CR2 and arthritic joint disease: Moreover, specially designed inhibitors of the alternative pathway, such as low molecular weight chondroitin sulfate (LMWCS) [185] as well as a CR2-fH fusion protein combining complement receptor 2 (CR2) and factor H (fH) [186], were found to attenuate cartilage degeneration in a mouse PTOA and arthritis model, respectively.