[Biologics and infections in rheumatic diseases]

The successful use of a chimeric monoclonal antibody targeting TNF alpha (infliximab) to treat rheumatoid arthritis (RA) two decades ago, ushered in a new era of therapy with the so-called biopharmaceuticals, commonly referred to as "biologics". Their use rapidly spread to other indications such as Crohns disease, and their commercial success led to rapid extension of the concept using other forms of monoclonal antibodies and receptor recombinant molecules with specificities to other cytokines, growth factors and immune cell subsets. Soon after their introduction into the clinic, the first indications of increased risk of infection appeared in the form of reactivation of tuberculosis, mostly in the first months after treatment and often extrapulmonary. It was later recognised that an overall increased risk of bacterial infection under TNF-alpha blockade exists with a relative increased risk of around 2 - 3, and that classical symptoms of infection may be masked by cytokine blockade. Biologics against other cytokines such as IL-6, co-stimulatory molecules, and anti B cells seem less associated with infection, though this may be in part related to more careful patient monitoring. Increasing experience led to guidelines concerning pre-treatment screening, vaccination and perioperative advice, as well as the use of biologics in the presence of chronic viral infection, e. g. HIV, hepatitis B and C. Biologics have changed the outcome for patients with RA and other autoimmune diseases, but this success should not lead to complacency when assessing potential infectious complications of treatment in individual patients.