[Biological roles of complement and recent topics in clinical medicine].

The complement has been identified as a complementation factor to compensate for the function of an antibody. The complement consists of C1-C9, a complement-related molecule, and its regulating molecules. Three major biological roles of the complement have been classified: First: opsonization following phagocytosis and the elimination of microbes; second: direct destruction of bacteria due to membrane attack complex (MAC); third: complement activation following the induction of anaphylactoid factors and local recruitment and activation of neutrophilic leukocytes. In this review, the basic findings and recent treatments of paroxysmal nocturnal hemoglobinuria (PNH) and hereditary angioedema (HAE) are summarized. Finally, there is a short review of a rare autosomal recessive disorder of 3MC syndrome and new biological functions of complement factors except for that of innate immunity are proposed.