BSG and rheumatoid arthritis: Our previous studies investigated the expression of CD147 on different immune cells, including neutrophils, monocytes, macrophages, and synoviocytes from RA patients, and demonstrated that all of these cells expressed high levels of CD147.21–23 Furthermore, blocking CD147 with a specific antibody inhibited the induction of matrix metalloproteinases and angiogenesis in RA.