Interestingly, active RA patients exhibited higher levels of IL-33 protein (Figure 1A) and mRNA (Figure 1D) compared with patients with inactive RA and HCs, but there were no distinct difference in ST2 (Figure 1B, 1E) and IL-10 (Figure 1C, 1F) protein and mRNA levels between active RA and inactive RA. Here, IL33 is linked to rheumatoid arthritis.