Modern Complement Analysis

Complement, as a vital part of the body's immune system, provides a highly effective means for the destruction of invading microorganisms and for immune complex elimination (for reviews, see references 77 and 78).Through activation and interaction with its respective receptors on various immune cells, complement is closely linked to the adaptive immune response.A normally functioning complement system is also required for physiological tissue regeneration and repair (37).Thus, complement defects (Table 1) increase the susceptibility to infection and, if classical pathway components are affected, are frequently associated with autoimmune disorders (11).Protection against complement-mediated tissue destruction is provided by various soluble and membrane-bound regulatory proteins (Fig. 1) (51).Defects in this regulation may therefore lead to serious disorders due to unrestricted activation.In addition, as a key mediator of inflammation, complement also significantly contributes to tissue damage in various clinical disorders (50,76).The present paper briefly reviews clinical indications for complement analysis and gives an overview on current methods in routine and experimental complement diagnostics.