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

Background and 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 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: 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. 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. Results: We demonstrated Oxidative Stress Balance was elevated at the time of admission in comparison to normal subjects. ROC curve analyze revealed that Oxidative Stress Balance (AUC = 0.7337; P<0.0001) was acceptable diagnostic value to discriminate IS patients from normal subjects. Kaplan-Meier survival analyze shown that Oxidative Stress Balance (P=0.8584) had no prognostic value. 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+Tcells.