and Queen Elizabeth Hospital/Hong Kong Government Virus Unit/Ciphergen SARS

Background: A new strain of coronavirus (CoV) has caused an outbreak of severe acute respiratory syn-drome (SARS), with 8098 individuals being infected and 774 deaths worldwide. We carried out protein chip array profiling analysis in an attempt to identify biomarkers that might be useful in monitoring the clinical course of SARS patients. Methods: We performed surface-enhanced laser desorp-tion ionization time-of-flight mass spectrometry on 89 sera collected from 28 SARS patients, 72 sera from 51 control patients with various viral or bacterial infec-tions, and 10 sera from apparently healthy individuals. Results: Nine significantly increased and three signifi-cantly decreased serum biomarkers were discovered in the SARS patients compared with the controls. Among these biomarkers, one (11 695 Da) was identified to be serum amyloid A (SAA) protein by peptide mapping and tandem mass spectrometric analysis. When we monitored the SAA concentrations longitudinally in 45 sera from four SARS patients, we found a good correla-tion of SAA concentration with the extent of pneumonia as assessed by a serial chest x-ray opacity score. In-creased SAA occurred in three of four patients at the time of extensive pneumonia as indicated by high x-ray scores. Over the course of gradual recovery in two patients, as assessed clinically and radiologically, SAA concentrations gradually decreased. In the third patient, the concentrations were initially increased, but were further increased with superimposed multiple bacterial infections. SAA was not markedly increased in the fourth patient, who had low x-ray scores and whose clinical course was relatively mild. Conclusions: Protein chip array profiling analysis could be potentially useful in monitoring the severity of disease in SARS patients