Update in Tuberculosis 2006

Identification of Mycobacterium tuberculosis-specific Th1, Th17 and Th22 cells using the expression of CD40L in tuberculous pleurisy

Important advances have been made in the immunodiagnosis of tuberculosis (TB) based on the detection of Mycobacterium tuberculosis (MTB)-specific T cells. However, the sensitivity and specificity of the immunological approach are relatively low because there are no specific markers for antigen-specific Th cells, and some of the Th cells that do not produce cytokines can be overlooked using this approach. In this study, we found that MTB-specific peptides of ESAT-6/CFP-10 can stimulate the expression of CD40L specifically in CD4⁺ T cells but not other cells from pleural fluid cells (PFCs) in patients with tuberculous pleurisy (TBP). CD4⁺CD40L⁺ but not CD4⁺CD40L⁻ T cells express IFN-γ, IL-2, TNF-α, IL-17 or IL-22 after stimulation with MTB-specific peptides. In addition, CD4⁺CD40L⁺ T cells were found to be mostly polyfunctional T cells that simultaneously produce IFN-γ, IL-2 and TNF-α and display an effector or effector memory phenotype (CD45RA⁻CD45RO⁺CCR7⁻CD62L⁻ICOS⁻). To determine the specificity of CD4⁺CD40L⁺ T cells, we incubated PFCs with ESTA-6/CFP-10 peptides and sorted live CD4⁺CD40L⁺ and CD4⁺CD40L⁻ T cells by flow cytometry. We further demonstrated that sorted CD4⁺CD40L⁺, but not CD4⁺CD40L⁻ fractions, principally produced IFN-γ, IL-2, TNF-α, IL-17 and IL-22 following restimulation with ESTA-6/CFP-10 peptides. Taken together, our data indicate that the expression of CD40L on MTB-specific CD4⁺ T cells could be a good marker for the evaluation and isolation of MTB-specific Th cells and might also be useful in the diagnosis of TB.

Rapid diagnosis of tuberculous pericarditis by ELISPOT assay

We describe a case in which the rapid diagnosis of tuberculous pericarditis was made using the Mycobacterium tuberculosis (MTB)-specific enzyme-linked immunospot (ELISPOT) assay on pericardial effusion mononuclear cells (PEMCs). The analysis of MTB-specific T-cells in PEMCs by ELISPOT may be useful for rapid decision-making in anti-tuberculous treatment.

Evidence-based comparison of commercial interferon-gamma release assays for detecting active TB: a metaanalysis

Test accuracy of interferon-gamma release assays (IGRAs) for diagnosing TB differs when using older or precommercial tools and inconsistent diagnostic criteria. This metaanalysis critically appraises studies investigating sensitivity and specificity of the commercial T-Spot.TB and the QuantiFERON-TB Gold In-Tube Assay (QFT-IT) among definitely confirmed TB cases. We searched Medline, EMBASE, and Cochrane bibliographies of relevant articles. Sensitivities, specificities, and indeterminate rates were pooled using a fixed effect model. Sensitivity of the tuberculin skin test (TST) was evaluated in the context of IGRA studies. In addition, the rates of indeterminates of both IGRAs were assessed. The pooled sensitivity of TST was 70% (95% CI, 0.67-0.72) compared with 81% (95% CI, 0.78-0.83) for the QFT-IT and 88% (95% CI, 0.85-0.90) for the T-Spot.TB. Sensitivity increased to 84% (95%CI, 0.81-0.87) and 89% (95% CI, 0.86-0.91) for the QFT-IT and T-Spot.TB, respectively, when restricted to performance in developed countries. In contrast, specificity of the QFT-IT was 99% (95% CI, 0.98-1.00) vs 86% for the T-Spot.TB (95% CI, 0.81-0.90). The pooled rate of indeterminate results was low, 2.1% (95% CI, 0.02-0.023) for the QFT-IT and 3.8% (95% CI, 0.035-0.042) for the T-Spot.TB, increasing to 4.4% (95% CI, 0.039-0.05) and 6.1% (95% CI, 0.052-0.071), respectively, among immunosuppressed hosts. The newest commercial IGRAs are superior, in comparison with the TST, for detecting confirmed active TB disease, especially when performed in developed countries.

Rhinofacial Conidiobolus coronatus infection presenting with nasal enlargement

Rhinofacial Conidiobolus coronatus infection is a rare form of zygomycosis in humans living in the northern hemispheres. Most human cases are observed in the periequatorial areas of Africa, Asia, or South America. Only limited information regarding optimal treatment is available. We report a case of rhinofacial C. coronatus infection in an emigrated Sudanese patient. The infection was successfully treated with terbinafin and itraconazole for 12 months. Diagnosis was confirmed by microbiological culture from a tissue biopsy. Antimicrobial susceptibility testing of this organism was not predictive of optimal therapy.