A 25-year-old woman presents with a 2-week history of febrile illness and chest pain. She has an erythematous, macular facial rash and tender joints, paicularly in her left wrist and elbow. A CBC shows mild anemia and thrombocytopenia. She is noted to have increased serum levels of ceruloplasmin, fibrinogen, a2-macroglobulin, serum amyloid A protein and C-reactive protein. Together, these markers belong to which of the following families of proteins?

These proteins are synthesized primarily by the liver and are released into the circulation in response to an acute inflammatory challenge. Changes in the plasma levels of acute phase proteins are mediated primarily by cytokines (IL-1, IL-6 and TNF-a). Increased plasma levels of some acute phase proteins are reflected in an accelerated erythrocyte sedimentation rate ESR is an index used clinically to monitor the activity of many inflammatory diseases.