Sibling versus unrelated donor allogeneic hematopoietic cell transplantation for chronic myelogenous leukemia: refined HLA matching reveals more graft-versus-host disease but not less relapse.

Unrelated donor (URD) hematopoietic cell transplantation (HCT) can eradicate chronic myelogenous leukemia (CML). It has been postulated that greater donor-recipient histoincompatibility can augment the graft-versus-leukemia (GVL) effect. We previously reported similar, but not equivalent, outcomes of URD versus sibling donor HCT for CML using an older, less precise classification of HLA matching. Here, we used our recently refined HLA-matching classification, which is suitable for interpretation when complete allele-level typing is unavailable, to reanalyze outcomes of previous HCT for CML. We found that using our new matching criteria identifies substantially more frequent mismatching than older, less precise "6 of 6 antigen-matched" URD-HCT. Under the new criteria, only 37% of those previously deemed "HLA- matched" were HLA well matched, and 44% were partially matched. Using our refined matching criteria confirms the greater risk of graft failure in partially matched or mismatched URD-recipient pairs compared with either sibling or well-matched URD-recipient pairs. Acute and chronic graft-versus-host disease (aGVHD, cGVHD) are significantly more frequent with all levels of recategorized URD HLA matching. Importantly, overall survival (OS) and leukemia-free survival (LFS) remain significantly worse after URD-HCT at any matching level. No augmented GVL effect accompanied URD HLA mismatch. Compared with sibling donor transplants, we observed only marginally increased (not statistically significant) risks of relapse in well-matched, partially matched, and mismatched URD-HCT. These data confirm the applicability of revised HLA-matching scheme in analyzing retrospective data sets when fully informative, allele-level typing is unavailable. In this analysis, greater histoincompatibility can augment GVHD, but does not improve protection against relapse; thus the best donor remains the most closely matched donor.

Unrelated donor hematopoietic cell transplantation for non-hodgkin lymphoma: long-term outcomes.

We analyzed the outcomes of 283 patients receiving unrelated donor allogeneic hematopoietic cell transplantation for non-Hodgkin lymphoma (NHL) facilitated by the Center for International Blood and Marrow Transplant Research/National Marrow Donor Program (CIBMTR/NMDP) between 1991 and 2004. All patients received myeloablative conditioning regimens. The median follow-up of survivors is 5 years. Seventy-three (26%) patients are alive. The day 100 probability of death from all causes is estimated at 39%. The cumulative incidence of developing grade III-IV acute graft-versus-host disease (aGVHD) at day 100 is 25%. The estimated 5-year survival and failure free survival are 24% (95% confidence interval [CI]: 19-30) and 22% (95% CI: 17-28), respectively. Factors adversely associated with overall survival (OS) included increasing age, decreased performance status, and refractory disease. Follicular lymphoma (FL) and peripheral T cell lymphoma had improved survival compared to aggressive B cell lymphomas. Factors adversely associated with progression-free survival (PFS) included performance status, histology, and disease status at transplant. Long-term failure-free survival is possible following unrelated donor transplantation for NHL, although early mortality was high in this large cohort.

Analyzing center specific outcomes in hematopoietic cell transplantation.

Reporting transplant center-specific survival rates after hematopoietic cell transplantation is required in the United States. We describe a method to report 1-year survival outcomes by center, as well as to quantify center performance relative to the transplant center network average, which can be reliably used with censored data and for small center sizes. Each center's observed 1-year survival outcome is compared to a predicted survival outcome adjusted for patient characteristics using a pseudovalue regression technique. A 95% prediction interval for 1-year survival assuming no center effect is computed for each center by bootstrapping the scaled residuals from the regression model, and the observed 1-year survival is compared to this prediction interval to determine center performance. We illustrate the technique using a recent center specific analysis performed by the Center for International Blood and Marrow Transplant Research, and study the performance of this method using simulation.

Twenty years of unrelated donor hematopoietic cell transplantation for adult recipients facilitated by the National Marrow Donor Program.

For more than 20 years the National Marrow Donor Program has facilitated unrelated donor hematopoietic cell transplants for adult recipients. In this time period, the volunteer donor pool has expanded to nearly 12 million adult donors worldwide, improvements have occurred in the understanding and technology of HLA matching, there have been many changes in clinical practice and supportive care, and the more common graft source has shifted from bone marrow (BM) to peripheral blood stem cells (PBSCs). The percentage of older patients who are receiving unrelated donor transplants is increasing; currently over 1 in 10 adult transplant recipients is over the age of 60 years. Chronic myelogenous leukemia (CML) was previously the most common diagnosis for unrelated donor transplantation, but it now comprises less than 10% of transplants for adult recipients. Transplants for acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), non-Hodgkin lymphoma (NHL), and myelodysplastic syndromes (MDS) all outnumber CML. Treatment-related mortality (TRM) has declined significantly over the years, particularly in association with myeloablative transplant preparative regimens. Correspondingly, survival within each disease category has improved. Particularly gratifying are the results in severe aplastic anemia (AA) where 2-year survival has doubled in just 10 years.

Twenty years of unrelated donor bone marrow transplantation for pediatric acute leukemia facilitated by the National Marrow Donor Program.

The National Marrow Donor Program (NMDP) has facilitated unrelated donor hematopoietic cell transplants for more than 20 years. In this time period, there have been many changes in clinical practice, including improvements in HLA typing and supportive care, and changes in the source of stem cells. Availability of banked unrelated donor cord blood (incorporated into the NMDP registry in 2000) as a source of stem cells has become an important option for children with leukemia, offering the advantages of immediate availability for children with high-risk disease, the need for a lesser degree of HLA match, and expanding access for those with infrequent HLA haplotypes. Overall survival (OS) in children with acute leukemia transplanted with unrelated donor bone marrow (BM) is markedly better in more recent years, largely attributable to less treatment-related mortality (TRM). Within this cohort, 2-year survival was markedly better for patients with acute lymphoblastic leukemia (ALL) in first complete response (CR1) (74%) versus second complete response (CR2) (62%) or more advanced disease (33%). Similar findings are observed with patients with AML, suggesting earlier referral to bone marrow transplant (BMT) is optimal for survival. Notably, this improvement over time was not observed in unmodified peripheral blood stem cell (PBSC) recipients, suggesting unmodified PBSC may not be the optimal stem cell source for children.

A high degree of HLA disparity arises from limited allelic diversity: analysis of 1775 unrelated bone marrow transplant donor-recipient pairs.

The allelic diversity and associated human leukocyte antigen (HLA) disparity of 1775 bone marrow recipients and their unrelated donors, matched for six of six (1361/1775,77%), five of six (397/1775, 22%), or four of six (17/1775, 1%) HLA-A, -B, -DR antigens, were retrospectively evaluated. The comprehensive HLA analysis included the class I (A, B, C) and II (DRB1, DQA1, DQB1, DPA1, DPB1) loci. Most (>66%) of the predominantly Caucasian study population carried one or two of five to seven common alleles at each HLA locus. In spite of this limited diversity, 29% of the six of six antigen-matched transplants carried allele mismatches at HLA-A, -B, and/or -DRB1, and 92% carried at least one allele mismatch at one of the eight HLA loci tested. Of the 968 HLA-A,-B,-DRB1 allele-matched pairs, 89% carried mismatches at other HLA loci, predominantly at DP loci. The substantially greater than expected HLA allelic disparity between donor and recipient suggests extensive haplotypic diversity and underscores the importance of enhancing approaches to mitigate the deleterious effect of HLA mismatches.

The effect of KIR ligand incompatibility on the outcome of unrelated donor transplantation: a report from the center for international blood and marrow transplant research, the European blood and marrow transplant registry, and the Dutch registry.

Matching for HLA class I alleles, including HLA-C, is an important criterion for outcome of unrelated donor transplantation. However, haplotype-mismatched transplantations for myeloid malignancies, mismatched for killer immunoglobulin-like receptor (KIR) ligands in the graft-versus-host (GVH) direction, is associated with lower rates of graft-versus-host disease (GVHD), relapse, and mortality. This study investigated the effect of KIR ligand mismatching on the outcome of unrelated donor transplantation. The outcomes after 1571 unrelated donor transplantations for myeloid malignancies where donor-recipient pairs were HLA-A, -B, -C, and -DRB1 matched (n = 1004), GVH KIR ligand-mismatched (n = 137), host-versus-graft (HVG) KIR ligand-mismatched (n = 170), and HLA-B and/or -C-mismatched but KIR ligand-matched (n = 260) were compared using Cox regression models. Treatment-related mortality (TRM), treatment failure, and overall mortality were lowest after matched transplantations. Patients who received grafts from donors mismatched at the KIR ligand in the GVH or HVG direction and mismatched at HLA-B and/or C but matched at the KIR ligand had similar rates of TRM, treatment failure, and overall mortality. There were no differences in leukemia recurrence between the 4 groups. These results do not support the choice of an unrelated donor on the basis of KIR ligand mismatch determined from HLA typing.

The National Vegetation Classification Standard applied to the remote sensing classification of two semiarid environments.

The National Vegetation Classification Standard (NVCS) was implemented at two US National Park Service (NPS) sites in Texas, the Padre Island National Seashore (PINS) and the Lake Meredith National Recreation Area (LMNRA), to provide information for NPS oil and gas management plans. Because NVCS landcover classifications did not exist for these two areas prior to this study, we created landcover classes, through intensive ground and aerial reconnaissance, that characterized the general landscape features and at the same time complied with NVCS guidelines. The created landcover classes were useful for the resource management and were conducive to classification with optical remote sensing systems, such as the Landsat Thematic Mapper (TM). In the LMNRA, topographic elevation data were added to the TM data to reduce confusion between cliff, high plains, and forest classes. Classification accuracies (kappa statistics) of 89.9% (0.89) and 88.2% (0.87) in PINS and LMNRA, respectively, verified that the two NPS landholdings were adequately mapped with TM data. Improved sensor systems with higher spectral and spatial resolutions will ultimately refine the broad classes defined in this classification; however, the landcover classifications created in this study have already provided valuable information for the management of both NPS lands. Habitat information provided by the classifications has aided in the placement of inventory and monitoring plots, has assisted oil and gas operators by providing information on sensitive habitats, and has allowed park managers to better use resources when fighting wildland fires and in protecting visitors and the infrastructure of NPS lands.

Allogeneic bone marrow transplantation for chronic myelogenous leukemia: comparative analysis of unrelated versus matched sibling donor transplantation.

Allogeneic bone marrow transplantation (BMT) offers the only curative therapy for chronic myelogenous leukemia. We compared prospectively collected results of 2464 unrelated donor (URD) transplantations with 450 HLA-identical, matched sibling donor (MSD) transplantations performed at collaborating National Marrow Donor Program institutions. A total of 63% of URDs were matched at HLA-A, -B, and at -DRB1 alleles; all MSDs were genotypically identical at major histocompatibility loci. URD recipients were younger (median 36 vs 39, P =.001) than MSDs and underwent BMT later after diagnosis (median 17 [0-325 months] vs 7 [1-118 months], P =.001) and less often in chronic phase (CP) (67% vs 82%, P =.001). Multivariate analysis demonstrated a significantly increased risk of graft failure and acute graft versus host disease after URD BMT. The risk of hematologic relapse was low after either matched URD or MSD transplantations. We observed significantly though modestly poorer survival and disease-free survival (DFS) after URD transplantations. However, for those undergoing transplantation during CP within 1 year from diagnosis, 5-year DFS was similar or only slightly inferior after matched URD versus MSD transplantation (age < 30: URD 61% +/- 8% vs MSD 68% +/- 15%, P =.18; 30-40: URD 57% +/- 9% vs MSD 67% +/- 10%, P =.05; > 40: URD 46% +/- 9% vs MSD 57% +/- 9%, P =.02). Delay from diagnosis to BMT in CP patients led to substantially poorer 5-year DFS after matched URD than MSD BMT (CP 1-2 years: URD 39% +/- 6% vs MSD 63% +/- 12%; beyond 2 years: URD 33% +/- 7% vs MSD 50% +/- 20%). Outcome of matched URD BMT for early CP chronic myelogenous leukemia yields survival and DFS approaching that of MSD transplantation. However, delay may compromise URD outcomes to a greater extent. Improvements in URD and MSD transplantation are still needed, and results of newer, nontransplantation therapies should be evaluated against the established curative potential of URD and MSD marrow transplantation.

Unrelated donor bone marrow transplantation for children with juvenile myelomonocytic leukaemia.

Children with juvenile myelomonocytic leukaemia (JMML) have a poor outcome, with survival in a minority of patients. The major limitation on success of sibling donor bone marrow transplantation for JMML has been reported to be relapse. A total of 46 children with a diagnosis of JMML underwent unrelated donor marrow (URD) transplantation facilitated by the National Marrow Donor Program. Forty-three of 46 patients had neutrophil engraftment at a median of 20 d post transplant, with platelet recovery in 28 of 40 evaluable patients at a median of 34.5 d. Thirty-two of 44 evaluable patients developed acute graft-versus-host-disease (GVHD) (Grades 2-4) and chronic GVHD developed in 14 of 35 evaluable patients. At a median follow-up of 2.0 years, probabilities of survival and disease-free survival were 42% and 24% respectively. The probability of relapse was 58% at 2 years and represents the major cause of treatment failure. Multivariate analysis revealed that chronic GVHD was associated with reduced relapse [risk ratio 0.20 (95% CI 0.04-1.02, P=0.05)] improved survival [risk ratio 0.13 (95% CI 0.03-0.68, P=0.02)] and event-free survival [risk ratio 0.23 (95% CI 0.06-0.94, P=0.04)]. This study demonstrates that relapse is the major cause of treatment failure in patients with JMML undergoing URD transplantation. With lower relapse observed in patients with chronic GVHD, new treatment strategies that focus on enhancing the graft-versus-leukaemia effect may improve survival.