[Possible mechanisms of peripheral elevated CD8+ IL-17+ T cells in rheumatoid arthritis].

Objective: To identify interleukin-17 (IL-17 )-producing CD8 positive T cells from patients with rheumatoid arthritis (RA), and investigate its cytokines as well as their correlations.

Methods: Peripheral blood got from 39 RA patients and 40 healthy donors. Flow cytometry was used to analyze the subsets of T cells in peripheral blood from these 39 RA patients and 27 healthy donors. 11-17, IL-6, and IL-23 levels in sera of all these people were tested by ELISA.

Results: The median of CD8 IL-17+ T cells from RA patients was 2.7% (95% confidence internal was 1.55%-3.74%); the median of these cells from healthy controls was 1.61% (95% confidence internal was 1.25%-2.61%). CD8+ IL-17+ T cells elevated significantly in RA(P < 0.05). As the production of CD8+ IL-17+ T cells, the IL-17 levels in sera of RA patients and healthy controls were (429 +/- 502) ng/L and (13 +/- 30) ng/L respectively. The IL-17 level in RA is higher than that in healthy people (P < 0.01). Meanwhile, to constitute CD8+ IL-17+ T cell polarizing condition, IL-23 and IL-6 in sera of RA were (157.83 +/- 27.07) ng/L and (32.67 +/- 34.50) x ng/L individually. These two cytokines in healthy controls were (21.97 +/- 3.52) ng/L and (1.82 +/- 1.51) ng/L severally. IL-6 and IL-23 increased clearly in peripheral blood of RA patients as compared with healthy donors (P < 0.01).

Conclusions: This study suggested that elevated CD8+ IL-17+ T cells which involved in IL-17 secretion may depend on increased IL-6 and IL-23 in peripheral blood of rheumatoid arthritis.