MX1 and rheumatoid arthritis: Expect for LN, MX1 up-regulation also exists in rheumatoid arthritis, idiopathic interstitial pneumonia, alopecia areata and other autoimmune diseases (McDonagh and Tazi-Ahnini, 2002; Hamano et al., 2017; Yokoyama-Kokuryo et al., 2020).