Alterations in peripheral T-cell and B-cell subsets in the ankylosing spondylitis patients with gut inflammation

This study investigates changes in immune cell subsets in peripheral blood of ankylosing spondylitis (AS) patients with colitis or terminal ileitis. It aims to explore the connection between changes in lymphocyte subsets and gut inflammation, providing insights for early detection.

Overall, 50 AS patients undergoing colonoscopy were enrolled. Flow cytometry was employed to analyze lymphocyte subsets, including T and B cells, in peripheral blood. Disease activity was assessed using CRP, ESR, BASDAI, ASDAS-CRP, and ASDAS-ESR.

Compared to AS patients without gut inflammation, those with colorectal inflammation showed a significant increase in total T cells (p < .05), an increase in exhausted CD4⁺ T cells (p < .05), and a decrease in Th2 cells and total Tc cells (p < .05). Notably, in AS patients with terminal ileitis, there was an increase in total B cells and classic switched B cells (p < .05), with a decrease in double-positive T cells (p < .05). However, no significant differences were observed in the distribution of Tfh-cell subpopulations (Tfh1, Tfh2, Tfh17) and Tc-cell subpopulations (Tc1, Tc2, Tc17) between AS patients with either colorectal inflammation or terminal ileitis (p > .05). We explored the relationship between disease activity scores, ESR, CRP, and lymphocyte subsets, but found no statistically significant correlation between them.

Distinct immune patterns may exist in AS with different types of intestinal inflammation. Colitis in AS is primarily characterized by a significant increase in exhausted CD4⁺ T cells, along with a decrease in Th2 cells. In contrast, terminal ileum inflammation in AS is marked by an increase in total B cells and classic switched B cells. These findings offer new insights for early detection and therapeutic intervention.