[Introduction to biological drugs].

Biological therapies have revolutionized the treatment of chronic systemic diseases in which the immune system disorders form a part of the disease mechanism. In these diseases, the patients follow different drug treatments for long periods of time that causes serious adverse reactions and often obtain unsatisfactory efficacy results. Due to the research conducted in the last 10 years, biological drugs have been introduced into the treatment that are aimed against specific targets, such as inflammatory and immunopathological responses that give rise to tissue injury. The new biological therapies have improved the currently available treatments due to greater efficacy, fast action and greater tolerability. The present work aims to provide a global and up-dated view on the biological agents used most in the usual clinical practice and their importance in the management of the chronic immunologically based inflammatory diseases.