PURPOSE: Pleural IFN-γ and ADA are laboratorial markers used for the diagnosis of pleural tuberculosis. However, other clinical conditions may elevate these markers, misunderstanding the etiological diagnosis. The aim of this study was to evaluate the role of IFN-γ in the diagnosis of tuberculosis in patients with high ADA levels and lymphocytic pleural fluids.
METHODS: Fifteen patients with lymphocytic pleural effusions and ADA>40.0U/L were selected: seven with pleural tuberculosis and 8 with other pleural exudates. IFN-γ (pg/mL) was measured by ELISA and the results were expressed in pg/mL. Statistical analysis: t-test. Significant difference between the groups was considered for p<0.05.
RESULTS: ADA and IFN-γ are expressed as mean ± SD (Table below). Using 15.0 pg/mL as the cut-off level for IFN-γ, all the patients were correctly diagnosed as having tuberculosis or as having non-tuberculous pleural effusions.
CONCLUSION: IFN-γ was able to discriminate tuberculosis from the other lymphocytic pleural effusions.
CLINICAL IMPLICATIONS: Despite the usefulness of ADA for the diagnosis of pleural tuberculosis, its use has some limitations, mainly when we consider the lymphoproliferative diseases and diseases with T lymphocytes stimulation. In these situations, the association with IFN-γ may help in the etiological diagnosis.
DISCLOSURE: Leila Antonangelo, None.