Figure 1: Complement synovial infiltration in the early pathogenesis of OA. ELISA quantification of C3a des-arginine in synovial fluid of healthy (), early-stage OA (), and end-stage OA () patients. C3a des-arginine is a carboxypeptidase-cleaved, stable form of C3a that is generated from C3 during activation of the complement cascade. ** by one-way analysis of variance (ANOVA) and Dunnett’s post hoc test (reproduction of image with permission and modified caption from Wang et al. [17]).