MYD88 and rheumatoid arthritis: However, with the exploration and development of epigenetics, the epigenetic enzyme histone deacetylase 6 (HDAC6) attracts increasing attention in RA study as it deacetylates not only histones, but also non-histone proteins including α-tubulin and myeloid differentiation primary response 88 (MyD88) [12,13].