ESAT-6-ELISpot and interferon gamma in the diagnosis of pleural tuberculosis

Appropriate diagnostic methods for tuberculous pleural effusion are vital. The IFN-gamma tests using specific Mycobacterium Tuberculos is antigens in samples from the site of infection may be promising in diagnosis of tuberculosis. Objective we examined the ability of ELISpot test using circulating peripheral blood mononuclear cells [PBMC] and compartmentalized pleural fluid mononuclear cells [PFMC] for diagnosis of active TB infection in patients with tuberculous pleural effusion. Methods PBMC and PFMC-based ELISpot test for IFN-gamma test using specific M. tuberculosis antigen: Early Secretory Antigen Target-6 protein [ESAT-6] was used for diagnosis of active TB infection. Thirty-five patients with clinically suspected tuberculous pleural effusion were enrolled over a 12-month period. Results 11 patients out of 35 were positive by culture and PCR [31.4%]. Incubation of PBMC with ESAT-6 for 8 h showed sensitivity and specificity of 82% and 92%, respectively, for the PBMC-ELISpot as compared to PFMC-ELISpot that was 54% and 96% respectively. With 24 h incubation of ESAT-6 there was around 2.5 fold increase in the median number of spot forming cells [SFCs] in PFMC from 30 to 74, whereas there was minimal increase of median number of SFCs in PBMC from 55 to 60. Conclusion ESAT-6 - ELISpot using PBMC and PFMC is useful as a tool for diagnosis of TB effusion. PFMC needs longer period of incubation for processing of ESAT-6 than PBMC. Moreover, IFN-gamma in pleural effusion [PE] is another useful way for diagnosis of TB pleurisy which is sensitive, simple and cheap

Evaluation of serum and pleural levels of angiopoietin-1 and angiopoietin-2 in children with transudative and exudative pleural effusions

Angiopoietins are involved in the pathogenesis of a variety of human diseases. We tried to evaluate the application of pleural and serum Angiopoietin-1 and 2 in categorizing pleural effusions [PEs] into exudates and transudates in children. Pleural fluid [PF] and serum Angiopoietin [Ang]-1 and Ang-2 were measured in 80 children with PEs [40 transudative and 40 exudative] by using enzyme-linked immunosorbent assay. PF Ang-2 levels were significantly higher in pleural exudates than in transudates [P 0.012]. PF Ang-2 levels were significantly higher than serum Ang-2 levels in patients with pleural exudates and transudates [P<0.001]. PF Ang-2 levels were higher in tuberculous than in non-tuberculous pneumonic PEs and empyema [P=0.01]. PF Ang-2 levels correlate with serum Ang-2 levels [P<0.003]. PF Ang-1 levels were significantly lower than serum Ang-1 levels both in patients with exudates and those with transudates [P<0.001]. Cutoff points of serum and PF Ang-2, differentiating between transudative and exudative effusions were 3ng/ml and 8ng/ml respectively. Predictive potentials of serum and PF Ang-2 cutoff points were: Sensitivity 90% and 95% respectively, specificity 92.50% and 97.50% respectively, positive predictive value 92.30% and 97.40% respectively and negative predictive value 90.20% and 95.10% respectively. Ang-2 levels were elevated in exudative PEs and correlated with levels of markers of pleural inflammation and pleural vascular hyperpermeability. It could categorize PE to exudates and transudates with valuable discriminative properties. That was detected more obviously in pleural fluids than in serum