Ex Vivo Induction of Multiple Myeloma-specific Immune Responses by Monocyte-derived Dendritic Cells Following Stimulation by Whole-tumor Antigen of Autologous Myeloma Cells.

The introduction of novel agents has significantly expanded treatment options for multiple myeloma (MM), albeit long-term disease control cannot be achieved in the majority of patients. Vaccination with MM antigen-loaded dendritic cells (DCs) represents an alternative strategy that is currently being explored. The aim of this study was to assess the immunogenic potential of ex vivo-generated monocyte-derived DCs (moDCs), following stimulation with the whole-antigen array of autologous myeloma cells (AMC). MoDCs were loaded with antigens of myeloma cells by 2 different methods: phagocytosis of apoptotic bodies from γ-irradiated AMC, or transfection with AMC total RNA by square-wave electroporation. Twenty patients with MM were enrolled in the study. Following stimulation and maturation, moDCs were tested for their capacity to induce T-helper 1 and cytotoxic T lymphocyte responses in vitro. Both strategies were effective in the induction of myeloma-specific cytotoxic T lymphocyte and T-helper 1 cells, as demonstrated by cytotoxicity and ELISpot assays. On the whole, T-cell responses were observed in 18 cases by either method of DC pulsing. We conclude that both whole-tumor antigen approaches are efficient in priming autologous antimyeloma T-cell responses and warrant further study aiming at the development of individualized DC vaccines for MM patients.

BCR-ABL fusion protein detection in peripheral blood and bone marrow samples of adult precursor B-cell acute lymphoblastic leukemia patients using the flow cytometric immunobead assay.

BACKGROUND: The ability to detect the BCR-ABL fusion gene in precursor B-cell acute lymphoblastic leukemia (pB-ALL) is essential for making accurate treatment decisions. METHODS: We used a new flow cytometric immunobead assay for BCR-ABL fusion protein detection in peripheral blood and/or bone marrow samples from 38 adult pB-ALL patients and the results were compared with polymerase chain reaction (PCR) detection of BCR-ABL transcript. RESULTS: The fusion protein was detected in peripheral blood and bone marrow samples from seven of the 38 (18%) patients, and results for both the p190 and p210 were confirmed by PCR. One case, which was positive by cytogenetics and fluorescence in situ hybridization (FISH), was negative by PCR but positive by flow cytometry. Another case, which was positive by PCR and negative by flow cytometry, was from a patient on steroid treatment. CONCLUSIONS: The cytometric immunobead assay for BCR-ABL fusion protein detection was found to be suitable for the investigation of pB-ALL patients. This assay is reliable, rapid and simple to use for peripheral blood and bone marrow samples.