Assessment of CD27 expression as a tool for active and latent tuberculosis diagnosis

There are still no reliable tests to distinguish active tuberculosis (TB) from latent TB infection (LTBI). Assessment of CD27 modulation on CD4⁺ T-cells has been suggested as a tool to diagnose different TB stages.

OBJECTIVES

To use several cytometric approaches to evaluate CD27 expression on Mycobacterium tuberculosis (Mtb)-specific CD4⁺ T-cells to differentiate TB stages.

METHODS

55 HIV-uninfected subjects were enrolled: 13 active TB; 12 cured TB; 30 LTBI. Whole blood was stimulated with RD1-proteins or Cytomegalovirus-lysate (CMV). Interferon (IFN)-γ response was evaluated by cytometry. The proportion of CD27(±) within the IFN-γ⁺ CD4⁺ T-cells or RATIO of the CD27-median fluorescence intensity (MFI) of CD4⁺ T-cells over the CD27 MFI of IFN-γ⁺ CD4⁺ T-cells was evaluated.

RESULTS

The greatest diagnostic accuracy in discriminating active TB vs. LTBI or cured TB was reached by evaluating the CD27(+) CD45RA(-) cells within the IFN-γ⁺ CD4⁺ T-cell subset (76.92 sensitivity for both, and 90% and 91.67% specificity, respectively), although the use of the CD27 MFI RATIO allows for stricter data analysis, independent of the operator.

CONCLUSIONS

the study of CD27 expression using different approaches, whether it involves evaluation of CD45RA expression or not, is a robust biomarker for discriminating TB stages.

IL-4 specific-response in whole blood associates with human Cystic Echinococcosis and cyst activity

OBJECTIVES

Human Cystic Echinococcosis (CE) is estimated in 2-3 million global cases. CE diagnosis and clinical management are based on imaging and serology, which lacks sensitivity and does not provide cyst stage information. This study aimed to evaluate tools for improving diagnosis by analysing the Interleukin (IL)-4-response to Antigen B (AgB) of Echinococcus granulosus.

METHODS

Whole blood (WB) and peripheral blood mononuclear cells were stimulated with AgB. IL-4 levels were measured by enzyme-linked immunosorbent assay.

RESULTS

WB 1-day stimulation resulted the best experimental condition for evaluating AgB IL-4-response. IL-4 levels were significantly higher in CE patients than healthy donors (p ≤ 0.0001). A ROC analysis showed significant area under the curve (AUC) results (AUC, 0.85; p = 0.0001) identifying an IL-4 level cut-off point ≥0.39 pg/mL which predicted CE with 71.4% sensitivity and 93.3% specificity. Moreover, we found that IL-4 levels were significantly increased in patients with active cysts compared to those with inactive cysts (p ≤ 0.0001). ROC analysis showed significant AUC results (0.94; p = 0.0001) with a cut-off point of 4.6 pg/mL which predicted active cysts with 84.6% sensitivity and 92% specificity.

CONCLUSIONS

We found immunological correlates associated with CE and biological cyst activity.

[The new tools of microbiological diagnosis of tuberculosis]

This review focuses on the role of new tools in the "modern" microbiological diagnosis of tuberculosis. Traditional techniques of microscopy and culture remain essential to diagnostic certainty, but some innovations replace daily the older techniques such as the identification of Mycobacterium tuberculosis complex by immunochromatography or mass spectrometry MALDI-TOF type from positive cultures, or susceptibility testing in liquid medium. New tools that use molecular techniques have become important. They all have in common to optimize the fight against tuberculosis by reducing diagnostic delay. They also allow rapid detection of drug resistance. However, the techniques of gene amplification directly from clinical samples are still less sensitive than culture. Bacteriological diagnosis of tuberculosis disease therefore still relies on the complementarities of different phenotypic and molecular techniques.

A toolbox for tuberculosis (TB) diagnosis: an Indian multicentric study (2006-2008). Evaluation of QuantiFERON-TB gold in tube for TB diagnosis

BACKGROUND

The aim of this multicentric prospective study in India was to assess the performance of the QuantiFERON TB-Gold in tube (QFT-GIT), Tuberculin Skin Test (TST) and microbiological results as additional tools for diagnosing active tuberculosis (TB) and latent infection (LTBI) according to Human Immunodeficiency Virus (HIV) status.

METHODS

Individuals with and without active TB and HIV infection were enrolled between 2006-2008. QFT-GIT and TST results were analyzed per se and in combination with microbiological data.

RESULTS

Among the 276 individuals (96 active pulmonary TB and 180 no active TB) tested by QFT-GIT, 18 indeterminate results (6.5%) were found, more significantly numerous in the HIV-infected (15/92; 16.3%) than the HIV-uninfected (3/184; 1.6%)(p<0.0001). QFT-GIT sensitivity for active TB was 82.3% and 92.9% respectively after including or excluding indeterminate results. Clinical sensitivity was significantly lower in the HIV-infected (68.4%) than the HIV-uninfected (91.4%) patients (p = 0.0059). LTBI was detected in 49.3% of subjects without active TB but varied according to TB exposure. When the TST and QFT-GIT were concomitantly performed, the respective sensitivity for active TB diagnosis was 95.0% and 85.0% in the HIV-uninfected (p = 0.60), and 66.7% and 51.5% in the HIV-infected patients (p = 0.32). QFT-GIT and TST respective specificity for active TB in the HIV-uninfected was 25.0% and 57.1% (p = 0.028), and 64.8% and 83.3% in the HIV-infected (p = 0.047). In those with active TB, QFT-GIT results were not associated with microbiological parameters (smear grade, liquid culture status, time-to-positivity of culture) or clinical suspicion of active TB score (provided by the clinicians at enrollment). Combining microbiological tests with both immunological tests significantly increased sensitivity for active TB diagnosis (p = 0.0002), especially in the HIV-infected individuals (p = 0.0016).

CONCLUSION

QFT-GIT and TST have similar diagnostic value for active TB diagnosis. In HIV-infected patients, combining microbiological tests with both immunological tests significantly increases the sensitivity for active TB diagnosis.