Luo et al. (14, 15) demonstrated that the expression of YTHDF2 had associations with RBC, lymphocyte%, neutrophil%, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio in patients with RA and had connections with C3, lymphocyte%, neutrophil-to-lymphocyte ratio, and fever in patients with SLE. Here, C3 is linked to rheumatoid arthritis.