Infections Related to Biologics: Agents Targeting B Cells.

B cells are an essential component of the adaptive immune system. Since the late 1990s biologic drugs targeting B cells have been used to treat not only lymphoproliferative diseases of B-cell lineage cells but also autoimmune diseases, in particular, those associated with autoantibody production. Although some of these agents are relatively safe, they have been associated with serious infections including opportunistic infections. To what extent the infectious complications reported are directly related to the use of the B-cell targeting agent or to previous and/or concomitant immunosuppressive therapies and/or the specific disease being treated is often difficult to ascertain.