We found relatively weak, though frequently present, reactivity in the RA cohort, with 20.2% towards the cit-Fib α-35, 12.5% towards cit-Fib α-216,218, 21.0% towards cit-Fib α-263,271 and 17.0% towards cit-Fib α-425,426 (Fig. 1). Here, FBL is linked to rheumatoid arthritis.