Eotaxin-3 and interleukin-5 pleural fluid levels are associated with pleural fluid eosinophilia in post-coronary artery bypass grafting pleural effusions.

OBJECTIVES The primary aim of this study was to examine the association between pleural fluid (PF) eosinophilia, and the PF and serum levels of interleukin (IL)-5, eotaxin-2, eotaxin-3, and vascular cell adhesion molecule (VCAM)-1 in patients with post-coronary artery bypass grafting (CABG) pleural effusions. DESIGN A prospective observational study. SETTING A tertiary teaching hospital. PATIENTS AND METHODS Thirty-eight patients with post-CABG pleural effusions were recruited into the study. An effusion that contained at least 10% eosinophils was called "eosinophilic." The PF and serum levels of the cytokines and VCAM-1 were measured using an enzyme-linked immunosorbent assay. RESULTS (1) The number of PF eosinophils significantly correlated with the number of blood eosinophils. (2) PF IL-5 levels were significantly higher than the corresponding serum levels, and there was a significant correlation between the PF and serum IL-5 levels. PF IL-5 levels significantly correlated with the PF eosinophil count, and serum IL-5 levels significantly correlated with the number of blood eosinophils. (3) PF eotaxin-3 levels were significantly higher than serum levels, and PF eotaxin-3 levels significantly correlated with the PF eosinophil count. (4) PF VCAM-1 levels were significantly lower than the corresponding serum levels, and PF VCAM-1 levels were significantly higher in eosinophilic pleural effusions (EPEs) than in non-EPEs. CONCLUSION In patients with post-CABG pleural effusions, IL-5 and eotaxin-3 are produced preferentially in the pleural cavity, and they are strongly associated with PF eosinophilia.