A serum protein signature with high diagnostic value in bacterial endocarditis: results from a study based on surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.
BACKGROUND
Bacterial endocarditis is a serious disease. Surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) based on serum protein profiling is a powerful approach that can generate biomarkers with diagnostic value.


METHODS
To identify a protein signature associated with bacterial endocarditis, we retrospectively performed SELDI-TOF MS profiling of serum samples from 88 patients hospitalized because of clinical suspicion of endocarditis. The diagnosis was confirmed by conventional criteria for 34 patients (endocarditis positive) and was excluded for 54 patients (endocarditis negative). Serum samples were incubated with cation-exchange ProteinChip arrays. The protein profiles generated were subjected to biostatistical processing.


RESULTS
Fifty-nine samples (23 endocarditis positive and 36 endocarditis negative) were randomly selected for a learning set, with the 29 remaining samples (11 endocarditis positive and 18 endocarditis negative) serving as an independent testing (validation) set. Sixty-six protein peaks were differentially expressed between the endocarditis-positive and the endocarditis-negative patients. By combining partial least squares and logistic regression methods, we built a serum protein model that perfectly discriminated between endocarditis-positive and endocarditis-negative patients. Importantly, when this model was tested on the independent testing set, a correct prediction rate of nearly 90% was demonstrated. Overall, sensitivity, specificity, positive predictive value, and negative predictive value were 94%, 98%, 96%, and 96%, respectively.


CONCLUSIONS
SELDI-TOF MS profiling revealed a serum signature with high diagnostic potential for endocarditis.
Fenollar
Florence
F
Unite des Rickettsies, Centre National de la Recherche Scientifique 6020, Institut Federatif de Rechercher 48, Faculte de Medecine, Marseille, France.
Goncalves
Anthony
A
Esterni
Benjamin
B
Azza
Said
S
Habib
Gilbert
G
Borg
Jean-Paul
JP
Raoult
Didier
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001798:Blood Proteins / Q000032:analysis*; D004697:Endocarditis, Bacterial / Q000175:diagnosis*; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D016015:Logistic Models; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008875:Middle Aged; D011237:Predictive Value of Tests; D040081:Protein Array Analysis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D001798:Blood Proteins