Histopathological analyses of RA synovium and cartilage grafts in the SCID-HuRAg model and the effects of ARG098. The RA synovium tissues and cartilage were stained with HE. RA synovium was injected with 10 μg human IgM (A, B), or 10 μg ARG098 (C, D). The arrows indicate the cartilage erosion by RA synovium. C indicates cartilage.