Expression of NKB1 on peripheral T cells in patients with rheumatoid arthritis.

NKB1 inhibits cytoxic activity of T lymphocytes mediated by superantigens, which is one of the contributing factors in the pathogenesis of rheumatoid arthritis (RA). In this study, we determined the expression of NKB1 on peripheral blood T cells in patients with RA. Our findings revealed that among patients with RA, NKB1(+) CD8(+ )T cells decreased significantly in comparison to controls (ratio: P < 0.05; absolute number: P < 0.005), and this decrease was not related to or influenced by HLA-Bw4 as a ligand of NKB1. This result may suggest that decreased expression of NKB1(+) CD8(+ )T cells contributes to the pathogenesis of RA mediated by the activation of CD8(+) T cells.