This study aimed to evaluate a panel of proinflammatory and antiinflammatory cytokines in noncomplicated and complicated parapneumonic pleural effusions and to correlate their levels with pleural fluid biochemical parameters.
Serum and pleural effusion were collected from 60 patients with noncomplicated (n = 26) or complicated (n = 34) parapneumonic effusions and assayed for cytologic, biochemical, and proinflammatory and antiinflammatory cytokines. Student t test was used to compare serum and pleural fluid values, Spearman correlation to analyze the relationship between pleural fluid cytokines and biochemical parameters, and accuracy of pleural fluid cytokine levels to determine the optimal cutoff value for identification of complicated effusions. Corrections for multiple comparisons were applied and a P value < .05 was accepted as significant.
Serum and pleural fluid cytokine levels of IL-8, vascular endothelial growth factor (VEGF), IL-10, and tumor necrosis factor (TNF) soluble receptor (sR) II were similar between groups. In contrast, complicated effusions had higher levels of pleural fluid IL-1β, IL-1 receptor antagonist (ra), and TNF sRI. Negative correlations were found between pleural fluid glucose with IL-1β and TNF sRI and positive correlations between lactic dehydrogenate (LDH) with IL-1β, IL-8, and VEGF. Pleural fluid levels of IL-1β, IL-1ra, and TNF sRI were more accurate than IL-8, VEGF, IL-10, and TNF sRII in discriminating complicated effusions.
Both proinflammatory and antiinflammatory cytokine levels in pleural fluid are elevated in complicated in comparison with noncomplicated parapneumonic pleural effusions, and they correlate with both pleural fluid glucose and LDH levels. IL-1β, IL-1ra, and TNF sRI had higher sensitivity and specificity than IL-8, VEGF, IL-10, and TNF sRII in discriminating complicated effusions.