Detection of minimal residual disease in unselected patients with acute myeloid leukemia using multiparameter flow cytometry for definition of leukemia-associated immunophenotypes and determination of their frequencies in normal bone marrow.

Background And Objectives: Detection of minimal residual disease (MRD) by multiparameter flow cytometry is an emerging prognostic factor in patients with acute myeloid leukemia (AML). The present analysis aimed at improving the applicability of this approach to more patients with AML.

Design And Methods: Bone marrow samples from unselected patients with AML at diagnosis and from healthy volunteers were immunophenotyped applying triple-stainings of 31 antigens.

The effects of Bcr-Abl on C/EBP transcription-factor regulation and neutrophilic differentiation are reversed by the Abl kinase inhibitor imatinib mesylate.

The clinical progression of chronic myeloid leukemia (CML) from chronic phase to blast crisis is characterized by the increasing failure of myeloid precursors to differentiate into mature granulocytes. This study was undertaken to investigate the influence of Bcr-Abl and of the small molecule Abl tyrosine-kinase inhibitor imatinib mesylate on granulocyte colony-stimulating factor (G-CSF)-induced neutrophilic differentiation. We show that differentiation of 32Dcl3 cells into mature granulocytes is accompanied by the increased expression of the antigens macrophage adhesion molecule-1 (Mac-1) and Gr-1, of the G-CSF receptor (G-CSFR), of myeloid transcription factors (CCAAT/enhancer-binding protein-alpha [C/EBPalpha], C/EBPepsilon, and PU.

Efficient gene transfer of CD40 ligand into primary B-CLL cells using recombinant adeno-associated virus (rAAV) vectors.

B cells of chronic lymphocytic leukemia (B-CLL) are resistant to transduction with most currently available vector systems. Using an optimized adenovirus-free packaging system, recombinant adeno-associated virus (rAAV) vectors coding for the enhanced green fluorescent protein (AAV/EGFP) and CD40 ligand (AAV/CD40L) were packaged and highly purified resulting in genomic titers up to 3 x 10(11)/mL. Cells obtained from 24 patients with B-CLL were infected with AAV/EGFP or AAV/CD40L at a multiplicity of infection (MOI) of 100 resulting in transgene expression in up to 97% of cells as detected by flow cytometry 48 hours after infection.

The activation of intracellular tyrosine kinases by interferon-alpha (IFNalpha) correlates with its antiproliferative activity in B-lymphoid cell lines, but not in B-cell chronic lymphocytic leukemia patients.

The response to interferon-alpha (IFNalpha) treatment in leukemias of the B-cell lineage shows a marked heterogeneity. A distinct subset of patients with B-CLL responds to treatment with IFNalpha, while the drug has no therapeutic effect in the majority of patients. The mechanism of this phenomenon is poorly understood.