Pleural fluid and serum soluble interleukin-2 receptors in pleural effusions.

Pleural fluid and serum soluble Interleukin-2 receptors (sIL-2R) were measured by an enzyme-immunoassay in 13 patients with tuberculous pleurisy, in 28 patients with carcinomatous pleurisy and in 17 transudates from patients with congestive heart failure. Significantly higher values of sIL-2R were observed in exudative than in transudative (mean +/- SEM = 713 +/- 111 U/ml) pleural fluid samples, the highest being found in tuberculous (3777 +/- 501 U/ml) and the intermediate in carcinomatous exudates (1981 +/- 160 U/ml) (p less than 0.0001; on way ANOVA). Serum sIL-2R were significantly higher in carcinomatous and transudative groups than in age- and sex- matched controls (p less than 0.002; one way ANOVA), while there was no significant difference between the tuberculous group and controls. The pleural/serum sIL-2R ratio was significantly higher in tuberculous (5.32 +/- 0.60), than in carcinomatous pleurisy (2.67 +/- 0.20) and higher still than in transudates (0.76 +/- 0.10) (p less than 0.001; one way ANOVA). In conclusion, the pleura/serum sIL-2R ratio may be a helpful parameter in differentiating tuberculous from carcinomatous pleurisy and an additional confirmatory one for distinguishing transudates from exudates.