Anti-PAD4 IgG and IgA were observed in 25.0% (26/104) and 21.2% (22/104) of the RA patients, as well as in 5.8% (9/155) and 5.3% (8/155) of the controls, respectively (Figure 1A,B). This evidence concerns the gene PADI4 and rheumatoid arthritis.