ABSTRACT
The complement system provides a first line of defense and mediates a large variety
of cellular and humoral interactions within the immune response, including chemotaxis,
phagocytosis, cell adhesion, and B-cell differentiation. The system involves more
than 30 serum components and numerous cell surface regulators and receptors. Similar
to the blood clotting system, complement activation is initiated through a series
of complex activation cascades involving enzymatic cleavage. Three independent complement
activation cascades, the classical, the alternative, and the lectin pathway, have
been described. The liver is the main site of biosynthesis for most of the serum components
of complement and diseases of the liver can lead to alterations of the normally stable
plasma levels of complement. Deficiencies of single components can lead to a broad
variety of secondary diseases, caused by either imbalanced activation or defects in
the humoral or cellular response to microbial infections.
KEY WORDS
liver - complement - biosynthesis - deficiencies - immunity
