RT Journal Article SR Electronic T1 Acute phase response of serum amyloid A protein and C reactive protein to the common cold and influenza. JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 312 OP 316 DO 10.1136/jcp.38.3.312 VO 38 IS 3 A1 J T Whicher A1 R E Chambers A1 J Higginson A1 L Nashef A1 P G Higgins YR 1985 UL http://jcp.bmj.com/content/38/3/312.abstract AB C reactive protein (CRP) and serum amyloid A protein (SAA) are sensitive and rapid acute phase reactants, and their measurement for monitoring inflammatory disease and assessing the prognosis in secondary amyloidosis is gaining widespread acceptance. The changes in these proteins in eight subjects suffering from natural colds, 15 subjects with experimentally induced colds (rhinoviruses E1, 3, 9, 14, or 31), and eight with experimentally induced influenza (A/Eng/40/83) were studied. SAA concentration increased in 21 of the 23 subjects with natural or experimental rhinovirus colds (mean increase 95 mg/l); CRP concentration increased in 11 (mean increase 11 mg/l). All subjects with influenza showed pronounced increases in SAA concentrations (mean increase 642 mg/l) while six showed increases in CRP concentration (mean increase 22 mg/l). All these increases were highly significant (p less than 0.001). Asymptomatic excretors of both rhinovirus and influenza virus showed significant increases in SAA concentration (p = 0.015 for rhinovirus and p less than 0.001 for influenza virus) but not in CRP concentration. No changes in SAA or CRP values were seen in 12 volunteers after challenge with saline. These observations suggest that caution is required in the interpretation of estimations of SAA concentration and that it may be too sensitive an acute phase protein for clinical use as its concentration may be raised in both trivial and asymptomatic viral infections.