Development of various assay technologies, such as the ones described above, together with reagents which specifically detect complement activation products in tissues (284), has resulted in an explosion in the number of clinical conditions in which complement is implicated. This technical revolution has been reinforced by an increased awareness of the effects of complement on nucleated cells which has led to the realisation that complement is not merely a lytic agent (285,286). The list is long and varied. In almost all of these conditions complement is not the cause but it is one of several factors involved in pathogenesis; nevertheless, the contribution of complement may be an important component and, perhaps, one amenable to therapy. Evidence implicating complement in a particular may be obtained from animal models or from patients.
Clinical complementology is entering an exciting phase, the advances over recent years which have revealed the molecular details of the complement system and its control are beginning to be applied in a clinical setting. With the increasing recognition of the pathological relevance of complement, and the growing ability to control activation, complement will become much more relevant in the future. The study of the complement system still holds much interest, and promises to do so for quite some time.
