[The role of complement system in infections].

The complement system plays an important role in host defence against infection, which includes localization and destruction of microorganisms. However, in the course of evolution pathogenic microorganisms have evolved mechanisms to escape complement attack. Furthermore, pathogenic microorganisms may mimic human complement proteins and use complement activation as a prerequisite for infectivity. This review focusses on the complex and often paradoxical role of the complement system in host defence against infection.