C5 and neurodegenerative disease: However, besides local anti-C5a antibody effects, the clearance of C5a from the periphery, which we were able to show in Fig. 4, may play a crucial role in the treatment of neurodegenerative diseases, since a secondary systemic inflammatory stimulus is hypothesized to affect exaggerated response of microglia which possibly contributes to disease progression (reviewed in [56, 57]).