Dendritic cells (DC) and leukaemia derived DC (DC_leu) are potent stimulators of anti-leukaemic activity in acute myeloid leukaemia (AML) and can be generated from mononuclear cells in vitro following standard DC/DC_leu-generating protocols. With respect to future clinical applications though, DC/DC_leu-generating protocols specifically designed for application in a whole-blood-(WB)-environment must be established. Therefore, we developed ten new DC/DC_leu-generating protocols (kits; Kit-A/-C/-D/-E/-F/-G/-H/-I/-K/-M) for the generation of DC/DC_leu from leukaemic WB, containing calcium-ionophore, granulocyte-macrophage-colony-stimulating-factor (GM-CSF), tumour-necrosis-factor-alpha, prostaglandin-E₁ (PGE₁), prostaglandin-E₂ (PGE₂) and/or picibanil (OK-432). All protocols were evaluated regarding their performance in generating DC/DC_leu using refined classification and/or ranking systems; DC/DC_leu were evaluated regarding their performance in stimulating anti-leukaemic activity using a cytotoxicity fluorolysis assay. Overall, we found the new kits capable to generate (mature) DC/DC_leu from leukaemic WB. Through refined classification and ranking systems, we were able to select Kit-I (GM-CSF + OK-432), -K (GM-CSF + PGE₂) and -M (GM-CSF + PGE₁) as the most efficient kits in generating (mature) DC/DC_leu, which are further competent to stimulate immunoreactive cells to show an improved anti-leukaemic cytotoxicity as well. This great performance of Kit-I, -K and -M in mediating DC/DC_leu-based anti-leukaemic immunity in a WB-environment in vitro constitutes an important and directive step for translating DC/DC_leu-based immunotherapy of AML into clinical application.

Background/Objectives: Acute myeloid leukemia (AML) is characterized by impaired anti-leukemic immune responses, and the ex vivo or in vivo generation of dendritic cells (DCs), including leukemic dendritic cells (DC_leu), represents a promising strategy to stimulate immune cells and improve anti-leukemic activity. Methods: This study examined the generation, phenotype and functional relevance of DCs and DC_leu produced ex vivo from blast-containing PBMNCs and whole blood (WB) in AML. Using both standard DC/DC_leu-generating protocols and available Kits. Results: We show that DC/DC_leu can be reliably generated with both methods. Generated DC/DC_leu effectively activated T cells during mixed lymphocyte cultures (MLCs), resulting in enhanced anti-leukemic cytotoxicity. Improved blast lysis correlated with specific immunological features, including higher frequencies of generated DC_leu and mature DC subsets, as well as a certain cytokine pattern after DC/DC_leu cultures or MLC. In addition, the frequencies of proliferating T cells after MLC strongly correlated with the degree of achieved blast lysis, underscoring the importance of efficient DC/DC_leu-mediated T cell stimulation. Both the frequencies of generated DC/DC_leu and the resulting blast lytic activity were linked to overall survival (OS) in AML patients. Individuals who failed to demonstrate improved blast lysis exhibited significantly reduced OS, suggesting inadequate immune responsiveness of patients in vivo. Conclusions: These findings identify phenotypic and functional immune parameters as predictors of clinical outcome and highlight the prognostic relevance of ex vivo immune profiling. This approach may help to optimize and personalize future immunotherapeutic strategies in AML.