Challenges and perspectives for improved management of HIV/Mycobacterium tuberculosis co-infection.

HIV and Mycobacterium tuberculosis (MTB) are two widespread and highly successful microbes whose synergy in pathogenesis has created a significant threat for human health globally. In acknowledgement of this fact, the European Union (EU) has funded a multinational support action, the European Network for global cooperation in the field of AIDS and TB (EUCO-Net), that brings together experts from Europe and those regions that bear the highest burden of HIV/MTB co-infection. Here, we summarise the main outcome of the EUCO-Net project derived from an expert group meeting that took place in Stellenbosch (South Africa) (AIDS/TB Workshop on Research Challenges and Opportunities for Future Collaboration) and the subsequent discussions, and propose priority areas for research and concerted actions that will have impact on future EU calls.

Higher human CD4 T cell response to novel Mycobacterium tuberculosis latency associated antigens Rv2660 and Rv2659 in latent infection compared with tuberculosis disease.

One third of the world's population is infected with Mycobacterium tuberculosis (M.tb). A vaccine that would prevent progression to TB disease will have a dramatic impact on the global TB burden.

Human gene expression profiles of susceptibility and resistance in tuberculosis.

Tuberculosis (TB) still poses a profound burden on global health, owing to significant morbidity and mortality worldwide. Although a fully functional immune system is essential for the control of Mycobacterium tuberculosis infection, the underlying mechanisms and reasons for failure in part of the infected population remain enigmatic. Here, whole-blood microarray gene expression analyses were performed in TB patients and in latently as well as uninfected healthy controls to define biomarkers predictive of susceptibility and resistance.

Hypercytokinaemia accompanies HIV-tuberculosis immune reconstitution inflammatory syndrome.

Increased access to combination antiretroviral therapy in areas co-endemic for tuberculosis (TB) and HIV-1 infection is associated with an increased incidence of immune reconstitution inflammatory syndrome (TB-IRIS) whose cause is poorly understood. A case-control analysis of pro- and anti-inflammatory cytokines in TB-IRIS patients sampled at clinical presentation, and similar control patients with HIV-TB prescribed combined antiretroviral therapy who did not develop TB-IRIS. Peripheral blood mononuclear cells were cultured in the presence or absence of heat-killed Mycobacterium tuberculosis for 6 and 24 h.

Suppressor of cytokine signaling-3 is affected in T-cells from tuberculosisTB patients.

T-cells and T-cell-derived cytokines are crucial mediators of protection against Mycobacterium tuberculosis infection, but these factors are insufficient as biomarkers for disease susceptibility. In order to define T-cell molecules involved in tuberculosis (TB), we compared gene expression profiles of T-cells from patients with active TB, healthy donors with latent M. tuberculosis infection (LTBIs) and non-infected healthy donors (NIDs) by microarray analysis.

Biomarkers and diagnostics for tuberculosis: progress, needs, and translation into practice.

Human infection with Mycobacterium tuberculosis can progress to active disease, be contained as latent infection, or be eradicated by the host response. Tuberculosis diagnostics classify a patient into one of these categories. These are not fixed distinct states, but rather are continua along which patients can move, and are affected by HIV infection, immunosuppressive therapies, antituberculosis treatments, and other poorly understood factors.

Interferon-gamma release assays for the detection of Mycobacterium tuberculosis infection in children with cancer.

Setting: The paediatric oncology unit at Tygerberg Children's Hospital, South Africa.

Objectives: To assess the use of the tuberculin skin test (TST) and two commercial interferon-gamma release assays (IGRAs) for the detection of Mycobacterium tuberculosis infection in children with cancer before initiating chemotherapy treatment.

Design: Prospective hospital-based study, including children newly diagnosed with cancer; all underwent TST and IGRA testing.

Baseline sputum time to detection predicts month two culture conversion and relapse in non-HIV-infected patients.

Background: Few biomarkers are available to identify tuberculosis (TB) patients at risk of delayed sputum conversion and relapse.

Objectives: To investigate whether baseline pre-treatment time to detection (TTD) of culture predicted 2-month bacteriological conversion and TB relapse.

Methods: A total of 263 non-HIV-infected smear-positive previously untreated pulmonary TB patients were prospectively followed from diagnosis until treatment outcome after 6 months' treatment and TB recurrence within 24 months.

Plasma cytokine levels during acute HIV-1 infection predict HIV disease progression.

Background: Both T-cell activation during early HIV-1 infection and soluble markers of immune activation during chronic infection are predictive of HIV disease progression. Although the acute phase of HIV infection is associated with increased pro-inflammatory cytokine production, the relationship between cytokine concentrations and HIV pathogenesis is unknown.

Objectives: To identify cytokine biomarkers measurable in plasma during acute HIV-1 infection that predict HIV disease progression.

Biomarker discovery in heterogeneous tissue samples -taking the in-silico deconfounding approach.

Background: For heterogeneous tissues, such as blood, measurements of gene expression are confounded by relative proportions of cell types involved. Conclusions have to rely on estimation of gene expression signals for homogeneous cell populations, e.g.

Direct comparison of the diagnostic yield of ultrasound-assisted Abrams and Tru-Cut needle biopsies for pleural tuberculosis.

Background: Tuberculous pleuritis remains the commonest cause of exudative effusions in areas with a high prevalence of tuberculosis and histological and/or microbiological confirmation on pleural tissue is the gold standard for its diagnosis. Uncertainty remains regarding the choice of closed pleural biopsy needles.

Objectives: This prospective study compared ultrasound-assisted Abrams and Tru-Cut needle biopsies with regard to their diagnostic yield for pleural tuberculosis.

Delaying BCG vaccination from birth to 10 weeks of age may result in an enhanced memory CD4 T cell response.

Background: In most tuberculosis (TB) endemic countries, bacillus Calmette-Guérin (BCG) is usually given around birth to prevent severe TB in infants. The neonatal immune system is immature. Our hypothesis was that delaying BCG vaccination from birth to 10 weeks of age would enhance the vaccine-induced immune response.

Differential cytokine/chemokines and KL-6 profiles in patients with different forms of tuberculosis.

Cytokines are involved in the mediation and regulation of immunity, inflammation, and haematopoiesis. Secretion patterns may reflect the pathology or etiology of different diseases. In an attempt to increase our understanding of immunopathology during different forms of tuberculosis, and identify potential biological markers that may differentiate between forms of tuberculosis, we investigated the levels of 29 cytokines and KL-6 in the plasma of HIV uninfected patients with active pulmonary tuberculosis (TB) without pleural effusions and in pleural TB with and without HIV-co-infection.

Immunogenicity of novel DosR regulon-encoded candidate antigens of Mycobacterium tuberculosis in three high-burden populations in Africa.

Increasing knowledge about DosR regulon-encoded proteins has led us to produce novel Mycobacterium tuberculosis antigens for immunogenicity testing in human populations in three countries in Africa to which tuberculosis (TB) is endemic. A total of 131 tuberculin skin test-positive and/or ESAT-6/CFP10-positive, human immunodeficiency virus-negative adult household contacts of active pulmonary TB cases from South Africa (n = 56), The Gambia (n = 26), and Uganda (n = 49) were tested for gamma interferon responses to 7 classical and 51 DosR regulon-encoded M. tuberculosis recombinant protein antigens.

Short-term reproducibility of a commercial interferon gamma release assay.

Interferon gamma release assays (IGRAs) have been shown to be sensitive and highly specific for the detection of immune memory against Mycobacterium tuberculosis. Little is known about the reproducibility and within-person variability of these assays. Various aspects of short-term reproducibility of a commercial IGRA, the QuantiFERON-TB Gold In-Tube (QFT-IT) assay, were assessed.

Host markers in QuantiFERON supernatants differentiate active TB from latent TB infection: preliminary report.

Background: Interferon gamma release assays, including the QuantiFERON TB Gold In Tube (QFT) have been shown to be accurate in diagnosing Mycobacterium tuberculosis infection. These assays however, do not discriminate between latent TB infection (LTBI) and active TB disease.

Methods: We recruited twenty-three pulmonary TB patients and 34 household contacts from Cape Town, South Africa and performed the QFT test.

Differential cytokine secretion and early treatment response in patients with pulmonary tuberculosis.

Biomarkers for treatment response would facilitate the testing of urgently needed new anti-tuberculous drugs. The present study investigated the profiles of 30 proinflammatory, anti-inflammatory and angiogenic factors [epidermal growth factor, eotaxin, fractalkine, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1alpha, IL-1beta, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-12p70, IL-13, IL-15, IL-17, interferon-gamma, interferon-inducible protein-10, Krebs von den Lungen-6, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, sCD40L, transforming growth factor-alpha, tumour necrosis factor-alpha and vascular endothelial growth factor] in the plasma of 12 healthy tuberculin skin test-positive community controls and 20 human immunodeficiency virus-negative patients with active tuberculosis (TB) and identified potential biomarkers for early treatment response. We showed differences in the level of circulating cytokines between healthy controls and TB patients, but also between fast responders and slow responders to anti-tuberculosis treatment.

Pleural tuberculosis in patients with early HIV infection is associated with increased TNF-alpha expression and necrosis in granulomas.

Although granulomas may be an essential host response against persistent antigens, they are also associated with immunopathology. We investigated whether HIV co-infection affects histopathological appearance and cytokine profiles of pleural granulomas in patients with active pleural tuberculosis (TB). Granulomas were investigated in pleural biopsies from HIV positive and negative TB pleuritis patients.

Highly discordant T cell responses in individuals with recent exposure to household tuberculosis.

Background: There are limited data comparing interferon-gamma release assays (IGRAs) for the detection of Mycobacterium tuberculosis infection in highly endemic settings.

Methods: A cross-sectional household contact study was conducted to measure the agreement of two IGRAs in relation to the tuberculin skin test (TST) to detect M tuberculosis infection and to assess the influence of M tuberculosis exposure and age.

Results: In 82 individuals in household contact, 93% of children and 42% of adults had a high M tuberculosis contact score.

Biomarkers for TB treatment response: challenges and future strategies.

Currently the ultimate success of anti-TB therapy is measured by the relapse rate within the first 2 years after treatment. The long duration of clinical trials that rely on this outcome constitute a disincentive for the pharmaceutical industry to develop new TB drugs. Biomarkers for relapse measurable during early treatment may shorten clinical trials.

An evaluation of commercial fluorescent bead-based luminex cytokine assays.

The recent introduction of fluorescent bead-based technology, allowing the measurement of multiples analytes in a single 25-50 microl sample has revolutionized the study of cytokine responses. However, such multiplex approaches may compromise the ability of these assays to accurately measure actual cytokine levels. This study evaluates the performance of three commercially available multiplex cytokine fluorescent bead-based immunoassays (Bio-Rad's Cytokine 17-plex kit; LINCO Inc's 29-plex kit; and RnD System's Fluorokine-Multi Analyte Profiling (MAP) base kit A and B).

Differential expression of interleukin-4 (IL-4) and IL-4 delta 2 mRNA, but not transforming growth factor beta (TGF-beta), TGF-beta RII, Foxp3, gamma interferon, T-bet, or GATA-3 mRNA, in patients with fast and slow responses to antituberculosis treatment.

This study investigated interleukin-4 (IL-4), IL-4 delta 2, transforming growth factor beta (TGF-beta), TGF-beta RII, Foxp3, GATA-3, T-bet, and gamma interferon (IFN-gamma) transcription in peripheral blood samples of adult pulmonary tuberculosis patients prior to and after 1 week of therapy. Twenty patients with positive results for sputum culture for Mycobacterium tuberculosis were enrolled and treated with directly observed short-course antituberculosis chemotherapy. Early treatment response was assessed.

Evaluation of adapted whole-blood interferon-gamma release assays for the diagnosis of pleural tuberculosis.

Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic tools. Recently, in vitro interferon (IFN)-gamma-based assays have been introduced in the diagnosis of latent TB, but these techniques have not been established in the diagnosis of active TB disease, including pleural TB.

Objectives: It was the aim of this study to assess the accuracy of the commercially available QuantiFERON TB Gold assay and adapted variants of the assay, using pleural fluid or isolated pleural fluid cells for the diagnosis of pleural TB.

High level of discordant IGRA results in HIV-infected adults and children.

Setting: Tygerberg district, Western Cape Province, South Africa.

Objective: To measure the agreement of two interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) for the detection of Mycobacterium tuberculosis infection in human immunodeficiency virus (HIV) infected adults and children in a setting highly endemic for tuberculosis (TB).

Design: Cross-sectional study.