Conversely, increasing A2 glycan (GP2) and decreasing FA2G2 glycan (GP14) are consistent with the changing of certain IgG N-GPs which have been observed in association studies on chronic diseases (Supplementary Table 8), such as dyslipidemia (DL) (67), SLE (62), RA (68), and chronic kidney disease (CKD) (69). Here, GP2 is linked to rheumatoid arthritis.