CD8A and rheumatoid arthritis: Taken together, these data show an increase in CD8+ memory and antigen experienced T cells in lymphoid tissue during the earliest phases of RA, even before clinical onset of the disease, which is accompanied by an increased frequency of non-circulating or recently activated (CD69+) CD8+CD45RA+ T cells in lymphoid tissue and increased frequency of (CD69+) CD8+CD45RO+ T cells in peripheral blood.