Furthermore, the downregulation of miR-146 brings about the increased secretion of cytokines from hematopoietic progenitors (Zhao et al., 2014), and a polymorphism in the 3'-UTR of IRAK1 in the recognition region of miR-146a, which has been shown to be a factor of susceptibility of RA (Chatzikyriakidou et al., 2010). Here, IRAK1 is linked to rheumatoid arthritis.