Various cathepsins are involved in lysosomal protein recycling and in several physiological processes such as antigen (Ag) processing, wound healing, bone remodeling, prohormone, and proenzyme activation, as well as in pathological conditions including cancer, bronchial asthma, atherosclerosis, periodontitis, rheumatoid arthritis (RA), and osteoarthritis.26, 27, 28. This evidence concerns the gene CTSS and rheumatoid arthritis.