Differential diagnostic efficiency of T cells subsets versus interferon-gamma, tumor necrosis factor-alpha and adenosine deaminase in distinguishing tuberculous from malignant pleural effusions

BackgroundThe differential diagnosis of tuberculous and malignant pleural effusion (PE) is extremely difficult and continues to pose clinical challenges.Aim of the studyTo evaluate the utility of pleural fluid interferon gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), adenosine deaminase (ADA) levels with T cells subsets in differential diagnosis of malignant (MPE) and tuberculous pleural effusions (TPE).MethodsForty patients with pleural effusion (20 tuberculous and 20 malignant) were included in the study. The percentages of CD3+ lymphocytes, CD4+ lymphocytes and Treg (CD4+ CD25+) cells in pleural effusion from patients with tuberculous and malignant PE were determined by flow cytometry. The concentrations of IFN-γ, TNF-α, and ADA were simultaneously determined in pleural fluids by enzyme linked immunosorbent assay and colorimetric methods.ResultsIFN-γ, TNF-α and ADA concentrations were significantly higher in TPE than MPE (2.26 ± 1.62 vs. 0.3 ± 0.20 IU/ml: P < 0.0001, 122.45 ± 47.69 vs. 35.03 ± 31.88 pg/ml: P < 0.0001 and 84.22 ± 41.47 vs. 23.19 ± 17.93 U/l: P < 0.0001 respectively). T-cells markers (CD3+ T-cells, CD4+ T-cells and T reg cells) were significantly higher in TPE than MPE (76.46% vs. 65.29%; P 0.004, 51.21% vs. 43.50%; P 0.044 and 14.60% vs. 12.43%; P 0.032 respectively). CD3+ plus CD4+ as well as CD3+ plus CD4+ plus T reg combinations were all 100% specific for discriminating TPE from MPE. TNF-α plus IFN-γ, TNF-α plus ADA, as well as IFN-γ plus TNF-α plus ADA, were 100% specific for discriminating TPE from MPE. Furthermore, the specificity of combined-diagnostic value of IFN-γ, TNF-α and ADA with T cells subsets was >95%.ConclusionsThe combinations of pleural fluid IFN-γ, TNF-α and ADA levels and T cells subsets could effectively address the challenge of distinguishing tuberculous pleural effusion from malignant pleural effusion.