Our group emerged from a close and long-standing collaboration between basic and clinical researchers in the fields of Immunology and Rheumatology. Several members of the group have a long history of studying B-lymphocyte populations and their differentiation into plasma cells (PCs), which are responsible for antibody production and, therefore, humoral immunity. The process of B-lymphocyte maturation into plasma cells involves a series of phases during which the physiological and phenotypic characteristics of plasma cells gradually change until they reach full maturity. At this stage, in which PCs produce high-affinity antibodies against a specific antigen, they are directed and selected in their final target tissues—such as the bone marrow—where these cells, although they lose their ability to proliferate, acquire a long-lived status. In addition to studying the characteristics of the different phases of B lymphocytes and plasma cells in humans, our group also investigates the transcriptional regulation of a transcription factor called PRDM1, which plays a key role in this process of cellular differentiation. Alternative isoforms of PRDM1 have been found to be overexpressed in multiple myeloma, the neoplastic counterpart of plasma cells.