PLEURAL FLUID INTERFERON-GAMMA AND TUMOR-NECROSIS-FACTOR-ALPHA IN TUBERCULOUS AND RHEUMATOID PLEURISY

Tuberculous and rheumatoid pleural effusions show features suggesting a strong local cellular immune response Pleural fluid (Pf) from patien ts with tuberculosis, rheumatoid arthritis (RA) and other diseases wer e compared with respect to interferon-gamma (IFN-gamma) and tumour nec rosis factor-alpha (TNF-alpha). Immunoassays were used to determine Pf -IFN-gamma and Pf-TNF-alpha in 102 patients, including 11 with RA, 31 with verified tuberculosis, 23 with suspected tuberculosis, 11 with pn eumonia, 14 with lung cancer and 12 with congestive heart failure. Mea surable Pf-IFN-gamma occurred exclusively in patients with verified (m edian 1.8 ng . mL(-1); 95% confidence interval (95% CI) 0.63-4.0 ng . mL(-1)) or suspected (0.37 ng . mL(-1); 95% CI 0-0.7 ng . mL(-1)) tube rculosis, The highest median Pf-IFN-gamma was observed in those patien ts who showed a positive pleural fluid culture for Mycobacterium tuber culosis. In pleural effusions due to other diseases, including RA, IFN -gamma was undetectable. The highest Pf-TNF-alpha occurred in verified tuberculosis (median 198 ng . L(-1); 95% CI 169-222 ng . L(-1)) and R A (210 ng . L(-1); 95% CI 147-231 ng . L(-1)). Pleural fluid interfero n-gamma is a highly useful marker for diagnosing tuberculous pleurisy, Although tuberculous and rheumatoid pleural effusions share several b iochemical features, they are strikingly different with respect to int erferon-gamma.