Many researchers reported that IL-29 can be expressed in many cell types and be displayed immunoregulatory activities in naïve PBMCs.1, 15 Wang et al. have demonstrated that IL-29 enhances TLR-induced proinflammatory cytokine production in RA-FLS via up-regulation of TLRs.16 Here, IFNL1 is linked to rheumatoid arthritis.