MYD88 and rheumatoid arthritis: Moreover, and perhaps consistent with the proposed proinflammatory roles of TLRs in CIA/RA pathogenesis [28, 29], LPS/TLR4 signalling substantially increases miR-155 levels in Naïve-SFs and this increase is associated with similar kinetics of MyD88 and IL-6 (although not Traf6) upregulation, at the mRNA level (Fig 4A).