CD19 and rheumatoid arthritis: The synovial tissue from patients with RA also contained significantly higher proportions of T-lymphocytes (CD3+, 4.32 [1.87–11.68]%, Figure 1c) and B-lymphocytes (CD19+, 0.61 [0.21–2.65]%, Figure 1d) than the synovial tissue from control patients (CD3+, 0.92 [0.34–3.63]%, p = 0.020; CD19+, 0.08 [0.04–0.3]%, p = 0.010, Mann–Whitney test).