Complement system assessment

CH50 determinations can be used to analyze the total serum complement and are useful for monitoring immune complex diseases (Sullivan, 1989) activation of complement (Table 15.13) in the presence of autoantibodies is indicative of immune complex diseases and autoimmunity. The various components of the complement system (C3, C4) can also be measured to assess the integrity of the system. For instance, low serum concentrations of C3 and C4, with a concomitant decrease in CH50 may indicate activation of complement, while a low C4 alone is a sensitive indicator of reduced activation of the complement system. Since C3 is used as an alternate complement pathway, it usually measures high. Therefore, a low C3 with a normal C4 may indicate an alternate pathway of activation. 

These limitations of the current system of assessing aquatic environment quality indicate that further research and newer, more reliable tools are needed. Such tools introduced into analytical practice would enable fresh information to be obtained. This information would then complement the data obtained from chemical monitoring and would enable the real risk from the presence of a mixture of diverse pollutants in the environment to be adequately assessed. 

As a result of the contact of blood with none-ndothelial surfaces, several humoral and cellular systems can be activated. Exposure of blood proteins and cells to blood contacting medical devices can activate plasma proteolytic systems (coagulation (blood clotting system), fibrinolysis (process by which clot is broken down), complement cascade (a system of soluble proteins involved in microbiocidal activity and the release of inflammatory components), Kallekrein-kinin and contact systems) and at least three cellular elements (leukocytes, endothelial cells, and platelets). Contrary to the normal situations whereby these mechanisms are localized and intended to promote wound healing, activation of these systems by medical devices can result in nonlocalized systemic reactions. The preclinical and clinical assessments of hemocompatibility are designed to minimize modification of these systems. 

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