PRF1 and rheumatoid arthritis: A significant increase (p ≤ 0.05) in the number of CD8+ T cells expressing surface TLR4 (RA: 44.00 ± 6.4% vs HC: 19.78 ± 5.3%), Granzyme B (RA: 16.83 ± 2.6% vs HC: 5.4 ± 3.06%), Perforin (RA: 19.60 ± 2.2% vs HC: 3.31 ± 3.27%) and IFNγ (22.53 ± 2.9% vs HC: 0.14 ± 0.04%) was observed, post stimulation with LPS, in RA patients in comparison to those from healthy individuals (Fig. 4f and Supplementary Fig. 4).