The hematopoietic stem cell in chronic phase CML is characterized by a transcriptional profile resembling normal myeloid progenitor cells and reflecting loss of quiescence.

We found that composition of cell subsets within the CD34+ cell population is markedly altered in chronic phase (CP) chronic myeloid leukemia (CML). Specifically, proportions and absolute cell counts of common myeloid progenitors (CMP) and megakaryocyte-erythrocyte progenitors (MEP) are significantly greater in comparison to normal bone marrow whereas absolute numbers of hematopoietic stem cells (HSC) are equal. To understand the basis for this, we performed gene expression profiling (Affymetrix HU-133A 2.0) of the distinct CD34+ cell subsets from six patients with CP CML and five healthy donors. Euclidean distance analysis revealed a remarkable transcriptional similarity between the CML patients' HSC and normal progenitors, especially CMP. CP CML HSC were transcriptionally more similar to their progeny than normal HSC to theirs, suggesting a more mature phenotype. Hence, the greatest differences between CP CML patients and normal donors were apparent in HSC including downregulation of genes encoding adhesion molecules, transcription factors, regulators of stem-cell fate and inhibitors of cell proliferation in CP CML. Impaired adhesive and migratory capacities were functionally corroborated by fibronectin detachment analysis and transwell assays, respectively. Based on our findings we propose a loss of quiescence of the CML HSC on detachment from the niche leading to expansion of myeloid progenitors.

High-dose idarubicin, cyclophosphamide and melphalan as conditioning for autologous stem cell transplantation increases treatment-related mortality in patients with multiple myeloma: results of a randomised study.

We conducted a randomised trial comparing an intensified versus a standard conditioning regimen for high-dose chemotherapy followed by autologous stem-cell transplantation in patients with multiple myeloma. In this study, 56 patients were randomly assigned for high-dose therapy with melphalan 200 mg/m2 or with idarubicin 42 mg/m2, melphalan 200 mg/m2 and cyclophosphamide 120 mg/kg. The primary objective was response rate. Acute toxicity, mainly because of infections, was higher in the intensified treatment arm with a treatment-related mortality of 20% versus 0% in the standard arm. This lead to the early discontinuation of the study. Response rates did not differ significantly between both treatment arms {intensified versus standard: complete response+near complete remission 50% [95% confidence interval (CI) 26-74%] vs. 33% (95% CI 17-55%), partial remission 35% (95% CI 16-61%) vs. 50% (95% CI 30-70%)}. After a follow-up of 5 years, the median time-to-progression and overall survival were not significantly different between both patient groups. Analysis restricted to patients surviving the first 100 d after transplant showed a better outcome for patients with >or=2 bad prognostic risk factors in the intensified treatment arm, however all treatment-related deaths occurred within this group of patients. In conclusion, intensified conditioning for high-dose therapy had intolerably high toxicity without improving outcome in patients with multiple myeloma.

Transplantation of allogeneic CD34+-selected cells followed by early T-cell add-backs: favorable results in acute and chronic myeloid leukemia.

BACKGROUND: The aim of this study was to investigate preservation of anti-leukemic activity and protection from opportunistic infections after transplantation of allogeneic + cells in patients with hematologic malignancies and bad prognosis. Methods Thirty-three patients [median age 42 years, range 23-55 years, diagnosis AML/myelodysplastic syndrome (MDS) 14, ALL nine, CML seven and multiple myeloma (MM) three] received myeloablative conditioning followed by infusion of selected CD34+ cells from matched unrelated donors (31) or HLA-identical siblings (two). Early donor lymphocyte infusions (DLI; 0.5 and 1.0 x 10(6) CD3+ cells/kg) were given while patients were on immunosuppressive therapy. RESULTS: Ninety-seven per cent of patients engrafted and 24 of 29 patients surviving more than 30 days received at least one pre-emptive DLI. Three patients (10%) developed acute (a)GvHD (two grade I-II, one grade III-IV) spontaneously, and 16 patients (67%) developed aGvHD after DLI (12 grade I-II, four grade III-IV). Eight of 24 evaluable patients developed chronic (c)GvHD (33%, six limited, two extensive). After a median follow-up of 590 days (range 138-1610 days) 18 patients were alive (55%), 16 in complete remission (CR), one in hematologic and one in molecular relapse. Seven patients died after relapse (21%) and eight died from transplantation-related causes (24%). Patients with myeloid malignancies had a significantly better survival than patients with ALL or MM (74%+/-10 vs. 30%+/-13, P<0.05). DISCUSSION: Early pre-emptive low-dose DLI following transplantation of selected CD34+ cells from unrelated donors after myeloablative conditioning is feasible and effective without undue toxicity, especially in patients with myeloid malignancies.