Protein profiling of pleural fluid in guiding management of infectious parapneumonic effusion in children

Abstract

Background: Infectious parapneumonic effusion contains proteins originated from circulation as well as proteins locally released by inflammatory pulmonary cells. The purpose of this study was to investigate the value of total protein analysis in guiding management of infectious parapneumonic effusion by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Methods: Fifty-seven children with pneumonia followed by parapneumonic effusions were consecutively enrolled into our study. Protein profiles generated by MALDI-TOF MS after fractionating samples with functionalized magnetic beads (C8) were used for differentiating complicated parapneumonic effusion (CPE) from non-CPE. A training set was used to generate classification models and the clinical efficacy of these models in detecting CPE and the need for intervention was then evaluated in an independent set. Results: A total of 123 m/z values were identified and 23 m/z values which were significant with p value less than 0.05 were used as classifiers. An optimized genetic algorithm (GA) model containing enforced selection of 3 significant down-regulated m/z values (2,127, 2,232, and 2,427) was able to classify CPE with 100% positive predictive value (PPV) and predict the need of aggressive therapeutic intervention with 77% PPV. Conclusion: A diagnostic model construction comprising three potential biomarkers can predict CPE and need for surgical intervention rapidly and precisely. Pleural fluid proteins down-regulated during the progression of pneumonia could potentially guide the management of infectious parapneumonic effusion.