Potential Biomarkers in Pleural Effusions: ACE1, ACE2, and KLK12 Levels

Aim: This study aims to investigate the potential roles of angiotensin converting enzyme (ACE) 1 and ACE2, along with kallikrein-related peptidase 12 (KLK12) levels in pleural fluids and serum, in distinguishing between transudative and exudative pleural effusions.

Methods: Pleural fluid and serum samples were collected from a total of 46 patients. Levels of ACE1, ACE2, and KLK12 were measured using the ELISA method. Patients were classified as having transudative or exudative pleural effusions based on Light’s criteria. Data were analyzed using statistical methods.

Results: According to the study findings, ACE1 levels in pleural fluid were significantly higher in the exudative group compared with the transudative group. There was no significant difference observed in ACE2 levels between the two groups. Interestingly, KLK12 levels were found to be higher in the transudative group compared with the exudative group. In serum, both ACE1 and ACE2 levels were significantly higher in the exudative group.

Discussion: These results indicate that ACE1 and KLK12 may serve as important biomarkers in the diagnostic evaluation of pleural effusions. In particular, the pleural fluid to serum (PF/S) ratios of ACE1 and KLK12 showed statistically significant differences between transudative and exudative groups, highlighting their potential in differentiating pleural effusion etiologies. While pleural fluid ACE2 levels alone did not show a significant difference, serum ACE2 concentrations and PF/S ACE2 ratios differed significantly, suggesting possible systemic changes. These findings underscore the importance of evaluating serum parameters alongside pleural fluid analysis as such comparisons may enhance diagnostic accuracy. However, the relatively small sample size limits the generalizability of these results, and further studies with larger cohorts are warranted to confirm these findings.