RESUMEN
Biological disease-modifying antirheumatic drugs target specific components of the immune response related to pathogenesis of autoimmune and inflammatory diseases. Introduction of biologic therapies has enabled better disease control than conventional drugs and thus a reduction in comorbidity and mortality. However, there is concern about adverse effects of these drugs including infections, cancers and drug-induced autoimmune diseases. Patients undergoing biologic treatment are at small but significant risk of serious infections. The overall risk of malignancies in patients on biologics compared with the general population is not increased, but there is evidence of a higher risk of individual cancers. Surprisingly, biological treatment may induce autoantibody production and, rarely, development of autoimmune diseases. A growing body of literature has evaluated the risk of adverse effects during biologic therapies. This paper outlines adverse effects of biological disease-modifying antirheumatic drugs related to immune system disorders, both immunodeficiency and autoimmunity.