Genetic Variation in Toll-Like Receptors (TLRs) 2, 4, and 9 Influences HIV Disease Progression Toward Active TB and AIDS.

Background: Toll-like receptors (TLRs) are identified as one of the key components of the innate immune system. The objective of this study was to explore the influence of genetic variability in these TLRs on human immunodeficiency virus (HIV) disease progression with and without tuberculosis (TB) co-infection. Materials and Methods: This prospective, cross-sectional, and longitudinal study included 373 HIV-positive patients without TB infection. This study aimed to examine the genetic variation in TLRs (TLR2, TLR4, and TLR9) between patients with HIV-1 infection and those who progressed to active TB during the two years of follow-up. Results: During the two year follow-up of 373 positive patients, 98 patients progressed to active TB/AIDS (acquired immunodeficiency syndrome). When comparing 98 HIV patients who developed active TB/AIDS to 275 HIV patients who did not, it was discovered that the frequency of the A allele in TLR9 was considerably higher (p <0.001) in HIV patients progressed to active TB/AIDS. Ninety eight HIV individuals who advanced to active TB/AIDS showed a significantly higher frequency of the AA genotype in TLR9 than did in HIV patients who had no TB/AIDS (p <0.001). Conclusion: The increased association of the AA genotype of TLR9 in HIV patients who progressed to active TB during follow-up suggests that HIV-positive patients with the AA genotype of TLR9 have increased susceptibility towards TB during the disease progression.

Efficacy and safety of thrice weekly DOTS in tuberculosis patients with and without HIV co-infection: an observational study.

BACKGROUND: Despite the latest World Health Organization guidelines advocating daily therapy in HIV-TB co-infected individuals, there are few recent studies comparing outcomes of thrice-weekly anti-tuberculosis treatment in HIV-positive and HIV-negative patients with TB. The present study sets out to compare TB treatment outcomes in these two groups in the Indian national programme, which currently involves thrice-weekly therapy for all, regardless of HIV status. METHODS: HIV-positive and HIV-negative were consecutively screened for enrolment into this prospective observational study, carried out at the All India Institute of Medical Sciences hospital, New Delhi, India, between 2006 and 2010. Patients were given short-course thrice-weekly rifampicin-based therapy, with all HIV-positive patients being started on highly active antiretroviral therapy at least 14 days after commencing TB treatment. Patients were regularly followed-up for 24 months after completion of treatment. RESULTS: 150 HIV-positive, 155 HIV-negative patients were enrolled consecutively for the study. Significantly higher treatment success (93.5% vs. 76.7% at end of treatment, p < 0.001) and lower mortality (2.8% vs. 21.6% on follow up, p < 0.001) were observed in HIV-negative patients. No significant difference was found in treatment failure (p = 0.16), sputum smear (p = 0.58) and culture conversion (p = 0.55), and non-serious adverse event incidence (p = 0.851) between the two groups. Low baseline CD4 cell count (<100 cells/ mm3) was the only predictor of mortality in HIV-TB patients (odds ratio 8 · 43, p = 0 · 013). CONCLUSIONS: Thrice-weekly anti-tuberculosis therapy is more effective in HIV-negative than in HIV-positive patients. However, outcomes in this HIV co-infected cohort were found to be similar to those reported previously with daily therapy, with no safety concerns. This should prompt further study into whether intermittent or daily therapy should be used universally in resource-poor settings, using large well executed randomised controlled trials. TRIAL REGISTRATION: NCT No. 00698334.

Influence of genetic variability in toll-like receptors (TLR 2, TLR 4, and TLR 9) on human immunodeficiency virus-1 disease progression.

Background: It has been demonstrated that toll-like receptors (TLR2), TLR4, and TLR9 which were initially known for recognizing bacterial products are involved in the detection of viral components. It was planned to undertake a prospective longitudinal study among ethnically homogeneous antiretroviral treatment and antitubercular treatment naïve human immunodeficiency virus (HIV)-positive patients representing the north Indian population. The aim of the study was to investigate the influence of TLR2, TLR4, and TLR9 polymorphism in HIV disease progression. Methods: The present study was designed to investigate genetic polymorphism in TLRs (TLR2, TLR4, and TLR9) among HIV-infected patients with and without TB coinfection. The study population consisted of two groups: (i) HIV-positive patients without TB infection and disease (n = 223, HIV-positive patients); (ii) HIV-positive patients with latent tuberculosis infection (LTBI) (n = 150, HIV-positive LTBI patients). These participants were of either gender between 18 and 60 years of age and treatment naïve for both TB and HIV. HIV-positive and HIV-positive LTBI patients were longitudinally followed up for t2 years to study HIV disease progression. Results: On comparing TLR2 and TLR4 allelic and genotypic frequencies between 306 HIV-positive patients (no TB/AIDS) and 47 HIV-positive patients progressed to active TB/AIDS, no significant difference was observed between the two groups. The frequency of "A" allele in TLR9 was found to be significantly increased in 47 HIV-positive patients who progressed to active TB/AIDS (61.7%) as compared to 42.16% in 306 HIV-positive patients (no TB/AIDS), (P < 0.001). Furthermore, a significantly increased frequency of "AA" genotype in TLR9 was observed in 47 HIV-positive patients progressed to active TB/AIDS (55.32%) as compared to 20.26% in HIV-positive patients (no TB/AIDS). Conclusion: Findings of the present study revealed that genetic variability in TLR9 may influence HIV disease progression. The AA genotype in TLR9 may be associated with progression to TB/AIDS for 2 years in HIV-positive patients.

Predictive performance of interferon-gamma release assays and the tuberculin skin test for incident tuberculosis: an individual participant data meta-analysis.

Background: Evidence on the comparative performance of purified protein derivative tuberculin skin tests (TST) and interferon-gamma release assays (IGRA) for predicting incident active tuberculosis (TB) remains conflicting. We conducted an individual participant data meta-analysis to directly compare the predictive performance for incident TB disease between TST and IGRA to inform policy. Methods: We searched Medline and Embase from 1 January 2002 to 4 September 2020, and studies that were included in previous systematic reviews. We included prospective longitudinal studies in which participants received both TST and IGRA and estimated performance as hazard ratios (HR) for the development of all diagnoses of TB in participants with dichotomised positive test results compared to negative results, using different thresholds of positivity for TST. Secondary analyses included an evaluation of the impact of background TB incidence. We also estimated the sensitivity and specificity for predicting TB. We explored heterogeneity through pre-defined sub-group analyses (e.g. country-level TB incidence). Publication bias was assessed using funnel plots and Egger's test. This review is registered with PROSPERO, CRD42020205667. Findings: We obtained data from 13 studies out of 40 that were considered eligible (N = 32,034 participants: 36% from countries with TB incidence rate ≥100 per 100,000 population). All reported data on TST and QuantiFERON Gold in-Tube (QFT-GIT). The point estimate for the TST was highest with higher cut-offs for positivity and particularly when stratified by bacillus Calmette-Guérin vaccine (BCG) status (15 mm if BCG vaccinated and 5 mm if not [TST5/15 mm]) at 2.88 (95% CI 1.69-4.90). The pooled HR for QFT-GIT was higher than for TST at 4.15 (95% CI 1.97-8.75). The difference was large in countries with TB incidence rate <100 per 100,000 population (HR 10.38, 95% CI 4.17-25.87 for QFT-GIT VS. HR 5.36, 95% CI 3.82-7.51 for TST5/15 mm) but much of this difference was driven by a single study (HR 5.13, 95% CI 3.58-7.35 for TST5/15 mm VS. 7.18, 95% CI 4.48-11.51 for QFT-GIT, when excluding the study, in which all 19 TB cases had positive QFT-GIT results). The comparative performance was similar in the higher burden countries (HR 1.61, 95% CI 1.23-2.10 for QFT-GIT VS. HR 1.72, 95% CI 0.98-3.01 for TST5/15 mm). The predictive performance of both tests was higher in countries with TB incidence rate <100 per 100,000 population. In the lower TB incidence countries, the specificity of TST (76% for TST5/15 mm) and QFT-GIT (74%) for predicting active TB approached the minimum World Health Organization target (≥75%), but the sensitivity was below the target of ≥75% (63% for TST5/15 mm and 65% for QFT-GIT). The absolute differences in positive and negative predictive values between TST15 mm and QFT-GIT were small (positive predictive values 2.74% VS. 2.46%; negative predictive values 99.42% VS. 99.52% in low-incidence countries). Egger's test did not show evidence of publication bias (0.74 for TST15 mm and p = 0.68 for QFT-GIT). Interpretation: IGRA appears to have higher predictive performance than the TST in low TB incidence countries, but the difference was driven by a single study. Any advantage in clinical performance may be small, given the numerically similar positive and negative predictive values. Both IGRA and TST had lower performance in countries with high TB incidence. Test choice should be contextual and made considering operational and likely clinical impact of test results. Funding: YH, IA, and MXR were supported by the National Institute for Health and Care Research (NIHR), United Kingdom (RP-PG-0217-20009). MQ was supported by the Medical Research Council [MC_UU_00004/07].

Messenger RNA expression of toll-like receptors (TLR2, TLR4, and TLR9) in HIV-1 infected patients with and without tuberculosis co-infection.

Background: Gene expression levels of TLRs (TLR2, TLR4 and TLR9) are directly involved in the virus recognition and initiation of innate immune responses, therefore, the effect of HIV infection on TLRs gene expression was investigated in functional context through mRNA levels estimations of selected TLRs. Methods: In the present study mRNA gene expression of TLR2, TLR4 and TLR9 has been investigated in HIV+ and HIV+TB patients and compared with healthy subjects. Result: The increase expression of TLR2, TLR4 and TLR9 (mRNA level) relative to the internal gene GAPDH was observed in HIV+ and HIV+TB patients as compared to healthy subjects. Similarly, increase in TLRs mRNA expression was observed in HIV+TB patients as compared to HIV+ patients. Conclusion: A modest increase in expression of TLRs in HIV+ patients with and without TB co-infection suggest a potential role for these TLRs in HIV-1 immunopathogenesis.

Genetic polymorphism of toll-like receptors in HIV-I infected patients with and without tuberculosis co-infection.

Background: Toll-like receptors (TLRs) are identified as one of the key components of innate immune system due to their ability to sense conserved molecular motifs associated with several pathogens. It has been implicated from several evidence that mutations in genes encoding TLRs are associated with increased or decreased susceptibility to various infectious diseases. Methods: The study was prospective, cross-sectional, as well as longitudinal in nature, which includes 223 HIV-positive patients, 150 HIV-positive patients with latent tuberculosis (TB) infection, 150 HIV-positive patients with active TB, 200 HIV-negative newly diagnosed sputum smear positive pulmonary TB patients, and 205 healthy subjects. Results: A statistically significant difference was observed in allelic frequencies of TLR4 between healthy subjects and HIV + TB patients (P < 0.001), healthy subjects, and pulmonary TB (PTB) Category-I patients (P < 0.01) and between healthy subjects and HIV + TB patients (P < 0.001). TLR4 genotype frequencies were also significantly different between healthy subjects and PTB Cat I patients (P < 0.001) and HIV + and HIV + TB patients (P < 0.01). A statistically significant difference was also observed between HIV + and PTB Cat I patients (P = 0.04), HIV + LTBI and HIV + TB patients (P = 0.01), and between HIV + TB and PTB Cat I patients (P < 0.01). Conclusion: This study implicates that Asp299Gly polymorphism in TLR4 gene is associated with increased susceptibility to active TB in HIV-seropositive patients. Increased frequency of 'A' allele in TLR9 gene was also discovered at the time of active TB development in ART naïve HIV + patients, who developed active TB on follow-up.

Infant BCG vaccination and risk of pulmonary and extrapulmonary tuberculosis throughout the life course: a systematic review and individual participant data meta-analysis.

BACKGROUND: BCG vaccines are given to more than 100 million children every year, but there is considerable debate regarding the effectiveness of BCG vaccination in preventing tuberculosis and death, particularly among older children and adults. We therefore aimed to investigate the age-specific impact of infant BCG vaccination on tuberculosis (pulmonary and extrapulmonary) development and mortality. METHODS: In this systematic review and individual participant data meta-analysis, we searched MEDLINE, Web of Science, BIOSIS, and Embase without language restrictions for case-contact cohort studies of tuberculosis contacts published between Jan 1, 1998, and April 7, 2018. Search terms included "mycobacterium tuberculosis", "TB", "tuberculosis", and "contact". We excluded cohort studies that did not provide information on BCG vaccination or were done in countries that did not recommend BCG vaccination at birth. Individual-level participant data for a prespecified list of variables, including the characteristics of the exposed participant (contact), the index case, and the environment, were requested from authors of all eligible studies. Our primary outcome was a composite of prevalent (diagnosed at or within 90 days of baseline) and incident (diagnosed more than 90 days after baseline) tuberculosis in contacts exposed to tuberculosis. Secondary outcomes were pulmonary tuberculosis, extrapulmonary tuberculosis, and mortality. We derived adjusted odds ratios (aORs) using mixed-effects, binary, multivariable logistic regression analyses with study-level random effects, adjusting for the variable of interest, baseline age, sex, previous tuberculosis, and whether data were collected prospectively or retrospectively. We stratified our results by contact age and Mycobacterium tuberculosis infection status. This study is registered with PROSPERO, CRD42020180512. FINDINGS: We identified 14 927 original records from our database searches. We included participant-level data from 26 cohort studies done in 17 countries in our meta-analysis. Among 68 552 participants, 1782 (2·6%) developed tuberculosis (1309 [2·6%] of 49 686 BCG-vaccinated participants vs 473 [2·5%] of 18 866 unvaccinated participants). The overall effectiveness of BCG vaccination against all tuberculosis was 18% (aOR 0·82, 95% CI 0·74-0·91). When stratified by age, BCG vaccination only significantly protected against all tuberculosis in children younger than 5 years (aOR 0·63, 95% CI 0·49-0·81). Among contacts with a positive tuberculin skin test or IFNγ release assay, BCG vaccination significantly protected against tuberculosis among all participants (aOR 0·81, 95% CI 0·69-0·96), participants younger than 5 years (0·68, 0·47-0·97), and participants aged 5-9 years (0·62, 0·38-0·99). There was no protective effect among those with negative tests, unless they were younger than 5 years (0·54, 0·32-0·90). 14 cohorts reported on whether tuberculosis was pulmonary or extrapulmonary (n=57 421). BCG vaccination significantly protected against pulmonary tuberculosis among all participants (916 [2·2%] in 41 119 vaccinated participants vs 334 [2·1%] in 16 161 unvaccinated participants; aOR 0·81, 0·70-0·94) but not against extrapulmonary tuberculosis (106 [0·3%] in 40 318 vaccinated participants vs 38 [0·2%] in 15 865 unvaccinated participants; 0·96, 0·65-1·41). In the four studies with mortality data, BCG vaccination was significantly protective against death (0·25, 0·13-0·49). INTERPRETATION: Our results suggest that BCG vaccination at birth is effective at preventing tuberculosis in young children but is ineffective in adolescents and adults. Immunoprotection therefore needs to be boosted in older populations. FUNDING: National Institutes of Health.

Clinical characteristics of tuberculosis-associated immune reconstitution inflammatory syndrome in North Indian population of HIV/AIDS patients receiving HAART.

BACKGROUND & OBJECTIVE: IRIS is an important complication that occurs during management of HIV-TB coinfection and it poses difficulty in diagnosis. Previous studies have reported variable incidence of IRIS. The present study was undertaken to describe the pattern of TB-associated IRIS using recently proposed consensus case-definitions for TB-IRIS for its use in resource-limited settings. METHODS: A prospective analysis of ART-naïve adults started on HAART from November, 2008 to May, 2010 was done in a tertiary care hospital in north India. A total 224 patients divided into two groups, one with HIV-TB and the other with HIV alone, were followedup for a minimum period of 3 months. The diagnosis of TB was categorised as ''definitive" and ''probable". RESULTS: Out of a total of 224 patients, 203 completed followup. Paradoxical TB-IRIS occurred in 5 of 123 (4%) HIV-TB patients while 6 of 80 (7.5%) HIV patients developed ART-associated TB. A reduction in plasma viral load was significantly (P = .016) associated with paradoxical TB-IRIS. No identifiable risk factors were associated with the development of ART-associated TB. CONCLUSION: The consensus case-definitions are useful tools in the diagnosis of TB-associated IRIS. High index of clinical suspicion is required for an early diagnosis.

Comparison of TST and IGRA in Diagnosis of Latent Tuberculosis Infection in a High TB-Burden Setting.

BACKGROUND: There are currently two tests for diagnosing latent tuberculosis infection (LTBI); TST and IGRA. However, it is still unclear that which one of these tests performs better in high TB-burden settings. METHODS: 1511 household contacts of pulmonary TB patients were enrolled to compare the performance of TST and IGRA for LTBI. At baseline all participant underwent testing for IGRA [QuantiFERON-TB® Gold In-tube (QFT-GIT) assay] and TST [2 tuberculin unit (TU), purified protein derivative (PPD), RT23, Staten Serum Institute (SSI), Copenhagen, Denmark]. All the household contacts were followed-up for two years for incident TB cases. RESULTS: Active TB was diagnosed in 76 household contacts at an incidence rate of 2.14 per 1000 person-years. Both, TST [Hazard Ratio (HR): 1.14, 95% confidence interval (CI): 0.72-1.79, p = 0.57], as well as QFT-GIT assay (HR: 1.66, 95% CI: 0.97-2.84, p = 0.06) results at baseline were not significantly associated with subsequent development of active TB among household contacts of pulmonary TB patients. CONCLUSION: Neither TST nor IGRA predicted subsequent development of active TB among household contacts of pulmonary TB patients during follow-up. However, keeping in view the cost, and other logistics, TST remains the most preferred method for LTBI diagnosis in resource-limited, high TB-burden settings.