MYD88 and rheumatoid arthritis: In synovial membrane cultures from RA tissue, the expression of dn forms of MyD88 (MyD88 aa 53-296 P56N) and MAL/TIRAP (MAL/TIRAP P125H) significantly down-regulated the production of TNF-α, IL-6, IL-8 and VEGF cytokines and metalloproteinases [133].