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Human leukocyte antigen (HLA) mismatches in stem cell transplantation can be well-tolerated with the use of post-transplant cyclophosphamide (PTCy) for graft-versus-host-disease (GvHD) prophylaxis. Haploidentical (Haplo) and HLA-mismatched unrelated donors become acceptable donors. This review focuses on Haplo and unrelated donor selection in the context of PTCy-transplant for hematological malignancy, in comparison with conventional GvHD prophylaxis. Evaluating patient's donor-specific antibody (DSA) is critical in donor selection regardless of donor type or the use of PTCy. High DSA levels and positive C1q increase the risk of engraftment failure and unsuccessful desensitization. On the other hand, the degree of donor HLA matching is less critical under PTCy compared to conventional GvHD prophylaxis. Donor age was found to be important, as younger donors improve survival outcomes. HLA-B leader match appears to be preferable. The impacts of donor gender, donor cytomegalovirus serostatus, and ABO mismatch are unclear or non-significant. Additionally, available studies suggest that, in PTCy-transplant, preferred Haplo-donors are HLA class II mismatched (DRB1 mismatch and DPB1 non-permissive), siblings or offspring over parents, and if parent, father over mother, while preferred unrelated donors are HLA class I matched. Further study is warranted. [ABSTRACT FROM AUTHOR]

Carbon emissions have become a critical concern in the global effort to combat climate change, with each country or region contributing differently based on its economic structures, energy sources, and industrial activities. The factors influencing carbon emissions vary across countries and sectors. This study examined the factors influencing CO2 emissions in the 7 South American countries including Argentina, Brazil, Chile, Colombia, Ecuador, Peru, and Venezuela. We used the Seemingly Unrelated Regression (SUR) model to analyse the relationship of CO2 emissions with gross domestic product (GDP), renewable energy use, urbanization, industrialization, international tourism, agricultural productivity, and forest area based on data from 2000 to 2022. According to the SUR model, we found that GDP and industrialization had a moderate positive effect on CO2 emissions, whereas renewable energy use had a moderate negative effect on CO2 emissions. International tourism generally had a positive impact on CO2 emissions, while forest area tended to decrease CO2 emissions. Different variables had different effects on CO2 emissions in the 7 South American countries. In Argentina and Venezuela, GDP, international tourism, and agricultural productivity significantly affected CO2 emissions. In Colombia, GDP and international tourism had a negative impact on CO2 emissions. In Brazil, CO2 emissions were primarily driven by GDP, while in Chile, Ecuador, and Peru, international tourism had a negative effect on CO2 emissions. Overall, this study highlights the importance of country-specific strategies for reducing CO2 emissions and emphasizes the varying roles of these driving factors in shaping environmental quality in the 7 South American countries. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion There is an imbalance between demand for and availability of stem cell donors worldwide. The purpose of this systematic review is to provide the first comprehensive understanding of facilitators and barriers influencing unrelated stem cell donation (USCD) in adults, through a data synthesis of qualitative and quantitative evidence. Identification of the facilitators and barriers associated with stem cell donation intention and behaviour is essential to inform the development of behaviour change interventions to meet the current demand.Four databases were searched (Embase, PsycINFO, MEDLINE and CINAHL) and the last search was in February 2021. The search was limited to studies written in English and published from 1980 to present. Screening, quality assessment, data extraction and data synthesis incorporating the COM‐B model were undertaken in line with the Joanna Briggs Institute methodology for an integrated mixed‐methods review.Fifty studies were included in the review, analysis and mapping produced four integrated findings. Donation‐related knowledge was a facilitator and conversely, lack of knowledge was a barrier to donation related behaviours. Perceived convenience, positive social influences, religious beliefs and the accessibility of positive donation‐related social norms promoted positive donation related behaviours. Altruism and sense of duty were the most commonly cited motives for donation related behaviours.Through mapping to the COM‐B model, Communication/Marketing, and Service Provision are the primary policy categories that can be used to change donation related behaviours.Future interventions should focus on targeted education regarding unrelated stem cell donation and creating recruitment campaigns that emphasise the life‐saving potential of donation. [ABSTRACT FROM AUTHOR]

In malleable job scheduling, jobs can be executed simultaneously on multiple machines with the processing time depending on the number of allocated machines. In this setting, jobs are required to be executed non-preemptively and in unison, in the sense that they occupy, during their execution, the same time interval over all the machines of the allocated set. In this work, we study generalizations of malleable job scheduling inspired by standard scheduling on unrelated machines. Specifically, we introduce a general model of malleable job scheduling, where each machine has a (possibly different) speed for each job, and the processing time of a job j on a set of allocated machines S depends on the total speed of S with respect to j. For machines with unrelated speeds, we show that the optimal makespan cannot be approximated within a factor less than e e - 1 , unless P = N P . On the positive side, we present polynomial-time algorithms with approximation ratios 2 e e - 1 for machines with unrelated speeds, 3 for machines with uniform speeds, and 7/3 for restricted assignments on identical machines. Our algorithms are based on deterministic LP rounding. They result in sparse schedules, in the sense that each machine shares at most one job with other machines. We also prove lower bounds on the integrality gap of 1 + φ for unrelated speeds (φ is the golden ratio) and 2 for uniform speeds and restricted assignments. To indicate the generality of our approach, we show that it also yields constant factor approximation algorithms for a variant where we determine the effective speed of a set of allocated machines based on the L p norm of their speeds. [ABSTRACT FROM AUTHOR]

Heterogeneous multiprocessors can offer high performance at low energy expenditures. However, to be able to use them in hard real-time systems, timing guarantees need to be provided, and the main challenge is to determine the worst-case schedule length (also known as makespan) of an application. Previous works that estimate the makespan focus mainly on the independent-task application model or the related multiprocessor model that limits the applicability of the makespan. On the other hand, the directed acyclic graph (DAG) application model and the unrelated multiprocessor model are general and can cover most of today's platforms and applications. In this work, we propose a simple work-conserving scheduling method of the tasks in a DAG and two new approaches to finding the makespan. A set of representative OpenMP task-based parallel applications from the BOTS benchmark suite and synthetic DAGs are used to evaluate the proposed method. Based on the empirical results, the proposed approach calculates the makespan close to the exhaustive method and with low pessimism compared to a lower bound of the actual makespan calculation. [ABSTRACT FROM AUTHOR]

This paper presents a federated scheduling algorithm for implicit-deadline sporadic DAGs that execute on an unrelated heterogeneous multiprocessor platform. We consider a global work-conserving scheduler to execute a single DAG exclusively on a subset of the unrelated processors. Formal schedulability analysis to find themakespan of aDAG on its dedicated subset of the processors is proposed. The problem of determining each subset of dedicated unrelated processors for each DAG such that the DAG meets its deadline (i.e., designing the federated scheduling algorithm) is tackled by proposing a novel processors-to-task assignment heuristic using a new concept called processor value. Empirical evaluation is presented to show the effectiveness of our approach. [ABSTRACT FROM AUTHOR]

Background: Greater use of unrelated donors to support hematopoietic cell transplantation can be hampered by unavailability of registrants when identified as potential candidates for donation. Methods: Multivariate analysis was performed to identify donor factors associated with availability for verification of human leukocyte antigen typing (VT) needed before donor activation. All VT requests for registrants on the Canadian Blood Services Stem Cell Registry between 1 January and 31 December 2018 were reviewed (n = 1358). Results: Potential donors identified by transplant centers were categorized as available at the time of VT but ineligible for medical or other reasons (n = 130 and excluded from further analysis), available (n = 622) or unavailable (n = 566) due to scheduling, loss of interest, and/or inability to contact. With multivariate analysis, registrants who previously donated blood, those recruited online or from blood donation clinics, and a shorter interval between registration and VT request were significantly correlated with increased donor availability. Donor sex and geographic location, however, displayed no correlation. Conclusion: Online registration and recruitment at whole blood donation centers should be enhanced to increase the availability of registrants at VT. More insight is needed to maintain registrant availability following community in‐person recruitment events, especially if the interval between registration and activation is prolonged. Recruitment of male registrants who are well informed should not negatively impact availability. [ABSTRACT FROM AUTHOR]

• HLA-A-B-C-DRB1-DQB1 haplotypes carry significantly differing DPB1 associations. • DPB1 associations impact the likelihood of finding URDs with permissive DPB1 genotype. • The DPB1 associations in Finland differ from the worldwide population. • With increasing data, DPB1 associations could be assessed in different populations. • Predicting DPB1 permissiveness of DPB1 nontyped donors is feasible. Although HLA-DPB1 has long been considered of lesser importance in the selection of an unrelated donor (URD) hematologic stem cell transplantation, currently in many instances the DPB1 type of the donor is relevant or even critical. At present, however, only a minority of registry donors are DPB1 typed. It is also unclear to what extent the DPB1 alleles are linked to the 5-locus HLA-A-, B-, C-, DRB1, -DQB1 haplotypes. We sought to study whether there is such a linkage by using donors in the Finnish Stem Cell Registry as the study population. The 6-locus HLA-A, -B, -C, -DRB1, -DQB1, -DPB1 haplotype frequencies were estimated from a group of 43,365 Finnish registry donors using the German National Bone Marrow Registry algorithm. Five-locus haplotype (HLA-A, -B, -C, -DRB1, -DQB1) and HLA-DPB1 allele frequencies were calculated as marginal frequencies of the estimated 6-locus haplotype frequencies. The Finnish average frequency of individual DPB1 alleles was compared with their respective frequencies in association with individual 5-locus HLA haplotypes (haplotype-specific frequencies). Finally, the probability of DPB1 matching in 10/10 matched URD transplants was assessed. Haplotype-specific DPB1 frequencies differed significantly from the average DPB1 frequencies in 81 of 100 most frequent Finnish 5-locus HLA haplotypes, including some infrequent DPB1 alleles that were associated almost exclusively with certain individual 5-locus haplotypes. Five-locus haplotypes that are enriched in Finland but rare among other Europeans carried stronger DPB1 associations than haplotypes that are frequent European-wide. Finally, 10/10 matched transplants from domestic registry donors were significantly more likely to also be DPB1 matched than those from foreign donors. The results indicate an extension of linkage disequilibrium in the MHC complex in the Finnish population. With continuing upfront DPB1 typing of registry donors, it will be possible to perform similar extended 6-locus haplotype frequency estimations also in other registries. The associations are likely to be population specific but may be weaker in more heterogeneous populations. In the future the results might be used to predict the probability of DPB1 match or permissive/nonpermissive DPB1 mismatch for non-DPB1 typed donors in registry donor searches. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a curative treatment option for multiple myeloma (MM), but few patients are eligible due to its high risk of treatment-related toxicity and relapse. Here, we report the feasibility and efficacy of allo-SCT after myeloablative conditioning with 8 Gy of total body irradiation (TBI) for reducing relapse of MM. We retrospectively analyzed data from 30 consecutive patients who received allo-SCT for MM after 8 Gy of TBI at Japanese Red Cross Medical Center between 2012 and 2021. Median age at allo-SCT was 47 (range 31-61) years. Stem-cell sources were peripheral blood from an HLA-matched related donor (MRD, n=5), bone marrow from an HLA-matched unrelated donor (MUD, n=5), bone marrow from an HLA-mismatched unrelated donor (MMUD, n=13), and cord blood (n=7). All patients received conditioning with 8 Gy of TBI combined with Flu/Mel (n=28) or others (n=2). Five-year PFS and 5-year OS were 36.7% and 46.2%, respectively. Sixteen patients died during the observation period (12 of primary disease and 4 of treatment-related toxicity). Patients with VGPR or better before allo-SCT had significantly better PFS (p=0.009) and OS (p=0.01) than others. Patients who received MMUD cells tended to have better PFS than those with other cell sources. Our report showed that allo-SCT for MM after 8 Gy of TBI is feasible, and the better PFS of MMUD suggests graft-versus-myeloma effects.

Zika virus has emerged as a potential threat to the Canadian blood supply system. Stem cell donors within Canadian Blood Services' Cord Blood Bank (CBB) and OneMatch Stem Cell and Marrow Network (OM) now undergo screening measures designed to reduce the risk of Zika virus transmission. The impact these screening measures have on cord blood and unrelated adult stem cell donations is currently unknown. Among 146 donor workups initiated by OM between July 2016 and May 2017, 102 were completed and 44 workups were canceled. There were 17 potential donors (11.6%) with a risk of Zika virus exposure identified by the donor questionnaire (13 completed, 4 canceled workups). None of the workups involved a donor diagnosed with confirmed Zika virus within the past 6 months. Only 1 of the 44 canceled workups (and only 1 of 4 cases with a risk of Zika transmission) was canceled because of the risk of Zika transmission, and a backup donor was selected. Canadian Blood Services' CBB identified 25 of 875 cord blood units (2.9%) from women who donated their infants' cord blood and underwent screening that otherwise met the initial cell number thresholds for banking and had at least 1 risk factor for exposure to Zika virus. No women were diagnosed with Zika virus at any point of their pregnancy. All 25 units were discarded. Unrelated donors at OM have a higher incidence of a risk of exposure to Zika virus compared with cord blood donors. Only rarely did transplant centers cancel donor workups due to potential Zika virus exposure. The impact of screening for Zika virus exposure risk on cord blood banking was minor. Continued vigilance and surveillance is recommended. [ABSTRACT FROM AUTHOR]

Europeans have often been considered a homogenous group in registry donor match predictions, but it is now evident that HLA haplotype frequencies vary across the European continent. Earlier studies have indicated that Finns in northeastern Europe have unique HLA characteristics, and the increasing availability of high-resolution registry donor data is now making more detailed comparisons possible. In the first phase of the present study, estimated HLA haplotype frequencies in stem cell donor registries of Finland and its neighbors Sweden and Russia were calculated using the algorithm of the German National Bone Marrow Donor Registry (ZKRD) and their frequencies were compared with one another and also with that of Germany. Virtual donor searches for 1492 high-resolution typed Finnish patients in the Finnish, Swedish and German registries were then performed, using individual match predictions for each registry. In the last phase, the impact of specifically Finnish-enriched HLA haplotypes on Finnish patients and the use of Finnish registry donors was assessed by analyzing 647 consecutive hematopoietic stem cell transplantation (HSCT) donor searches and 40 exported Finnish HSCTs. The Finnish HLA landscape was more homogenous than the 3 other studied populations, but also genetically distinct from them. The match predictions found a probable 10/10 match for 71%, 41%, and 31% of the Finnish patients in the German, Finnish, and Swedish registries, respectively. Thirty-four of Finland's 100 most frequent HLA haplotypes were represented with a frequency of <.0003 in Germany, and with an 8- to 3262-fold greater frequency in Finland than in Germany. Patients carrying these Finnish-enriched haplotypes were less likely to receive a matched HSCT but more likely to receive it from a domestic donor. Registry donors carrying them were more likely to donate stem cells, both nationally and internationally. The Finnish HLA isolate has a significant impact on both Finnish patients and registry donors, explaining the high use of national registry donors for Finnish patients. Haplotype frequency estimations are an important tool for small registries as well, to help optimize donor match predictions and the size of individual registries. [ABSTRACT FROM AUTHOR]

Assessing the performance of scheduling heuristics through simulation requires one to generate synthetic instances of tasks and machines with well-identified properties. Carefully controlling these properties is mandatory to avoid any bias. We consider the scheduling problem consisting of allocating independent sequential tasks on unrelated machines while minimizing the maximum execution time. In this problem, the instance is a cost matrix that specifies the execution cost of any task on any machine. This article proposes two measures for quantifying the heterogeneity properties of a cost matrix. An analysis of two classical methods used in the literature reveals a bias in previous studies. We propose new methods to generate instances with given heterogeneity properties and we show that heterogeneity has a significant impact on twelve heuristics. [ABSTRACT FROM AUTHOR]

To evaluate the safety and efficacy of donor lymphocyte infusion (DLI), we retrospectively analyzed 414 recipients who received unrelated DLI (UDLI) for the treatment of relapsed hematological malignancy after unrelated bone marrow transplantation (BMT). UDLI was administered for acute myelogenous leukemia (n = 184), myelodysplastic syndrome (n = 69), acute lymphocytic leukemia (n = 57), chronic myelogenous leukemia (CML, n = 36), lymphoid neoplasms (n = 38), adult T cell leukemia/lymphoma (n = 18), and multiple myeloma (n = 12). Sixty-five patients (16%) were in cytogenetic/molecular relapse and 349 (84%) were in hematological relapse after BMT. In total, 266 out of 414 (64%) patients received chemotherapy and/or molecular-targeted agents in combination with UDLI. The median time from BMT to UDLI was 244 days. The median number of infused CD3 + cells was 3.51 × 10 7 /kg. Response and survival rates were evaluated at 100 days after UDLI. Complete response was obtained in 37 (57%) of 65 patients with cytogenetic/molecular relapse and in 69 (20%) of 349 patients with hematological relapse ( P  < .001). Two hundred forty-seven patients (60%) were alive, whereas 110 (26%) had died because of disease progression, 26 (6%) because of infections, 12 (3%) because of graft-versus-host disease (GVHD), and 13 (3%) because of organ failure. Multivariate analysis identified molecular/cytogenetic relapse, GVHD after UDLI, and CML but not combination with chemotherapy as significant prognostic factors. These results indicate that UDLI may have efficacy in relapsed patients with CML, low tumor burden, or occurrence of GVHD after UDLI. [ABSTRACT FROM AUTHOR]

Some retrospective studies have suggested that long-term donor statin use may protect against graft-versus-host disease (GVHD) in patients receiving cyclosporine (CSP)-based immunosuppression after allogeneic hematopoietic cell transplantation (HCT), but prospective studies of short-term treatment of donors with statin have shown conflicting results. We conducted 2 consecutive prospective clinical trials to assess whether donor statin treatment was associated with protection against severe acute GVHD (aGVHD). In a single-arm phase II trial (study 1), we evaluated whether short-term statin treatment of HLA-matched related donors for 14 days before HCT prevented grade III-IV aGVHD. In a prospective observational cohort study (study 2), we evaluated whether longer-term (>14 days) donor statin use was required for GVHD-protective effects. Study 1 was terminated after 6 of the 35 recipients (17%) developed grade III-IV GVHD. For study 2, we identified 135 patients whose unrelated donors had received long-term treatment with statins up to the time of HCT and 4942 patients whose donors had not received long-term statin treatment. The adjusted odds ratio for grade III-IV aGVHD (statin versus no statin) was .83 (95% confidence interval [CI], .46 to 1.50; P = .54). Multivariable analysis showed no statistically significant differences between the 2 groups in the risk of grade II-IV aGVHD, chronic GVHD, nonrelapse mortality, recurrent malignancy, or overall mortality. Among patients receiving CSP-based immunosuppression, including 35 with donors receiving long-term statin treatment and 973 with donors who did not receive statins, the adjusted odds ratio of grade III-IV aGVHD was .30 (95% CI, .07 to 1.35; P = .12). In study 1, short-term statin treatment of donors was ineffective in preventing grade III-IV GVHD. In study 2, in the prespecified subgroup of recipients given CSP-based immunosuppression, nondefinitive evidence suggested that donor statin use was associated with a reduced risk of severe aGVHD., (Copyright © 2023. Published by Elsevier Inc.)

Besides donor T cells, natural killer (NK) cells are considered to have a major role in preventing relapse after allogeneic hematopoietic stem cell transplantation (HSCT). After T-cell-depleted haploidentical HSCT, a strong NK alloreactivity has been described. These effects have been attributed to killer-cell immunoglobulin-like receptors (KIR). Abundant reports suggest a major role of KIR not only on outcome after haploidentical HSCT but also in the unrelated donor setting. In this review, we give a brief overview of the mechanism of NK cell activation, nomenclature of KIR haplotypes, human leukocyte antigen (HLA) groups, and distinct models for prediction of NK cell alloreactivity. It can be concluded that KIR-ligand mismatch seems to provoke adverse effects in unrelated donor HSCT with reduced overall survival and increased risk for high-grade acute graftversus- host disease. The presence of activating KIR, as seen in KIR haplotype B, as well as the patient's HLA C1/x haplotype might reduce relapse in myeloid malignancies. [ABSTRACT FROM AUTHOR]

At the beginning of 2014 over 24 million of unrelated donors being listed in the registries worldwide and number of hematopoietic stem cell collections exceed 16 000 per year. In order to insure the quality of unrelated donor searches Quality Assurance Working Group at the World Marrow Donor Association defined global key performance indicators for bone marrow donor registries, which were retrospectively evaluated also within Czech National Marrow Donors Registry. The aim of the study was evaluate the performance of quality indicators, perform further analysis for those that do not meet the specified criteria and compare the observed result with published data. For the year 2013 three of the five analysed quality indicators were fulfilled: the rate of extended typing performed within two weeks of receipt of the request, the rate of donors available during work up examination and the rate of discrepant typing identified in the verification typing. Two quality indicators were not fulfilled: the rate of samples of the donors available during verification typing (79% in the CNMDR compared to 80% WMDA recommended) and the rate of samples sent for verification typing within two weeks from receipt of the request (64% in the CNMDR compared to 80% WMDA recommended). Due to this unfulfilled indicators reasons for the unavailability of the donors were analysed and the lack of contact was identified as the main reason. Looking at the detail we identified the risk group of donors with only contact address and phone number provided upon entry to the registry. On the contrary minimum of unavailable donors were in the group of donor with e-mail contact. Based on the findings of unfulfilled quality indicators further quality improvement objectives were defined for the future. [ABSTRACT FROM AUTHOR]

We studied 459 consecutive patients with hematologic malignancies, median age 44 years (range, 15 to 71 years), who underwent transplantation with grafts from identical sibling donors (SIB; n = 176), matched unrelated donors (MUD; n = 43), mismatched unrelated donors (mmUD; n = 43), unrelated cord blood (UCB; n = 105) or HLA-haploidentical family donors (HAPLO; n = 92). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate in the SIB recipients; antithymocyte globulin for the MUD, mmUD, and UCB recipients; and post-transplantation cyclophosphamide, cyclosporine, and mycophenolate in the HAPLO recipients. Conditioning regimens were mostly myeloablative (69%). Advanced disease phase was more frequent, but not significantly so, in the HAPLO and mmUD groups ( P = .08). Acute GVHD grade II-IV was significantly less frequent in the HAPLO, UCB, and MUD groups (14% to 21%) compared with the SIB (31%) and mmUD (42%) groups ( P < .001), and there was a trend toward less moderate-severe chronic GVHD in the HAPLO and UCB groups ( P = .053). The proportion of patients off cyclosporine at 1 year ranged from 55% for the SIB group to 81% for the HAPLO group ( P < .001). Transplantation-related mortality at 2 years was lower in the HAPLO and SIB groups (18% to 24%) compared with the MUD, mmUD, and UCB groups (33% to 35%; P = .10). Relapse rate was comparable in the 5 groups ( P = .80). The 4-year actuarial survival was 45% in the SIB group, 43% in the MUD group, 40% in the mmUD group, 34% in the UCB group, and 52% in the HAPLO group ( P = .10). In multivariate analysis, advanced disease was a negative predictor of survival (hazard ratio [HR], 2.4; P < .0001), together with a diagnosis of acute leukemia (HR, 1.8; P = .0001); HAPLO grafts were comparable to SIB ( P = .80), whereas UCB had inferior survival ( P = .03). In conclusion, unmanipulated haploidentical family donor transplants are an additional option for patients lacking a matched sibling donor. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated adult donors is currently the standard and in many cases the only curative treatment option for a wide range of malignant and non-malignant haematological diseases. In the Czech Republic, it involves approximately 70-80% of patients indicated for allogeneic HSCT who do not have a related donor. The demand for unrelated donors has risen over the last decade and it is likely that a similar trend will continue. Longer time from diagnosis to transplantation appears to be a significant adverse negative factor affecting the outcome of unrelated HSCT. The provision of unrelated donors has been identified as a key source of delay. The article defines and analyses all the major causes that delay unrelated HSCT. It also aims to establish recommendations how to eliminate or minimize these factors. On the basis of these recommendations, the unrelated donor search process should be optimized both in medical and economic terms. The recommendations are based primarily on current international practice and recommendations of the WMDA (World Marrow Donor Association) and also take into account current practices and specificities of the transplant program in our country. [ABSTRACT FROM AUTHOR]

The therapeutic effect of unrelated donor stem cell transplantation (SCT) is predominantly determined by genetic non-identity - HLA-mismatch - between recipient and donor. This facilitates both the desirable graft versus leukaemia (GVL) effect, which reduces the risk of relapse in malignancies as well as the graft-versus-host disease (GVHD), which increases mortality. This paper attempts to summarize the current view on the overall significance of HLA match and to interpret the qualitative and quantitative effect of mismatches in individual HLA genes on the outcome of SCT from an unrelated adult donor, particularly in malignant diseases. The current standard involves an effort to find an allele-level matched donor at least in HLA-A,-B,-Q-DRB1, because isolated mismatch in each of these genes increases mortality by approximately 10% and multiple mismatches actually have a negative synergistic effect. However, the consequences of incompatibility are significantly influenced by disease stage, as in high-risk patients these are much less significant or even negligible because of the accentuated GVL response. With the possible exception of the HLA-C locus, mismatches either on allelic or antigenic level seem to be comparably tolerated in peripheral blood stem cell transplantation. If it is necessary to accept a mismatched donor, then in the case of bone marrow it is best to avoid mismatches in HLA-A and DRB1, while in the case of peripheral blood stem cells the worst tolerated "antigenic" mismatch involves HLA-C. Apart from HLA match, there are many factors on the donor side that affect SCT outcome. These especially include timely transplantation, as the speed of finding an unrelated donor and SCT within the shortest possible time are almost as important as the degree of HLA-compatibility. [ABSTRACT FROM AUTHOR]

Abstract: We performed a retrospective analysis on the outcomes of 135 hematopoietic stem cell transplantations (HSCTs) for primary immunodeficiency disorders in Australian and New Zealand Children’s Haematology Oncology Group transplantation centers between 1992 and 2008. The most common indications for HSCT were severe combined immunodeficiency, Wiskott-Aldrich syndrome, and chronic granulomatous disease. Five-year overall survival (OS) was 72% for the entire cohort. Disease-specific 5-year OS was 70% for severe combined immunodeficiency, 81% for Wiskott-Aldrich syndrome, and 69% for chronic granulomatous disease. Transplantation-related mortality (TRM) was 10% at day +100. TRM and OS were equivalent in recipients of related and unrelated donor transplants. Source of stem cells had no impact on TRM or OS with outcomes following unrelated umbilical cord blood similar to unrelated bone marrow. The presence of interstitial pneumonitis, active cytomegalovirus infection, or veno-occlusive disease were all independent variables that significantly decreased OS. This large series supports the use of HSCT as curative therapy for a range of primary immunodeficiency disorders, demonstrating excellent survival after both related and unrelated donor transplantation. [Copyright &y& Elsevier]

Lesch-Nyhan syndrome (LNS) is a chronic, progressive neurodevelopmental disorder causing motor and behavioral dysfunction due to decreased synthesis of the enzyme hypoxantine-guanine phosphoribosyltransferase (HPRT). Affected boys have mental retardation, delayed development, extrapyramidal motor disturbances and self-injuring behavior. As hematopoietic stem cell transplantation (HSCT) has been shown to be effective in several neurodevelopmental inborn errors, we hypothesized that it could be favorable in LNS as well. Following a myeloablative conditioning regimen (busulphan 3.2 mg/kg/day for 4 days, cyclophosphamide 60 mg/kg/day for 2 days with ATG Thymoglobin 2.5 mg/kg/day for 4 days) an unrelated umbilical cord blood unit was transfused at the age of 2 years. The graft was a 6/6 HLA-matched at HLA-A, B loci by antigen level, and at DRB1 by allelic level typing. Infused total nucleated cell dose was 3.6 × 10e7 per kilogram body weight. Serum HPRT levels reached normal values by the end of the sixth month post transplant. Slow neurodevelopmental improvement seen during the three-year follow-up and the missing self-injuring behavior can be considered as a proof for the presence of enzyme-competent cells behind the blood-brain barrier. [ABSTRACT FROM AUTHOR]

Scheduling problems have been analyzed by several researchers for over forty years. Much progress has been made in the scheduling theory, approximate solutions, complexity aspects, and practical algorithms. The focus of this paper is on one class of scheduling problems known as unrelated parallel machines. We look at the progress made in this area since the author's thesis (Suresh ) in the early 1990's. Suggestions for further research is made with a discussion of some of the areas not explored in this paper. [ABSTRACT FROM AUTHOR]

In the current study, we evaluated a combination of tacrolimus and mycophenolate mofetil (MMF) as GvHD prophylaxis in 50 patients undergoing truly nonmyeloablative (NM; 90 mg/m2 fludarabine, 2 Gy TBI) hematopoietic SCT (HSCT) from unrelated donors. Median patient age was 51 years (range, 25-67 years). After a median follow-up of 1123 days (range, 47-2729 days), 20 patients (40%) are alive and free from disease. The probabilities of 1-, 2- and 3-year survival were 57, 47 and 39%, respectively. Patients who achieved a remission before HSCT had a significantly better OS compared with those who had active disease (P=0.01). The incidences of grade II-IV and III-IV acute GvHD (aGvHD) were 54% (n=27) and 16% (n=8). Remarkably, using tacrolimus and MMF, the median onset of aGvHD occurred distinctly late on day +66 (range, 12-119 days). A total of 46 patients were evaluable for chronic GvHD (cGvHD). Out of these, 26 (56%) patients developed cGvHD, with 16 (34%) of them showing limited and 10 (21%) showing extensive disease. We conclude that the combination of tacrolimus and MMF as post transplant immunosuppression for patients receiving NM unrelated donor HSCT permits stable engraftment and effective prophylaxis for acute and cGvHD. In particular, the occurrence of severe early-onset aGvHD was attenuated. [ABSTRACT FROM AUTHOR]

Infectious complications following allogeneic hematopoietic cell transplantation (HCT) from unrelated donors (URD) result in significant morbidity. We hypothesized that recipients of a URD with an activating natural killer cell immunoglobulin-like receptor (KIR) (B/x) genotype would have decreased infectious complications because of enhanced natural killer (NK) cell function. We compared the infectious complications in 116 recipients of a graft from a donor with an A/A KIR (n = 44) genotype and a B/x KIR (n = 72) genotype. All recipients participated in the prospective National Marrow Donor Program infection project collecting infection data from conditioning until 6 months posttransplant. The cohort with a B/x donor had fewer initial bacterial infections by day 180 (A/A: 86%; 95% confidence interval [CI], 75-95; B/x: 68%; 95% CI, 57-78; P = .02). There was no difference in the incidence of viral or fungal infections. When accounting for multiple infections, fewer bacterial infections were seen in the B/x cohort (A/A: 3.55/patient; B/x: 2.63/patient; P = .09). During the study period, only 19 patients had no infections; of these, 15 had received cells from a B/x KIR donor. The role of donor KIR genotype on infection complications is intriguing and warrants further investigation. [Copyright &y& Elsevier]

In the absence of a related donor, unrelated cord blood transplant (CBT) may be a potential option for patients with a primary immune deficiency (PID). Most published experience consists of single-center data using multiple preparative regimens and GVHD prophylaxis. We report the results of a multicenter prospective trial of unrelated CBT for PID. A total of 24 children with PID, with a median age of 1 year (range: 0.23–7.81 years) and a median weight of 10.5 kg (range: 4–24.4 kg) received unrelated CBT between 1999 and 2003. All patients received a fully ablative conditioning regimen with identical GVHD prophylaxis and supportive care. Most patients (79%) received a 1 or 2 HLA Ag-mismatched cord unit with a median nucleated cell infused of 9.3 × 107/kg (range: 1.0–31.2) and a median CD34 of 2.7 × 105/kg 2.9 (range: 0.6–84.5). The cumulative incidence of neutrophil engraftment by day 42 was 58% (95% CI: 38–79%) at a median of 19 days. Cumulative incidence estimates of grade III–IV acute GVHD at day 100 and chronic GVHD at 1 year were 29% (95% CI: 10–48%) and 24% (95% CI: 3–44%), respectively. The probability of survival at 180 days and 1 year was 66.7% (95% CI: 44.3–81.7%) and 62.5% (95% CI: 40.3–78.4%), respectively. Unrelated CBT should be considered in children with PID. [ABSTRACT FROM AUTHOR]

We compared outcomes of 916 diffuse large B cell lymphoma (DLBCL) patients aged ≥18 years undergoing first autologous (n = 837) or myeloablative (MA) allogeneic hematopoietic cell transplant (HCT) (n = 79) between 1995 and 2003 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Median follow-up was 81 months for allogeneic HCT versus 60 months for autologous HCT. Allogeneic HCT recipients were more likely to have high-risk disease features including higher stage, more prior chemotherapy regimens, and resistant disease. Allogeneic HCT was associated with a higher 1 year treatment-related mortality (TRM) (relative risk [RR] 4.88, 95% confidence interval [CI], 3.21-7.40, P < .001), treatment failure (RR 2.06, 95% CI, 1.54-2.75, P < .001), and mortality (RR 2.75, 95% CI, 2.03-3.72, P < .001). Risk of disease progression was similar in the 2 groups (RR 1.12, 95% CI, 0.73-1.72, P = .59). In fact, for 1-year survivors, no significant differences were observed for TRM, progression, progression-free (PFS) or overall survival (OS). Increased risks of TRM and mortality were associated with older age (>50 years), lower performance score, chemoresistance, and earlier year of transplant. In a cohort of mainly high-risk DLBCL patients, upfront MA allogeneic HCT, although associated with increased early mortality, was associated with a similar risk of disease progression compared to lower risk patients receiving autologous HCT. [Copyright &y& Elsevier]

The optimal alternative donor for adult hematopoietic stem cell transplantation (HSCT) candidates who lack an ideal histocompatible sibling remains controversial. We studied the clinical outcomes of 88 adult patients with hematologic malignancies who received a partially matched related donor (PMRD) transplant (n=36) or a matched unrelated donor (MUD) transplant (n=52) with a uniform myeloablative protocol without ex vivo T cell depletion. Age and other characteristics were comparable in the 2 groups, except that the PMRD group had a higher proportion of bone marrow (BM) grafts. Primary engraftment was achieved in nearly 98% of the whole cohort. The incidences of acute grade III-IV and extensive chronic graft-versus-host disease (aGVHD, cGVHD) were 15% and 16% in the PMRD group and 16% and 14% in the MUD group. Although treatment-related mortality (TRM) was 42% in the PMRD group and 31% in the MUD group (P =.29), the relapse rate was<11% for the whole cohort. With a median follow-up of 30 months, no statistically significant difference was observed in 3-year overall survival (OS) and event-free survival (EFS) between the PMRD group (45% and 38%) and the MUD group (54% and 50%). These data demonstrate that HSCT performed with PMRD can be an alternative option for treating adult patients with hematologic malignancies. [Copyright &y& Elsevier]

Abstract: Myeloablative allogeneic hematopoietic cell transplantation (HCT) may cure patients with relapsed or refractory Hodgkin lymphoma (HL), but is associated with a high treatment-related mortality (TRM). Reduced-intensity and nonmyeloablative (RIC/NST) conditioning regimens aim to lower TRM. We analyzed the outcomes of 143 patients undergoing unrelated donor RIC/NST HCT for relapsed and refractory HL between 1999 and 2004 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Patients were heavily pretreated, including autologous HCT in 89%. With a median follow-up of 25 months, the probability of TRM at day 100 and 2 years was 15% (95% confidence interval [CI] 10%-21%) and 33% (95% CI 25%-41%), respectively. The probabilities of progression free survival (PFS) and overall survival (OS) were 30% and 56% at 1 year and 20% and 37% at 2 years. The presence of extranodal disease and the Karnofsky Performance Scale (KPS) <90 were significant risk factors for TRM, PFS, and OS, whereas chemosensitivity at transplantation was not. Dose intensity of the conditioning regimen (RIC versus NST) did not impact outcomes. Unrelated donor HCT with RIC/NST can salvage some patients with relapsed/refractory HL, but relapse remains a common reason for treatment failure. Clinical studies should be aimed at reducing the incidence of acute graft-versus-host disease (GVHD) and relapse. [Copyright &y& Elsevier]

Several recipient and donor risk factors affect outcome after transplantation with allogeneic hematopoietic stem cells. The most important recipient risk factors are patient age, comorbidity, performance status, cytomegalovirus (CMV) status, and disease considerations, such as diagnosis, stage, and cytogenetic risk. Prior chemotherapy regimens, patient race, and IL10 promoter polymorphism also appear to have some impact, but to a lesser extent. The most important donor factor is the level of HLA mismatch. Donor gender, relation, age, and KIR genotype also affect outcome. Donor CMV serology, parity, and race do not appear to affect outcome. These factors must all be considered in relation to one another when selecting whether to recommend patients for transplant. [Copyright &y& Elsevier]

Evaluation of the impact of live unrelated kidney donor (LURD) source on the outcome of renal transplantation is not adequately studied. We aimed to compare the long-term outcome of kidney transplantation from LURDs to that from living related donors (LRDs) among a pediatric recipient population. This study comprised 235 pediatric recipients who received their kidney grafts between 1976 and 2005 at our center. These patients were further subdivided into two groups according to donor source (211 with LRDs) and (24 with LURDs). All patients’ data were assessed with special emphasis on graft and patient survival as well as posttransplant medical complications. Both groups were comparable regarding graft and patient survival at 1, 5, and 10 years. Despite higher incidence of acute vascular rejection among recipients with LURD (12%) vs. LRD (2.8%) ( P = 0.03), there was no difference in the incidence of chronic allograft nephropathy. Moreover, the overall incidence of posttransplant complications was comparable among the two groups. In our series, kidney survival was poorer in LURDs compared with LRDs. However, the number of patients with LURD was small, and the difference in results was also small and justifies LURD in exceptional cases when LRD is not possible. [ABSTRACT FROM AUTHOR]

Abstract: We sought to determine whether patients with hematologic malignancies treated by nonmyeloablative hematopoietic cell transplantation (HCT) at a single institution between December 1997 and June 2006 had worse outcomes with grafts from unrelated donors (URDs) (n = 184) compared with HLA-identical related donors (n = 221). The nonmyeloablative preparative regimen consisted of 2 Gy of total body irradiation (TBI) with (78%) or without (22%) fludarabine, along with posttransplantation mycophenolate mofetil (MMF) and cyclosporine (CSa). After adjusting for the HCT comorbidity index, relapse risk, patient age, stem cell source, preparative regimen, previous cytomegalovirus (CMV) infection, and sex mismatch of donor and recipient in multivariate analysis, we found no statistically significant differences between unrelated and related HCT recipients in terms of risk of nonrelapse mortality (NRM; hazard ratio [HR] = 0.98; 95% confidence interval = 0.6-1.6; P = .94), relapse (HR = 1.04; 95% confidence interval = 0.7-1.5; P = .82), or overall mortality (HR = 0.99; 95% confidence interval = 0.7-1.4; P = .94). Overall rates of severe acute and extensive chronic graft-versus-host disease (aGVHD, cGVHD) also were not significantly different between the 2 groups. We conclude that within the limitations of a retrospective study, these results indicate that candidates for nonmyeloablative HCT without suitable related donors may expect similar outcomes with grafts from URDs. [Copyright &y& Elsevier]

Transplantation is the best treatment of end-stage renal disease (ESRD); however, organ shortage is a reality. Deceased donor organ donation is inadequate; hence, the number of patients on the waiting lists is increasing progressively. Since many ESRD patients do not have living genetically related donors, living unrelated transplantation is considered. These transplantations offer excellent graft and patient survival rates if practiced in conventional situations, while the results are not so favorable or even poor in unconventional transplantations, which mostly take place in developing countries. Ethical aspects of living unrelated transplantation are more complicated than the medical side due to concern of commercialization. Making payment to the donors has been considered strictly as nonethical by many authors, while some others suggest reopening previous debates for kidney sales. The latter claim that if exploitation of donors is avoided, the reward (or payment) to the donor can be morally justified. Apart from these controversies, it is uniformly accepted that commercial transplantation is certainly unethical when brokers are involved or the aim is just profit for transplant physicians, because the main reason in favor of organ sales is improving the quality of life of the patients and the donors, not the brokers or the physicians. All these theoretical ethical arguments in the Western countries turn out to become vital concerns in developing countries, because transplantation is the cheapest renal replacement therapy. Recently, it has been suggested that organ shortage problems can partly be solved by establishing controlled donor compensation programs in these countries, which may also prevent exploitation of the donors. However, it is impossible to suggest a uniform solution for all countries because of deep differences in economical status as well as social and cultural values. Thus, every country should build its own ethical standards for commercial transplantation. [ABSTRACT FROM AUTHOR]

Evans syndrome is an autoimmunopathy characterized by thrombocytopenia and autoimmune hemolytic anemia with poor response to immunosuppression. A 2-yr-old boy with Evans syndrome showed only short-lasting responses to immunosuppressive treatment including double autologous peripheral stem cell transplantation (SCT). Intracranial bleeding required emergency splenectomy and external ventricular drainage. Unrelated umbilical cord blood was given following conditioning with busulfan, thiotepa, etoposide and antithymocyte globulin. One year after SCT the patient shows stable blood counts without immunosuppression. This is the first child reported with Evans syndrome successfully treated by means of unrelated cord blood transplantation. [ABSTRACT FROM AUTHOR]

We report the results of 84 patients with ALL after related (n=46) or unrelated (n=38) allogeneic SCT. Mean recipient age was 23 years (range: 1-60) and median follow-up was 18 months (range: 1-133). Forty-three patients were transplanted in CR1; 25 in CR2 or CR3; four were primary refractory; four in PR; eight in relapse. The conditioning regimen consisted of TBI/VP16/CY (n=76), TBI/VP16 (n=2), TBI/CY (n=2), Bu/VP16/CY (n=4). The OS at 3 years was 45% (44% unrelated, 46% related). Univariate analysis showed a significantly better OS for patients <18 years (P=0.03), mismatched sex-combination (P=0.03), both with a stronger effect on increasing OS after unrelated SCT. Factors decreasing TRM were patient age <18 years (P=0.004), patient CMV-seronegativity (P=0.014), female recipient (P=0.04). There was no significant difference in TRM and the relapse rate was similar in both donor type groups. Multivariate analysis showed that factors for increased OS which remained significant were mismatched sex-combination (RR: 0.70,95% Cl: 0.51-0.93, P=0.015), patient age < 18 years (RR: 0.66, 95% Cl: 0.47-0.93, P=0.016). A decreased TRM was found for female patients (RR: 0.56, 95% Cl: 0.33-0.98, P=0.042), negative CMV status of the patient (RR: 0.57, 95% Cl: 0.36-0.90, P=0.015). Unrelated stem cell transplantation for high-risk ALL patients with no HLA-compatible family donor is justifiable. [ABSTRACT FROM AUTHOR]

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Summary:Graft-versus-host disease (GVHD) remains a major barrier to successful hematopoietic stem cell transplant for patients who lack a matched related donor. Partial T-cell depletion (TCD) of the graft may decrease the risk of severe GVHD with unrelated donors (URD) and partially matched related donors (PMRD) while retaining an antileukemic effect. We analyzed our experience using URD and PMRD for pediatric patients with leukemias from 1990 to 2001. A subgroup of‘matched’URD donor pairs was retrospectively analyzed for high-resolution class I. Partial TCD was accomplished with monoclonal antibody T10B9 or OKT3 and complement. There were 76 URD (45%matched) and 28 PMRD recipients. Event-free survival (EFS) was 38.3%, and overall survival (OS) 45.1%at 3 years. On multivariate analysis, there was no difference in survival based upon marrow source, but nonrelapse mortality was higher with the use of PMRD. Relapse occurred in 6%of ALL patients, and 22.8%of AML/MDS patients. Grades III-IV GVHD was observed in only 6.7%of patients. Partial TCD allows use of matched or mismatched URD, or PMRD with little mortality from GVHD, durable engraftment, and no increase in relapse risk.Bone Marrow Transplantation (2005) 35, 151-158. doi:10.1038/sj.bmt.1704754 Published online 8 November 2004 [ABSTRACT FROM AUTHOR]

Gustafsson JernbergÅ, Remberger M, Ringdén O, Winiarski J. Risk factors in pediatric stem cell transplantation for leukemia.Pediatr Transplantation 2004: 8: 464–474.© 2004 Blackwell MunksgaardTo investigate which factors impact on survival, relapse, relapse free survival, transplant-related mortality (TRM) and graft-versus-host disease (GVHD) in children who undergo allogeneic stem cell transplantation, we included all 181 children transplanted due to leukemia at our unit. At the end of follow up 54% of the patients were alive, 27% had died due to relapse while 19% had died of other causes. Survival was similar in recipients of related (55%) and unrelated grafts (48%). Risk factors identified in univariate analysis were brought into a multivariable analysis. However, an unrelated donor was not identified as a risk factor for any of the five end-points analysed. A donor positive for three to four herpes viruses increased the risk of acute GVHD, TRM and death. A female to male transplant increased the risk of TRM, particularly if combined with a mismatch. Early stage of disease as well as human leukocyte antigen (HLA)-matching independently predicted survival. The risk of relapse increased after 1992. Chronic GVHD independently decreased the risk of relapse (relative risk RR, 0.39) and death (RR 0.42). We conclude that in children with leukemia other specific donor characteristics such as HLA-matching, gender, parity, and exposure to herpes viruses were more important for outcome than relationship. [ABSTRACT FROM AUTHOR]

We report the results of unrelated cord blood transplantation (CBT) after myeloablative conditioning in 21 patients over the age of 45 years. Among the patients the median age was 48 years (range, 45–53 years), the median weight was 58·6 kg (range, 43·6–76·2 kg) and the median number of cryopreserved nucleated cells was 2·45 × 107/kg (range, 1·63–3·71 × 107/kg). Nineteen patients had myeloid reconstitution and the median time to more than 0·5 × 109/l absolute neutrophil count was 22 d. A self-sustained platelet count more than 50 × 109/l was achieved in 17 patients at a median time of 49 d. Acute graft- versus-host disease (GVHD) above grade II occurred in 7 of 19 evaluable patients and chronic GVHD occurred in 14 of 16 evaluable patients. Among 14 chronic GVHD patients, in seven patients the disease was extensive. Fifteen patients were alive and free of disease at between 217 and 1798 d after transplantation. With a median follow-up of 847 d, the probability of disease-free survival at 2 years was 71·4%. These results suggest that patients over 45 years of age without suitable related or unrelated bone marrow donors should be considered as candidates for CBT. [ABSTRACT FROM AUTHOR]

Fifty-seven patients receiving unrelated donor (UD) BMT were matched for disease and stage with 57 recipients of genotypically matched related donor (MRD) BMT. All UD recipients were matched serologically for A and B and by high resolution for DR and DQ antigens. All patients received CsA and ‘short course’ methotrexate with folinic acid. Unrelated donor BMT patients also received thymoglobulin 4.5 mg/kg (6 mg/kg if <30 kg) in divided doses over 3 days pretransplant. For UD and RD BMT, respectively, incidence of acute GVHD grade II–IV was 19 ± 6% vs 36 ± 8%, grade III–IV 10 ± 6% vs 18 ± 7%, chronic GVHD 44 ± 8% vs 51 ± 8%, non-relapse mortality 15 ± 5% vs 8 ± 4% at 100 days, 28 ± 8% vs 36 ± 7% at 3 years. At 3 years, relapse was 45 ± 7% vs 42 ± 7%, and disease-free survival 39 ± 7% vs 37 ± 7%. None of these differences are significant. Three-year overall survival was identical at 42 ± 7%. For 29 patients with low/intermediate risk leukemia, disease-free survival was 68 ± 10% after UD BMT vs 59 ± 9% for RD BMT recipients (P = NS). Corresponding figures for high risk patients were 14 ± 7% and 21 ± 8%, respectively. We conclude that UD BMT recipients matched as above and given pretransplant ATG have similar outcomes to recipients of MRD BMT using conventional drug prophylaxis. Unrelated donor BMT should be considered in any circumstance where MRD BMT is routine. [ABSTRACT FROM AUTHOR]

Summary. We performed a clinical comparison of unrelated cord blood transplantation (UCBT) and unrelated bone marrow transplantation in adult acute leukaemia patients in complete remission (CR) who received the same conditioning regimen, graft-versus-host disease (GvHD) prophylaxis and supportive treatment. The incidence of acute GvHD was almost the same between the two groups, but the haematopoietic recovery was delayed and the incidence of chronic GvHD was higher in the UCBT group. The probability of 2 year disease-free survival was similar between the two groups. These results suggest that adult acute leukaemia patients in CR without a suitable donor should be considered as candidates for UCBT. [ABSTRACT FROM AUTHOR]

Cord blood (CB) has emerged as a potential source of hematopoietic stem cells for patients who □ are in need of hematopoietic stem cell transplant (HSCT). The authors analyzed the Pediatric Blood and Marrow Transplant Consortium's (PBMTC) data of consecutive unrelated CB transplants performed during the initial 2 years of using placental blood grafts. From January 1995 to December 1996 PBMTC performed a total of 44 unrelated CB transplant for a variety of diseases consisting of acute leukemias (n = 29), congenital conditions (n = 9), and bone marrow failure (n = 6). There were 15 females and 29 males with median age of 5 years (range 0.4-20.6 years) and median weight of 18.2 kg (range 6.3-70 kg). The median volume of CB units was 80 mL (range 44.5-215 mL) and the median cell dose given was 4.3 × 10[sup 7]/kg of recipient weight (range 1.1-23 × 10[sup 7]/kg). Techniques used for human leukocyte antigen (HLA) matching were serologic typing for class I HLA antigens and high-resolution molecular typing for HLA-DRB[sub 1] alleles. HLA disparities were as follows: 4 were 6/6 matches, 21 were 5/6, 15 were 4/6, and 4 were 3/6. Twenty-nine (66%) of CB units were DRB[sub 1] matched with recipients. Conditioning regimens consisted of either total body irradiation containing (n = 31) or chemotherapy only (n = 11) regimens. All but 3 patients receive cyclosporine as part of graft vs. host disease (GvHD) prophylaxis in combination with either methotrexate (MTX) or methylprednisolone (Pred). The other 3 patients had FK506 and MTX for GvHD prophylaxis. Myeloid engraftment (absolute neutrophil count ≥ 500) occurred at a median of 21 days (range 10-43 days) and platelet ≥ 50,000/mm[sup 3] was noted at a median of 44 days (range 16-102 days). Eight patients died too early (< day + 28) for evaluation of engraftment (5 for infection, 2 for multiorgan failure, 1 for toxic epidermolysis). The probability of having grade II-IV acute GvHD for all patients was 44 ± 0.7%. The incidence of a GvHD is similar for 4/6 and 5/6 antigen when DRB[sub 1] matched, at 47 and 52%, respectively. Chronic GvHD was noted in 28% of patients surviving > 90 days. The Kaplan-Meier estimate of 4-year event-free survival was 43%. A Cox model for analysis of factors associated with survival was DRB [sub 1] matching, p = .001; cell dose, p = .009; and younger age, p = .03. In conclusion, CB transplant offers a good alternative to bone marrow transplant Although GvHD occurs, it is usually of low severity despite the high frequency of multiple HLA antigen mismatches. It also appears that a 4/6 is as good as a 5/6 matched antigen CB unit when DRB[sub 1] matched especially in the pediatric setting. [ABSTRACT FROM AUTHOR]