Possible clinical benefits of the use of peripheral blood stem cells over bone marrow in the allogeneic transplantation setting for the treatment of childhood leukemia

Peripheral blood stem cell transplantation in children with beta-thalassemia

Fifteen patients with beta-thalassemia received an allogeneic peripheral blood stem cell transplant. Median age was 3.5 years (1-15 years). Six were class I, four class II and five class III according to the Pesaro criteria. All of the donors were HLA-phenotypically identical (13 siblings and two parents). Nine patients were given BU + CY and six BU + CY plus ATG as conditioning. All patients received MTX (+1, +3, +6) and CsA (9-12 months) post transplant for GVHD prophylaxis. The median neutrophil and platelet engraftment times were day 12 and day 16, respectively. cGVHD was observed in three patients. Two patients died. Thirteen patients are well, and transfusion-independent 2-30 months after PSCT. No recurrences of thalassemia have been seen. Overall and event-free survival were 86.6%. In conclusion, we suggest that PSCT can be considered a safe and effective treatment for children with beta- thalassemia.

The roles of adoptive and active forms of immunotherapy in the cure of children suffering from acute lymphoid leukemia: a) underestimation of active immunotherapy benefit, b) its immunogenetic indications to select sensitive patients, hence prevent chemotherapy's late effects

Children's acute lymphoid leukemia (ALL) chemotherapy started in 1948 with antimetabolites combined with steroids. It was enriched in 1959 with vincristine and cyclophosphamide and, in 1970, with daunomycin. It induced more and more apparently what were called complete remissions, and prolonged more and more the survivals without reducing however, until 1973, the (100%) mortality. It started to reduce it at the fifth year, to 20 and even 40% between 1973 and 1976, due to progressive and maximal intensification and duration of chemotherapy. It is in the same period that we proposed to apply in ALL remissions after relapses and in the first remissions of the most malignant type, allogeneic bone marrow grafts; we published the first success in human ALL in 1963, and clinically observed the same actions as those described experimentally: cytoablation of both leukemia and hematopoiesis, the latter being restored by the graft, whose reaction versus the residual neoplastic cells (called graft versus leukemia or GvL) appeared to be able to often eradicate them, at the cost however of a graft-versus-host reaction (both reactions sharing the same mechanism). One of us became a member of the Committee of the International Bone Marrow Transplant Registry, whose results showed the improvement in the prognosis of the aggressive form of ALL. The intensity and length established for chemotherapy for the most severe form of children's ALL have often been applied to the intermediary and to the least aggressive ones. The global 5-year survival increased to 60% between 1976 and 1984, and is around 80% today. But the registration of late debilitating or malignant effects of chemotherapy toxicities makes us wonder if some patients have not received an excessively intense and long application of cytostatics (often combined with ionizing radiations on CNS). In fact, the patients belonging to some HLA phenotypes (A33 and B17) have appeared to be especially often cured with active immunotherapy (killed leukemic cells and/or BCG), whose action was shown by specific cytotoxicity amplification, which was applied after short adjuvant chemotherapy, and hence is able to reduce the long chemotherapy incidence of debilitating or malignant late effects. Sakurai's group confirmed our absence of late relapses after ALL active immunotherapy, which contrasts with their risk after maintenance chemotherapy, whose minimal residual disease is a worrisome stumbling block to the cure.