Expression of Programmed Death-1 (PD-1) on CD4+ and CD8+ T cells in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by chronic inflammatory process that targets the synovial lining of diarthrodial joints. Programmed death 1 (PD-1) plays a key role in the negative regulation of the immune response. In the current study, we investigated the expression of PD-1 on peripheral CD4+ and CD8+ T cells in RA patients. Percentage of PD-1+ cells was measured by flow cytometry in 82 RA cases and 90 healthy controls. Results showed that PD-1 expression was significantly decreased in both peripheral CD4+ and CD8+ T cells in RA ( p = 0.002 and p