depend on a specific early diagnosis. Since 1994, we have come a long way in understanding the role of proinflammatory cytokines at the cellular level both within the fetus and in a possible relationship to fetal brain damage. Heretofore, birth markers such as Apgar scores, electronic fetal monitoring, neuroimaging, and onset of seizures in the first 48 hours are not specific and not sensitive. In the 1994 editorial, I stated that more accurate markers of hypoxia were needed and should develop as our understanding of the biochemical mechanisms unfold. Now that the biochemical mechanisms are unfolding, and once we can get specific levels of cytokines in the blood and the cerebrospinal fluid, interventions can be tried under randomized and controlled conditions with the hope of preventing some of the devastating consequences of hypoxic-ischemic brain damage.-RCC)
ABSTRACTAt present, an estimated 1 in 5 leukemic patients receives a bone marrow or stem cell transplant from an unrelated donor or an HLA-mismatched related donor. Cord blood grafts from unrelated donors have been successful, most often in children. Hematopoiesis recovers more slowly than with bone marrow grafts, contributing to relatively high rates of infection and early death. This study examined outcomes in adults with leukemia, from 16 to 60 years of age, who received transplants of hematopoietic stem cells from unrelated donors. Data were acquired from the International Bone Marrow Transplant Registry and from the National Cord Blood Program of the New York Blood Center. Cord blood was mismatched for 1 HLA antigen in 34 cases and for 2 antigens in 116 others. Bone marrow had 1 HLA mismatch in 83 cases, whereas 367 patients received HLA-matched bone marrow. The patients given cord blood were younger than those given marrow transplants and likelier to have advanced leukemia.Median follow-up intervals were 4 years for marrow recipients and 40 months for those given cord blood transplants. For patients whose neutrophils and platelets recovered, recovery times were shorter after marrow transplantation and longest (27 days) after cord blood transplantation. A similar pattern was found for platelet recovery, with a median recovery interval of 60 days after cord blood transplantation. There were no major differences in recovery of either neutrophils or platelets after 12 months. Acute graft-versus-host disease (GVHD) was less likely after transplanting mismatched cord blood than mismatched bone marrow. Among patients who lived 3 months or longer, chronic GVHD was most frequent in patients given cord blood. The fewest treatment-related deaths were in patients given HLAEthics, Medicolegal Issues, and Public Policy 295
SUMMARY
Background
Umbilical cord blood (UCB) is increasingly considered as an alternative to peripheral blood progenitor cells (PBPC) or bone marrow (BM), especially when a HLA-matched adult unrelated donor is not available.
Methods
In order to establish the appropriateness of current graft selection practices, we retrospectively compared leukemia-free survival and other outcomes for each graft source in patients aged >16 years transplanted for acute leukemia using Cox regression. Data were available on 1525 patients transplanted between 2002 and 2006 using UCB (n=165), PBPC (n=888) and BM (n=472). UCB units were matched at HLA-A and B at antigen level and DRB1 at allele level (n=10) or mismatched at one (n=40) or two antigens (n=115). PBPC and BM grafts from unrelated adult donors were matched for allele-level HLA-A, B, C and DRB1 (n=632; n=332) or mismatched at one locus (n=256; n=140).
Findings
Leukemia-free survival after UCB transplantation was comparable to that observed after 8/8 and 7/8 allele-matched PBPC or BM transplantation. Transplant-related mortality, however, was higher after UCB transplantation compared to 8/8 allele-matched PBPC (HR 1.62, p<0.01) or BM (HR 1.69, p<0.01). Grades 2–4 acute and chronic graft-versus-host disease were lower in UCB recipients compared to allele-matched PBPC (HR 0.57, p<0.01 and HR 0.38, p<0.01, respectively), while chronic and not acute graft-versus-host disease was lower after UCB compared to allele-matched BM transplantation (HR 0.63, p=0.01).
Interpretation
Together, these data support the use of UCB for adults with acute leukemia when an HLA-matched unrelated adult donor is lacking and when transplant is urgently needed.
HLA-mismatched cord blood should be considered an acceptable source of hematopoietic stem-cell grafts for adults in the absence of an HLA-matched adult donor.
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