Peripheral CD4⁺ /CD8⁺ T cell composition distinct from healthy individuals is shared by ankylosing spondylitis and...

Ankylosing spondylitis (AS) and rheumatoid arthritis (RA) are chronic inflammatory joint diseases, linking to the alterations of immune cells. We attempted to assess whether the alterations in the composition of CD4⁺ /CD8⁺ T cells are different between AS and RA and identify the characteristic cells between male and female patients.

The proportions of CD3⁺ or double positive T cells, 6 CD4⁺ T subsets and 9 CD8⁺ T cell subsets were detected by flow cytometry and compared in 30 healthy individuals, 42 AS patients and 45 RA patients. The differentially altered cells were individually analyzed for associations with disease activity parameters. In addition, their proportions were compared between different genders in the 3 groups.

The proportions of CD4⁺ T cells, naive CD4⁺ T cells and central memory CD4⁺ T cells were lower in AS patients (P = 0.001, P = 0.002 and P = 0.007, respectively) and RA patients (P = 0.032, P < 0.001 and P = 0.016, respectively), but the proportion of effector memory ones was higher when compared with healthy populations (both P < 0.001), as were the decrease of naive/central memory CD8⁺ T cells in AS (P = 0.003 and P = 0.016, respectively) and RA (P < 0.001 and P = 0.006, respectively), and the increased tendency of terminally differentiated CD8⁺ T cells. However, these above-mentioned cells, regulatory T (Treg) cells and CD8⁺ T cells with different CD127 expressions between AS and RA were similar in proportion. Furthermore, naive CD4⁺ T cells were positively associated with C-reactive protein (CRP) in AS, whereas CD4⁺ T cells and terminally differentiated CD8⁺ T of RA patients were associated with CRP in RA. The gender-related alterations predominantly displayed the overexpressions of Treg cells and naive CD8⁺ T cells in female patients with AS and RA, respectively.

AS patients and RA patients have some similar peripheral CD4⁺ /CD8⁺ T cell subsets but are distinct from healthy individuals, which may contribute to disease severity. Females are respectively characterized by the up-regulation of Treg cells and naive CD8⁺ T cells in AS patients and RA patients. The study offers an in-depth understanding of the role of T cell subsets in the similarities of the disorders and helps us to monitor disease changes and may offer a theoretical basis of developing novel therapies against common targets.