Meanwhile, despite the presence of CD8+ PD-1+ cell populations in peripheral blood from established RA patients, albeit at a lower frequency than in synovial fluid (SF)10 and a high frequency of CD8+ PD-1+ cells in early RA ST14, similar studies into the role of CD8+ T cells in RA, also remain scarce14. The gene discussed is CD8A; the disease is rheumatoid arthritis.