CTSB and rheumatoid arthritis: The cysteine protease, cathepsin B, is a potential drug target for several diseases (32), including, for example, various cancers (33–36), pancreatitis (37), liver fibrosis (38), rheumatoid arthritis (RA) (39, 40) viral Ebola (41), bacterial Streptococcus pneumoniae meningitis (42), and parasitic Trypanosoma cruzi infections (43).