Background |
Acute phase proteins (APPs) are blood proteins released from hepatocytes as an integral part of acute phase responses (APR). The APR, as a part of the innate host defense system, is triggered by tissue damage and inflammation caused by infectious, immunologic, or neoplastic agents. One of the well-characterized APPs, C-reactive protein (CRP) is an annular pentameric protein consisting of 224 amino acids (25kDa). CRP binds to the phosphocholine expressed on the surface of dead cells and bacteria. These complexes activate the complement system, leading to the phagocytic removal of the complexes by macrophages. CRP levels in canine serum are significantly elevated after inflammatory irritation, surgical trauma, or inflammatory diseases such as pyometra, panniculitis, acute pancreatitis, polyarthritis, septic arthritis, and hemangiosarcoma. Therefore, serum CRP is considered a measure of inflammation in canines. Interestingly, CRP is also found in canine saliva, and saliva CRP levels correlate with serum CRP levels. Because blood collection is an invasive procedure, saliva collection presents an alternative method for CRP collection. Like serum CRP, saliva CRP can be used as a marker to monitor inflammation status. However, as saliva CRP levels are about 1% of serum CRP levels, a highly sensitive and reliable assay is required. |