Acute phase proteins

Acute phase proteins are proteins whose levels fluctuate in response to tissue injury of a variety of kinds - including trauma, myocardial infarction, acute infections, burns, chronic inflammation - as in Crohn's disease, rheumatoid arthritis and malignancy

• synthesised by hepatocytes and are produced in high numbers in response to cytokines released from macrophages (for example, inflammatory cytokines such as interleukin-1, interleukin-6 and TNF)

Serum proteins that may increase include:

• C-reactive protein
• alpha-1 anti-chymotrypsin
• alpha-1 anti-trypsin
• haptoglobins
• caeruloplasmin
• serum amyloid A
• fibrinogen
• ferritin
• complement components C3, C4

Those that may decrease include:

• pre-albumin and albumin
• transferrin

The acute phase proteins function to:

• regulate inflammatory mediator levels during inflammation in response to demand
• opsonize foreign organisms and particles