Pablo Rubinstein

BACKGROUND: Data regarding the outcome of cord-blood transplantation in adults are scant, despite the fact that these grafts are increasingly used in adults. METHODS: We compared the outcomes of the transplantation of hematopoietic stem cells from unrelated donors in adults with leukemia who had received cord blood that was mismatched for one HLA antigen (34 patients) or two antigens (116 patients), bone marrow that had one HLA mismatch (83 patients), and HLA-matched bone marrow (367 patients). We used Cox proportional-hazards models to analyze the data. RESULTS: Cord-blood recipients were younger and more likely to have advanced leukemia than were bone marrow recipients, and they received lower doses of nucleated cells. Hematopoietic recovery was slower with transplantation of mismatched bone marrow and cord blood than with matched marrow transplantations. Acute graft-versus-host disease (GVHD) was more likely to occur after mismatched marrow transplantation, and chronic GVHD was more likely to occur after cord-blood transplantation. The rates of treatment-related mortality, treatment failure, and overall mortality were lowest among patients who received matched marrow transplants. Patients who received mismatched bone marrow transplants and those who received mismatched cord-blood transplants had similar rates of treatment-related mortality (P=0.96), treatment failure (P=0.69), and overall mortality (P=0.62). There were no differences in the rate of recurrence of leukemia among the groups. There were no differences in outcome after cord-blood transplantation between patients with one HLA mismatch and those with two HLA mismatches. CONCLUSIONS: 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.

BACKGROUND: Transplantation of bone marrow from unrelated donors is limited by a lack of HLA-matched donors and the risk of graft-versus-host disease (GVHD). Placental blood from sibling donors can reconstitute hematopoiesis. We report preliminary results of transplantation using partially HLA-mismatched placental blood from unrelated donors. METHODS: Twenty-five consecutive patients, primarily children, with a variety of malignant and non-malignant conditions received placental blood from unrelated donors and were evaluated for hematologic and immunologic reconstitution and GVHD. HLA matching was performed before transplantation by serologic typing for class I HLA antigens and low-resolution molecular typing for class II HLA alleles. In donor-recipient pairs who differed by no more than one HLA antigen or allele, high-resolution class II HLA typing was done retrospectively. Fordonor-recipient pairs who were mismatched for two HLA antigens or alleles, high-resolution typing was used prospectively to select the best match for HLA-DRB1. RESULTS: Twenty-four of the 25 donor-recipient pairs were discordant for one to three HLA antigens. In 23 of the 25 transplant recipients, the infused hematopoletic stem cells engrafted. Acute grade III GVHD occurred in 2 of the 21 patients who could be evaluated, and 2 patients had chronic GVHD. In vitro proliferative responses of T cells and B cells to plant mitogens were detected 60 days after transplantation. With a median follow-up of 12 1/2 months and a minimal follow-up of 100 days, the overall 100-day survival rate among these patients was 64 percent, and the overall event-free survival was 48 percent. CONCLUSIONS: HLA-mismatched placental blood from unrelated donors is an alternative source of stem cells for hematopoietic reconstitution in children.

Acute graft-versus-host disease (aGVHD) is associated with high risk of morbidity and mortality and is a common complication after double umbilical cord blood (UCB) transplantation. To reduce these risks, we established a method of CD4(+)CD25(+)FoxP3(+) T regulatory cell (Treg) enrichment from cryopreserved UCB followed by a 18 (+) 1-day expansion culture including anti-CD3/anti-CD28 antibody-coated beads and recombinant human interleukin-2. In a "first-in-human" clinical trial, we evaluated the safety profile of UCB Treg in 23 patients. Patients received a dose of 0.1-30 × 10(5)UCB Treg/kg after double UCB transplantation. The targeted Treg dose was achieved in 74% of cultures, with all products being suppressive in vitro (median 86% suppression at a 1:4 ratio). No infusional toxicities were observed. After infusion, UCB Treg could be detected for 14 days, with the greatest proportion of circulating CD4(+)CD127(-)FoxP3(+) cells observed on day (+)2. Compared with identically treated 108 historical controls without Treg, there was a reduced incidence of grade II-IV aGVHD (43% vs 61%, P = .05) with no deleterious effect on risks of infection, relapse, or early mortality. These results set the stage for a definitive study of UCB Treg to determine its potency in preventing allogeneic aGVHD. This study is registered at http://www.clinicaltrials.gov as NCT00602693.

SPEISER, PHYLLIS W.; DUPONT, B O; RUBINSTEIN, PABLO; PIAZZA, ALBERTO; KASTELAN, ANDRIJA; NEW, MARIA I. Author Information