Unsurprisingly, lysosomal cysteine cathepsins (particularly cathepsin B, S, and L) have been implicated in the processing of autoantigens and thus associated with the pathogenesis of a multitude of autoimmune conditions (for review see: Vasiljeva et al. 2007) [1–3, 7, 10, 15–20]. Here, CTSB is linked to Autoimmunity.