As seen, the linear and the cyclic peptides were very efficient in inhibiting antibody reactivity to LCPb and CCPb (Fig 3A and 3B), whereas the non-citrullinated controls (CCPg and LCPg) were not able to inhibit antibody reactivity, although a few RA sera occasionally were inhibited for ACPA reactivity to the LCPb peptide by the control peptide CCPg (Fig 3A). Here, FAM120B is linked to rheumatoid arthritis.