CD19 and rheumatoid arthritis: Initial cellular phenotyping revealed that RA and (a subset of) RA-risk individuals have increased frequencies of CXCR3 + CCR6 − CCR4 − Th1 cells [3], ILC1 (c-Kit-NKp44 − ILCs) [12], memory CD8 + T cells [11], CD69 + CD8 + T cells, follicular helper T cells [13], and CD19 + B cells compared to HCs [14].