[Significance of determination of gamma-interferon in the diagnosis of tuberculous exudative pleurisy].

The pleural fluid concentration of gamma-interferon (gamma-IFN) was studied in 44 patients with exudative pleurisy. The tuberculous nature of exudative pleurisy was established in 25 patients on the basis of X-ray study, a follow-up, microbiological study of pleural exudate specimens, and morphological studies of biopsy specimens obtained at video-assisted thoracoscopy or surgery. The the pleural exudate concentrations of gamma-IFN were over 300 pg/ml (mean 1019 +/- 161 pg/ml) in 19 out of 21 patients with exudative pleuritis in a phase of active inflammation. The patients with the fibrous outcome of pleurisy of tuberculous etiology and those with exudative pleurisy of non-tuberculous etiology, including that in malignancies and papapneumonic pleurisy, were observed to have lower concentrations of gamma-IFN (mean 118 +/- 16 pg/ml). With the discriminating level of above 300 pg/ml, the sensitivity and specificity of the test were 90.5 and 100%, respectively.