PURPOSE: Sputum smear examinations for acid-fast bacilli are positive in about 60% of pulmonary tuberculosis. Association of methods is frequently required in those patients with clinical and radiological evidence of disease and negative sputum. The aim of this study is to evaluate the contribution of IFN-γ and ADA in PT diagnosis, using samples of BAL from patients with pulmonary tuberculosis and negative smear and culture sputum.
METHODS: Samples of BAL from 18 patients with pulmonary tuberculosis, 8 with other pulmonary diseases than tuberculosis and 5 healthy patients (control) were evaluated for cellular counts (total and differential), IFN-γ (Elisa) and ADA (Giusti method). Statistical analysis: ANOVA and Pearson correlation. Significant difference between the groups was considered when p< 0.05.
RESULTS: The values obtained for ADA, IFN-γ and lymphocytes (mean± SD) are showed in the table. In tuberculosis, IFN-γ and ADA were correlated (R=0.63; p=0.039), as well as IFN-γ and total lymphocytes (R=0.60; p=0.034) and ADA and total lymphocytes (R=0.97; p<0.001).
CONCLUSION: Although IFN-γ and ADA in the BAL have been significantly higher in tuberculosis than in controls, they were not capable to differentiate tuberculosis from other pulmonary diseases. However, in tuberculosis, they are correlated with the total number of lymphocytes.
CLINICAL IMPLICATIONS: IFN-γ and ADA are not useful for diagnosis in patients with clinical or radiological suspicious of tuberculosis and negative sputum.
DISCLOSURE: Leila Antonangelo, None.