Quantification and phenotype of regulatory T cells in rheumatoid arthritis according to Disease Activity Score-28

Abstract

Here we studied and characterized different peripheral blood (PB) regulatory T cell (Treg) subsets in rheumatoid arthritis (RA) patients and tested the hypothesis that changes in these cells can be linked to the degree of inflammation and relapsing/remission periods. PB cells were examined from RA subjects (n = 60) with different disease activity score-28 (DAS28) and from healthy controls (n = 40). Frequencies of Treg subsets expressing characteristic membrane antigens, FoxP3 or intracellular cytokines were quantified by flow cytometry. We observed a decrease in the percentages of CD4⁺CD25^high, CD4⁺CD25^int, CD4⁺CD25^int/highFoxP3⁺, CD4⁺CD38⁺, CD4⁺CD62L⁺, CD8⁺CD25^highCD45RA⁺ and CD8⁺CD25^intCD45RA⁺ T cells in PB of RA patients compared to healthy controls. In addition, we found increased percentages of cells expressing membrane/intracellular regulatory antigens such as OX40 (CD134), CD45RB^low or CTLA-4 (CD152), and a higher proportion of other T cell subsets including CD4⁺CTLA-4⁺, CD4⁺IL10⁺, CD4⁺CD25^intIL10⁺, CD4⁺CD25^int TGFβ⁺, CD4⁺CD25^low TGFβ⁺ and CD8⁺CD28⁻ . We show that most of these changes parallel the intensity of inflammation, with lowest or highest values in patients with moderately/very active disease compared to healthy controls and at times to patients with inactive RA. The balance between these cell subsets and their antigen expression would determine the inflammation levels and could thus be linked to the relapsing/remission periods of the disease.

Keywords::

• Rheumatoid arthritis
• DAS28
• regulatory T-cells
• membrane phenotype
• intracellular antigens
• flow cytometry

Acknowledgements

We are grateful for the altruistic collaboration of the nurses from the hospital and university in obtaining samples, and to C. Mark for editorial assistance.

Declaration of interests. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Disclosure of funding sources

This research was supported by grants from the Spanish Ministerio de Sanidad y Consumo (FIS PI042060) and the Generalitat de Valenciana (GV04B531).