Objectives: To explore the significance of TNF, IL-8, sICAM-1 and CD11b/CD18 in pleural effusions and/or in peripheral blood in formation of pleural effusions and the possible role in differential diagnosis.
Methods: Levels of TNF, IL-8, sICAM-1 and PMN CD11b/CD18 expression were measured by radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA) and flow cytometry (FCM). 31 patients with tuberculous pleural effusions, 31 malignant pleural effusions and 31 healthy persons as control were studied.
Results: The serum levels of TNF, IL-8 and PMN CD11b/CD18 expression in benign and malignant effusions were markedly higher than those in controls (P < 0.01). The levels of TNF, IL-8 and PMN CD11b/CD18 in patients with tuberculous pleural effusions were elevated higher than those with malignant effusions (P < 0.01). The levels of sICAM-1 in pleural effusions were much lower in tuberculosis than malignancy (P < 0.01). TNF levels in pleural effusions were positively correlated to the IL-8 and sICAM-1 levels (r = 0.74 and 0.79, respectively, P < 0.01). TNF levels in serum was positively correlated to the PMN CD11b/CD18 expression (r = 0.61, P < 0.01), but the latter was negatively correlated to sICAM-1 levels of pleural effusions (Y = 1442.31 - 36.85X + 0.25X(2), R(2) = 0.59, F = 19.83, P < 0.01).
Conclusions: The results show that TNF, IL-8, sICAM-1 and CD11b/CD18 may work and affect each other in immunopathological process of tuberculous and malignant pleural effusions. The changes of TNF, IL-8 in pleural effusions and the expressions of PMN CD11b/CD18 are of clinically diagnostic value in distinguishing tuberculous from malignant pleural effusions.