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Between 1981 and 2000, 6609 children (

Purpose Stem cell transplantation (SCT) can definitely cure chronic myeloid leukemia (CML), a rare disease in childhood. We prospectively evaluated the results of early SCT in pediatric CML after standardized pretreatment with hydroxyurea+/-interferon. Patients and methods Between 1995 and 2004, 200 children (median age: 12.4 years) were enrolled and stratified: given the availability of an HLA-matched related donor (MRD), SCT was scheduled within 6 months and otherwise from an unrelated donor (UD) within 12 months following diagnosis. Results 176 patients underwent SCT; from MRD within median 4 months and from UD within median 11 months after diagnosis. At SCT, 158 patients were in chronic phase (CP1 or CP2), 9 patients were in accelerated phase and 9 patients were in blast crisis (BC). The conditioning regimen - total body irradiation or busulfan - exerted no different impact on overall survival (OS). Probability of OS at 5 years was 87+/-11% if grafted from a sibling (n=41), 52+/-9% from matched UD (MUD, n=71), and 45+/-16% from mismatched donors (MMD, n=55), respectively. A trend for better OS in CP1 was observed if SCT was performed within 6 months (n=49; 74+/-9%), compared to 7-12 months (n=52; 62+/-15%), and >12 months (n=43; 62+/-17%) after diagnosis, respectively (p=0.157). Probability of relapse at 5 years was 20+/-12%. Transplant-related mortality and graft-versus-host disease mainly contributed to the inferior outcome in UD and HLA-mismatched SCT. Conclusion These data from the first prospective trial on CML restricted to children and adolescents might be considered for decision making when balancing the risks of SCT against the increasing use of imatinib as upfront treatment for CML.

The trial ALL-BFM 95 for treatment of childhood acute lymphoblastic leukemia was designed to reduce acute and long-term toxicity in selected patient groups with favorable prognosis and to improve outcome in poor-risk groups by treatment intensification. These aims were pursued through a stratification strategy using white blood cell count, age, immunophenotype, treatment response, and unfavorable genetic aberrations providing an excellent discrimination of risk groups. Estimated 6-year event-free survival (6y-pEFS) for all 2169 patients was 79.6% (± 0.9%). The large standard-risk (SR) group (35% of patients) achieved an excellent 6y-EFS of 89.5% (± 1.1%) despite significant reduction of anthracyclines. In the medium-risk (MR) group (53% of patients), 6y-pEFS was 79.7% (± 1.2%); no improvement was accomplished by the randomized use of additional intermediate-dose cytarabine after consolidation. Omission of preventive cranial irradiation in non–T-ALL MR patients was possible without significant reduction of EFS, although the incidence of central nervous system relapses increased. In the high-risk (HR) group (12% of patients), intensification of consolidation/reinduction treatment led to considerable improvement over the previous ALL-BFM trials yielding a 6y-pEFS of 49.2% (± 3.2%). Compared without previous trial ALL-BFM 90, consistently favorable results in non-HR patients were achieved with significant treatment reduction in the majority of these patients.

Background DNA Ligase IV deficiency syndrome is a rare autosomal recessive disorder caused by hypomorphic mutations in the DNA ligase IV gene (LIG4). The clinical phenotype shows overlap with a number of other rare syndromes, including Seckel syndrome, Nijmegen breakage syndrome, and Fanconi anemia. Thus the clinical diagnosis is often delayed and established by exclusion. Methods We describe a patient with pre- and postnatal growth retardation and dysmorphic facial features in whom the diagnoses of Seckel-, Dubowitz-, and Nijmegen breakage syndrome were variably considered. Cellular radiosensitivity in the absence of clinical manifestations of Ataxia telangiectasia lead to the diagnosis of DNA ligase IV (LIG4) deficiency syndrome, confirmed by compound heterozygous mutations in the LIG4 gene. At age 11, after a six year history of progressive bone marrow failure and increasing transfusion dependency the patient was treated with matched sibling donor hematopoetic stem cell transplantation (HSCT) using a fludarabine-based conditioning regimen without irradiation. Results The post-transplantation course was uneventful with rapid engraftment leading to complete and stable chimerism. Now at age 16, the patient has gained weight and is in good clinical condition. Conclusion HSCT using mild conditioning without irradiation qualifies as treatment of choice in LIG4-deficient patients who have a matched sibling donor.

Myelodysplastic syndromes (MDS) are a heterogenous group of acquired hematopoietic stem cell disorders. Refractory cytopenia (RC) is the most common subtype of childhood MDS and hematopoietic stem cell transplantation (HSCT) is the only curative treatment. HSCT following a myeloablative preparative regimen is associated with a low probability of relapse and considerable transplant-related mortality. In the present European Working Groups of MDS pilot study, we investigated whether a reduced intensity conditioning regimen (RIC) is able to offer reduced toxicity without increased rates of graft failure or relapse. Nineteen children with RC were transplanted from an unrelated donor following RIC consisting of fludarabine, thiotepa and anti-thymocyte globulin. Three patients experienced graft failure. Neutrophil and platelet engraftment occurred at a median time of 23 and 30 days, respectively. Cumulative incidence of grade II-IV and grade III and IV acute graft-versus-host disease (GVHD) was 0.48 and 0.13, respectively; three patients developed extensive chronic GVHD. Although infections were the predominant complications, only one patient with extensive chronic GVHD died from infectious complications. Overall and event-free survival at 3 years were 0.84 and 0.74, respectively. In conclusion, our results were comparable to those of patients treated with myeloablative HSCT. Long-term follow-up is needed to demonstrate the expected reduction in long-term sequelae.

Background: Monitoring of minimal residual disease (MRD) has become a strong diagnostic tool in acute lymphoblastic leukemia. It is used for risk-adapted therapy and for the recognition of pending relapses. In acute myeloid leukemia (AML), there is still a need for more suitable MRD markers. Experimental Design: A stepwise approach which combined genome-wide expression profiling, TaqMan low density arrays, and a TaqMan real-time PCR-based screening was used to identify new markers for the monitoring of MRD in AML. Leukemic cells from 52 children with AML and 145 follow-up samples from 25 patients were analyzed. Results: Seven genes were identified which are vastly overexpressed in many patients with AML compared with healthy bone marrow: CCL23, GAGED2, MSLN, SPAG6, and ST18 as well as the previously described markers WT1 and PRAME. The expression of all genes decreased to normal levels in patients who achieved a continuous complete remission. Elevated levels of at least one gene were found prior to relapse in 7 out of 10 patients who relapsed. Conclusions: This set of genes should allow a sensitive and specific monitoring of MRD in AML. Notably, some of these markers could also serve as therapeutic targets or might be involved in leukemogenesis. MSLN is already used as a target for immunotherapy in clinical trials in other malignancies.

Chimaerism analysis was performed by polymerase chain reaction amplification of short-tandem repeat markers in 30 children following haematopoietic stem cell transplantation for juvenile myelomonocytic leukaemia (JMML). Fourteen patients always had complete chimaerism (CC); one of them relapsed after the discontinuation of the study and 13 continued in complete remission (CR). Mixed chimaerism (MC) was noted in 16 patients. Of those 12 patients demonstrated increasing MC (i-MC); 10 relapsed and two achieved CC following discontinuation of immunosuppressive therapy (IST). Four other patients demonstrating only transient MC are alive in CR. MC with up to 20% of autologous cells could be successfully eradicated without induction of severe graft-versus-host disease when IST was reduced or discontinued directly after the first demonstration of MC. At the same time, MC with up to 10% of autologous cells could disappear without intervention. The interval between MC and relapse ranged from 0-320 d (median 38 d). Donor leucocyte infusion was given to six patients with i-MC, but only one patient responded. Peripheral blood seems as valuable as bone marrow for chimaerism studies. In conclusion, serial quantitative chimaerism studies can identify patients with i-MC who are at high risk for relapse of JMML. Immediate withdrawal of IST is advised in these patients.