Healthcare professionals have a good understanding of B cells in normal immunity. Although the role of lymphocytes and the lymphoid system in lymphoma is understood, the role of B cells is less clear in several autoimmune diseases, such as rheumatoid arthritis, idiopathic thrombocytopenic purpura, and autoimmune hemolytic anemia. This article will present an overview of malignant and nonmalignant B-cell disorders. Experts hypothesize that some monoclonal antibodies can deplete the B-cell population and prevent B- and T-cell responses in autoimmune diseases. Nurses should understand the data surrounding monoclonal therapy, which are not always presented clearly. Nurses' ability to interpret data is important to their patients and colleagues.