What are Acute Phase Proteins?
"The diagnosis, prognosis and monitoring of treatment (of animals) will be enhanced by measuring the levels of the major acute phase proteins."
Guest Editorial of the Veterinary Journal (2004) 168:3-5
Acute phase proteins (APPs) are plasma proteins that rapidly increase in concentration following infection, inflammation, or trauma. The concentration of these proteins such as C-reactive protein, haptoglobin and serum amyloid A alters significantly 24 to 48 hours after the inflammatory stimulus. The circulating concentrations of these proteins can provide an objective measure of the health status of an animal and are increasingly being used as markers of animal health and welfare. Serum concentrations of APPs are related to the severity of the underlying condition, and provide a ready means of evaluating both the presence and extent of disease.
The APPs are grouped into major, moderate or minor depending on their concentration and the APPs in each group vary according to species.
Measuring the concentration of these proteins is now recognised as being an important laboratory test in monitoring disease in research, development and validation and is especially useful in detecting the presence of sub-clinical infection.
APPs have a higher diagnostic sensitivity in comparison with other markers of inflammation. For example Hp levels can be up to 6 times more sensitive than leukocyte counts in detecting inflammation and are increased in cases in which the total white blood cell count shows no changes.
We have made many of the major advances in monitoring the APP response in animals for clinical and experimental purposes and research has established various quantitative APP assays, thereby recognising the species-related difference of the APP behaviour on some key proteins.
"there are further important applications for acute phase proteins as end-point biomarkers for the pro-inflammatory cytokine network"
"using acute phase proteins as a health screen prior …….. will enable identification of animals at risk of subsequently developing disease"
Guest Editorial of the Veterinary Journal (2004) 168:3-5
C-reactive protein in dogs, AGP in cats, haptoglobin in cattle has been shown to identify both clinical and sub clinical disease in animals such as canine inflammatory bowel disease, bovine mastitis and feline infectious peritonitis. In addition to these, haptoglobin and CRP in dogs and pigs have been used to monitor experimental models of infection, in vaccine studies and drug safety assessments and to detect both clinical and sub clinical disease in animals.
