The acute phase proteins are biochemically and functionally unrelated protein predominantly
synthesized in the liver. The local inflammatory cells i.e. macrophages and neutrophils secretes
various cytokines like IL-1, IL-6, IL-8 (interleukins) and TNF-α into bloodstream in response
to injury and tissue damage, which stimulate hepatocytes to produce protein and release them into
the circulation; these proteins are called as acute phase protein (e.g. C-reactive protein (CRP), serum
amyloid A (SAA), metal binding protein, lysozyme, lectin, etc.). The acute phase proteins are involved
in variety of defence related activities e.g., inactivation of proteolytic enzymes, preventing the
distribution of infectious agents (i.e. either by destruction of microorganism or making microbial cell
suitable for cell response by modifying surface targets) and restoration of damage tissue and healthy
condition. A number of well-known acute phase proteins have disease prognosis importance and
change in the APPs level reflects the presence and intensity of inflammation during infection or injury.
Further studies are still necessary to develop our knowledge in diagnostic importance of different
acute phase proteins in fish and more efforts are needed to differentiate the APPs levels in case of
viral, bacterial and parasitic diseases.