No abstract

Allogeneic transplantation of peripheral blood progenitor cells (PBPC) makes the general anaesthesia of the donor unnecessary and may result in more rapid engraftment and faster recovery of the immune system. We have studied G-CSF-mediated PBPC mobilization in healthy donors and analysed the cellular composition of the resulting PBPC grafts. PBPC grafts were obtained from nine healthy donors (18-67 years old) for allogeneic or syngeneic transplantation. Six donors received 10 micrograms/kg G-CSF per day, the others 5-6 micrograms/kg. Mobilization and harvesting were well tolerated except for moderate bone pain which occurred in all donors primed with 10 micrograms/kg. With 10 micrograms/kg, a 31-fold (9-62) enrichment of circulating CD34+ cells was observed with peak values constantly occurring on day 5 after the start of G-CSF administration. Starting harvest on day 5, one to three collections on consecutive days yielded 5.5 x 10(6)/kg (0.9-10.7) CD34+ cells, 219 x 10(6)/kg (106-314) T cells, and 34 x 10(6)/kg (23-67) NK cells per 10 litres leukapheresis volume. Altogether, PBPC grafts contained 3 times more CD34+ cells, 7 times more T cells, and 20 times more NK cells than five allogeneic marrow grafts that were analysed for comparison. The yield of CD34+ cells per 10 litres apheresis volume as well as the height of the CD34+ peak in peripheral blood were inversely correlated to the age of the donor. In the donors primed with 5-6 micrograms/kg G-CSF the increase of circulating CD34+ cells (4-7-fold enrichment) and the CD34+ cell yield per 10 litres leukapheresis volume (1 x 10(6)/kg [0.8-2.2]) was much smaller compared with the 10 micrograms/kg group. In conclusion, sufficient amounts of PBPC capable of restoring haemopoiesis in allogeneic recipients can be mobilized safely by administration of G-CSF (10 micrograms/kg s.c. for 5 d) in healthy donors, and harvested with one or two leukapheresis procedures. Whether the large numbers of T-cells and NK cells that are contained in the collection products may influence graft-versus-host and graft-versus-leukaemia reactivities of PBPC grafts remains to be determined.

Blood is arguably the most important bodily fluid and its analysis provides crucial health status information. A first routine measure to narrow down diagnosis in clinical practice is the differential blood count, determining the frequency of all major blood cells. What is lacking to advance initial blood diagnostics is an unbiased and quick functional assessment of blood that can narrow down the diagnosis and generate specific hypotheses. To address this need, we introduce the continuous, cell-by-cell morpho-rheological (MORE) analysis of diluted whole blood, without labeling, enrichment or separation, at rates of 1000 cells/sec. In a drop of blood we can identify all major blood cells and characterize their pathological changes in several disease conditions in vitro and in patient samples. This approach takes previous results of mechanical studies on specifically isolated blood cells to the level of application directly in blood and adds a functional dimension to conventional blood analysis.

Chronic myelogenous leukemia (CML) in children is relatively rare. Because of a lack of robust clinical study evidence, management of CML in children is not standardized and often follows guidelines developed for adults. Children and young adults tend to have a more aggressive clinical presentation than older adults, and prognostic scores for adult CML do not apply to children. CML in children has been considered to have the same biology as in adults, but recent data indicate that some genetic differences exist in pediatric and adult CML. Because children with CML may receive tyrosine kinase inhibitor (TKI) therapy for many decades, and are exposed to TKIs during a period of active growth, morbidities in children with CML may be distinct from those in adults and require careful monitoring. Aggressive strategies, such as eradication of CML stem cells with limited duration and intensive regimens of chemotherapy and TKIs, may be more advantageous in children as a way to avoid lifelong exposure to TKIs and their associated adverse effects. Blood and marrow transplantation in pediatric CML is currently indicated only for recurrent progressive disease, and the acute and long-term toxicities of this option should be carefully evaluated against the complications associated with lifelong use of TKIs.

Transplantation of allogeneic peripheral blood progenitor cells (PBPCs) may have advantages over bone marrow transplantation (BMT) with regards to the speed of hematopoietic and immunologic recovery, which may then shorten the time spent in hospital and decrease costs. The recipient might also profit by an enhanced graft-versus-leukemia reaction exerted by the high number of natural killer cells contained in such grafts. The donor could be spared the discomfort and risks of general anesthesia and marrow harvesting. Primary transplantation of unmanipulated allogeneic PBPCs has not been reported so far because the vast amount of T cells contained in the collection product was thought to cause severe graft-versus-host disease. We present preliminary data on primary transplantation of allogeneic PBPCs in patients who either suffered from advanced leukemia or had a donor unable to undergo general anesthesia. Eight patients with a median age of 42 years suffering from acute myelogenous leukemia (AML) in first remission (n = 3), AML in third remission, AML in relapse (n = 2), acute lymphoblastic leukemia in second remission, or chronic myelogenous leukemia in accelerated phase received myeloablative therapy followed by transplantation of unmanipulated allogeneic PBPCs mobilized with granulocyte colony-stimulating factor (5 to 10 micrograms/kg of body weight of filgrastim administered for 5 to 6 days) in their HLA- identical donors. Hematopoietic reconstitution was achieved in all patients with a median of 15.5 (16.5) days after transplant needed to surpass an absolute neutrophil count of 0.5 (1.0) x 10(9)/L. The median time to an unsupported platelet count greater than 20 (> 50) x 10(9)/L was 19.5 (41) days after grafting. Three patients did not exhibit signs of acute graft-versus-host disease (GVHD), grade I disease was seen in one patient, and three patients experienced grade II disease limited to the skin. The only patient with severe acute GVHD (grade III) refused to take his oral cyclosporin regularly and had ineffective serum levels for most of the time until relapse. Six of eight patients are currently alive without evidence of disease between 61 and 533 days after grafting; two patients grafted for AML in relapse achieved a complete remission after transplantation but relapsed again and died of leukemia on days +48 and +70, respectively. Primary transplantation of unmanipulated allogeneic PBPCs is feasible and results in long-term engraftment without causing detrimental GVHD.

A total of 156 patients (age range 1.3-18.0 years, median 13.2 years; 91 (58.3%) male) with newly diagnosed CML (N = 146 chronic phase (CML-CP), N = 3 accelerated phase (CML-AP), N = 7 blastic phase (CML-BP)) received imatinib up-front (300, 400, 500 mg/m, respectively) within a prospective phase III trial. Therapy response, progression-free survival, causes of treatment failure, and side effects were analyzed in 148 children and adolescents with complete data. Event-free survival rate by 18 months for patients in CML-CP (median follow-up time 25 months, range: 1-120) was 97% (95% CI, 94.2-99.9%). According to the 2006 ELN-criteria complete hematologic response by month 3, complete cytogenetic response (CCyR) by month 12, and major molecular response (MMR) by month 18 were achieved in 98, 63, and 59% of the patients, respectively. By month 36, 86% of the patients achieved CCyR and 74% achieved MMR. Thirty-eight patients (27%) experienced imatinib failure because of unsatisfactory response or intolerance (N = 9). In all, 28/148 patients (19%) underwent stem cell transplantation (SCT). In the SCT sub-cohort 2/23 patients diagnosed in CML-CP, 0/1 in CML-AP, and 2/4 in CML-BP, respectively, died of relapse (N = 3) or SCT-related complications (N = 2). This large pediatric trial extends and confirms data from smaller series that first-line imatinib in children is highly effective.

SummaryHaemophagocytic lymphohistiocytosis (HLH) in the context of malignancy is mainly considered a challenge of adult haematology. While this association is also observed in children, little is known regarding inciting factors, appropriate treatment and prognosis. We retrospectively analysed 29 paediatric and adolescent patients for presenting features, type of neoplasm or preceding chemotherapy, treatment and outcome. Haemophagocytic lymphohistiocytosis was considered triggered by the malignancy (M-HLH) in 21 patients, most of whom had T-(n = 12) or B-cell neoplasms (n = 7), with Epstein-Barr virus as a co-trigger in five patients. In eight patients, HLH occurred during chemotherapy (Ch-HLH) for malignancy, mainly acute leukaemias (n = 7); an infectious trigger was found in seven. In Mand Ch-HLH, median overall survival was 1Á2 and 0Á9 years, and the 6 month survival rates were 67% and 63%, respectively. Seven of 11 deceased M-HLH patients exhibited active malignancy and HLH at the time of death, while only two out of five deceased Ch-HLH patients had evidence of active HLH. To overcome HLH, malignancy-and HLH-directed treatments were administered in the M-HLH cohort; however, it was not possible to determine superiority of one approach over the other. For Ch-HLH, treatment ranged from postponement of chemotherapy to the use of etoposide-containing regimens.

Evidence-based recommendations have been established for treatment of chronic myeloid leukemia (CML) in adults treated with tyrosine kinase inhibitors (TKIs), but the rarity of this leukemia in children and adolescents makes it challenging to develop similar recommendations in pediatrics. In addition to imatinib, which was approved for pediatric CML in 2003, the second-generation TKIs dasatinib and nilotinib were recently approved for use in children, expanding the therapeutic options and pushing allogeneic stem cell transplantation to a third-line treatment of most pediatric cases. Yet, without sufficient data on efficacy and safety specific to pediatric patients, the selection of a TKI continues to rely on clinical experience in adults. Here, we present 4 case scenarios highlighting common yet challenging issues encountered in the treatment of pediatric CML (suboptimal response, poor treatment adherence, growth retardation, and presentation in advanced phases). Limited experience with very young children, the transition of teenagers to adult medicine, and the goal of achieving treatment-free remission for this rare leukemia are additional significant obstacles that require further clinical investigation through international collaboration.