Apheresis and Biocompatibility: Complement Activation

Abstract

When blood comes into contact with plastic surfaces of extracorporeal circuits activation of different biological systems occurs, among them the complement. This will be activated mainly through the alternative pathway but also through the classical one. The activation through the latter pathway occurs when antibodies directed against polymeric materials used for the production of extracorporeal circuits or substances utilized for their sterilization are produced by the patient's immunosystem. Even if complement activation occurs almost constantly during apheretic procedures the natural inhibitory mechanisms of this system attenuate and disguise this phenomenon. Important and clinical manifestations occur in particular patients or in case of technologically more complex techniques. In apheresis the complement activation may be implicated in the relatively frequent complications such as fever and chills, hypotension, as well as in the rare but severe cases of ARDS.