Diagnostic performance of CTLA-4, carcinoembryonic antigen and CYFRA 21-1 for malignant pleural effusion

ABSTRACT

Objectives: The diagnosis of malignant pleural effusion (MPE) remains a clinical challenge. As a negative regulator of T-cell activation, cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) has been associated with many malignant diseases. However, there is limited data about the relationship between CTLA-4 and MPE. The present study aims to investigate whether CTLA-4 levels may correlate with presence of MPE and to assess its potential diagnostic accuracy relative to that of the established markers carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA21–1).

Methods: Pleural effusion samples were collected from 36 patients with MPE and 48 patients with benign pleural effusion (BPE). Pleural levels of CTLA-4 were measured by ELISA; levels of CEA and CYFRA 21-1, by electrochemiluminescence immunoassay. Receiver operating characteristic curves were calculated to evaluate the ability of CTLA-4, CEA and CYFRA 21-1 to differentiate MPE from BPE.

Results: Pleural levels of CTLA-4 were significantly higher in MPE than in BPE patients (471.73 ± 378.86 vs. 289.22 ± 173.67 pg/ml, p = 0.004). At a cut-off value of 351.25 pg/ml, the sensitivity and specificity of CTLA-4 in diagnosing MPE were 58.30% and 83.30%, respectively, and the area under the curve was 0.72. Pleural levels of CEA and CYFRA 21-1 were also higher in MPE. Using the combination of CTLA-4, CEA and CYFRA 21-1 increased diagnostic sensitivity to 88.89% and the area under the curve to 0.92.

Conclusion: The results of this preliminary study suggest that increased levels of CTLA-4 correlate with MPE, and that CTLA-4 may have some diagnostic usefulness when used in combination with conventional tumor markers such as CEA and CYFRA 21-1. These results justify larger, more rigorous studies to validate our findings.

KEYWORDS:

• CTLA-4
• carcinoembryonic antigen
• CYFRA 21-1
• malignant pleural effusion
• diagnosis

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

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Funding

This work was supported by the Projects in the Science and Technology Pillar Program from the Department of Science and Technology of Sichuan Province (2015SZ0151).