Investigation of novel dendritic cell-based immunotherapy strategies for Richter's Syndrome conducting in-depth immune and molecular characterization.
Progetto Richter’s Syndrome (RS) is a transformation of Chronic Lymphocytic Leukemia (CLL) that manifests as a concomitant disease with a diffuse pattern of large B cells in the nodal or extra-nodal anatomic compartment. It develops with an annual rate of 0.5-1%, in extremely aggressive form, leading to an average overall survival of less than two years. So far, most therapeutic endeavors have yielded inconclusive results; however attempts using immunotherapy are starting to show promise. Yet further studies are needed to prove their effectiveness on RS. Monocyte derived DC (moDC) vaccines were used in CLL and never in RS patients but objective clinical responses were rarely attained. Discordant studies on the functionality of moDC from CLL patients and the administration of DCs contaminated with leukemic cells prompt us to hypothesis that DC cells derived from a health anatomic compartment and administrated in a pure mode have a higher capacity to boost the immune response. This proposal aims to investigate the therapeutic effectiveness of autologous dermal fibroblast-derived dendritic cells (fDCs) in targeting and eliminating RS cells. Given the low incidence of RS patients, we will standardize all experimental protocols using commercially available healthy dermal fibroblasts to generate DCs and assess their maturation and PBMCs with skin biopsies from CLL patients to evaluate the ability of fDCs to activate T cells and eliminate leukemic cells. The antigens with which DCs are pulsed are crucial to ensure the development of the right T cell clones in the patient. We will take advantage of the Rhapsody single-cell analysis system. Custom AbSeq assays of over 60 antibodies linked to the immunity will be used on fresh biopsies to determine the accurate immunophenotype of RS cells to be sorted, lysed and used to pulse DCs, The in-depth immune characterization and the transcriptome obtained from this analysis will also add insight into the biology of RS. All the steps of the therapy will then be tested in a syngenic graft approach using a preclinical murine model of RS. Finally, to fast translate our research to the clinic, fDCs from CLL patients will be prepared to comply GMP requirements. The impact of this high risk/high gain proposal will be tremendous because, if successful, will give a therapeutic option to patients with a fatal disease.