Patent ID: 8329414

Claim:
A method for diagnosing rheumatoid arthritis, which comprises: measuring an amount of an N-terminal fragment of osteopontin cleaved by a thrombin in a sample, from a subject, with an isolated or purified monoclonal antibody 34E3, wherein the measuring is obtained by contacting the sample with the antibody; and diagnosing the subject with rheumatoid arthritis if a) the measured amount is higher than, with statistical significance, a mean value of amounts of an N-terminal fragment of osteopontin cleaved by a thrombin in samples, from subjects without rheumatoid arthritis, with an isolated or purified monoclonal antibody 34E3, or b) the measured amount is not lower than, with statistical significance, a mean value of amounts of an N-terminal fragment of osteopontin cleaved by a thrombin in samples, from subjects with rheumatoid arthritis, with an isolated or purified monoclonal antibody 34E3; wherein statistical significance is a p value of less than 0.01, wherein the isolated or purified monoclonal antibody 34E3 is produced by a hybridoma deposited as FERM BP-10897, wherein the isolated or purified monoclonal antibody 34E3 recognizes a protein or a polypeptide in which the C-terminal amino acid sequence is YGLR (SEQ ID NO: 1) but substantially does not recognize a protein or a polypeptide which has the amino acid sequence YGLR outside of the C-terminal, and wherein the protein or the polypeptide in which the C-terminal amino acid sequence is YGLR (SEQ ID NO: 1) is the N-terminal fragment of osteopontin cleaved by the thrombin, and the protein or the polypeptide which has the amino acid sequence YGLR outside of the C-terminal is osteopontin.