Patent ID: 8481332

Claim:
A method to determine whether autoantibodies that are found in sera of patients afflicted with rheumatoid arthritis (RA) are present in a sample comprising serum from a subject, which method comprises (a) contacting said sample suspected of containing said antibodies with at least two peptide units for a time sufficiently long to allow a complex to be formed between at least one of said peptide units and any said autoantibodies, and (b) detecting the presence or absence of any said complex; whereby the presence of at least one said complex determines said antibodies are present and the absence of any complex determines said antibodies are not present, and wherein at least one peptide unit comprises XG, and at least one peptide unit comprises XnonG, wherein X is a citrulline (Cit) residue or an analog thereof, G is the amino acid glycine and nonG is an amino acid other than glycine, and wherein the XG peptide unit is selected from the group consisting of: (SEQ ID NO: 1) 0002-27 H Q K R G Cit G W S R A A (SEQ ID NO: 2) 0002-29 H Q R R V Cit G W S R A A (SEQ ID NO: 3) 0002-31 H Q R R T Cit G G S R A A (SEQ ID NO: 4) 0002-32 H Q R K W Cit G A S R A A (SEQ ID NO: 5) 0002-36 H Q F R F Cit G Cit S R A A (SEQ ID NO: 6) 0002-37 H Q K W R Cit G R S Cit A A and (SEQ ID NO: 7) 0002-63 H Q F R F Cit G W S R A A and the XnonG peptide unit is selected from the group consisting of: (SEQ ID NO: 8) 0107-32 K P Y T V Cit K F M R R P (SEQ ID NO: 9) 0107-35 A R F Q M Cit H Cit R L I R (SEQ ID NO: 10) 0107-45 Y S F V W Cit S H A R P R (SEQ ID NO: 11) 0113-30 A R F Q M R H Cit R L I R and (SEQ ID NO: 12) 0218-36 R N L R L Cit R E R N H A.