The expression of P-selectin on platelets from patients with RA correlated with DAS44 (Pearson’s r=0.4708, P<0.05), C-reactive protein (CRP) levels (Pearson’s r=0.4239, P<0.05) and the percentage of ACPA (Pearson’s r=0.5497, P<0.01) (Fig. 4a–c). Here, CRP is linked to rheumatoid arthritis.