INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by the presence of different autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies. CD4T cells expressing CXCR5, referred as follicular helper T cells (Tfh), collaborate with B cells to produce antibodies. Differential expression of CXCR3 and CCR6 within CD4CXCR5 T cells defines three mayor subsets: CXCR3CCR6 (Tfh1), CXCR3CCR6 (Tfh2) and CXCR3CCR6 (Tfh17). The aim of the study was to assess whether there is an association between the percentage of these cells and RA and whether there is a correlation with disease activity.

MATERIAL AND METHODS

Twenty-four RA patients, 22 healthy controls (HC) and 16 undifferentiated arthritis (UA) patients were included. Percentage of CD4CXCR5 T cells and their subsets were analyzed by flow cytometry.

RESULTS

No differences were found in the percentages of CD4CXCR5 T cells in the comparison of RA vs HC or RA vs UA patients. Tfh1, Tfh2 and Tfh17 subsets showed no differences either. There was no correlation between CD4CXCR5T cells, Tfh1, Tfh2 and Tfh17, and Disease Activity Score in twenty-eight joints (DAS28) or erythrocyte sedimentation rate. Surprisingly, there was a positive correlation between Tfh17 cells and C-reactive protein. Finally, there was no correlation between CD4CXCR5 T cells, or their subsets, and anti-mutated citrullinated vimentin, or between the cells and RF.

CONCLUSION

There were no differences between the percentages of CD4CXCR5 T cells and their subsets in peripheral blood of RA patients and the percentages of cells in the control groups. This finding does not rule out a pathogenic role of these cells in the development and activity of RA.