The role of interleukin-6 gene in distinction of transudate-exudate in pleural effusions

Purpose: This study aims to appraise IL-6 gene expression in pleural fluid samples and establish a connection between expression levels and promoter polymorphisms for more accurate pleural effusion classification. Materials and Methods: A total of 38 adult patients (transudate (19) and exudate (19)) with pleural fluid and 33 healthy controls were included in the study. For the IL-6 gene expression study, RNA was isolated from transudate and exudate pleural fluids, and expression levels were compared between the two groups. Then, -174G>C (rs1800795), -572G>C (rs1800796) and, -597G>A (rs1800797) polymorphisms were analyzed using LightCycler® 480 II with real-time polymerase chain reaction from genomic DNA of controls and patients. Results: IL-6 levels were 7.13-fold more expressed in the exudate group than in the transudate group. No significant difference was found between the transudate-exudate groups in terms of polymorphisms. However, when we compared the transudate-exudate patient groups with the control groups, -174 G>C polymorphism and -597 G>A polymorphism were statistically significant. Conclusion: Pleural effusion treatment initiates with fluid characterization. In challenging cases, the current parameters are inadequate. Our findings indicate that IL-6 is a robust biomarker, independently distinguishing exudative and transudative states, surpassing traditional criteria. IL-6 shows promise for precise pleural effusion characterization, offering insights into pathophysiology and enabling targeted therapeutic interventions.