As shown in Figure 1F, the percentage of peripheral B cells (CD19+) GM-CSF+ cells was significantly higher in RA patients (4.1 ± 2.2%, n = 40) compared to disease (1.7 ± 0.9%, n = 31, p < 0.0001) and healthy (0.3 ± 0.2%, n = 16, p < 0.0001) controls. Here, CD19 is linked to rheumatoid arthritis.