BSG and rheumatoid arthritis: The proportion of CD147 expression on Mon2 monocytes in active or patients with inactive RA compared with that of the healthy controls was significantly (3.56-fold or 1.82-fold, respectively) higher than the proportion of Mon1 (1.55-fold or 1.17-fold, respectively) and Mon3 (1.58-fold or 1.25-fold, respectively) cells (Figure 3B).