Complement has long been regarded as a pivotal effector arm of the innate im-mune response, eliciting important immunoregulatory functions in the context of inflammation and also serving as a vital link between the innate and adaptive immune response. In the post-genomic era, our knowledge of the innate immune system is enriched by findings that point to novel functions that do not strictly correlate with immunological defense and surveillance, immune modulation or inflammation. Several studies indicate that complement proteins exert functions that are either more complex than previously thought, or go well beyond the innate immune character of the system. The advent of high-throughput platforms for genome and proteome-wide profiling, together with the enormous amount of raw genetic information that has accumulated in the databases, have stirred new expectations in biomedical research. They have led complementologists to revisit established biological systems, such as the com.