Regarding the S100A8/A9 protein, in the study of Hyoun-Ah Kim et al. [44], serum levels of S100A8/A9 were higher in AOSD patients than in those observed in RA and controls and correlated with leukocyte count, erythrocyte sedimentation rate, C-reactive protein, ferritin, and systemic disease score. This evidence concerns the gene S100A8 and rheumatoid arthritis.