TIGIT and rheumatoid arthritis: RA patients exhibited significantly higher TIGIT expression percentages and greater MFI on CD8+ T cells relative to healthy volunteers (47.95 (23.65), (N = 48) vs. 25.4 (12.9), (N = 27), p < 0.0001; MFI: 662 (187), (N = 33) vs. 567 (120.5), (N = 25), p = 0.0183).