Fig. 6

RA sera contain antibodies that specifically bind FIBA peptides bearing a citrulline substitution at Arg 271. In an ELISA, RA, SLE or control (C) sera were incubated with plate-immobilized peptides corresponding to FIBA 259–287 with (271X) or without (271R) a citrulline at position 271, or to filaggrin 619–631 (fil) with a citrulline at position 625. Sera that reacted with 271R include: two out of 18 normals, four out of 12 RA, one out of 10 SLE. Sera that reacted with 271X include: two out of 18 normals, 10 out of 12 RA, one out of 10 SLE. Sera that reacted with fil include: one out of 18 normals, three out of 12 RA, one out of 10 SLE