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?