In addition to the above 3 pathways, proteases released by neutrophils and macrophages (Ward and Zvaifler 1973; Huber-Lang et al. 2002) , factors such as Kallikrein, plasmin and factor XIIa (Hageman factor) can generate complement activation products. Thrombin, a member of the coagulation pathway, can locally generate C5a in in vivo in C3deficient mice which are unable to generate the conventional C5 convertase .