GZMB and rheumatoid arthritis: Western blot analyses performed on SF from 12 patients with RA demonstrated the presence of 2 TNC fragments of approximately 70 kDa and 30 kDa (Figure 5D), matching 2 of the 3 TNC fragments generated (Figure 2B) and solubilized (Figure 3B) after GzmB cleavage in vitro.