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Context. Accurate and early diagnosis of active tuberculosis (TB) is problematic as current diagnostic methods show low sensitivity (acid-fast bacilli smears), are time-consuming (culture of biological samples) or show variable results [ Mycobacterium tuberculosis (MTB)-specific PCR]. Objectives. In the course of infection, MTB-specific T cells clonally expand at the site of infection and may thus be used as diagnostic marker for active disease. Design. In this cohort study, the frequency of MTB-specific, interferon (IFN)-γ expressing CD4+ T cells obtained from peripheral blood and the site of disease in 25 patients with suspected TB was assessed ( n = 11, bronchoalveolar lavage; n = 7, pleural fluid; n = 1, ascites; n = 1, joint fluid; n = 5, cerebrospinal fluid). Results. Amongst 15 patients who showed proven active TB infection, a striking increase of MTB-specific T cells was detected at the site of infection compared with peripheral blood (median increase: 28.5-fold, range: 7.25–531 fold; median of IFN-γ-producing CD4+ T cells from blood: 0.02%, range: 0–0.52%; median of IFN-γ-producing CD4+ T cells from the site of infection: 1.81%, range: 0.29–6.55%, P < 0.001). Main outcome measure. Recruitment of MTB-specific T cells to the site of infection yielded a sensitivity of 100% and specificity of 90%, irrespective of the compartment affected. Conclusions. The accumulation of MTB-specific T cells at the site of infection may prove as useful diagnostic marker for an accurate and rapid diagnosis of active TB. [ABSTRACT FROM AUTHOR]

Rationale: Multidrug-resistant tuberculosis (MDR-TB) is a major burden to public health in Europe. Reported treatment success rates are around 50% or less, and cure rates are even lower., Objectives: To document the management and treatment outcome in patients with MDR-TB in Europe., Methods: We performed a prospective cohort study, analyzing management and treatment outcomes stratified by incidence of patients with MDR-TB in Europe. Treatment outcomes were compared by World Health Organization and alternative simplified definitions by the Tuberculosis Network European Trialsgroup (TBNET)., Measurements and Main Results: A total of 380 patients with MDR-TB were recruited and followed up between 2010 and 2014 in 16 European countries. Patients in high-incidence countries compared with low-incidence countries were treated more frequently with standardized regimen (83.2% vs. 9.9%), had delayed treatment initiation (median, 111 vs. 28 d), developed more additional drug resistance (23% vs. 5.8%), and had increased mortality (9.4% vs. 1.9%). Only 20.1% of patients using pyrazinamide had proven susceptibility to the drug. Applying World Health Organization outcome definitions, frequency of cure (38.7% vs. 9.7%) was higher in high-incidence countries. Simplified outcome definitions that include 1 year of follow-up after the end of treatment showed similar frequency of relapse-free cure in low- (58.3%), intermediate- (55.8%), and high-incidence (57.1%) countries, but highest frequency of failure in high-incidence countries (24.1% vs. 14.6%)., Conclusions: Conventional standard MDR-TB treatment regimens resulted in a higher frequency of failure compared with individualized treatments. Overall, cure from MDR-TB is substantially more frequent than previously anticipated, and poorly reflected by World Health Organization outcome definitions.

Drug-resistant Mycobacterium tuberculosis is challenging elimination of tuberculosis (TB). We evaluated risk factors for TB and levels of second-line drug resistance in M. tuberculosis in patients in Europe with multidrug-resistant (MDR) TB. A total of 380 patients with MDR TB and 376 patients with non-MDR TB were enrolled at 23 centers in 16 countries in Europe during 2010-2011. A total of 52.4% of MDR TB patients had never been treated for TB, which suggests primary transmission of MDR M. tuberculosis. At initiation of treatment for MDR TB, 59.7% of M. tuberculosis strains tested were resistant to pyrazinamide, 51.1% were resistant to ≥1 second-line drug, 26.6% were resistant to second-line injectable drugs, 17.6% were resistant to fluoroquinolones, and 6.8% were extensively drug resistant. Previous treatment for TB was the strongest risk factor for MDR TB. High levels of primary transmission and advanced resistance to second-line drugs characterize MDR TB cases in Europe.

Background: A test for diagnosis of active Tuberculosis (TB) from peripheral blood could tremendously improve clinical management of patients., Methods: Of 178 prospectively enrolled patients with possible TB, 60 patients were diagnosed with pulmonary and 27 patients with extrapulmonary TB. The frequencies of Mycobacterium tuberculosis (MTB) specific CD4(+) T cells and CD8(+) T cells producing cytokines were assessed using overnight stimulation with purified protein derivate (PPD) or early secretory antigenic target (ESAT)-6, respectively., Results: Among patients with active TB, an increased type 1 cytokine profile consisting of mainly CD4(+) T cell derived interferon (IFN)-γ was detectable. Despite contributing to the cytokine profile as a whole, the independent diagnostic performance of one cytokine producing T cells as well as polyfunctional T cells was poor. IFN-γ/Interleukin(IL)-2 cytokine ratios discriminated best between active TB and other diseases., Conclusion: T cells producing one cytokine and polyfunctional T cells have a limited role in diagnosis of active TB. The significant shift from a "memory type" to an "effector type" cytokine profile may be useful for further development of a rapid immune-diagnostic tool for active TB.