Assaying of tumor necrosis factor α, complement factors, and α-1-antitrypsin in the diagnosis of malignant serous effusions

The objective of this study was to measure the concentrations of tumor necrosis factor-alpha (TNFalpha) in pleural and peritonea] effusions of different causes and to verify whether TNTalpha, alpha-1-antitrypsin (alpha(1)AT), and complement factors C-3 and C-4 can be used in the differential diagnosis of serous effusion. One hundred forty-five serous effusions of various origins were analyzed. TNFalpha, alpha(1)AT, and complement factors C-3 and C-4 concentrations were measured simultaneously in blood and serous effusion using commercially available methods. Serous effusions were classified as follows: 102 exudates and 43 transudates, All variables were found to have good diagnostic value in the differential diagnosis of serous effusion. In the stepwise discriminant analysis, four variables were selected, producing a significant discriminant function (p < 0.001). Their order of selection was alpha(1)AT effusion, C-4 serum, TNFalpha-effusion, and C3 effusion. Combined use of these variables increased remarkably the diagnostic value (in diagnosing exudates versus transudates) giving sensitivity = 93.14%; specificity = 90.70%; positive predictive value = 95.96%: negative predictive value = 84.78%. Determination of TNFalpha, complement factors C-3 and C-4, and alpha(1)AT may be a significant parameter in the differential diagnosis of serous effusions, particularly in those patients with malignant disease. Moreover, the combination of them significantly increased their diagnostic power.