Process for diagnosing rheumatic diseases

1. A polypeptide variant of native vimentin comprising SEQ ID NO: 1, wherein said polypeptide variant comprises an amino acid sequence wherein

at least one amino acid residue at position 16, 17, 19, 41, 58, 59, 60, 68, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 is substituted by arginine and wherein optionally

(a) at least one amino acid residue at positions 3, 20, 33, 36, 37, 94, 165, 361, 399 or 426 in said SEQ ID NO: 1 is substituted by leucine;

(b) at least one amino acid residue at positions 21, 41, 43, 50, 54, 62, 64 or 89 in said SEQ ID NO: 1 is substituted by proline;

(c) at least one amino acid residue at positions 24, 35 or 99 in said SEQ ID NO: 1 is substituted by threonine; or

(d) at least one amino acid residue at positions 25, 39, 42, 49, 55 or 67 in said SEQ ID NO: 1 is substituted by tyrosine.

2. The polypeptide variant according to claim 1 , wherein at least two amino acid residues at said positions 16, 17, 19, 41, 58, 59, 60, 68, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 are substituted by arginine.

3. The polypeptide variant according to claim 2 , wherein at least three amino acid residues at said positions 16, 17, 19, 41, 58, 59, 60, 68, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 are substituted by arginine.

4. The polypeptide variant according to claim 1 , wherein at least one amino acid residue at positions 3, 20, 33, 36, 37, 94, 165, 361, 399 or 426 in said SEQ ID NO: 1 is substituted by leucine.

5. The polypeptide variant according to claim 4 , wherein at least two amino acid residues at positions 3, 20, 33, 36, 37, 94, 165, 361, 399 or 426 in said SEQ ID NO: 1 is substituted by leucine.

6. The polypeptide variant according to claim 1 , wherein at least one amino acid residue at positions 21, 41, 43, 50, 54, 62, 64 or 89 in said SEQ ID NO: 1 is substituted by proline.

7. The polypeptide variant according to claim 6 , wherein at least two amino acid residue at said positions 21, 41, 43, 50, 54, 62, 64 or 89 in said SEQ ID NO: 1 are substituted by proline.

8. The polypeptide variant according to claim 1 , wherein at least one amino acid residue at positions 24, 35 or 99 in said SEQ ID NO: 1 is substituted by threonine.

9. The polypeptide variant according to claim 8 , wherein at least two amino acid residues at positions 24, 35 or 99 in said SEQ ID NO: 1 are substituted by threonine.

10. The polypeptide variant according to claim 1 wherein at least one amino acid residue at positions 25, 39, 42, 49, 55 or 67 in said SEQ ID NO: 1 is substituted by tyrosine.

11. The polypeptide variant according to claim 10 , wherein at least two amino acid residues at said positions 25, 39, 42, 49, 55 or 67 in said SEQ ID NO: 1 are substituted by tyrosine.

12. The polypeptide variant according to claim 1 , wherein at least one arginine residue in the variant polypeptide sequence is a citrulline residue.

13. The polypeptide variant according to claim 12 , which has a citrulline residue in at least one of positions 4, 12, 23, 28, 36, 45, 50, 64, 71, 100, 320, 364 or 378 in the variant polypeptide sequence.

14. The polypeptide variant according to claim 13 , which has a citrulline residue in at least two of said positions 4, 12, 23, 28, 36, 45, 50, 64, 71, 100, 320, 364 or 378 in the variant polypeptide sequence.

15. A polypeptide fragment which comprises at least six contiguous amino acids of a polypeptide variant of native vimentin and which exhibits reactivity to rheumatoid arthritis-associated autoantibodies, wherein said native vimentin comprises the amino acid sequence set forth in SEQ ID NO: 1 and said variant comprises an amino acid sequence which is located within the region of amino acids 30-70 of said SEQ ID NO: 1, wherein at least one amino acid residue at position 41, 58, 59, 60, or 68 in said SEQ ID NO: 1 is substituted for arginine, and wherein at least one of said six contiguous amino acids in said polypeptide fragment is said substituted arginine.

16. A peptide derivative which is a retro polypeptide, an inverso polypeptide or a cyclic polypeptide of a variant of native vimentin comprising SEQ ID NO: 1, wherein said variant comprises an amino acid sequence wherein at least one amino acid residue at position 16, 17, 19, 41, 58, 59, 60, 68, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 is substituted by arginine.

17. The polypeptide variant according to claim 1 , which comprises the sequence set forth in SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9.

18. The polypeptide fragment according to claim 15 , which comprises at least six contiguous amino acids of the polypeptide having amino acids 50-70 of said SEQ ID NO: 1, wherein at least one amino acid residue at position 58, 59, 60 or 68 in said SEQ ID NO: 1 is substituted by arginine.

19. The polypeptide fragment according to claim 15 , which comprises amino acids 51-65 (C2) of said variant polypeptide sequence, wherein at least one amino acid residue in said fragment is said substituted arginine.

20. The polypeptide fragment according to claim 15 , which comprises 17 amino acids of a variant vimentin polypeptide sequence set forth in SEQ ID NO: 9.

21. A polypeptide variant of native vimentin comprising SEQ ID NO: 1, wherein said variant comprises an amino acid sequence wherein glycine at positions 16, 41, 59 and 76 in said SEQ ID NO: 1 is substituted for arginine and which exhibits reactivity to rheumatoid arthritis-associated autoantibodies.

22. A 17-mer fragment of a polypeptide variant of native vimentin comprising SEQ ID NO: 1, wherein said polypeptide variant comprises an amino acid sequence wherein

(a) at least one glycine at amino acid residue at position 16, 17, 19, 41, 58, 59, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 is substituted by arginine; or

(b) at least one valine at amino acid residue at position 60 or 68 in said SEQ ID NO: 1 is substituted by arginine; or

(c) at least one glycine at amino acid residue at position 16, 17, 19, 41, 58, 59, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 1 is substituted by arginine and at least one valine at amino acid residue at position 60 or 68 in said SEQ ID NO: 1 is substituted by arginine;

wherein at least one of the 17 amino acids in said fragment of said polypeptide variant of native vimentin is said substituted arginine.

23. The fragment of claim 15 which is a 17-mer fragment, wherein at least one amino acid residue at position 41, 58, 59, 60, or 68 in said SEQ ID NO: 1 is substituted by arginine, and wherein at least one of said 17 amino acids in said polypeptide fragment is said substituted arginine.

24. The polypeptide variant according to claim 1 , which comprises proline to threonine substitution in SEQ ID NO: 1, which variant comprises the polypeptide sequence of SEQ ID NO: 9.

25. The polypeptide variant according to claim 1 , which comprises serine to tyrosine substitution in SEQ ID NO: 1, which variant comprises the polypeptide sequence of SEQ ID NO: 8.

26. The polypeptide variant according to claim 1 , which comprises arginine to citrulline substitution in SEQ ID NO: 1, which variant comprises the polypeptide sequence of SEQ ID NO: 7.

27. A polypeptide fragment which comprises at least six contiguous amino acids of a polypeptide variant of native vimentin, which polypeptide variant comprises the amino acid sequence of SEQ ID NO: 9 and which further exhibits reactivity to rheumatoid arthritis-associated autoantibodies, wherein at least one of said six contiguous amino acids in said polypeptide fragment is the arginine at position 16, 17, 19, 41, 58, 59, 60, 68, 76, 140, 142, 147, 363, 406 or 452 in said SEQ ID NO: 9.

28. A diagnostic agent which comprises a polypeptide variant according to claim 1 and at least one customary component which is a buffer, a solvent, a carrier or a labeling group.

29. A diagnostic kit for detecting rheumatoid arthritis, which comprises, in one or separate packages, said diagnostic agent and said customary component according to claim 28 .

30. The diagnostic kit as claimed in claim 29 , wherein the carrier is DNA, RNA, a medically compatible polymer, a synthetic biopolymer or a protein.

31. A medicament, which comprises a polypeptide variant according to claim 1 and an acceptable carrier.

32. A medicament, which comprises the polypeptide fragment according to claim 15 and an acceptable carrier.

33. A process for in vitro detection of a rheumatoid arthritis, comprising

contacting a body fluid of a subject with a diagnostic agent according to claim 28 or a kit comprising said diagnostic agent; and

determining the concentration of autoantibodies in said body fluid of said subject, wherein said concentration is useful in the diagnosis, classification or evaluation of the severity of said rheumatic disease.

34. A method for the treatment of rheumatoid arthritis, comprising administering a polypeptide variant according to claim 1 to a subject in need thereof.

35. The method according to claim 34 , further comprising administering epigallocatechin gallate (EGCG) to said subject.

36. The method according to claim 34 , further comprising administering an extract of green tea to said subject.

37. The method according to claim 36 , comprising administering an organic or organic-aqueous extract or a product obtainable from said green tea extract.

38. The method according to claim 36 , wherein the active ingredient of said extract is epigallocatechin gallate (EGCG).

39. A method of making the polypeptide variant according to claim 1 , comprising

culturing a host cell which comprises a polynucleotide encoding said polypeptide variant under conditions sufficient to express said polypeptide; and

harvesting said polypeptide.