Transplantation of mobilized peripheral blood cells to HLA-identical siblings with standard-risk leukemia.

Allogeneic mobilized peripheral blood progenitor cells instead of bone marrow are increasingly used to restore hematopoiesis after myeloablative therapy. Data supporting this important change of clinical practice are scarce. We therefore assigned patients with early leukemias to peripheral blood or bone marrow transplantation; the occurrence of acute and chronic graft versus host disease, survival, transplantation-related mortality, and relapse rates were compared. A total of 350 patients between 18 and 55 years of age with acute leukemias in remission or chronic myelogenous leukemia in first chronic phase were randomized to receive either filgrastim-mobilized peripheral blood progenitor cells or bone marrow cells from HLA-identical sibling donors after standard high-dose chemoradiotherapy. Neutrophil and platelet recovery occurred significantly faster after transplantation of peripheral blood progenitor cells than after bone marrow transplantation. Acute graft versus host disease of grades II-IV was significantly more frequent in recipients of peripheral blood progenitor cells than in recipients of marrow cells (52% vs 39%, odds ratio 1.74, 95% confidence interval 1.12-2.69, P =.013). The cumulative incidence of chronic graft versus host disease was 67% with peripheral blood progenitor cells and 54% with bone marrow cells (hazard ratio 1.67, 95% confidence interval 1.15-2.42, P =.0066). The estimated overall probability of survival at 2 years was 65% with either source of stem cells (hazard ratio 1.15, 95% confidence interval 0.79-1.67, P =.46). Disease-free survival, transplantation-related mortality at day 100, and relapse rates did not significantly differ between treatment arms. Peripheral blood is an equivalent source of hematopoietic stem cells compared with bone marrow if administered to patients with standard-risk leukemias. Long-term observation of patients with different diseases and stages of disease is necessary to ultimately define the role of both sources of stem cells.

Allogeneic haemopoietic cell transplants in Australia, 1996--a multi-centre retrospective comparison of the use of peripheral blood stem cells with bone marrow.

A retrospective comparison was carried out on adult patients receiving HLA-identical allogeneic haemopoietic stem cell transplants from siblings in Australia in 1996, comparing bone marrow with G-CSF-mobilised peripheral blood stem cells. A total of 131 transplant recipients from nine centres were included in this study, of whom 79 received bone marrow, 44 blood stem cells and eight both. All but three of the 131 patients had cyclosporin and methotrexate as graft-versus-host disease prophylaxis. The minimum follow-up time for surviving patients is 27 months. Comparisons were carried out between the BM and PBSC groups. There were no significant differences between groups in age, sex, diagnosis, donor characteristics or pretransplant conditioning. Median time to neutrophil recovery of 0.5 x 10(9)/l was 14 days for PBSC recipients, compared to 19 days for marrow recipients (P < 0.0005). median time to platelet recovery of 20 x 10(9)/l was 17 days for PBSC recipients, compared to 28 days for marrow recipients (P < 0.0005). there were no significantly increased risks of either acute or chronic GVHD in the PBSC recipients. there were no significant differences between the groups in the incidence of major transplant-related complications, disease-free survival or overall survival.

Host marrow stem cell potential and engraftability at varying times after low-dose whole-body irradiation.

High levels of chimerism in syngeneic BALB/c transplants were reported when hosts were exposed to 1 Gy (100 cGy) whole body irradiation (WBI) and infused with 40 x 10(6) marrow cells. The recovery of host stem cells and alterations of enhanced host engraftability at varying times after 1 Gy WBI have now been evaluated in this study. Male BALB/c marrow (40 x 10(6) cells) was infused into female BALB/c hosts immediately or at 6, 12, and 24 weeks after 1 Gy WBI of host female BALB/c mice; engraftment percentages 8 weeks after cell injection at week 0, 6, 12, or 24 were 68% +/- 12%, 45% +/- 15%, 51% +/- 12%, or 20% +/- 8%, respectively. Eight-week engraftment levels in nonirradiated hosts average 7.7%. Conversely, engraftable stem cells measured at 8 weeks postengraftment in 1 Gy--exposed hosts were reduced to 8.6% +/- 3% of nonirradiated mice at time 0, 35% +/- 12% 6 weeks later, 49% +/- 10% at 3 months, and 21% +/- 7% at 6 months. Engraftment was still increased and stem cell decreased 1 year after 1 Gy. Furthermore, the primary cells transplanted into 1 Gy hosts can be serially transplanted, and the predominant effect of 1 Gy is directly on engrafting stem cells and not through accessory cells. These data show that transplantation in 1 Gy mice may be delayed until recovery of hematopoiesis, suggesting strategies in allogeneic transplantation to avoid the adverse effects of cytokine storm. The incomplete recovery of engraftable stem cells out to 12 months indicates that stem cell expansion, especially in patients previously treated with radiomimetic drugs, may not be feasible. (Blood. 2001;98:1246-1251)

In utero transplantation of fetal liver cells in the mucopolysaccharidosis type VII mouse results in low-level chimerism, but overexpression of beta-glucuronidase can delay onset of clinical signs.

Mice with the lysosomal storage disease mucopolysaccharidosis (MPS) VII, caused by a deficiency of beta-glucuronidase (GUSB), have signs of disease present at birth. Bone marrow transplantation (BMT) or retroviral vector-mediated gene transfer into hematopoietic stem cells can partially correct the disease in adult mice, and BMT performed at birth results in a better clinical outcome. Thus, treatment in utero may result in further improvement. However, this must be done without cyto-ablation, and the donor cells do not have a competitive repopulating advantage over host cells. Transplantation in utero of either syngeneic fetal liver hematopoietic stem cells marked with a retroviral vector, or allogeneic donor cells that constitutively express high levels of human GUSB from a transgene, resulted in only about 0.1% engraftment in the adult. Immuno-affinity enrichment of stem and progenitor cells of 5- to 10-fold resulted in significantly higher GUSB activities at 2 months of age, but by 6 months engraftment was about 0.1%. Attempts to further increase the number of stem and progenitor cells were deleterious to the recipients. Nevertheless, GUSB expressed during the first 2 months of life in MPS VII fetuses could delay the onset of overt signs of disease. This suggests that the expression of some normal enzyme activity beginning in fetal life may offer the possibility of slowing the progression of the disease until more definitive postnatal transplantation or gene transfer to stem cells could be accomplished.

Mayo Clinic experience with allogeneic and syngeneic bone marrow transplantation, 1982 through 1990.

Between April 1982 and July 1990, 101 patients underwent allogeneic or syngeneic bone marrow transplantation at the Mayo Clinic. This patient population consisted of 30 with acute nonlymphocytic leukemia, 25 with acute lymphoblastic leukemia, 29 with chronic granulocytic leukemia, and 17 with other diseases (aplastic anemia in 7, myelodysplastic syndrome in 5, and lymphoma in 5). The results achieved in our patients who underwent transplantation in first complete remission of both acute nonlymphocytic leukemia and acute lymphoblastic leukemia compare favorably with previously reported results. Only 1 of 15 patients (7%) with acute nonlymphocytic leukemia and 2 of 8 patients (25%) with acute lymphoblastic leukemia who underwent transplantation in first complete remission had a relapse. Thus, we recommend early bone marrow transplantation during initial complete remission for patients with either of these disorders who have adverse prognostic factors. In contrast, of 12 patients with either acute nonlymphocytic leukemia or acute lymphoblastic leukemia who underwent transplantation during relapse, 11 died within 6 months. Therefore, such patients should be offered new experimental treatments. Our patients with chronic granulocytic leukemia fared better when they underwent transplantation early during the course of their disease rather than during the accelerated or blast phase. Prospective studies are needed to determine the best approach in these patients.