BioScience Trends. 2017;11(1):69-76. (DOI: 10.5582/bst.2016.01171)

The immune dysfunction in ankylosing spondylitis patients.

Duan ZL, Gui YY, Li C, Lin J, Gober HJ, Qin JX, Li DJ, Wang L

Ankylosing spondylitis (AS) is a spinal arthritic disease that is often associated with human leukocyte antigen (HLA)-B27, while only part of HLA-B27 carriers become AS patients. T cells have been reported to play an important role in the pathology of AS. T-cell immunoglobulin and mucin-domain-containing molecule 3 (Tim-3) and programmed death-1 (PD-1) have been known to negatively regulate the immune response. In this study, we used flow cytometry to analyze the immunological differences of peripheral blood from 21 patients with AS, 22 cases who didn't have AS but were found to be HLA-B27 positive (HLA-B27+ group), and 16 normal healthy individuals (Healthy group). The level of CD4⁺, CD8⁺ T cells, and Treg of each group was observed. The expression of Tim-3 and PD-1 and the production of IFN-γ, IL-6, TNF-α, IL-4, and IL-10 were examined as well. We found that the percentage of Treg in AS group was lower than that of healthy group. The expression of PD-1 on CD8⁺ T cells and Tim-3 on CD4⁺ T cells was lower in the AS group. AS group had lower IL- 10 production by CD4⁺ T cells and higher IL-6 production by CD8⁺ T cells. The results of HLA-B27+ group were similar to that of the healthy group. These data suggested that patients with AS had an impairment in the ability to negatively regulate the immune response, which might be related to the etiology of AS. To further investigate the roles of Tim-3 and PD-1 on CD4⁺ T cells and CD8⁺ T cells, we tested IFN-γ and IL-10 production by Tim-3⁺, Tim-3^-, PD- 1⁺, and PD-1- CD4⁺ and CD8⁺ T cells from AS patients. We found that Tim-3⁺CD4⁺, Tim- 3⁺CD8⁺ and PD-1⁺CD8⁺ T cells produced more IL-10 than other subsets. In conclusion, there is a dysfunction of T cells in AS that is associated with PD-1 and Tim-3.

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