The Complement System of Man

Abstract

Inherited ArnormalitiesThe diagnosis of a selective deficiency of a complement component or inhibitor requires the demonstration, by functional or immunochemical technics, of a reduced serum level. A normal total hemolytic complement (CH50) does not exclude heterozygous deficiency states or absence of the C1̄ inhibitor. Stoichiometric hemolytic_ titrations, which have been described for C1,¹¹³ C1̄ inhibitor,¹² C4,¹¹⁴ C2,¹¹³ C3¹⁴ and C9,¹¹⁵ provide sensitive measurements of the activities of individual complement components in normal human serum. Immunochemical determinations, which use monospecific antibody against complement proteins to quantitate serum levels by radial or electroimmunodiffusion, are available for C1q,¹¹⁶ C1s,¹¹⁷ C1̄ inhibitor,¹² C4, . . .