Increased Tim-3 expression on peripheral lymphocytes from patients with rheumatoid arthritis negatively correlates with disease activity

Tim-3 has been reported as an important regulatory molecule and plays a pivotal role in several autoimmunity diseases. Here, we demonstrated the increased expression of Tim-3 on peripheral CD4⁺ T, CD8⁺ T, NKT cells and monocytes from RA patients compared to those from healthy controls. Percentage of Tim-3⁺ cells in peripheral blood mononuclear cells (PBMCs) showed an inverse correlation with disease activity score 28 (DAS28) and plasma TNF-α level. Similar negative correlations were found between disease activity and Tim-3 levels on CD4⁺ T, CD8⁺ T and NKT cells. Consistently, Tim-3 expression on CD3⁺ T cells was further increased in patients with disease remission after treatment. Tim-3 expression on CD8⁺ T and NKT cells negatively correlates with plasma TNF-α. Our results suggest that Tim-3 might participate in the proceeding of RA by its negative regulation on various T cell subsets. Tim-3 might be a potential new marker for assessing severity of RA.