Expression of Galectin-9 and correlation with disease activity and vascular endothelial growth factor in rheumatoid arthritis

Objective Despite the important role of Galectin-9 (Gal-9) in inflammation and angiogenesis, only a few studies on Galectin-9 expression have been performed in rheumatoid arthritis (RA) patients. The present study aimed to identify the concentration of Galectin-9 in plasma, its expression in peripheral blood T cell subsets in RA patients, and the association between Galectin-9 and vascular endothelial growth factor (VEGF) in RA. Methods One hundred and five active RA patients and 52 age- and sex-matched healthy controls (HCs) were enrolled in the study. Gal-9, vascular endothelial growth factor (VEGF), and tumour necrosis factor (TNF)-alpha level in plasma were determined by ELISA. The intracellular positive expression rates and medium fluorescence intensity (MFI) of Gal-9 and VEGF in T cell subsets, were examined by flow cytometry. Results Plasma Gal-9, TNF-alpha, and VEGF levels were higher in the RA group than in the HCs group. The plasma Gal-9 level positively correlated with Gal-9 expression in the total lymphocyte and CD3(+) T cell, CRP, SDAI, and CDAI of RA patients. The Gal-9 expressions in the cytoplasm of CD4(+) T, CD8(+) T, Treg, and DNT cells positively correlated with plasma TNF-alpha levels in RA patients. The Gal-9 expressions in CD4(+) T and CD8(+) T subsets also positively correlated with plasma VEGF levels. The plasma VEGF levels and VEGF expressions in CD4(+) T, CD8(+) T, and Treg subsets positively correlated with SDAI and CRP in RA patients. Conclusion Gal-9 can be a potential biomarker for RA disease activity. Gal-9 is probably associated with angiogenesis processing in RA.