IL-33 levels in pleural fluids from various etiologies differentially alter mesothelial cell adhesion and migration

Abstract

Background: Interleukin (IL33) has been scarcely studied in the context of pleural effusions (PE) pathophysiology. Aim: In this study we aimed at studying PE from various etiologies and assess the levels of IL33 and its soluble receptor sST2. Moreover, we used pleural fluids from PE with high and low levels of IL33 to investigate the in vitro effects on MeT-5A cell adhesion and migration. Materials and Methods: PE fluids from 40 patients (14 with transudative, 13 with parapneumonic and 13 with malignant pleural effusions) were used. IL33 and sST2 PE levels were measured by ELISA. PE samples with high or low levels of IL33 from each group were used in in vitro MeT-5A cell adhesion and migration assays (colorimetric cell adhesion and wound scratch assay respectively). Results: There was no significant difference in IL-33 concentration levels among transudative (3.52±0.82 pg/mL), parapneumonic (3.12±0.52 pg/mL) and malignant (4.07±0.62 pg/mL) PEs. Similarly there was no significant difference in sST2 levels among transudative (3044±906 pg/mL), parapneumonic (2538±892 pg/mL) and malignant (1536±559 pg/mL) PEs. Samples from malignant PEs high in IL33 showed increased MeT-5A cell adhesion as compared to low IL33 samples, while in samples from parapneumonic PEs the result was the opposite. Analogous results were obtained regarding MeT-5A cell migration. No differences in both phenotypes were observed in samples from transudative PEs. Conclusion: IL33 and sST2 levels do not differ among transudative, parapneumonic and malignant PEs. However, based on etiology high or low levels of IL33 have differential effects on mesothelial cell adhesion and migration.