Increased expression of PD-1 on CD4+ T cells subsets in Rheumatoid Arthritis patients

Abstract

Study objectives: Rheumatoid arthritis (RA) is a common chronic and systemic autoimmune disease, characterized by inflammation and the destruction of the joints. It is well known that CD4+ T cells play a major role in the pathogenesis of RA. Expanded subpopulations of CD4+ T cells have been reported in RA patients. Here, we investigated the expression of PD-1 and CXCR3 on subsets of CD4+ T cells (CD4+CD28- and CD4+CD28+ T cells) in the peripheral blood (PB) and synovial fluid (SF) of patients with RA. Methods: A total of 39 RA patients, including 7 newly diagnosed (ND) and 32 relapsed (RL) cases and also 20 healthy controls were enrolled. Phenotypic characterization subsets of CD4+ T cells were evaluated by flow cytometry, using fluorescence conjugated specific human monoclonal antibodies. Results: The frequency of CD4+CD28+ T cells was significantly increased in SF versus PB in ND and RL patients. In contrast, the percentage of CD4+CD28- T cells was elevated in PB of ND and RL patients comparison to SF. In PB of RL patients the expression of CXCR3 on CD4+CD28- T cells was significantly higher versus healthy controls. Expression of PD-1 on CD4+CD28+ and CD4+CD28- T cells in PB of ND and RL patients was significantly higher than the healthy controls. Furthermore, PD-1 expression on CD4+CD28+ and CD4+CD28- T cells in SF versus PB of RL patients were significant increased. Conclusion: These data suggest that CD4+ T cells subsets in RA patients were resistance to PD-1 mediated effects and PD-1 has insufficient ability to suppression of CD4+T cells.

Keywords

• cd4+cd28+ t cells
• cd4+cd28- t cells
• cxcr3
• pd-1
• rheumatoid arthritis