The diagnostic role of pleural fluid and serum Pentraxin-3 levels in the determination of the etiology of pleural effusion

Abstract

Aim: We aimed to analyze the levels of Pentraxin-3 (PTX3) in pleural effusion (PE), and to identify its role in the differential diagnosis. Methods: A total of 149 PE and serum samples were collected. Transudate effusions secondary to heart failure, malign pleural effusions (MPE), parapneumonic effusions (PPE), and tuberculous pleural effusions (TPE) were enrolled. Light criteria, PE culture, and cytologic examination were used to ascertain the etiology. PTX3 was measured using an ELISA kit (Quantikine ELISA-Human Pentraxin 3). Results: The study group included 97 M and 52 F with a mean age of 66.67±11.47 years. Of these, 22.8% had transudates, 19.5% had PPE, 42.3% had MPE, and 15.4% had TPE. Sixty-three MPE cases comprised effusions secondary to lung cancer (n=48), breast cancer (n=5), renal cell cancer (n=4), hematologic malinancies (n=3), mesothelioma (n=3) and malign melanoma (n=1). Primary lung tumors responsible for pleural effusion were adenocarcinoma (n=23), small cell carcinoma (n=15), and squamous cell carcinoma (n=9). PTX level in pleural effusion samples significantly differed by pleural fluid etiology (p=0.041). The mean pleural fluid PTX3 was significantly higher in patients with PPE than the other groups. At a cut-off point of 4.89 ng/ml, PTX3 had the best discriminatory power for PPE versus other exudative effusions (sensitivity 86.2%, specificity 87.7%). Conclusion: PTX3 could be a promising biomarker to differentiate PPE from other causes of pleural effusions. In PPE, an increased level of pleural fluid PTX3 level without a significant increase in serum PTX3 level may reflect a more intense local inflammation than those occur in MPE or TPE.