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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 × 107/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. [Copyright &y& Elsevier]

Minor histocompatibility antigens (miHA) are responsible for the occurrence of graft-versus-host disease in the setting of a major histocompatibility complex matched sibling allogeneic stem cell transplantation. These miHA are peptide fragments that are associated with major histocompatibility complex class I or class II antigens. Elegant experiments have led to the molecular characterization of these antigens. Efforts to prevent graft-versus-host disease could be targeted through this pathway by matching for these miHA or by preventing antigen recognition. Alternatively, these miHA could be exploited as targets for a more potent graft-versus-malignancy effect. This area of miHA promises to continue to be an exciting area of continued research. [Copyright &y& Elsevier]

Unrelated umbilical cord blood (UCB) transplantation has recently been explored in an increasing number of adult patients. The relative ease of procurement and the lower-than-anticipated risk of severe acute graft-versus-host disease has made UCB transplantation an appealing alternative to bone marrow-derived hematopoietic stem cells. The use of reduced-intensity or nonmyeloablative preparative regimens to allow engraftment of UCB broadens the scope of patients who may benefit from allogeneic immunotherapy, including elderly and medically infirm patients with no matched sibling donor. This review summarizes the available data on the use of UCB as an alternative source of hematopoietic stem cell transplantation in adult patients. [Copyright &y& Elsevier]

Hematologic malignancies are characterized by genetic heterogeneity, making classic gene therapy with a goal of correcting 1 genetic defect ineffective in many of these diseases. Despite initial tribulations, gene therapy, as a field, has grown by leaps and bounds with the recent development of gene editing techniques including zinc finger nucleases, transcription activator–like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR) sequences and CRISPR-associated protein-9 (Cas9) nuclease or CRISPR/Cas9. These novel technologies have been applied to efficiently and specifically modify genetic information in target and effector cells. In particular, CRISPR/Cas9 technology has been applied to various hematologic malignancies and has also been used to modify and improve chimeric antigen receptor–modified T cells for the purpose of providing effective cellular therapies. Although gene editing is in its infancy in malignant hematologic diseases, there is much room for growth and application in the future. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

• Delirium is common following hematopoietic stem cell transplantation. • In this select sample, greater age, treatment regimen intensity, and greater white matter burden were all associated with greater delirium incidence. 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. [ABSTRACT FROM AUTHOR]

Gastrointestinal (GI) complications including graft-versus-host disease (GVHD) are a major cause of morbidity and mortality in allogenic stem transplant recipients. Although several studies have previously looked into the acute GI complications, fewer smaller studies have reported late complications. In this large study we focus on the late (100 days post-transplant) GI complications in allogenic stem transplant recipients. In this single-center, retrospective study of all adult allogenic stem cell transplant recipients who had their transplant at Duke University over a 6-year period, 479 patients underwent allogenic stem cell transplant, of whom 392 recipients survived for at least 100 days post-transplant. Late GI symptoms were noted in 71 patients, prompting endoscopic evaluation. The primary endpoint of our study was the diagnosis of GI-GVHD based on endoscopic findings, whereas overall survival and nonrelapse mortality were the secondary endpoints. Of the 71 patients who underwent endoscopy, 45 (63%) had GI-GVHD. Of these 45 patients, 39 (87%) had late acute GVHD, 1 (2%) had chronic GVHD, and 5 patients (11%) had overlap disease. Of the patients who did not have GVHD, the symptoms were mostly related to infectious and inflammatory causes. Less common causes included drug toxicity, food intolerance, disease relapse, and motility issues. In a multivariate analysis the factors most indicative of GI-GVHD were histologic findings of apoptosis on the tissue specimen (odds ratio, 2.35; 95% confidence interval, 1.18 to 4.70; P  = .015) and clinical findings of diarrhea (odds ratio, 5.43; 95% confidence interval, 1.25 to 23.54; P  = .024). The median survival time from the first endoscopy was 8.5 months. The incidence of nonrelapse mortality at 6 months was 31% in patients with GI-GVHD and 19% in patients without GI-GVHD ( P  = .42). All patients with GI-GVHD were on steroid therapy, and 31% of them received total parenteral nutrition. In our population close to one-fifth of allogenic transplant recipients experienced late GI complications, warranting endoscopic evaluation. Most of these patients were found to have GI-GVHD that had a high incidence of nonrelapse mortality at 6 months and close to one-third of these patients needed total parenteral nutrition. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Combinations of cyclosporine (CSP) with methotrexate (MTX) have been widely used for immunosuppression after allogeneic transplantation for acquired aplastic anemia. We compared outcomes with tacrolimus (TAC)+MTX versus CSP+MTX after transplantation from HLA-identical siblings (SIB) or unrelated donors (URD) in a retrospective cohort of 949 patients with severe aplastic anemia. Study endpoints included hematopoietic recovery, graft failure, acute graft-versus-host disease (GVHD), chronic GVHD, and mortality. TAC+MTX was used more frequently in older patients and, in recent years, in both SIB and URD groups. In multivariate analysis, TAC+MTX was associated with a lower risk of mortality in URD recipients and with slightly earlier absolute neutrophil count recovery in SIB recipients. Other outcomes did not differ statistically between the 2 regimens. No firm conclusions were reached regarding the relative merits of TAC+MTX versus CSP+MTX after hematopoietic cell transplantation for acquired aplastic anemia. Prospective studies would be needed to determine whether the use of TAC+MTX is associated with lower risk of mortality in URD recipients with acquired aplastic anemia. [ABSTRACT FROM AUTHOR]

Abstract: 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 &y& Elsevier]

We studied whether allospecific CD4+ effector memory T cells (TEM) could induce graft-versus-host disease (GVHD) using a novel GVHD model induced solely by CD4+ T cell receptor transgenic TEa cells. Allospecific TEM generated in a lymphopenic host bore a typical memory phenotype. Moreover, these cells were able to elicit a faster and more effective proliferative response on challenge with alloantigen in vitro and to mediate “second-set” skin graft rejection in vivo. However, these allospecific TEM were unable to induce GVHD. Allospecific TEM recipients became tolerant to alloantigen as a result of clonal deletion. Even though allospecific TEM were able to respond to alloantigen initially, the expansion of these cells and inflammatory cytokine production during GVHD were dramatically decreased. The inability of allospecific TEM to sustain the alloresponse may be a result of enhanced activation-induced cell death. These observations provide insight into how allospecific CD4+ TEM respond to alloantigen during GVHD and underscore the fundamental differences in alloresponses mediated by allospecific TEM in graft rejection and GVHD settings. [Copyright &y& Elsevier]

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/m2). 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 × 107/kg (range: 3.2-7.7 × 107/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. [ABSTRACT FROM AUTHOR]

Hematologists/oncologists would provide essential care for victims of a catastrophic radiation incident, such as the detonation of an improvised nuclear device (IND). The US Radiation Injury Treatment Network (RITN) is a voluntary consortium of 37 academic medical centers, 8 blood donor centers, and 7 umbilical cord banks focused on preparedness for radiation incidents. The RITN conducted 2 tabletop exercises to evaluate response capability after a hypothetical IND detonation in a U.S. city. In the 2008 exercise, medical centers voluntarily accepted 1757 victims at their institutions, a small fraction of the number in need. In the 2009 exercise, each center was required to accept 300 victims. In response, the centers outlined multiple strategies to increase bed availability, extend staff and resources, and support family and friends accompanying transferred victims. The exercises highlighted shortcomings in current planning and future steps for improving surge capacity that are applicable to various mass casualty scenarios. [Copyright &y& Elsevier]

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) × 106 cells/kg and 9.21 (SD 5.6) × 106 cells/kg, respectively. The median number of contaminating CD3+CD56− T cells infused was .53 (1.1) × 106 and .27 (.78) × 106 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. [Copyright &y& Elsevier]

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/m2, days 1, 4, 8, and 11, plus melphalan 6 mg/m2 and prednisone 60 mg/m2, 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% ≥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 5.6×106 CD34+ cells/kg. Posttransplant response rates were 30% ≥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 &y& Elsevier]

Currently, no agents are approved by the United States Food and Drug Administration (FDA) for either prevention or treatment of acute graft-versus-host disease (aGVHD). Formal precedents establishing a comparative basis for assessing the efficacy and safety of new investigational agents are still lacking. As a step toward addressing this problem, a panel of experts met on 2 occasions to reach consensus on recommendations for terminology describing a clinically meaningful primary endpoint in studies assessing treatment for aGVHD. The panel recommended terminology for “very good partial response” (VGPR) that includes both diagnostic and functional criteria. The central hypothesis leading to this proposal is that the potential harm of giving more treatment than needed to produce or maintain complete response exceeds the harm of slight undertreatment that may be associated with less than complete response. VGPR clearly cannot be used as the sole outcome measure in GVHD treatment trials, and must be considered in the context of survival and safety. The proposed use of VGPR as the primary endpoint in GVHD treatment trials will remain provisional until its use has been validated through experience. [Copyright &y& Elsevier]

Gastrointestinal (GI) toxicity and acute graft versus host disease (GVHD) are significant morbidities associated with allogeneic hematopoietic stem cell transplantation (HSCT). The somatostatin analogue Octreotide ameliorates mucosal injury from radiation damage in pre-clinical mouse models. We hypothesized that administration of the longer-acting synthetic somatostatin analogue, Pasireotide, in the peri-transplant period would decrease acute GI toxicity and acute GVHD related to allogeneic HSCT. Adult patients who underwent matched allogeneic HSCT with myeloablative conditioning were eligible for this study. Exclusion criteria included severe cardiac and endocrine abnormalities. Pasireotide was administered at 0.9mg twice daily from the day before conditioning began to day +4. The co-primary endpoints were 1) Acute GI toxicity, defined as GI toxicity occurring from the day prior to conditioning to day +30, and 2) Acute GVHD. Results were compared with 50 historical controls matched by Transplant diagnosis, Donor, Graft, GVHD prophylaxis, and Conditioning regimen. 36 patients were consented for the study, 25 patients received the study drug (5 screen failures, 1 insurance denial, 3 withdrew consent, 1 switched trials, 1 enrolled at an alternate center without available follow-up). There was no difference in Acute GI toxicity, which occurred in all patients in both the Pasireotide and Control groups. Grade 3 or 4 GI toxicity was similar, occurring in 20 patients (80%) in the Pasireotide group and 35 patients (70%) in the Control group. Specific GI toxicities varied in incidence between the Control and Pasireotide study groups (Figure 1), most notable for numerically higher rates of the expected toxicities abdominal pain, bloating, and vomiting in the Pasireotide group. Other common toxicities that occurred in the Pasireotide and Control groups are listed in Figure 1. There was no significant difference in incidence of overall Acute GVHD or Acute GI GVHD (Figure 2). The subset of patients who received Total Body Irradiation (TBI) conditioning had numerically lower Acute GVHD in the Pasireotide group (5/9, 55%) compared to the Control group (16/20, 80%), however this was not statistically significant (Fisher's Exact Test, p=0.21); these patients also had a lower rate of combined upper and lower GI GVHD (3/9, 33% in the Pasireotide group versus 11/20, 55% in the Control group), though this was not statistically significant (Fisher's Exact Test, p=0.43). In this Phase 2 study, the somatostatin analogue Pasireotide did not decrease GI toxicity in allogeneic HSCT; however, in the subset of patients who received TBI conditioning, there was a numerically (but not statistically) significant decrease in overall and GI Acute GVHD. Further study in a larger cohort of patients undergoing TBI conditioning is warranted. [ABSTRACT FROM AUTHOR]

Abstract: Diffuse alveolar hemorrhage (DAH) after allogeneic hematopoietic stem cell transplantation (HSCT) is often fatal. Standard therapy with high-dose corticosteroid is not always effective. There is paucity of data in the literature about other potentially useful agents, such as aminocaproic acid (Amicar) in the post-transplantation setting. We retrospectively reviewed our data on 115 consecutive patients who underwent HSCT and had pulmonary complications, with the aim of determining the overall clinical outcome in recipients of allogeneic transplants and in the subgroup of these patients who were treated with concomitant Solu-Medrol and aminocaproic acid. Aminocaproic acid was added at the discretion of the attending physician. We identified 14 allogeneic transplant recipients (median age, 41 years) with 15 episodes of DAH who were treated with Solu-Medrol (250 mg to 1 g intravenously per day). Of these, 8 patients also received concomitant aminocaproic acid at 1000 mg intravenously every 6 hours. Failure to improve was the most common reason for adding aminocaproic acid. The incidence of DAH was 12.2% (10.3% in myeloablative versus 1.9% in nonmyeloablative recipients). The overall 100-day DAH mortality and median transplantation survival were 60% and 99 days, respectively. Among the subset of patients treated with the combination of Solu-Medrol and aminocaproic acid, we observed a 100-day DAH mortality and median transplantation survival of 44% and 167 days, respectively, compared with 83% and 96.5 days in those treated with Solu-Medrol alone. The median time to DAH was 40.5 days, and the median time to death was 53 days in the combined treatment group compared with 29.5 days in those treated with steroid alone. There were no significant differences in coagulation parameters between subsets. Infections (yeast, respiratory syncytial virus, herpes simplex virus, and parainfluenza) were isolated and treated from 6 diagnostic bronchial alveolar lavage samples and were more common in the subgroup treated with Solu-Medrol only. Respiratory failure was the documented cause of death in 89% of patients. There were no clinically significant side effects from aminocaproic acid. Although these historically lower DAH outcomes are intriguing, prospective studies are needed to confirm the role of aminocaproic acid in DAH occurring in the allogeneic transplantation setting. [Copyright &y& Elsevier]

Abstract: The risk of terrorism with nuclear or radiologic weapons is considered to be high over the coming decade. Ionizing radiation can cause a spectrum of hematologic toxicities, from mild myelosuppression to myeloablation and death. However, the potential regenerative capacity of human hematopoietic stem cells (HSCs) after radiation injury has not been well characterized. In this study, we sought to characterize the effects of ionizing radiation on human HSCs and to determine whether signals from vascular endothelial cells could promote the repair of irradiated HSCs. Exposure of human bone marrow CD34+ cells to 400 cGy caused a precipitous decline in hematopoietic progenitor cell content and primitive cells capable of repopulating nonobese diabetic/severe combined immunodeficient mice (SCID-repopulating cells), which was not retrievable via treatment with cytokines. Conversely, culture of 400 cGy–irradiated bone marrow CD34+ cells with endothelial cells under noncontact conditions supported the differential recovery of both viable progenitor cells and primitive SCID-repopulating cells. These data illustrate that vascular endothelial cells produce soluble factors that promote the repair and functional recovery of HSCs after radiation injury and suggest that novel factors with radiotherapeutic potential can be identified within this milieu. [Copyright &y& Elsevier]

Abstract: T-cell receptor variable β chain (TCRBV) repertoire spectratyping involves the estimation of CDR3 length distributions for monitoring T-cell receptor diversity and has proven useful for analyses of immune reconstitution and T-cell clonal expansions in graft-versus-host disease (GVHD) and graft-versus-leukemia after allogeneic stem cell transplantation. We performed a longitudinal spectratype analysis of 23 TCRBV families in 28 patients who underwent allogeneic T cell–depleted peripheral blood stem cell transplantation. Sixteen patients subsequently developed acute GVHD. We recently developed statistical methods that bring increased power and flexibility to spectratype analysis and allow us to analyze TCRBV repertoire development under appropriately complex statistical models. Applying these methods, we found that patients with acute GVHD demonstrated TCRBV repertoire development statistically distinct from that repertoire development in patients without GVHD. Specifically, GVHD patients showed spectratypes indicative of lower diversity and greater deviation from the spectratypes expected in healthy individuals at intermediate times. Most individual TCRBV subfamilies had spectratypes statistically distinguishable between GVHD and non-GVHD patients at 6 months after transplantation. These results suggest that the T-cell receptor repertoire perturbations associated with acute GVHD are widely spread throughout the TCRBV families. [Copyright &y& Elsevier]

Abstract: We conducted a phase II trial in 19 chronic graft-versus-host disease (cGVHD) patients with rapamycin, calcineurin inhibitors, and prednisone with the goals of controlling cGVHD, reducing prednisone use, and defining the safety of this regimen. Rapamycin was begun as second-line (n = 9) or more than second-line (n = 10) therapy. With a median follow-up of 42 months, 16 patients were evaluable for response. Nine patients discontinued rapamycin because of poor compliance/patient request (n = 2) or an adverse event (n = 7), 3 of whom were not evaluable because of withdrawal at ≤1 month or noncompliance. The adverse events included serum creatinine ≥2.4 mg/dL (n = 4), hemolytic uremic syndrome (n = 2), and relapse of malignancy (n = 1). Fifteen of 16 evaluable patients had a clinical response. Five of the 16 discontinued the drug, and 1 died of relapsed leukemia. Of the 10 patients who continued rapamycin, 2 discontinued and 1 successfully tapered all systemic immunosuppression. Three of the 10 developed progressive cGVHD with tapering immunosuppression; all responded to resumption of prior medications. Four of the 10 patients required alternate therapy for persistent or progressive cGVHD while receiving rapamycin; prednisone was discontinued (n = 2) or tapered at the time of progressive disease (n = 2). Seventeen of 19 original patients were alive. One death was due to relapsed malignancy, and 1 was due to congestive heart failure. In this report of rapamycin as cGVHD therapy, there is evidence of rapamycin’s efficacy. Given the significant toxicities described, investigation of altered administration of rapamycin and calcineurin inhibitors should be pursued in future cGVHD trials. [Copyright &y& Elsevier]

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 × 107/kg (range, 0.54–2.78 × 107/kg), and the median CD34+ cell dose was 1.37 × 105/kg (range, 0.02–12.45 × 105/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/μL was 26 (range, 12–55 days). The median time to an untransfused platelet count of >20 000/μL 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. [Copyright &y& Elsevier]

Abstract: 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/m2 every 12 hours × 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 × 16 doses, followed by etoposide of 60 mg/kg × 1 day (the patient with chronic myeloid leukemia received cyclophosphamide of 60 mg/kg/d × 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 μg/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. © 2003 American Society for Blood and Marrow Transplantation Biology of Blood and Marrow Transplantation 9:183-188 (2003) [Copyright &y& Elsevier]

Background Several professional societies have established nutrition guidelines for patients undergoing HSCT. We surveyed HSCT programs to understand how these compare with clinical practice. Methods Qualitative surveys were emailed to HSCT dietitians. Surveys addressed malnutrition screening; dietary recommendations including nutrition support, graft-versus-host disease (GVHD), immune enhancing nutrients, and prebiotics/probiotics; and nutrition-related preventive care screening. Results Twenty adult programs (19 United States (US), 1 Australia) and 3 pediatric programs (3 US) responded. Annual volume across the 22 US programs was 5405 patients, representing 25% of all transplants in the US. Nineteen programs (83%) follow guidelines for nutrition screening and fourteen for nutrition therapy in the inpatient setting (Table 1); six (26%) follow guidelines for screening and therapy in the outpatient setting. All programs adhere to food safety recommendations and 5 (22%) have additional institutional precautions. However, only 2 programs (9%) report frequent adherence to guidelines for use of enteral nutrition. While there are no guidelines for GVHD diet and uncertainty over alternative nutrition practices, 8 programs (35%) follow a stepwise GVHD diet; 4 (17%) allow immunonutrition supplements; 2 (9%) allow prebiotics, and 7 (30%) allow probiotics after the resolution of neutropenia. With regard to adherence to preventive screening recommendations, only 4 programs (17%) screen for diabetes, 6 (26%) screen for hyperlipidemia, and none screen for abdominal obesity. There are no guidelines for vitamin D deficiency screening, but 10 programs (43%) screen for this. Discussion Wide variations in nutrition practices exist across HSCT programs. Similarly, with the exception of food safety recommendations, there are also wide variations in adherence to established nutrition guidelines. The use of enteral nutrition and preventive screening is particularly varied. Efforts are needed to understand barriers to guideline implementation and their correlation to patient outcomes. Further research is needed regarding new interventions such as immunonutrition, prebiotics, and probiotics. [ABSTRACT FROM AUTHOR]

Introduction Prophylactic, donor lymphocyte infusion (DLI) is used to augment immune recovery and graft vs. tumor effect following a T-cell depleted alloSCT. However, it carries the risk of inducing severe GvHD. Our pre-clinical murine studies have implicated the naive T-cell, defined by CD62L marker, as the primary driver of alloreactivity. We hypothesize that transferring selected memory T-cells without naive-T cells would endow the patient with cells that do not cause GvHD while augmenting host defense against infection and tumor recurrence. Objectives The goal of the study was to determine the maximum tolerated dose of a prophylactic, delayed DLI that has been depleted of naive T-cells. Methods We enrolled 16 adult patients, median age 54 who met following criteria; a. underwent an alemtuzumab or thymoglobulin-containing non-myeloablative allogeneic transplant from an HLA-identical family donor or an 8/8 HLA-matched unrelated donor (MUD), b. at least 60 days from day of transplantation, c. no active acute GvHD grade II or higher. Primary diseases were CLL; n=1, MM; n=2, MF; n=1, NHL; n=5, MDS; n=1, AML; n=6. A dedicated, non-mobilized donor apheresis procedure was performed following enrollment. Naive, CD45RA+ T-cells were depleted from the collection under an IND using the Miltenyi clinimacs system. A standard phase I, 3+3 dose escalation schema was employed. The dose-limiting toxicity of the DLI was defined as development of grade III/IV acute GvHD within 90 days of the DLI. Results The DLI was infused on median 112.5 days (76 to 280 days) following transplant. 8 patients received matched sibling grafts and 8 received MUD grafts. 3 patients each received naive T-cell depleted CD3+ dose of 1 × 105/kg, 1 × 106/kg, and 5 × 106/kg. The top dose of 1 × 107/kg was expanded to 7 patients. No dose limiting toxicity or adverse event attributable to the DLI was observed at any dose level. 1 patient developed grade 2 acute GvHD and 1 developed moderate chronic GvHD attributable to the DLI. 4 patients had relapsed disease; 2 in the lowest dose and 2 in the highest dose levels. With a median follow-up of 2.75 years, 2-year relapse free and overall survivals are 56.25% and 68.75%, respectively (Fig 1 and 2). NK cells, CD3+T lymphocytes, CD4+ T lymphocytes and CD8+ T lymphocytes show positive correlations of 0.24, 0.40, 0.42 and 0.38 respectively with time following the DLI (Fig 3). Conclusion A prophylactic, naive T-cell depleted DLI can be provided safely, without significant risk of acute GvHD at a dose of 1 × 10e7 CD3/kg. Larger studies in a more homogeneous patient population will be needed to confirm the impact on immune recovery and relapse prevention. [ABSTRACT FROM AUTHOR]

Intestinal microbiota injuries in allo-HCT patients are characterized by loss of a-diversity and domination of microbial communities by single organisms. These injury patterns are associated with poor survival after allo-HCT and are likely attributable to antibiotic exposure, nutritional alterations, and regimen-related mucosal injury. As recipients of auto-HCT patients have similar exposures, we hypothesized that similar patterns of dysbiosis occur in auto-HCT patients. We present the first analysis of intestinal microbiota composition in auto-HCT patients at two independent institutions. From a prospectively collected cohort, we retrospectively identified 365 patients (median age 60) who received auto-HCT (May 2009 to Feb. 2018) at two transplant centers (MSK n = 316; Duke n = 49) with heterogeneous conditioning regimens, pre-HCT remission status, and diagnoses: 179 (49%) myeloma, 153 (42%) lymphoma, and 33 (9%) other diseases. 857 samples collected approximately weekly peri-transplant were 16S sequenced (V4-V5 region, Illumina platform) at a central laboratory. Stool samples from 17 volunteers at MSK and a publicly available dataset of 313 subjects from the Human Microbiome Project (HMP) served as healthy-control cohorts. The median pre-auto-HCT a-diversity during day -10 to 0 (as measured by Simpson reciprocal index, S) at both centers was significantly lower than healthy controls (Fig A) (HMP vs MSK auto-HCT, S =12.05 vs. 9.19, p<0.005; HMP vs Duke auto-HCT, S =12.05 vs 6.91, p<0.005, Wilcoxon test). Pre-HCT diversity was comparable in between auto-HCT and allo-HCT at each center (MSK auto-HCT vs MSK allo-HCT, S = 12.05 vs 8.74, p=0.53). Overall (days -10 to +30) diversity decreased comparably after auto-HCT and allo-HST across both centers, while auto-HCT patients demonstrated a slightly more rapid recovery at day +30 compared to allo-HCT patients (Fig 1B). Monodomination was observed in the samples (Fig 1C), with Streptococcus and Enterococcus as the most common genus, as defined by any single taxon comprising >30% of bacterial abundance. The cumulative incidence of intestinal domination by any organism was >50% by day 0 and was >75% by day +14. Microbial diversity is reduced prior to transplant in both auto-HCT and allo-HCT patients compared with healthy volunteers. Loss of diversity after auto-HCT occurs across transplant centers and the degree of injury is comparable to the dysbiosis observed in allo-HCT patients. We previously reported that intestinal monodomination increases the risk of bacteremia with corresponding organisms in allo-HCT patients. We now report these events are a common occurrence after auto-HCT, which suggests prevention or repair of microbiota injury as a strategy to reduce the toxicity of auto-HCT. [ABSTRACT FROM AUTHOR]

Delirium is common among adults undergoing hematopoietic stem cell transplant (HCT), although the clinical predictors and neuroimaging correlates of postoperative delirium have not been adequately delineated. We therefore examined the frequency of delirium and neuroimaging correlates of post-HCT delirium in a retrospective cohort of 115 adults undergoing BMT. Delirium was established using previously validated methods for retrospective identification of chart-assessed postoperative delirium. Chart reviews were independently conducted by a team including a HCT physician, a transplant psychiatrist, a transplant psychologist, and a psychiatry resident on consecutive allogeneic HCT patients who underwent neuroimaging assessments, transplanted between January, 2009 December, 2016Y. Neuroimaging markers of cortical volume loss and white matter hyperintensities were also recorded. One hundred fifteen patients were included, ranging in age from 20 to 74 (mean age = 49 [SD = 13]). Fifty-three patients (46%) developed post-HCT delirium. In an adjusted model, delirium incidence was associated with older age (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 treatment regimen intensity (OR = 6.37 [2.20, 18.45], P <.001) but was unrelated to cortical atrophy (P =.777). Greater incidence of delirium following BMT was associated with greater age, microvascular burden, and more severe treatment regimen. Pre-HCT consideration of microvascular burden and other neuroimaging biomarkers of risk may be warranted. [ABSTRACT FROM AUTHOR]

Hematopoietic cell transplant (HCT) is an increasingly common and curative treatment strategy to improve survival among individuals malignant and nonmalignant diseases, with over one million HCTs having been performed worldwide. Neurocognitive dysfunction is a common and untoward consequence of HCT for many recipients, although few studies have examined the profile of neurocognitive impairments in HCT or their association with clinical features, such as frailty. We examined the pattern and correlates of pre-transplant neurocognitive dysfunction in a prospective sample of adults undergoing HCT. Neurocognition was assessed using the Montreal Cognitive Assessment Battery. Frailty was assessed using the Short Physical Performance Battery. Linear regression analysis was used to examine the associations between neurocognitive performance and frailty. Profiles of neurocognitive performance were also examined by partitioning MoCA scores into relevant domains of interest, including Executive Function and Memory. Regression analyses controlled for age, gender, education, and disease type. One hundred and ten adults were evaluated across a wide age range (range: 19-75; mean age = 54.7 [SD = 14.1]). Neurocognitive performance tended to fall below published normative levels (mean MoCA = 25.5 [SD = 4.1]), with 20% of participants demonstrating impaired performance compared with medical patients (score < 24) and 34% exhibiting impaired performance relative to healthy normative samples (score <26). Examination of cognitive profiles revealed that while mild impairments in Executive Function were common across the entire sample, greater age was most closely associated with worse Memory performance (r = -0.33, P<.01) and greater levels of short physical performance battery score were most strongly associated with worse Executive Function (r = -0.39, P<.01). Neurocognitive impairments are common among adults undergoing HCT and the pattern of performance varies by age. Frailty is a strong correlate of neurocognitive function and particularly Executive Function components. [ABSTRACT FROM AUTHOR]

In order to learn more about the role of the microbiome in hematopoietic stem cell transplantation (HCT), researchers collect stool samples from patients at various time points throughout HCT. However, unlike blood samples or skin swabs, stool collection requires active subject participation, particularly in the outpatient setting, and may be limited by patient aversion to handling stool. By providing study participants with compensation for their stool samples, we hypothesize that we can significantly increase stool collection rates. We performed a prospective cohort study on the impact of financial incentives on stool collection rates for microbiome studies. The intervention group consisted of allo-HCT patients from 05/2017-05/2018 who were compensated with a $10 gas gift card for each stool sample. The intervention group was compared to a historical control group consisting of allo-HCT patients from 11/2016-05/2017 who provided stool samples before the incentive was implemented. To control for potential changes in collections over time, we also compared a contemporaneous control group of auto-HCT patients from 05/2017-05/2018 with a historical control group of auto-HCT patients from 11/2016-05/2017; neither auto-HCT groups were compensated. Allo-HCT patients were required to give samples at pre-HCT, day 0 (the day of HCT), and days 7, 14, 21, 30, 60, and 90 post-HCT. Auto-HCT patients were required to give samples at pre-HCT and days 7, 14, and 90 post-HCT. Collection rates were defined as the number of samples provided divided by the number of time points for which we attempted to obtain samples. There were 35 allo-HCT patients in the intervention group, 19 allo-HCT patients in the historical control group, 142 auto-HCT patients in the contemporaneous control group, and 75 auto-HCT patients in the historical control group. Allo-HCT patients in the intervention group had significantly higher average overall collection rates when compared to the historical control group allo-HCT patients (80% vs 37%, p<0.001), as well has significantly higher average outpatient collection rates (84% vs 23%, p<0.001) and average inpatient collection rates (71% vs 46%, p=0.04). In contrast, there were no significant differences in overall average collection rates between the auto-HCT patients in the contemporaneous control and historical control groups (36% vs 32%, p=0.28), as well as the average outpatient collection rates (30% vs 28%, p=0.54) and the average inpatient collection rates (46% vs 59%, p=0.25). Our results demonstrate that even a modest incentive can significantly increase collection rates. While this study uses a specialized HCT patient population, these results may be generalizable to informing the design of future studies and aid other researchers in obtaining stool samples needed for future microbiome studies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]