Cytokines and regulatory T cells in ankylosing spondylitis

Aims To investigate the correlations among cytokines and regulatory T cells (T- regs) in ankylos-ing spondylitis (AS) patients, and their changes after anti-tumour necrosis factor-alpha (TNF-alpha) treatment.Methods We included 72 AS patients with detailed medical records, disease activity score (Bath An-kylosing Spondylitis Disease Activity Index), functional index (Bath Ankylosing Spondylitis Functional Index), and laboratory data (interleukin (IL) -2, IL -4, IL -10, TNF-alpha, interferon (IF-N)-gamma, transforming growth factor (TGF)-beta, ESR, and CRP). Their peripheral blood mononu-clear cells (PBMCs) were marked with anti- CD4, anti- CD25, and anti- FoxP3 antibodies, and triple positive T cells were gated by flow cytometry as T- regs. Their correlations were calcu-lated and the changes after anti- TNF-alpha therapy were compared.Results The frequency of T- regs in PBMCs was positively correlated to ESR and CRP in AS (r = 0.35 and 0.43; p = 0.032 and 0.027, respectively), and there was also a significant correlation between serum level of TNF-alpha and CRP (p = 0.041). The frequency of T- regs in PBMCs positively cor-related to serum levels of TNF-alpha, IL -10, and TGF-beta, while IL -2, IL -4, and IFN-gamma showed oppo-site results. After anti- TNF-alpha treatment, there were significantly lower serum levels of TNF-alpha, IL-10, TGF-beta, and frequency of T- regs in PBMCs among these AS patients (p = 0.026, 0.032, 0.029, and 0.037, respectively).Conclusion In AS patients, proinflammatory cytokine may give positive feedback to induce more T- reg production and anti-inflammatory cytokine secretion to suppress this inflammatory status, and they can be reversed by anti- TNF-alpha therapy. However, the detailed interactions among T- regs and complex cytokine networks in autoinflammatory diseases still need more studies and further functional assay.

Automated summary

The aim of this study was to investigate the correlations among cytokines and regulatory T cells (T-regs) in ankylosing spondylitis (AS) patients, as well as their changes after anti-tumour necrosis factor-alpha (TNF-alpha) treatment. The results showed that the frequency of T-regs in peripheral blood was positively correlated to disease activity indices and inflammatory markers in AS patients. After TNF-alpha treatment, there was a significant decrease in TNF-alpha levels, IL-10 levels, TGF-beta levels, and frequency of T-regs in peripheral blood of AS patients.