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

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.

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.

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).

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.