Study of the Frequency of Mononuclear Cells Expressing MR1 Protein in the Synovial Fluid of Patients with Rheumatoid Arthritis

Vahid  Zare; Ali  Shams; Mohammad Taher  Tahoori; Ali  Dehghan

doi:10.18502/ssu.v34i4.22072

Vahid Zare Department of Immunology, Medicine Faculty, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Ali Shams Department of Immunology, Medicine Faculty, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mohammad Taher Tahoori Department of Immunology, Medicine Faculty, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Ali Dehghan Department of Rheumatology, Shahid Sadoughi Hospital, University of Medical sciences, Yazd, Iran

DOI: https://doi.org/10.18502/ssu.v34i4.22072

Keywords: Rheumatoid arthritis, Mucosal-Associated Invariant T, MHC Class I-related protein 1 (MR1).

Abstract

Introduction: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder with a prevalence of 0.5 to 1 percent in the population. Recently, a population of immune cells known as mucosal-associated invariant T cells (MAIT cells) has been identified in humans, although their role in RA remains unclear. These cells respond to antigens presented by MHC class I-like molecules called MR1. This study examined the expression level of MR1 molecules on the surface of mononuclear cells in the synovial fluid of patients with RA.

Methods: In this case-control study, 14 patients with advanced RA and 14 healthy individuals were selected. Synovial fluid and peripheral blood samples were collected from the patients. Additionally, only blood samples were collected from the healthy individuals. The frequency of MR1-expressing cells in synovial fluid and peripheral blood was measured using flow cytometry and reported as the average percentage of MR1-positive cells.

Results: On average, 12.5% of synovial fluid cells from patients with rheumatoid arthritis expressed the MR1 protein. In addition, 0.65% of peripheral blood cells in these patients were positive for MR1. In the control group, 0.61% of peripheral blood mononuclear cells showed MR1 expression. Statistical analysis showed that the expression level of MR1 on mononuclear cells in synovial fluid of rheumatoid arthritis patients was significantly higher than in the blood of these patients and in the blood of healthy individuals (P<0.001).

Conclusion: The increased expression of MR1 on the surface of mononuclear cells in the synovial fluid of RA patients may lead to the activation of MAIT cells.