Marrow transplantation in treatment of children with aplastic anaemia or acute leukaemia

Primary graft failure after myeloablative allogeneic hematopoietic cell transplantation for hematologic malignancies

Clinical outcomes after primary graft failure (PGF) remain poor. Here we present a large retrospective analysis (n=23,272) which investigates means to prevent PGF and early detection of patients at high risk. In patients with hematologic malignancies, who underwent their first myeloablative allogeneic hematopoietic cell transplantation, PGF was reported in 1,278 (5.5%), and there was a marked difference in PGFs using peripheral blood stem cell compared to bone marrow grafts (2.5 vs. 7.3%; P<0.001). A 4-fold increase of PGF was observed in myeloproliferative disorders compared to acute leukemia (P<0.001). Other risk factors for PGF included recipient age below 30, HLA-mismatch, male recipients of female donor grafts, ABO-incompatibility, busulfan/cyclophosphamide conditioning, and cryopreservation. In bone marrow transplants, total nucleated cell doses ≤2.4 × 10⁸/kg were associated with PGF (OR 1.39; P<0.001). The use of tacrolimus-based immunosuppression and granulocyte colony-stimulating factor were associated with decreased PGF risk. These data, allow clinicians to do more informed choices with respect to graft source, donor selection, conditioning and immunosuppressive regimens to reduce the risk of PGF. Moreover, a novel risk score determined on day 21 post-transplant may provide the rationale for an early request for additional hematopoietic stem cells.

Outcome of allogeneic bone marrow transplantation for children with advanced acute myeloid leukemia

Allogeneic bone marrow transplantation (BMT) may offer the only chance of cure for children with acute myeloid leukemia (AML) in second complete remission (CR2) or with relapsed disease, but the outcome of these patients has not been clearly defined. We conducted a retrospective study of 58 children, median age 7.4 years (range 0.8-17.3), who received matched related or unrelated BMT at our institution for AML in CR2 (n = 12), in untreated first relapse (n = 11) or with refractory disease (n = 35), to identify risk factors associated with disease-free survival (DFS). Life threatening to fatal regimen-related toxicity was observed in 22% of patients. Estimates of DFS at 5 years (95% confidence interval) for patients in CR2, with untreated first relapse and refractory disease were 58% (27-80%), 36% (11-63%) and 9% (2-21%), respectively. Non-relapse mortality estimates were 0%, 27% (0-54%) and 17% (5-30%), and relapse estimates were 42% (14-70%), 36% (8-65%) and 74% (60-89%), respectively. Advanced disease phase and cytogenetic abnormalities at the time of transplantation were each associated with decreased DFS and increased relapse in multivariable regression models. Survival for children transplanted in CR2 or untreated first relapse is higher than that previously reported, but relapse remains the major cause of treatment failure regardless of disease stage.

Hematopoietic stem-cell transplantation using unrelated cord-blood versus matched sibling marrow in pediatric bone marrow failure syndrome: one center's experience

Hematopoietic stem-cell transplantation (HSCT) is an effective mode of therapy in pediatrics for the treatment of both malignant and non-malignant disorders. We compared the course of children transplanted with unrelated umbilical cord blood (UCB) to those transplanted with allogeneic sibling bone marrow (BM) for bone marrow failure syndromes. Thirteen patients with a median age of 6.3 years were transplanted for the following diseases between April 1992 and November 1997: myelodysplastic syndromes, aplastic anemia, Diamond-Blackfan anemia, myelofibrosis, paroxysmal nocturnal hemoglobinuria, osteopetrosis and dyskeratosis congenita. The stem cell source was BM in ten patients and UCB in three. We retrospectively examined the conditioning regimens, stem cell source and dose, days to engraftment, survival and complication rate to see whether there was a significant advantage in using one source over the other. The median time to an absolute neutrophil count > 500 per microL was 25 days for UCB patients and 16 days for BM patients. The median time to a platelet count > 20,000 per microL was 55 days for UCB patients and 22 days for BM patients. The 100-day mortality was 66% in UCB patients and 20% in BM patients. The overall mortality rates were 66% and 40%, respectively. Three patients died prior to engraftment. Seven patients (54%) were still alive as of May 1999 with a median follow-up of 1574 days post-transplant. The patients transplanted with BM had faster engraftment and lower rates of graft-versus-host disease, 100-day mortality and overall mortality. HLA-matched sibling BM is preferred as a source but transplantation using unrelated UCB is still an option in treating pediatric bone marrow failure syndromes.

Aplastic anaemia in childhood: prognosis and approach to therapy

Thirty-four children with aplastic anaemia who presented between 1964 and 1984 are reviewed. Their ages ranged from one to 13 years (median, seven years). Twelve children had constitutional aplasia; nine of 11 children had responded to androgen and corticosteroid therapy. However, by actuarial analysis, only 48% would survive at five years and only 16% after 10 years. Twenty-two children had acquired aplasia; in 16 children this had no obvious cause. By means of the criteria of the International Aplastic Anemia Study Group, patients were categorized into severe and non-severe groups at diagnosis. Severe disease was present at diagnosis in nine of 22 children with acquired aplasia but in no child with constitutional disease. Two patients with severe acquired aplasia showed a transient response to androgen or corticosteroid therapy, whereas five of nine children with acquired aplasia which was not severe showed a sustained response to such therapy. A significant difference in survival times was seen between severe and non-severe groups at five years; two (17%) of nine children with severe aplasia survived, compared with eight (67%) of 12 children with non-severe aplasia. Three children with severe aplasia who were treated with antilymphocyte globulin showed no improvement. Of five children who underwent bone-marrow transplantation for severe or progressive disease, four survived. It is concluded that bone-marrow transplantation, as a matter of urgency, is the treatment of choice for severe acquired aplastic anaemia; it is also recommended for mild acquired or constitutional aplasia when progressive disease is present or where transfusion therapy will be required. Antilymphocyte globulin is an alternative form of treatment for acquired disease. Androgen therapy is effective in the treatment of non-severe acquired and constitutional aplastic anaemia.

Cytogenetic analysis in human bone marrow transplantation

Chromosome and sex chromatin studies have contributed significantly to the evaluation of human bone marrow transplants. In addition to their use in documenting bone marrow engraftment following transplantation, they have been used to (1) evaluate whether recurrent leukemia occurs in donor or recipient cells and whether recovery in aplastic anemia results from growth of host or donor cells, (2) demonstrate the bone marrow origin of pulmonary macrophages and hepatic Kupffer cells, (3) show that bone marrow fibroblasts have an origin different from that of the hematopoietic bone marrow cells, (4) evaluate twin zygosity in preparation for transplantation, and (5) show that the defect in Fanconi's anemia is intracellular.

Acquired aplastic anaemia in children treated with corticosteroids and anabolic steroids

30 children with acquired aplastic anaemia are presented. The mortality rate was 60%. The period of observation exceeded 8 years for patients. The importance of long control and the timely conclusion of therapy are emphasized. Prognostic criteria and alternatives to steroid therapy are discussed.

Evaluation of Vickers-Trexler isolator in children undergoing bone marrow transplantation

Four children, 5 months to 15 years of age, underwent bone marrow transplantation in Vickers-Trexler isolator tents. Two grafts were elective. During 170 days of isolation no clinical infections due to exogenous micro-organisms developed despite severe immunodeficiency. The decontamination regimen and sterile procedures used, as well as the microbiological results, are described. This form of isolation in paediatric practice was found to be highly acceptable to both patients and staff.