Positive anti-citrullinated protein antibody status is closely associated with bone loss in RA, and IGU can dose-dependently downregulate peptidyl arginine deiminase (PADI) 2 and PADI4 in neutrophils, thereby suppressing protein citrullination and alleviating bone loss (Li et al., 2020). This evidence concerns the gene PADI4 and rheumatoid arthritis.