This study reinforces the use of RIC allo-HCT as a platform for immunotherapy in FL and MCL patients., (Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The poor prognosis for patients with diffuse large B cell lymphoma (DLBCL) who relapse within 1 year of initial diagnosis after first-line rituximab-based chemo-immunotherapy has created controversy about the role of autologous transplantation (HCT) in this setting. We compared autologous HCT outcomes for chemosensitive DLBCL patients between 2000 and 2011 in 2 cohorts based on time to relapse from diagnosis. The early rituximab failure (ERF) cohort consisted of patients with primary refractory disease or those with first relapse within 1 year of initial diagnosis. The ERF cohort was compared with those relapsing >1 year after initial diagnosis (late rituximab failure [LRF] cohort). ERF and LRF cohorts included 300 and 216 patients, respectively. Nonrelapse mortality (NRM), progression/relapse, progression-free survival (PFS), and overall survival (OS) of ERF versus LRF cohorts at 3 years were 9% (95% confidence interval [CI], 6% to 13%) versus 9% (95% CI, 5% to 13%), 47% (95% CI, 41% to 52%) versus 39% (95% CI, 33% to 46%), 44% (95% CI, 38% to 50%) versus 52% (95% CI, 45% to 59%), and 50% (95% CI, 44% to 56%) versus 67% (95% CI, 60% to 74%), respectively. On multivariate analysis, ERF was not associated with higher NRM (relative risk [RR], 1.31; P = .34). The ERF cohort had a higher risk of treatment failure (progression/relapse or death) (RR, 2.08; P < .001) and overall mortality (RR, 3.75; P <.001) within the first 9 months after autologous HCT. Beyond this period, PFS and OS were not significantly different between the ERF and LRF cohorts. Autologous HCT provides durable disease control to a sizeable subset of DLBCL despite ERF (3-year PFS, 44%) and remains the standard-of-care in chemosensitive DLBCL regardless of the timing of disease relapse., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

There are limited data on the outcomes of autologous or allogeneic hematopoietic cell transplantation (HCT) in diffuse large B cell lymphoma transformed from follicular lymphoma. We analyzed transplantation outcomes in 141 subjects with biopsy-proven diffuse large B-cell lymphoma transformed from follicular lymphoma reported to the Center for International Blood and Marrow Transplant Research between 1990 and 2009. Two groups were identified: autologous HCT (auto-HCT; n = 108) and allogeneic HCT (allo-HCT; n = 33). Fewer auto-HCTs were done for transformed follicular lymphoma in 2003 to 2009, with a shift favoring allo-HCT. Auto-HCT was associated with a 1-year nonrelapse mortality (NRM) of 8% (95% confidence interval [CI], 4% to 14%), 5-year progression-free survival of 35% (95% CI, 26% to 45%), and 5-year overall survival of 50% (95% CI, 40% to 59%). In contrast, allo-HCT was associated with a 1-year NRM of 41% (95% CI, 23% to 58%), 5-year progression-free survival of 18% (95% CI, 6% to 35%), and 5-year overall survival of 22% (95% CI, 8% to 41%). Auto-HCT for transformed follicular lymphoma achieves sustained remission in a high proportion of subjects. The high NRM of allo-HCT offset any benefit that might be associated with this transplantation modality., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

We present a comparative study on 124 patients with hematologic malignancies who had undergone reduced-intensity conditioning and then received a transplant from an HLA-matched related (MRD), an HLA-matched unrelated (MUD), or an HLA-haploidentical related (HAPLO) donor. The conditioning regimen, which consisted of fludarabine, melphalan or busulfan, and alemtuzumab was administered to patients with lymphoid (n = 62) or myeloid disease (n = 62). Mycophenolate mofetil was used as prophylaxis for graft-versus-host disease (GVHD), and 38, 58, and 33 patients received transplants from MRD, MUD, and HAPLO donors, respectively. Only 2 patients experienced primary graft failure (GF) after melphalan-based regimen, whereas 8 of the 17 patients who received a transplant from HAPLO donors experienced a primary GF after busulfan-based regimen. The cumulative incidence of grade III to IV acute GVHD in engrafted patients who had received transplants from MRD, MUD, or HAPLO donors was 3%, 11%, and 27%, respectively, and the 2-year overall survival (OS) rates were 51%, 22%, and 23%, respectively. According to multivariate analysis, transplantation from either MUD or HAPLO donors compared with MRD were adverse factors that affected the OS (P = .006 and P = .002, respectively). In conclusion, the reduced-intensity regimen that included fludarabine, busulfan, or melphalan and alemtuzumab using only mycophenolate mofetil as the GVHD prophylaxis conferred favorable outcomes in the MRD group but lower survival rates in the MUD and HAPLO groups. The busulfan-based regimen led to a high incidence of GF in the HAPLO group, suggesting the need for modification or intensification of immunosuppression., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Prediction of subsequent leukemia-free survival (LFS) and chronic graft-versus-host disease (GVHD) in adults with acute leukemia who survived at least 1 year after allogeneic hematopoietic cell transplantation is difficult. We analyzed 3339 patients with acute myeloid leukemia and 1434 patients with acute lymphoblastic leukemia who received myeloablative conditioning and related or unrelated stem cells from 1990 to 2005. Most clinical factors predictive of LFS in 1-year survivors were no longer significant after 2 or more years. For acute myeloid leukemia, only disease status (beyond first complete remission) remained a significant adverse risk factor for LFS 2 or more years after transplantation. For lymphoblastic leukemia, only extensive chronic GVHD remained a significant adverse predictor of LFS in the second and subsequent years. For patients surviving for 1 year without disease relapse or extensive chronic GVHD, the risk of developing extensive chronic GVHD in the next year was 4% if no risk factors were present and higher if noncyclosporine-based GVHD prophylaxis, an HLA-mismatched donor, or peripheral blood stem cells were used. Estimates for subsequent LFS and extensive chronic GVHD can be derived for individual patients or populations using an online calculator (http://www.cibmtr.org/LeukemiaCalculators). This prognostic information is more relevant for survivors than estimates provided before transplantation., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Patients with chemorefractory non-Hodgkin lymphomas generally have a poor prognosis. We used the observational database of the Center for International Blood and Marrow Transplant Research to study the outcome of 533 patients with refractory diffuse large B cell lymphoma (DLBCL) or grade III follicular lymphoma (FL-III) who underwent allogeneic hematopoietic cell transplantation (allo-HCT) using either myeloablative (MA; n = 307) or reduced-intensity/nonmyeloablative conditioning (RIC/NST; n = 226) between 1998 and 2010. We analyzed nonrelapse mortality (NRM), relapse/progression, progression-free survival (PFS), and overall survival (OS). Only 45% of the patients at transplantation had a Karnofsky performance score of ≥90%. Median follow-up of surviving patients after MA and RIC/NST allo-HCT is 35 months and 30 months, respectively. At 3 years, MA allo-HCT was associated with a higher NRM compared with RIC/NST (53% versus 42%; P = .03), similar PFS (19% versus 23%; P = .40), and lower OS (19% versus 28%; P = .02), respectively. On multivariate analysis, FL-III histology was associated with lower NRM (relative risk [RR], .52), reduced risk of relapse/progression (RR, .42), and superior PFS (RR, .51) and OS (RR, .53), whereas MA conditioning was associated with reduced risk of relapse/progression (RR, .66). Despite a refractory state, a small subset of DLBCL and FL-III patients can attain durable remissions after allo-HCT. Conditioning regimen intensity was not associated with PFS and OS despite a higher risk of relapse/progression with RIC/NST allo-HCT., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Patients with chemorefractory mantle cell lymphoma (MCL) have a poor prognosis. We used the Center for International Blood and Marrow Transplant Research database to study the outcome of 202 patients with refractory MCL who underwent allogeneic hematopoietic cell transplantation (allo-HCT) using either myeloablative (MA) or reduced-intensity/nonmyeloablative conditioning (RIC/NST), during 1998-2010. We analyzed nonrelapse mortality (NRM), progression/relapse, progression-free survival (PFS), and overall survival (OS). Seventy-four patients (median age, 54 years) received MA, and 128 patients (median age, 59 years) received RIC/NST. Median follow-up after allo-HCT was 35 months in the MA group and 43 months in the RIC/NST group. At 3 years post-transplantation, no significant between-group differences were seen in terms of NRM (47% in MA versus 43% in RIC/NST; P = .68), relapse/progression (33% versus 32%; P = .89), PFS (20% versus 25%; P = .53), or OS (25% versus 30%; P = .45). Multivariate analysis also revealed no significant between-group differences in NRM, relapse, PFS, or OS; however, receipt of a bone marrow or T cell-depleted allograft was associated with an increased risk of NRM and inferior PFS and OS. Our data suggest that despite a refractory disease state, approximately 25% of patients with MCL can attain durable remission after allo-HCT, and conditioning regimen intensity does not influence outcome of allo-HCT., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Trends in utilization and outcomes after autologous or allogeneic hematopoietic cell transplantation (HCT) for Burkitt lymphoma were analyzed in 241 recipients reported to the Center for International Blood and Marrow Transplant Research between 1985 and 2007. The autologous HCT cohort had a higher proportion of chemotherapy-sensitive disease, peripheral blood grafts, and HCT in first complete remission (CR1). The use of autologous HCT has declined over time, with only 19% done after 2001. Overall survival at 5 years for the autologous cohort was 83% for those in CR1 and 31% for those not in CR1. Corresponding progression-free survival (PFS) was 78% and 27%, respectively. After allogeneic HCT, overall survival at 5 years was 53% and 20% for the CR1 and non-CR1 cohorts, whereas PFS was 50% and 19%, respectively. The most common cause of death was progressive lymphoma. Allogeneic HCT performed in a higher-risk subset (per National Comprehensive Cancer Network guidelines) resulted in a 5-year PFS of 27%. Autologous HCT resulted in a 5-year PFS of 44% in those undergoing transplantation in the second CR., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Immunologic reconstitution after allogeneic hematopoietic cell transplantation is a critical component of successful outcome. Umbilical cord blood (UCB) transplantation in adult recipients is associated with slow and often inadequate immune recovery. We characterized the kinetics and extent of immune recovery in 95 adult recipients after a dual UCB (n = 29) and matched sibling donor (n = 33) or matched unrelated donor (n = 33) transplantation. All patients were treated with myeloablative conditioning. There were no differences in the immune recovery profile of matched sibling donor and matched unrelated donor recipients. Significantly lower levels of CD3+, CD4+, and CD8+ T cells were observed in UCB recipients until 6 months after transplantation. Lower levels of regulatory T cells persisted until 1 year after transplantation. Thymopoiesis as measured by TCR rearrangement excision circle was comparable among all recipients by 6 months after transplantation. In a subset of patients 1 year after transplantation with similar levels of circulating T cells and TCR rearrangement excision circle, there was no difference in TCR diversity. Compared to HLA-identical matched sibling donor and matched unrelated donor adult hematopoietic cell transplantation recipients, quantitative lymphoid recovery in UCB transplantation recipients is slower in the first 3 months, but these differences disappeared by 6 to 12 months after transplantation., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

We analyzed the outcomes of 248 (61% male) adult recipients of HLA-matched unrelated and HLA-mismatched related donor hematopoietic cell transplantation (HCT) for non-Hodgkin lymphoma (NHL) after reduced or lower intensity conditioning (RIC), reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 1997 to 2004. Median age was 52 (range: 18-72 years); 31% had a Karnofsky performance score <90. Follicular NHL (43%) was the major histology. Incidence of grades II-IV acute graft-versus-host disease (aGVHD) was 43% at 100 days; and chronic GVHD (cGVHD) was 44% at 3 years. Treatment-related mortality (TRM) at 100 days was 24%. Three-year overall survival (OS) and progression-free survival (PFS) were 41% and 32%, respectively. In multivariate analysis, use of antithymocyte globulin (ATG) and HLA mismatch were associated with increased TRM. High-grade histology, ATG use, and chemotherapy resistance were associated with lower PFS. Older age, shorter interval from diagnosis to HCT, non-total body irridiation (TBI) conditioning regimens, ex vivo T cell depletion, and HLA-mismatched unrelated donors were associated with mortality. GVHD did not influence relapse or PFS. Older age, aggressive histology, and chemotherapy resistance correlated with poorer survival. For selected patients with NHL, lack of an available sibling donor should not be a barrier to allogeneic HCT., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

We compared the outcomes of patients age 60-70 years with acute myelogenous leukemia receiving reduced-intensity allogeneic hematopoietic cell transplantation (HCT) in first remission (CR1) reported to the Center for International Blood and Marrow Research (n = 94) with the outcomes in patients treated with induction and postremission chemotherapy on Cancer and Leukemia Group B protocols (n = 96). All patients included had been in CR1 for at least 4 months. The HCT recipients were slightly younger than the chemotherapy patients (median age, 63 years vs 65 years; P < .001), but there were no significant between-group differences in the proportion with therapy-related leukemia or in different cytogenetic risk groups. Time from diagnosis to CR1 was longer for the HCT recipients (median, 44 days vs 38 days; P = .031). Allogeneic HCT was associated with significantly lower risk of relapse (32% vs 81% at 3 years; P < .001), higher nonrelapse mortality (36% vs 4% at 3 years; P < .001), and longer leukemia-free survival (32% vs 15% at 3 years; P = .001). Although overall survival was longer for HCT recipients, the difference was not statistically significant (37% vs 25% at 3 years; P = .08). Our findings suggest that reduced-intensity conditioning allogeneic HCT in patients age 60-70 with acute myelogenous leukemia in CR1 reduces relapse and improves leukemia-free survival. Strategies that reduce nonrelapse mortality may yield significant improvements in overall survival., (Copyright © 2011 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

High treatment-related mortality (TRM) and high graft failure rate are serious concerns in HLA-mismatched umbilical cord blood (UCB) transplantation with myeloablative conditioning. We conducted a prospective trial of dual UCB transplantation using modified myeloablation consisting of total-body irradiation (TBI; 1350 cGy) and fludarabine (Flu) (160 mg/m(2)). Twenty-seven patients (median age, 33 years; range: 20-58 years) with hematologic malignancies were enrolled. The median combined cryopreserved total nucleated cell (TNC) dose was 4.3 × 10(7)/kg (range: 3.2-7.7 × 10(7)/kg). The cumulative incidences of neutrophil (≥500/μL) and platelet (≥50,000/μL) engraftment were 80% (95% confidence interval [CI], 58%-91%) and 68% (95% CI, 46%-83%), respectively. Among engrafted patients, a single cord blood unit was predominant by 100 days posttransplantation. A higher cryopreserved and infused TNC dose and infused CD3(+) cell dose were significant factors associated with the predominant UCB unit (P = .032, .020, and .042, respectively). TRM and relapse rates at 2 years were 28% (95% CI, 12%-47%) and 20% (95% CI, 7%-37%), respectively. Cumulative incidences of grades II-IV and grades III-IV acute graft-versus-host disease (aGVHD) were 37% (95% CI, 20%-55%) and 11% (95% CI, 3%-26%), respectively, and that of chronic GVHD was 31% (95% CI, 15%-49%). With a median follow-up of 23 months, overall survival and disease-free survival rates at 2 years were 58% (95% CI, 34%-75%) and 52% (95% CI, 29%-70%), respectively. This study supports the use of TBI 1350 cGy/Flu as an alternative to conventional myeloablative conditioning for dual UCB transplantation., (Copyright © 2011 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Infusing natural killer (NK) cells following transplantation may allow less infections and relapse with little risk of acute graft-versus-host disease (aGVHD). We delivered 51 total NK cell-enriched donor lymphocyte infusions (DLIs) to 30 patients following a 3-6/6 HLA matched T cell-depleted nonmyeloablative allogeneic transplant. The primary endpoint of this study was feasibility and safety. Eight weeks following transplantation, donor NK cell-enriched DLIs were processed using a CD56(+) selecting column with up to 3 fresh infusions allowed. Toxicity, relapse, and survival were monitored. T cell phenotype, NK cell functional recovery, and KIR typing were assessed for association with outcomes. Fourteen matched and 16 mismatched transplanted patients received a total of 51 NK cell-enriched DLIs. Selection resulted in 96% (standard deviation [SD] 8%) purity and 83% (SD 21%) yield in the matched setting and 97% (SD 3%) purity and 77% (SD 24%) yield in the mismatched setting. The median number of CD3(-) CD56(+) NK cells infused was 10.6 (SD 7.91) x 10(6) cells/kg and 9.21 (SD 5.6) x 10(6) cells/kg, respectively. The median number of contaminating CD3(+)CD56(-) T cells infused was .53 (1.1) x 10(6) and .27 (.78) x 10(6) in the matched and mismatched setting, respectively. Only 1 patient each in the matched (n = 14) or mismatched (n = 16) setting experienced severe aGVHD with little other toxicity attributable to the infusions. Long-term responders with multiple NK cell-enriched infusions and improved T cell phenotypic recovery had improved duration of responses (p = .0045) and overall survival (OS) (P = .0058). A 1-step, high-yield process is feasible, and results in high doses of NK cells infused with little toxicity. NK cell-enriched DLIs result in improved immune recovery and outcomes for some. Future studies must assess whether the improved outcomes are the direct result of the high doses and improved NK cell function or other aspects of immune recovery.

The purpose of this study was to evaluate the efficacy and safety of short-course bortezomib, melphalan, prednisone (VMP) in previously untreated multiple myeloma as frontline therapy for transplant-ineligible patients and induction prior to autologous stem cell transplantation (ASCT). Patients received up to 6 28-day cycles of bortezomib 1.3 mg/m(2), days 1, 4, 8, and 11, plus melphalan 6 mg/m(2) and prednisone 60 mg/m(2), days 1-7. After 2-6 cycles, eligible and consenting patients could proceed to ASCT. Responses were assessed by International Uniform Response Criteria. The primary endpoint was complete response (CR) rate with VMP. Forty-five patients were enrolled. Among 44 evaluable patients, response rate was 95%, including 18% >or=CR (9% stringent CR), 27% very good partial responses (VGPR), and 50% partial responses (PR). Twenty patients proceeded to ASCT. Stem cell collection was successful in all; median yield was 5.6 x 10(6) CD34(+) cells/kg. Posttransplant response rates were 30% >or=CR (10% stringent CR), 65% VGPR, and 5% PR. After median follow-up of 14.0/14.6 months, median time to progression and progression-free survival were both 19.8/27.9 months in non-ASCT/ASCT patients. Seven patients have died; 1-year survival rates were 82%/95% in non-ASCT/ASCT patients. The most common grade 3/4 toxicities were thrombocytopenia (20%), neutropenia (28%), and infection (9%). Peripheral neuropathy grade 2-4 was the most common nonhematopoietic side effect occurring 17 patients (38%), although it was typically reversible, and only 5 patients (11%) discontinued therapy as a result of it. Short-course VMP is highly effective and generally well tolerated, both as initial treatment in non-ASCT patients and induction prior to ASCT. VMP did not negatively affect stem cell collection. Longer follow-up and prospective phase III trials are required to validate these initial observations., (Copyright (c) 2010 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The efficacy of once-daily intravenous busulfan with fludarabine as a preparative regimen for partially matched umbilical cord blood transplantation has not been formally studied. We randomized 10 adult patients with myeloid malignancies to receive either concurrent or sequential administration of intravenous busulfan 130 mg/m(2) once daily x 4 days and fludarabine 40 mg/m(2) daily x 4 days, followed by dual umbilical cord blood transplantation. The median combined cryopreserved total nucleated cell dose was 3.6 x 10(7)/kg recipient body weight (range: 2.8-4.5 x 10(7)/kg). Graft-versus-host disease (GVHD) prophylaxis was provided by tacrolimus and mycophenolate mofetil (MMF). Donor-derived neutrophil recovery was observed in only 2 of 10 patients, resulting in premature closure of the study as per graft failure stopping rules. We conclude that the myeloablative conditioning regimen of once-daily intravenous busulfan with fludarabine provides insufficient immunosuppression to allow for engraftment of partially matched, dual umbilical cord blood grafts.

End-organ damage is common in patients with sickle cell disease (SCD) thereby limiting the use of allogeneic stem cell transplantation (SCT). We report the outcome of 2 adult SCD patients, 1 with end-stage renal disease (ESRD), who underwent fludarabine-based nonmyeloablative SCT from HLA-identical matched siblings. To prevent fludarabine toxicity, the patient with ESRD underwent aggressive dialysis following adjusted fludarabine dosing. Pharmacokinetics of the fludarabine metabolite F-Ara-A was studied on the patient with ESRD and 2 additional patients with normal renal function. Both patients with SCD achieved full donor erythroid chimerism, have normal blood counts, and are on no immunosuppressive medications. With a 20% dose reduction followed by daily dialysis, we achieved fludarabine drug exposure that is nearly identical to that achieved in patients with normal renal function. We conclude that fludarabine-based nonmyeloablative allogeneic SCT for adult patients with SCD is feasible, even in the setting of ESRD.

Haploidentical hematopoietic stem cell transplantation (HSCT) provides an opportunity for nearly all patients to benefit from HSCT when a human leukocyte antigen (HLA) genotypically matched sibling is not available. Initial results with the use of mismatched allografts led to limited enthusiasm because of graft-versus-host disease (GVHD) and infectious complications, resulting in an unacceptable treatment-related morbidity and mortality. Recent advances with effective T cell depletion, the use of a "megadose" of stem cells, earlier detection of severe infections, combined with better antimicrobial therapy and reduced-intensity conditioning (RIC) has significantly decreased the early transplant-related mortality and GVHD, whereas enabling prompt engraftment, hence advancing the therapeutic benefit of haploidentical transplantation. However, the cardinal problems related to delayed immune reconstitution allowing posttransplant infectious complications and relapse remain, limiting the efficacy of haploidentical HSCT. Preliminary data has demonstrated the potential for use of adoptive cellular immunity and selective allodepletion in rapidly reconstituting immunity without GVHD. The encouraging reports from haploidentical transplant using noninherited maternal antigen (NIMA)-mismatched or natural killer (NK) alloreactive donors may greatly increase the donor availability and open the way to more appropriate donor selection in HLA-haploidentical HSCT. Future challenges remain in determining the safest approach for haploidentical transplant to be performed with minimal risk of GVHD, whereas preserving effective graft-versus-leukemia activity and promoting prompt immune reconstitution.

We conducted this study to determine event-free and overall survival among women with hormone-insensitive or hormone-resistant metastatic breast cancer receiving consolidation with high-dose chemotherapy (HDC) and hematopoietic support versus no further chemotherapy after intensive induction chemotherapy. Eligible patients received induction doxorubicin, 5-fluorouracil, and methotrexate (AFM) for 2 to 4 cycles. Women in complete remission were randomized to immediate HDC with cyclophosphamide, cisplatin, and carmustine followed by autologous hematopoietic support or to no further therapy. Patients on the observation arm of therapy were offered salvage HDC at the time of relapse. Partial responders to AFM were offered immediate HDC. A total of 425 patients were enrolled onto the study. The median event-free survival for women randomized to induction therapy alone was 3.8 months, compared with 9.7 months for women who completed HDC (P < .006). Of the patients randomized to observation, 5 (10%) of 51 remain event free, compared with 13 (26%) of 49 patients who underwent immediate HDC (P = .03). Of women converted to a complete response by salvage HDC after a partial response to AFM, overall survival was similar to that in women randomized to immediate HDC. Follow-up is now in excess of 5 years. The 5-year event-free survival is 15% (95% confidence interval, 12%-18%), and the 5-year overall survival is 20% (95% confidence interval, 17%-25%). Immediate HDC after a complete response to AFM produced some durable long-term responses in hormone-insensitive/-resistant metastatic breast cancer. Salvage HDC converted 30% of partial responders to complete responders with similar survivals. The addition of novel targeted therapies to intensive-dose chemotherapy regimens may further improve survival in metastatic breast cancer.

We report the outcome of 13 patients with advanced malignancies who underwent nonmyeloablative conditioning therapy followed by infusion of partially matched unrelated cord blood cells. The median age of these patients was 49 years, and their median weight was 65.7 kg. The median nucleated cell dose infused was 2.07 x 10(7)/kg. Eight of the 13 patients demonstrated donor chimerism between 4 weeks and 6 months, and subsequent conversion to full donor chimerism was achieved in 5 patients. Three patients were alive and free of disease at 158 to 1054 days, with a median survival of 288 days after transplantation. The 100-day event-free survival is 69%, and overall survival is 77%. At 1 year, the event-free and overall survival was 43%. Treatment-related mortality observed within the first 100 days after transplantation was low: 1 previously extensively pretreated patient died of multiorgan failure. This result provides a basis for further exploring this potentially curative approach to selected patients who lack matched related or unrelated hematopoietic stem cell donors.

Since January 1996, we have administered myeloablative therapy followed by infusion of unrelated umbilical cord blood cells in 57 adult patients with high-risk disease. The median age was 31 years (range, 18-58 years), and the median weight was 70 kg (range, 46-110 kg). Two patients were treated for genetic disorders and 55 for advanced hematologic malignancies. The preparative regimens were total body irradiation or busulfan based, both with antithymocyte globulin. HLA matching between donor and recipient was 3 of 6 in 3 patients, 4 of 6 in 44 patients, 5 of 6 in 8 patients, and 6 of 6 in 2 patients. The median nucleated cell dose was 1.50 x 10(7)/kg (range, 0.54-2.78 x 10(7)/kg), and the median CD34(+) cell dose was 1.37 x 10(5)/kg (range, 0.02-12.45 x 10(5)/kg). All patients received granulocyte colony-stimulating factor after transplantation until neutrophil recovery. Graft-versus-host disease prophylaxis consisted of cyclosporine and steroids. The median number of days to an absolute neutrophil count of 500/microL was 26 (range, 12-55 days). The median time to an untransfused platelet count of >20000/microL was 84 days (range, 35-167 days). Seventeen patients developed grade II to IV acute GVHD. The median survival of the entire group was 91 days (range, 10-2251 days). Eleven patients were alive at a median follow-up of 1670 days (range, 67-2251 days), 1 with autologous recovery and 1 with relapsed lymphoma. The actuarial projected 3-year survival is 19%. Infection was the primary cause of death. These results suggest that unrelated umbilical cord blood transplantation is a viable option for adult patients and should be explored in patients with earlier-stage disease.

We have performed a phase I dose escalation of 4-Hydroperoxycyclophosphamide (4HC) purging of autologous peripheral blood progenitor cells (PBPCs) to improve the outcome of autologous transplantation for patients with myeloid leukemia. Peripheral blood stem cells were mobilized after cytosine arabinoside of 2 g/m(2) every 12 hours x 8 doses with etoposide of 40 mg/kg total dose infused over 4 days, followed by growth factor support. The preparative regimen included Busulfan of 1 mg/kg orally every 6 hours x 16 doses, followed by etoposide of 60 mg/kg x 1 day (the patient with chronic myeloid leukemia received cyclophosphamide of 60 mg/kg/d x 2 days in lieu of etoposide). PBPCs purged with 4HC were infused following this induction. Toxicities included grade 3 or 4 skin rashes, stomatitis/mucositis, and delay in time to hematopoietic recovery. The maximum tolerated dose of 4HC used to purge PBPCs in this trial was 20 microg/mL, which resulted in an average of 18 days for white blood cells and 28 days for platelet recovery. With a median follow-up of 2.25 years in surviving patients, the 3-year disease free survival rate is 44% and the overall survival rate is 89%. These data suggest that autologous PBPCs are more sensitive than marrow purged with 4HC, tolerating less intense purging, although a survival advantage may still be seen and should be assessed in larger studies. Approaches to minimize stomatitis and protect normal stem cells from the toxicity of 4HC may improve the tolerance and efficacy of this approach., (Copyright 2003 American Society for Blood and Marrow Transplantation)

Despite modern chemotherapy, advanced breast cancer remains a significant cause of cancer morbidity and mortality in women. Patients with disease involvement of multiple lymph nodes represent a subgroup with a high risk of relapse. In particular, 50% of patients with 4 to 9 axillary lymph nodes involved will relapse after standard chemotherapy. In an effort to improve the survival of patients with 4 to 9 involved nodes, we performed a phase II study in which 61 patients with surgically diagnosed stage II or III breast cancer and 4 to 9 positive lymph nodes received 3 cycles of doxorubicin and 5-fluorouracil followed by high-dose chemotherapy consisting of cisplatin, cyclophosphamide, and carmustine and infusion of autologous hematopoietic progenitor cells. All patients received posttransplantation localized radiotherapy unless contraindicated, and all patients with hormone receptor-positive disease received tamoxifen. After a median patient follow-up of 6.7 years (range, 4.6-8.6 years), the 5-year overall survival rate was 79% (95% CI, 69%-90%), with relapse-free survival of 73% (95% CI, 62%-85%). Treatment-related mortality was 3%. Interstitial pneumonitis occurred in 69% of patients but did not contribute to mortality. Our study presents long-term favorable results regarding the use of consolidative HDC with autologous hematopoietic support in previously untreated patients with high-risk primary breast cancer.

T-cell recovery following myeloablative preparatory regimens and cord blood transplantation in adult patients gen erally occurs between 1 and 3 years following allogeneic bone marrow transplantation. T-cell reconstitution may involve thymic education of donor-derived precursors or peripheral expansion of mature T-cells transferred in the graft. We measured quantitative and qualitative immunologic reconstitution, T-cell receptor spectratyping, and T-cell receptor excision circle (TREC) levels in adult recipients of umbilical cord blood transplants following a novel nonmyeloablative regimen. These results were compared to previously published results of similar patients receiving a myeloablative regimen and cord blood stem cells. With small numbers of patients treated so far, T-cells (CD3+) reached normal levels in adults 6 to 12 months following nonmyeloablative transplantation compared with 24 months in adults receiving a myeloablative regimen. At 12 months after transplantation, the numbers of phenotypically naive (CD45RA) T-cells were higher in those receiving the nonmyeloablative regimen. The T-cell repertoire in cord blood recipients treated with a nonmyeloablative regimen was markedly more diverse and robust compared with the repertoire in those receiving the myeloablative regimen at similar time points. TRECs (which are generated within the thymus and identify new thymic emigrants and those that have not divided) were detected 12 months after transplantation in the nonmyeloablative recipients, whereas TRECs were not detected in adults until 18 to 24 months in those receiving myeloablative regimens. Thus, in adults receiving a nonmyeloablative preparatory regimen, the quantitative and qualitative recovery of T-cells occurs through rapid peripheral expansion. The ability of patients receiving a nonmyeloablative regimen to recover within a few months suggests that the peripheral niches in which T-cells can proliferate are preserved in these patients compared to those receiving ablative regimens. Moreover, the presence of TREC-positive cells within 1 year suggests that thymic recovery is likewise accelerated in non myeloablative compared to myeloablative regimens.