Latent Tubercular Infection Research Articles

Hypersenstivity Signs of Tuberculosis — Is It Synonymous of Latent Tubercular Infection?

Hypersenstivity Signs of Tuberculosis — Is It Synonymous of Latent Tubercular Infection?

Simultaneous Adalimumab and Antitubercular Treatment for Latent Tubercular Infection: An Experience from Nepal.

Introduction In Nepal, adalimumab is the most common agent being used, but in a disease activity-based dose tapering to address the economic constraints. Another constraint is the high risk of reactivation of tuberculosis in countries with high burden, especially with the use of tumor necrosis factor blocking agents. Though there are recommendations for screening and treatment of latent tuberculosis infection (LTBI) before using adalimumab, data is not clear regarding the appropriate screening schedule and the timing of initiation of biologic therapy. Methodology This retrospective review of prospectively followed cohort of spondyloarthropathy patients aimed to evaluate the efficacy of simultaneous initiation of adalimumab with LTBI treatment. Patients fulfilling either the modified New York criteria for ankylosing spondylitis or Assessment in SpondyloArthritis international Society criteria and who were refractory to oral treatment were screened with Mantoux (≥10mm) and interferon gamma release assay (QuantiFERON) to detected LTBI. Those who tested positive were started on rifampicin/isoniazid combination for 3 months and adalimumab treatment on the same day. The patients were followed up at 2 weeks, 4 weeks, 12 weeks, and then every 3 months for 2 years. Results Out of 784 patients diagnosed, 92 were receiving adalimumab. LTBI was detected by positivity of either Mantoux or QuantiFERON in 29.3% patients. None of the patients with LTBI who were started on the 2 drug regime simultaneous with adalimumab developed activation of tuberculosis. However, two patients testing negative for both the tests developed tubercular pleural effusion during treatment. Conclusions Our findings indicate that screening for LTBI should be more frequent in patients from high tuberculosis burden countries; treatment of LTBI with rifampicin/isoniazid combination for 3 months is effective in preventing reactivation even when adalimumab is started simultaneously.

Latent tuberculosis infection detection and active tuberculosis prevention in patients receiving anti-TNF therapy: an Italian nationwide survey.

Primary: to investigate Italian rheumatology practice regarding latent tubercular infection (LTBI) detection and tuberculosis (TB) prevention in patients requiring anti-tumor necrosis factor (anti-TNF) therapy. Secondary: to assess the overall number of TB cases over 10years and their distribution by drug. An anonymous, 24 multiple-response questionnaire was completed by 393/449 (87.5%) rheumatologists prescribing anti-TNF therapy. Six questions provided setting information, and 18 the compliance with recommendations and the recorded TB cases. The Italian recommendations were used by 323 (82%) and other sets by 60 (15%). TB specialists were always consulted by 81 (21%) and occasionally by 73 (19%). LTBI screening was made using chest radiograph (CR) by 5%, tuburculin skin test (TST) by 5.3%, CR+TST by 35.6%, interferon-gamma release assay (IGRA) by 7.4%, CR+IGRAs by 26% and CR+TST+IGRA by 20.6%. Isoniazid was initiated in the presence of positivity of TST by 97 (24.7%), TST+IGRA by 101 (25.7%) and IGRA by 195 (49.6%). Anti-TNF starting delay was 1month in 63.1% of the cases, 3months in 27.7%, concomitantly in 5.6%. Overall, 317 TB reactivation cases occurred in 39353 patients, with an incidence rate of 80.5 cases/100000/year (10 times higher than in the Italian general population). TB occurred during TB prophylaxis in 192 (60.6%). TB cases incidence rate divided by drug was: etanercept (ETN) 51 (16%), 28/100000/year, adalimumab (ADA) 98 (31%), 89/100000/year, infliximab (IFX) 137 (43.2%), 211/100000/year, with a significantly lower frequency in the ETN group compared to ADA and IFX groups (χ(2) =P<0.001). Italian rheumatologists are highly aware of anti-TNF-related TB risk with variable LTBI screening and TB prevention strategies. TB outcome was significantly lower in the ETN group.

Could inducible protein-10 and heparin-binding hemagglutinin improve the detection of Mycobacterium tuberculosis-infected subjects in a country with low incidence of tuberculosis ?

Background: This study aimed to evaluate inducible protein-10 (IP-10) as a biomarker besides interferon-gamma (IFN-γ) to improve the identification of active tuberculosis (TB) and latent tubercular infection (LTBI) in a country with a low incidence of TB.Methods: Whole blood from Mycobacterium tuberculosis-infected subjects was stimulated with region-of-difference-1 (RD1)-specific peptides and with heparin-binding hemagglutinin (HBHA) to determine the release of IP-10 and IFN-γ.Results: No statistically significant difference was observed between positive rates of IP-10 and IFN-γ after RD1-specific peptide stimulation in the TB and LTBI groups; a different response was detected in QuantiFERON TB-gold test-negative (QFT–) subjects. A significantly different proportion of positive responses was observed between IP-10 and IFN-γ following HBHA stimulation in the TB group and in the QFT– group but not in the LTBI group.Conclusions: The IP-10 test seemed to identify false-negative QFT results in some subjects with a positive IFN-γ/IP-10/HBHA pattern.

Blau syndrome and latent tubercular infection: an unresolved partnership

Blau syndrome and latent tubercular infection: an unresolved partnership

Tuberculosis Reactivation in a Patient with Chronic HBV Infection Undergoing PEG-Interferon Therapy: Case Report and Literature Review

Pegylated (PEG) -interferon therapy is a first-line choice to treat both chronic hepatitis B and C. Its side effects are well known and include fatigue, anaemia, weight loss, neuropsychiatric disorders, immune disregulation and white blood cells decrease. All these events could play a role in reactivation of a latent tubercular infection (LTBI), and some authors reported development of Tuberculosis (TB) during anti-HCV treatment with PEG-interferon and ribavirin. We report here the first case of TB reactivation during PEG-interferon monotherapy for HBV in a Chinese man, managed with interruption of interferon and starting of a therapy with a nucleotide analogue, in combination to anti-tubercular standard regimen, which led to a successful treatment of both diseases without significant side effects. Our report highlights the need of increasing the control of TB, by diagnosing and treating people with latent tubercular infection, that add up to one third of global population, in particular those with a high risk of reactivation.

Prescription pattern of tuberculin skin test (TST) in a teaching hospital

Background: Tuberculin skin test (TST) is one of the tools for the identification of latent tubercular infection and is an ancillary test for diagnosis of active tuberculosis. Aims & Objective: The objective of this study was to assess specialty department wise prescription of Tuberculin Skin Test (TST) in a government teaching hospital. Material and Methods: Considering resource constraint and feasibility, one month was randomly selected during 2012 and two working days in each week were systematically covered i.e. Mon-Tue (first week), Wed-Thus (second week), Fri-Sat (third week) and again Mon-Tue (fourth week). Selected information of all patients reporting to receive TST on these days was recorded on a pre-structured proforma. TST was administered by a single investigator using standard protocol and results observed between 48-72 hours. Results: A total of 372 ambulatory suspect TB patients reported to received TST with mean age of 25 years (±18.13); female constituted 52.4%. Specialty department wise prescription of TST was as follows: paediatrics (29.3%); general medicine (18.0%); OBG (15.9%); surgery (12.9%); chest and TB (11.3%), orthopaedics (8.1%) and others (4.6%). The results of 227 (61.02%) patients who returned for follow up were grouped into < 10 mm (54.0%) and ≥ 10 mm (45.79%). Conclusion: Proportion of age distribution of patients in study sample was found to be similar in comparison to population structure of India. Paediatric (up to 14 years) patients were in majority (29.3%) amongst study samples where TST results could be of some significance.

Screening and Monitoring of Latent Tubercular Infection in Patients Taking Tumor Necrosis Factor- Blockers for Psoriatic Arthritis

Patients with arthritis who need treatment with biologics are carefully screened for possible previous exposure to tuberculosis to detect any latent tubercular infection (LTBI). The traditional method of screening for LTBI is not specific, because positivity could also depend on infection by atypical mycobacteria and bacillus Calmette-Guerin vaccination. In addition, the screening does not show high sensitivity, frequently presenting a false negativity because of immunosuppression caused by drugs used for arthritis. Recently, interferon-γ release assays (IGRA) have been used to screen LTBI with more sensitivity and specificity before treatment with anti-tumor necrosis factor-α drugs. Moreover, in our experience, IGRA are potentially useful in monitoring LTBI during biologic therapy.

Tabac et tuberculose

Smoking and tuberculosis represent two major world health issues particularly in developing countries. Tobacco smoke increases risk of Mycobaterium tuberculosis infection by several means: alteration of muco-ciliary clearance, reduced alveolar macrophage activity; immune-depression of pulmonary lymphocytes, reduction of cytotoxic activity of natural killer cells, alteration of the activity of the pulmonary dendritic cells. Both active and passive smoking increases the risk of latent tubercular infection and of pulmonary and extra-pulmonary tuberculosis. Active smoking increases the severity of pulmonary tuberculosis (gravity of radiological lesions). The diagnostic delay and recovery details are more important for smokers. Active smoking increases relapses of both pulmonary and extra-pulmonary tuberculosis after treatment with or without the Directly Observed Treatment Short course (DOTS) with poor observance of treatment. The mortality risk from tuberculosis is heightened among smokers. Smoking cessation represents an essential means of controlling tuberculosis epidemics in developing countries.

Serpiginous choroiditis (SC): patterns of progression and role of tuberculous infection

Abstract Purpose To relate patterns of progression and role of tuberculosis (TB) infection in serpiginous choroiditis (SC) by reviewing a series of cases of SC seen at Centre for Ophthalmic Specialized Care (COS), Lausanne, Switzerland and at the Ophthalmology Department of Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. Methods Retrospective review of clinical data, visual field (VF), fluorescein angiographic (FA), indocyanine green angiographic (ICGA) and optical coherence tomography (OCT) features and TB infectious status in cases of SC. Results In the time span of 9 years 16 SC cases were seen in the two centres. Interferon gamma release assays (IGRA) revealed positivity for latent tubercular infection in 11 out of 16 patients. Patterns of evolution under immunosuppressive therapy differed between the TB positive and TB negative cases Conclusion Even in non endemic areas TB infection, as a cause of SC has to be excluded. Typical behaviour of TB related SC is relentless progression despite immunosuppressive therapy.

Immunological assays in the diagnosis of tuberculosis infection at the beginning of 21st century

A subject infected by tubercle bacilli may immediately develop the disease (primary tuberculosis), witch occurs in a few number of infected persons, or may overcome the primary infection (a latent carrier of the infection). Nowadays there are about two milliard people with a latent tubercular infection. About 10% of them will develop active tuberculosis during their lifetime. Detection of latent tuberculosis and its treatment decreases the risk of developing the active form of the disease. Until recently, the tuberculin test was a single screening method to identify the subjects with tubercular infection. In recent years, some novel in vitro tests to diagnose the tubercular infection have been designed. These tests measure the cell-mediated immune response quantifying the emission of interferon gamma by T cells in response to stimulation by Mycobacterium tuberculosis specific antigens. These tests are more sensitive and specific than the tuberculin skin test, but they are just an accessory tool, i.e., a link in the diagnostic chain of the tubercular infection.

Newer diagnostic modalities for tuberculosis.

The gold standard for diagnosis of tuberculosis is demonstration of mycobacteria from various body fluids. This is often not possible in children due to pauci-bacillary nature of illness. Significant improvement in understanding of molecular biology of Mycobacterium tuberculosis has led to development of newer diagnostic techniques of tuberculosis. Polymerase chain reaction (PCR) is an emerging diagnostic tool for diagnosis of TB in children. However, its role in day-to-day clinical practice needs to be defined. A negative PCR never eliminates possibility of tuberculosis, and a positive result is not always confirmatory. The PCR may be useful in evaluating children with significant pulmonary disease when diagnosis is not readily established by other means, and in evaluating immunocompromised children (HIV infection) with pulmonary disease. In the absence of good diagnostic methods for tuberculosis, a lot of interest has been generated in serodiagnosis. ELISA has been used to detect antibodies to various purified or complex antigens of M. tuberculosis in children. Despite a large number of studies published over the past several years, serology has found little place in the routine diagnosis of tuberculosis in children, even though it is rapid and does not require specimen from the site of disease. Sensitivity and specificity depend on the antigen used, gold standard for the diagnosis of tuberculosis and the type of tubercular infection. Though most of these tests have high specificity, their sensitivity is poor. In addition, these tests may be influenced by factors such as age, prior BCG vaccination and exposure to environmental mycobacteria. The serological tests, theoretically, may not be able to differentiate between infection and disease. At present, serodiagnosis does not appear to have any role in diagnosis of childhood pulmonary tuberculosis. A new test (QuantiFERON-TB or QFT) that measures the release of interferon-gamma in whole blood in response to stimulation by purified protein derivative is comparable with the tuberculin skin testing to detect latent tubercular infection, and is less affected by BCG vaccination. It can also discriminate responses due to nontuberculous mycobacteria, and avoids variability and subjectivity associated with placing and reading the tuberculin skin test. Polymerase chain reaction based test for identification of katG and rpoB mutation which are associated with isoniazid and rifampicin resistance may help in early identification of drug resistance in mycobacterium.