TLR4 and rheumatoid arthritis: Other studies have shown that in RA patients some mycobacterial lipids, named pathogen associated molecular patterns (PAMPs), are able to increase the immune response via TLR-2 and TLR-4 binding, resulting in the increased maturation of dendritic cells, ROS production, synthesis of pro-inflammatory RA cytokines (such as IL-1, IL-6, IL-17 and IL-23), and TNF-α secretion by neutrophils [82].