MON2 and rheumatoid arthritis: The percentage of Mon3 was also higher in the co-culture with platelets from the RA patient group (32.67 ± 3.71%, P <0.01) compared with the no cellular contact (14.00 ± 1.53%, P <0.01) and control groups (10.03 ± 1.78%), but a significant (5.9-fold) increase in Mon2 was observed (Figure 5A).