Our group stems from the close and long-standing collaboration between basic and clinical researchers in the field of immunology and rheumatology. Several members of the group have a long tradition 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 maturation from B lymphocytes to PC cells involves a series of phases in which the physiological and phenotypic characteristics of PC cells gradually change until they reach final maturity. At this stage, in which PC cells produce high-affinity antibodies against a specific antigen, they are directed and selected in final host tissues, such as 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 PCs in humans, our group also studies the transcriptional regulation of a transcription factor called PRDM1, which is key in this cell differentiation process. The expression of alternative isoforms of PRDM1 has been found to be overexpressed in multiple myeloma, the tumor counterpart of PCs.