MMP-8 activation product, its determination and use

A method of treating a periodontal disease in a subject, the method comprising:

• providing an oral sample from the subject,
• determining matrix metalloproteinase-8 (MMP-8) activation in the sample by determining a level of a MMP-8 middle-part activation product from a middle region domain of MMP-8 sequence, having a size between 10-35 kDa and comprising SEQ ID NO:
• 1 and/or SEQ ID NO:
• 2, or a fragment of the MMP-8 middle-part activation product, in the oral sample;
• comparing the level of the MMP-8 activation product, or fragment thereof, to the MMP-8 activation product, or fragment thereof, in a reference sample wherein
• the reference sample is derived from a subject or a patient group that does not have periodontal disease, wherein the subject has periodontal disease if the level of the MMP-8 activation product, or fragment thereof, is greater than the level of the MMP-8 activation product, or fragment thereof, in the reference sample;
• or
• the reference sample is derived from a subject or a patient group that has periodontal disease, wherein the subject has periodontal disease if the level of the MMP-8 activation product, or fragment thereof, is about equal to or greater than the level of the MMP-8 activation product, or fragment thereof, detected in the reference sample;
• and
• treating the subject in need for periodontal disease.