[Clinical importance of the complement system (author's transl)].

It is intended to summarize the latest research in the complement field. After a short comment on the biochemical behaviour of proteins participating in the complement reaction, biochemistry of the complement reaction itself and its biological activities are described. The question of participation of the complement system in disease is examined by specifying the possibilities to analyse the complement system in clinical problems, and, on the other hand, by giving a review on our latest knowledge of modifications of the complement system in disease.