Biomarkers of osteoarthritis

An OA biomarker expression profile comprising polypeptide expression level information for two or more polypeptides selected from the group consisting of:

• MCP1, IL8, KC, MMP2, MMP3, IL6, MMP1, RANTES, MMP9, IL1B, Apolipoprotein A1, Apolipoprotein E, DCN, CILP and COMP and fragments of any thereof, and any combination thereof, obtained from a biological sample from a subject suspected of having osteoarthritis.

A diagnostic reagent for osteoarthritis comprising two or more antibodies against any two or more OA biomarkers or fragments thereof selected from the group consisting of:

• MCP1, IL8, KC, MMP2, MMP3, IL6, MMP1, RANTES, MMP9, IL1B, Apolipoprotein A1, Apolipoprotein E, DCN, CILP and COMP and fragments of any thereof.

A kit for diagnosing osteoarthritis in a subject, the kit comprising:

• at least two OA biomarker detection reagents that each specifically bind to an OA polypeptide selected from the group consisting of MCP1, IL8, KC, MMP2, MMP3, IL6, MMP1, RANTES, MMP9, IL1B, Apolipoprotein A1, Apolipoprotein E, DCN, CILP and COMP and fragments of any thereof, or at least two OA biomarker detection reagents that each specifically bind to at least part of a polynucleotide sequence coding for at least two of the OA polypeptides, wherein the specific binding of the reagent is indicative of the expression level of at least one OA polypeptide in a biological sample from a subject.

A method for identifying a candidate substance as a therapeutic agent for treating osteoarthritis, comprising:

• a) administering the candidate substance to a subject diagnosed with spontaneous osteoarthritis;
• b) measuring the expression level of two or more OA polypeptides selected from the group consisting of MCP1, IL8, KC, MMP2, MMP3, IL6, MMP1, RANTES, MMP9, IL1B, Apolipoprotein A1, Apolipoprotein E, DCN, CILP and COMP in a biological sample from the subject;
• and c) selecting the candidate substance as a candidate therapeutic agent for treating osteoarthritis if the expression level of each of the two or more OA polypeptides in the biological sample is lower than or equal to the expression level for the selected two or more OA polypeptides in a biological sample from a control subject not administered the test substance.

A method for monitoring the effect of a treatment of osteoarthritis in a subject comprising:

• a) obtaining a first OA biomarker expression profile comprising measuring the expression level of two or more OA polypeptides selected from the group consisting of MCP1, IL8, KC, MMP2, MMP3, IL6, MMP1, RANTES, MMP9, IL1B, Apolipoprotein A1, Apolipoprotein E, DCN, CILP and COMP in a first biological sample obtained from the subject before the osteoarthritis treatment is administered to the subject;
• b) obtaining a second OA biomarker expression profile comprising measuring the expression level of the two or more OA polypeptides selected in (a), in a second biological sample obtained from the subject after or while the osteoarthritis treatment is administered to the subject;
• and c) comparing the first OA biomarker expression profile with the second OA biomarker expression profile, wherein if the expression level of each of the two or more selected OA polypeptides in the first OA biomarker expression profile is lower than or equal to the expression level for the selected two or more OA polypeptides in the second biological sample from the subject is indicative of a therapeutic effect of the osteoarthritis treatment in the subject.