Cytokines are chemical mediators that control and modulate many infalmmatory processes. They work in different fashions in a variety of diseases. Discriminating between malignant effusion, tuberculous effusion, and parapneumonic effusion are crucial from the clinical view-point in Korea. In the current study, interferon-gamma(INF-γ), soluble interleukin-2 receptor(IL-2R), interleukin-6(IL-6) and interleukin-10(IL-10) were measured for this purpose.

Pleural fluids from patients with malignant disease, tuberculosis, parapneumonic effusion and lung empysema were collected and gauged using commercial ELISA kits.

34 patients were enrolled in this study. among these 15 cases were malignant effusions, 12 were tuberculosis pleurisy and 7 were paraneumonic effusion and lung empyema. The levels of cytokines measured in this study were as follows, in order of frequency, malignant effusion, tuberculous effusion, parapneumonic effusion and lung empyema. The levels of INF-γ were higher in tuberculous effusion than in malignant or parapneumonic effusion(295.5±585.5 vs. 16.7±50 vs. 10.0±0 pg/ml, p>0.05). The levels of IL-2R were higher in tuberculous effusion than in malignant or parapneumonic effusion(7423.5±3752.8 vs. 3247.4±1713.3 vs. 3790.2±3201.1 pg/ml, p<0.05). No significant differences were found in the levels of IL-6 between the groups(600±12.8 pg/ml in malignant effusion, 556.4±161.7 pg/ml in tuberculous effusion, 514.4±224.8 pg/ml in parapneumonic effusion). IL-10 levels were higher in parapneumonic effusion than in malignant or tuberculous effusions(98.4±141.7 vs. 28.2±55.5 vs. 11.3±11.7 pg/ml, p<0.05).

These results suggest that the measurement of IL-2R levels in pleural fluids may be a useful means of differentiating between tuberculous effusion and pleural effusions of other origins, and that the measurement of IL-10 levels in pleural fluids may be useful to differentiate between parapneumonic effusion and pleural effusions of other origins.