Multiple Myeloma (MM) is the 2nd most common hematological disorder and is characterized by accumulation of neoplastic plasma cells in the bone marrow Despite significant therapeutic advances, the majority of patients inevitably relapse due to an incomplete eradication of residual cancer cells MM could be an ideal tumor for immunotherapy as cancer cells express a unique idiotype antigen on the cell surface, a feature that is shared with other B-cell neoplasms The idiotype is exclusively present on the cancer cells and not on any normal cell, and is different in each patient So the therapy must be personalized, made especially for this patient To be cost- and time effective, the therapy should be made easily, with minimal differences in the manufacturing process between each individual therapy In the current project we aim to develop an individualized type of immune therapy, the so-called CAR-T cell therapy In this therapy, the patient's immune cells are isolated from blood and modified in such a way that they specifically recognize the idiotype on the malignant plasma cells and kill them We will develop a fast and reliable procedure to generate small elements, so-called nanobodies, that can specifically recognize the patient's idiotype When these nanobodies are put on the surface of immune cells, we predict that they will efficiently direct the immune cell to the malignant clonal B cell As such we aim to target MM residual cells and prevent disease relapse