Normal and chronic phase CML hematopoietic cells repopulate NOD/SCID bone marrow with different kinetics and cell lineage representation.

INTRODUCTION: Chronic myelogenous leukemia is characterized by a clonal expansion of abnormal hematopoietic cells, which eventually replaces normal hematopoiesis. We wanted to test the hypothesis that the growth kinetics of CML and normal hematopoietic cells are different. MATERIALS AND METHODS: We compared the growth kinetics and the phenotype of engraftment of chronic phase CML and normal human CD34(+) precursor cells in the bone marrow of immune deficient mice. RESULTS: High levels of engraftment of normal precursors occurred early and consisted of myeloid, erythroid, megakaryocytic, and lymphoid elements. This level and pattern of engraftment were maintained at later assessments. The level of CML cell engraftment was initially much lower, but it increased progressively at late time-points with no indication of a plateau in growth. Early engraftment of CML cells consisted almost entirely of myeloid and mast cells but soon after only mast cells were detectable. Conversely mast cells were infrequent in mice engrafted with normal progenitors. CONCLUSION: We conclude that in contrast to normal cell engraftment, engraftment of CML cells in NOD/SCID mice is characterized by a slow but progressive myeloid infiltration, which eventually consists almost entirely of mast cells.

Umbilical cord blood transplant from unrelated HLA-mismatched donors in children with high risk leukemia.

In the last 3 years, 14 children with high-risk leukemia (11 ALL, 2 AML and 1 CML) underwent cord blood transplantation from unrelated HLA-mismatched donors at a median of 99 days from the start of search. Eight patients were transplanted in second CR, one in accelerated phase, three at relapse and two patients in first CR. Conditioning regimen (fractionated TBI, etoposide, CY and anti-lymphocyte serum) and prophylaxis of GVHD (CsA and 6-methylprednisolone) were identical for all patients. Neutrophils >0.5x10(9)/l were reached at a median of 33 days from transplant, but in four cases we observed an autologous hematopoietic reconstitution (three spontaneous, one after autologous BM rescue). Acute and chronic GVHD were observed in 10/14 and 3/8 evaluable cases, respectively. Three patients died of transplant-related toxicity and three patients relapsed. The probabilities of event-free, disease-free and overall survival were 50, 53 and 64%, respectively. Cord blood transplant from HLA-mismatched unrelated donor is a valid option for the treatment of children with high-risk leukemia. With our eligibility criteria, conditioning regimen and prophylaxis of graft-versus-host disease, the main obstacles to successful transplant were represented by graft failure and fatal acute GVHD.

Fusarium infections in patients with severe aplastic anemia: review and implications for management.

BACKGROUND AND OBJECTIVE: The prognosis of severe fungal infections, such as fusarium infections, in patients with aplastic anemia is directly related to the recovery of bone marrow functions. In this study, in vitro anti-Fusarium activity of granulocytes was investigated, the case of disseminated infection in a child with very severe aplastic anemia is reported, and implications for management of such infective complications are discussed. DESIGN AND METHODS: The in vitro efficiency of PMNL from three untreated, normal blood donors and from two G-CSF-treated WBC donors in contrasting the growth of the Fusarium sp strain isolated from the patient we present was measured by a 3H-glucose uptake inhibition assay and confirmed by microscopic examination. RESULTS: Basic growth inhibitory activity of unstimulated PMNL on Fusarium cells was significantly enhanced in the presence of GM-CSF in all three blood donors tested. In one of the two G-CSF-treated donors, in vitro efficiency of PMNL in contrasting the growth of the fungus increased notably after G-CSF treatment. We report the case of a 3-year-old girl with very severe aplastic anemia unresponsive to conventional immunosuppressant therapy who developed a disseminated fusarium infection. The child initially responded to liposomal amphotericin B and granulocyte transfusions from G-CSF stimulated donors. Subsequently she was given a cord blood stem cell transplantation but died of disseminated infection. INTERPRETATION AND CONCLUSIONS: Including the present case, there are only ten reports of invasive infections caused by the genus Fusarium in aplastic anemia patients and only two of the patients survived. In vitro data seem to suggest that in vivo treatment with rh-G-CSF could have a stimulatory effect on the anti-Fusarium activity of neutrophils. Despite the efficacy of granulocyte transfusions by G-CSF-stimulated donors in the temporary control of fusarium infection, treatment of the underlying hematologic disease is required to cure the infection in patients with severe aplastic anemia. Granulocyte transfusions by G-CSF-stimulated donors while awaiting bone marrow recovery following the blood stem cell transplant should be considered.

Umbilical cord blood transplant from HLA-mismatched unrelated donor in high-risk leukemia.

Twelve consecutive children with high-risk leukemia have been submitted to UCB transplant from unrelated 1 or 2 loci HLA-mismatched donor. All patients received an identical regimen for conditioning and GVHD prophylaxis. The median dose of viable nucleated cells infused was 2.8 x 10(7)/kg bw (range 1.4-7.9). Of 11 patients evaluable for engraftment, the hematopoiesis was of full donor origin in seven patients and autologous in four. The probability of disease-free survival at 1 and 2 years from UCB transplant is 60 and 42%, respectively.

Umbilical cord blood (UCB) transplant from unrelated mismatched donor in patients with high risk (HR) leukemia.

Ten consecutive children with high risk leukemia have been submitted to UCB transplant from unrelated HLA mismatched donors. All patients received an identical regimen for conditioning and GVHD prophylaxis. The median dose of viable nucleated cells infused was 2.6 x 10(6)/kg b.w. Among the nine patients evaluable for engraftment the hematopoiesis was of full donor origin in six patients and autologous in three. At a median follow-up of 9 months, six of nine (67%) patients are alive in CR.

Immunophenotype of adult and childhood acute lymphoblastic leukemia: changes at first relapse and clinico-prognostic implications.

The immunologic features of leukemic cells at the time of 1st hematologic relapse were compared to those obtained at initial diagnosis in 128 patients (69 children and 59 adults) with acute lymphoblastic leukemia (ALL) treated at a single institution. An immunophenotypic change was observed in 59 cases (46%), more frequently in T (20/25) than in B (39/103) lineage ALL (80 vs 38%, P=0.0008), but with a similar incidence in adults and children. Of these cases, 34 (24 B- and 10 T-ALL) changed at relapse their intralineage subgroup affiliation, although no complete shift from B to T lineage ALL, or vice versa, was observed. The myeloid antigens CD13 and/or CD33 were frequently lost (2/5 cases) or acquired (12/123 cases) at relapse. In 21 cases, the immunophenotype at relapse was more undifferentiated than at diagnosis, while it was more differentiated in 13 cases. Initial treatment intensity or preceding treatment with teniposide did not affect the phenotypic profile at relapse. Complete response (CR) rate to salvage therapy and event-free survival were not influenced by the immunophenotypic shifts, nor by the presence, at relapse, of leukemic cells expressing the myeloid antigens CD13 and/or CD33. Univariate analysis suggested that prognosis after relapse was dependent on the duration of 1st CR, patients' age and immunophenotype at the time of diagnosis, with a worse outcome for patients with T lineage ALL and for patients with the less differentiated subgroup of B lineage ALL (CD19+ and CD10-). Multivariate analysis showed that only two factors, duration of 1st CR and grade of immunologic differentiation at diagnosis, have independent prognostic value in relapsed ALL.