Abstract
Review article about biological therapy and its infectious complications, which must be taken into the account, because the biologics interfere with many mechanisms of the host defense. Patients treated with biologics are prone to classical virulent infections (e.g., listeriosis, legionellosis and tuberculosis) and opportunistic infections such as progressive multifocal leukoencephalopathy.
Furthermore, suppression of immune response that is caused by biologics may lead to reactivation of latent infections such as tuberculosis or viral hepatitis B. The knowledge of basic mechanisms, by which the biologics modify the immune response, is important for a rapid clinical diagnosis of possible etiology of infectious complication, its prevention and prophylaxis.