Development Of Tuberculosis Disease Research Articles

Determinants of tuberculosis disease development in children in central Ethiopia: A matched case-control study

Background The risk factors for tuberculosis (TB) disease development in children remained understudied, particularly in low-income countries like Ethiopia. The objective of this study was to identify determinants of TB disease development in general and in relation to BCG vaccination in children in central Ethiopia. Methods We employed a 1:1 age-matched case-control design to compare the characteristics of children who developed TB (cases) with those who did not (controls). Data were collected in healthcare facilities in Addis Ababa city, Adama, and Bishoftu towns between September 25, 2021, and June 24, 2022. Two hundred and fifty-six cases were drawn at random from a list of childhood TB patients entered into SPSS software, and 256 controls were selected sequentially at triage from the same healthcare facilities where the cases were treated. A bivariate conditional logistic regression analysis was performed first to select candidate variables with p-values less than or equal to 0.20 for the multivariable model. Finally, variables with a p-value less than 0.05 for a matched adjusted odds ratio (mORadj) were reported as independent determinants of TB disease development. Results The mean age of the cases was nine years, while that of the controls was 10 years. Males comprised 126 cases (49.2%) and 119 controls (46.5%), with the remainder being females. Ninety-nine (38.7%) of the cases were not BCG-vaccinated, compared to 58 (22.7%) of the controls. Household TB contact was experienced by 43 (16.8%) of the cases and 10 (3.9%) of the controls. Twenty-two (8.6%) of the cases and six (2.3%) of the controls were exposed to a cigarette smoker in their household. Twenty-two (8.6%) of the cases and three (1.2%) of the controls were positive for HIV. Children who were not vaccinated with BCG at birth or within two weeks of birth had more than twice the odds (mORadj = 2.11, 95% CI = 1.28–3.48) of developing TB compared to those who were. Children who ever lived with a TB-sick family member (mORadj = 4.28, 95% CI = 1.95–9.39), smoking family members (mORadj = 3.15, 95% CI = 1.07–9.27), and HIV-infected children (mORadj = 8.71, 95% CI = 1.96–38.66) also had higher odds of developing TB disease than their counterparts. Conclusions Being BCG-unvaccinated, having household TB contact, having a smoker in the household, and being HIV-infected were found to be independent determinants of TB disease development among children.

Comparison of Tuberculin Skin Testing and Interferon-γ Release Assays in Predicting Tuberculosis Disease

Elimination of tuberculosis (TB) disease in the US hinges on the ability of tests to detect individual risk of developing disease to inform prevention. The relative performance of 3 available TB tests-the tuberculin skin test (TST) and 2 interferon-γ release assays (IGRAs; QuantiFERON-TB Gold In-Tube [QFT-GIT] and SPOT.TB [TSPOT])-in predicting TB disease development in the US remains unknown. To compare the performance of the TST with the QFT-GIT and TSPOT IGRAs in predicting TB disease in high-risk populations. This prospective diagnostic study included participants at high risk of TB infection (TBI) or progression to TB disease at 10 US sites between 2012 and 2020. Participants of any age who had close contact with a case patient with infectious TB, were born in a country with medium or high TB incidence, had traveled recently to a high-incidence country, were living with HIV infection, or were from a population with a high local prevalence were enrolled from July 12, 2012, through May 5, 2017. Participants were assessed for 2 years after enrollment and through registry matches until the study end date (November 15, 2020). Data analysis was performed in June 2023. At enrollment, participants were concurrently tested with 2 IGRAs (QFT-GIT from Qiagen and TSPOT from Oxford Immunotec) and the TST. Participants were classified as case patients with incident TB disease when diagnosed more than 30 days from enrollment. Estimated positive predictive value (PPV) ratios from generalized estimating equation models were used to compare test performance in predicting incident TB. Incremental changes in PPV were estimated to determine whether predictive performance significantly improved with the addition of a second test. Case patients with prevalent TB were examined in sensitivity analysis. A total of 22 020 eligible participants were included in this study. Their median age was 32 (range, 0-102) years, more than half (51.2%) were male, and the median follow-up was 6.4 (range, 0.2-8.3) years. Most participants (82.0%) were born outside the US, and 9.6% were close contacts. Tuberculosis disease was identified in 129 case patients (0.6%): 42 (0.2%) had incident TB and 87 (0.4%) had prevalent TB. The TSPOT and QFT-GIT assays performed significantly better than the TST (PPV ratio, 1.65 [95% CI, 1.35-2.02] and 1.47 [95% CI, 1.22-1.77], respectively). The incremental gain in PPV, given a positive TST result, was statistically significant for positive QFT-GIT and TSPOT results (1.64 [95% CI, 1.40-1.93] and 1.94 [95% CI, 1.65-2.27], respectively). In this diagnostic study assessing predictive value, IGRAs demonstrated superior performance for predicting incident TB compared with the TST. Interferon-γ release assays provided a statistically significant incremental improvement in PPV when a positive TST result was known. These findings suggest that IGRA performance may enhance decisions to treat TBI and prevent TB.

Bacillus Calmette-Guérin (BCG) Revaccination and Protection Against Tuberculosis: A Systematic Review.

Bacillus Calmette-Guérin (BCG) vaccination remains a cornerstone in global efforts to combat tuberculosis (TB), a persistent public health threat worldwide. The purpose of this systematic review is to find out how well BCG revaccination protects against TB. This systematic review synthesized recent studies investigating the efficacy of BCG vaccination in preventing TB infection and disease. A total of 15 relevant publications were identified through a comprehensive search across multiple databases, including Cochrane Library, PubMed, Medline, and Scopus. The inclusion criteria encompassed studies involving humans, written in English, and categorized as case-control, cohort, meta-analysis, or full-text. Studies were selected based on their relevance to BCG revaccination and protection against TB, and a standardized data extraction form was used to gather pertinent information from each study. Quality assessment was conducted using established tools to evaluate the rigor, study design, and risk of bias in each included study. The findings revealed significant insights into BCG's effectiveness across different populations and age groups. Several studies demonstrated a substantial reduction in latent TB infection (LTBI) and incidence rates of TB following BCG vaccination. However, the protective efficacy of BCG revaccination varied across studies and populations, with some indicating modest protection against TB disease development, particularly in high-risk populations like healthcare workers. Furthermore, investigations into the immunological mechanisms underlying BCG's protective efficacy provided valuable insights into cytokine/chemokine profiles and immunomodulatory properties.

Contact screening of children exposed to active pulmonary tuberculosis: A hospital-based study in Navi Mumbai, India

Abstract Background: Contact investigation is a proactive method employed for active case-finding to improve the detection of active tuberculosis (TB) cases, constituting a crucial component of National TB Programs. Household contacts face a higher exposure risk than individuals in the general population. Although integrated into national policy, the execution of contact investigations is not regularly undertaken, and the outcomes of these investigations are inadequately characterized. Objective: To evaluate risk factors and determine the occurrence of TB disease among household contacts of individuals diagnosed with sputum smear-positive TB in Kamothe, Navi Mumbai, India. Materials and Methods: From December 2018 to November 2020, active screening was carried out for 120 household contact children aged up to 18 years, linked to 52 index cases receiving care at MGM Medical College and Hospital in Navi Mumbai, India. Results: Out of the 120 screened children, 10 (8.3%) showed symptoms, whereas 110 (91.6%) were asymptomatic. Among those exhibiting symptoms, 5 (50%) had abnormal chest X-ray findings. The diagnosis of TB was established in eight cases, including five with pulmonary TB, two with lymph node TB, and one with central nervous system TB. All confirmed TB-positive cases underwent antitubercular treatment, with children under 5 years receiving Isoniazid Preventive Therapy. Conclusion: The study resulted in a 6.67% incidence rate, offering an opportunity to initiate chemoprophylaxis among children. This research identified risk factors associated with the development of TB disease, encompassing female gender, underweight status, residing in crowded conditions, prolonged contact, and extended duration of exposure.

Rifapentine and isoniazid for prevention of tuberculosis in people with diabetes (PROTID): protocol for a randomised controlled trial

BackgroundDiabetes mellitus (DM) increases the risk of tuberculosis (TB) and will hamper global TB control due to the dramatic rise in type 2 DM in TB-endemic settings. In this trial, we will examine the efficacy and safety of TB preventive therapy against the development of TB disease in people with DM who have latent TB infection (LTBI), with a 12-week course of rifapentine and isoniazid (3HP).MethodsThe ‘Prevention of tuberculosis in diabetes mellitus’ (PROTID) consortium will randomise 3000 HIV-negative eligible adults with DM and LTBI, as evidenced by a positive tuberculin skin test or interferon gamma release assay, to 12 weeks of 3HP or placebo. Participants will be recruited through screening adult patients attending DM clinics at referral hospitals in Tanzania and Uganda. Patients with previous TB disease or treatment with a rifamycin medication or isoniazid (INH) in the previous 2 years will be excluded. The primary outcome is the occurrence of definite or probable TB disease; secondary outcome measures include adverse events, all-cause mortality and treatment completion. The primary efficacy analysis will be intention-to-treat; per-protocol analyses will also be carried out. We will estimate the ratio of TB incidence rates in intervention and control groups, adjusting for the study site using Poisson regression. Results will be reported as efficacy estimates (1-rate ratio). Cumulative incidence rates allowing for death as a competing risk will also be reported. Approximately 1000 LTBI-negative, HIV-negative participants will be enrolled consecutively into a parallel cohort study to compare the incidence of TB in people with DM who are LTBI negative vs positive. A number of sub-studies will be conducted among others to examine the prevalence of LTBI and active TB, estimate the population impact and cost-effectiveness of LTBI treatment in people living with DM in these African countries and address gaps in the prevention and therapeutic management of combined TB-DM.DiscussionPROTID is anticipated to generate key evidence to guide decisions over the use of TB preventive treatment among people with DM as an important target group for better global TB control.Trial registrationClinicalTrials.govNCT04600167. Registered on 23 October 2020

Factors Associated with Development of Tuberculosis Disease Among Refugees, Massachusetts, 2008-2018.

Refugees and immigrants undergo tuberculosis screening prior to arrival in the United States. CDC Technical Instructions for screening changed in 2007. Our goal was to quantify TB disease in refugees after 2007 and identify risks for disease. Massachusetts refugee and tuberculosis databases were matched to identify refugees who arrived 2008-2017 and were diagnosed with tuberculosis infection or disease 2008-2018. Factors associated with disease were analyzed in SAS. Of 19,583 refugees, 4706 were diagnosed with infection at arrival and 60 with disease during the observation period. Lack of treatment for infection was strongly associated (OR = 26.5, p = 0.0001) with diagnosis of disease; in a multivariate logistic regression model, positive screening test (AOR = 12.5, p = 0.0001), class B1 status (AOR = 4.0, p = 0.0004), and < 2 years since arrival (AOR = 60.0, p = 0.0001) were associated with disease. Providers should continue screening new arrivals, providing accessible services, and treating infection to further reduce tuberculosis morbidity and mortality.

The challenge of minimizing tuberculosis burden in people living with HIV in the Asia Pacific.

The challenge of minimizing tuberculosis burden in people living with HIV in the Asia Pacific.

Cytomegalovirus acquisition in infancy and the risk of tuberculosis disease in childhood: a longitudinal birth cohort study in Cape Town, South Africa

SummaryBackgroundThe risk of tuberculosis disease after recent exposure is greatest before age 5 years; however, the mechanisms explaining this increased risk are not well elucidated. Acquisition of viral infections, such as cytomegalovirus, in early life might modulate the immune system. We aimed to evaluate the acquisition of cytomegalovirus infection in infancy and the development of tuberculosis disease in children.MethodsIn this prospective, birth cohort study we enrolled pregnant women who were between 20 and 28 weeks of gestation attending antenatal care in Paarl, a periurban setting outside of Cape Town, South Africa. Participants were recruited from two clinics (TC Newman and Mbekweni). Infants were given Bacillus Calmette–Guérin vaccination at birth as per national policy. Nasopharyngeal swabs for cytomegalovirus detection using qPCR were done for infants at birth, age 3 and 6 weeks, and age 3, 6, 12, and 24 months. Children were prospectively followed up for tuberculosis disease until age 9 years using tuberculin skin testing, radiographic examinations, GeneXpert, and sputum testing. Tuberculin skin tests were done at the 6-month visit and then at age 12, 24, 36, 48, and 60 months, and at the time of lower respiratory tract infection. We compared tuberculosis disease incidence after age 1 year or after age 6 months in children with and without cytomegalovirus infection using Cox regression and hazard ratios (HRs) with 95% CIs.FindingsBetween March 5, 2012, and March 31, 2015, 1225 pregnant women were recruited and enrolled in the birth cohort. 88 (7%) women were excluded because of loss to antenatal follow-up or pregnancy losses. Of 1143 livebirths, 68 (6%) mother–infant pairs were excluded. In total, 963 children were serially tested for cytomegalovirus (7186 cytomegalovirus measurements taken; median six tests per child, IQR 2–11). The prevalence of congenital cytomegalovirus at age younger than 3 weeks was 2% (18 of 816). Cytomegalovirus positivity increased continuously with age from 3% (27 of 825) by age 6 weeks to 21% (183 of 882) by 3 months, 35% (315 of 909) by 6 months, and 42% (390 of 933) by 12 months. Mother–infant pairs were followed up for a median of 6·9 years (IQR 6·0–7·8). The risk of tuberculosis disease in children after age 1 year was higher in those with cytomegalovirus infection by age 6 weeks (adjusted HR 4·1, 95% CI 1·2–13·8; p=0·022), 3 months (2·8, 1·4–5·8; p=0·0040), 6 months (3·6, 1·7–7·3; p<0·0001), 12 months (3·2, 1·6–6·4; p=0·0010), and 24 months (4·2, 2·0–8·8; p<0·0001). The risk of microbiologically confirmed tuberculosis disease was also higher among children acquiring cytomegalovirus infection before age 3 months (adjusted HR 3·2, 95% CI 1·0–10·6; p=0·048), 6 months (3·9, 1·2–13·0; p=0·027), 12 months (4·4, 1·2–16·3; p=0·027), and 24 months (6·1, 1·3–27·9; p=0·020). In children older than 1 year, the risk of tuberculosis disease was consistently greater in those with high cytomegalovirus loads than in those with low cytomegalovirus loads that were acquired before age 3 months (adjusted HR 2·0 vs 3·7; ptrend=0·0020; both groups compared with cytomegalovirus negative reference) and before age 12 months (2·7 vs 3·7; ptrend=0·0009).InterpretationInfants that acquire cytomegalovirus in the first year of life are at high risk of subsequently developing tuberculosis disease. Efforts to prevent tuberculosis in early childhood in high-burden countries might need to deter or delay acquisition of cytomegalovirus perinatally or in the first months of life.FundingBill & Melinda Gates Foundation, MRC South Africa, National Research Foundation South Africa, and Wellcome Trust.

The Interaction of Diabetes and Tuberculosis: Translating Research to Policy and Practice.

Diabetes Mellitus increases the risk of developing Tuberculosis (TB) disease by about three times; it also doubles the risk of death during TB treatment and other poor TB treatment outcomes. Diabetes may increase the risk of latent infection with Mycobacterium tuberculosis (LTBI), but the magnitude of this effect is less clear. Whilst this syndemic has received considerable attention, most of the published research has focussed on screening for undiagnosed diabetes in TB patients or observational follow-up of TB treatment outcomes by diabetes status. There are thus substantial research and policy gaps, particularly with regard to prevention of TB disease in people with diabetes and management of patients with TB–diabetes, both during TB treatment and after successful completion of TB treatment, when they likely remain at high risk of TB recurrence, mortality from TB and cardiovascular disease. Potential strategies to prevent development of TB disease might include targeted vaccination programmes, screening for LTBI and preventive therapy among diabetes patients or, perhaps ideally, improved diabetes management and prevention. The cost-effectiveness of each of these, and in particular how each strategy might compare with targeted TB prevention among other population groups at higher risk of developing TB disease, is also unknown. Despite research gaps, clinicians urgently need practical management advice and more research evidence on the choice and dose of different anti-diabetes medication and effective medical therapies to reduce cardiovascular risks (statins, anti-hypertensives and aspirin). Substantial health system strengthening and integration may be needed to prevent these at risk patients being lost to care at the end of TB treatment.

The potential of CBC-derived ratios (monocyte-to-lymphocyte, neutrophil-to-lymphocyte, and platelet-to-lymphocyte) to predict or diagnose incident TB infection in Tanzanian adolescents

BackgroundRatios of different immune cell populations (i.e., monocyte-to-lymphocyte, neutrophil-to-lymphocyte, and platelet-to-lymphocyte ratios) have been studied as a means of predicting future tuberculosis (TB) disease risk or to assist in the diagnosis of incident TB disease. No studies to-date, however, have evaluated the potential of these ratios to predict or assist in the diagnosis of incident TB infection - the first step in the natural history of TB disease.MethodsIn this prospective study, we evaluated the complete blood count (CBC)-derived metrics of monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) as predictors of future TB infection risk or aids in the diagnosis of TB infection among 145 Tanzanian adolescents enrolled in the DAR-901 vaccine trial, using paired CBCs and interferon-gamma release assays (IGRAs) obtained at 0, 60 and 720 days after study enrollment.ResultsAt baseline, there were no significant differences between study participants who remained persistently IGRA negative throughout the study period and those who subsequently converted to IGRA positive with respect to MLR (0.18 vs 0.17, p = 0.10), NLR (0.88 vs 1.02, p = 0.08), or PLR (115 vs 120, p = 0.28). Similarly, no significant differences were noted with respect to MLR, NLR, and PLR between IGRA converters and time-matched negative controls at the time of IGRA conversion. With respect to other blood cell measures, however, there were modest but significant differences between IGRA negatives and IGRA converters with respect to red blood cell count (4.8 vs 4.6 × 106 cells/mcL, p = 0.008), hemoglobin (12.6 vs 12.3 g/dL, p = 0.01), and hematocrit (38.8 vs 37.8%, p = 0.005).ConclusionsIn contrast to prior studies that have suggested that the ratios of different immune cell populations are associated with development of TB disease, our present findings do not demonstrate an association between these ratios and the development of TB infection. However, decreased red blood cell measures were associated with the subsequent development of TB infection, suggesting either that dysregulation of iron metabolism may play a role in TB pathogenesis or that following TB infection, iron dysregulation may precede IGRA positivity.Trial registrationClinicaltrials.gov NCT02712424. Date of registration: March 14, 2016.

Tools for Assessing the Protective Efficacy of TB Vaccines in Humans: in vitro Mycobacterial Growth Inhibition Predicts Outcome of in vivo Mycobacterial Infection.

Tuberculosis (TB) remains a leading global cause of morbidity and mortality and an effective new vaccine is urgently needed. A major barrier to the rational development of novel TB vaccines is the lack of a validated immune correlate or biomarker of protection. Mycobacterial Growth Inhibition Assays (MGIAs) provide an unbiased measure of ability to control mycobacterial growth in vitro, and may represent a functional correlate of protection. However, the biological relevance of any potential correlate can only be assessed by determining the association with in vivo protection from either a controlled mycobacterial infection or natural development of TB disease. Our data demonstrate that the direct MGIA using peripheral blood mononuclear cells (PBMC) is measuring a biologically relevant response that correlates with protection from in vivo human BCG infection across two independent cohorts. This is the first report of an MGIA correlating with in vivo protection in the species-of-interest, humans, and furthermore on a per-individual as well as per-group basis. Control of mycobacterial growth in the MGIA is associated with a range of immune parameters measured post-BCG infection in vivo including the IFN-γ ELISpot response, frequency of PPD-specific IFN-γ or TNF-α producing CD4+ T cells and frequency of specific sub-populations of polyfunctional CD4+ T cells. Distinct transcriptomic profiles are associated with good vs. poor mycobacterial control in the MGIA, with good controllers showing enrichment for gene sets associated with antigen processing/presentation and the IL-23 pathway, and poor controllers showing enrichment for hypoxia-related pathways. This study represents an important step toward biologically validating the direct PBMC MGIA for use in TB vaccine development and furthermore demonstrates the utility of this assay in determining relevant immune mechanisms and pathways of protection.

Dihydrolipoamide dehydrogenase-Lpd (Rv0462)-specific T cell recall responses are higher in healthy household contacts of TB: a novel immunodominant antigen from M. tuberculosis.

The partial effectiveness against pulmonary tuberculosis (PTB), displayed by the existing tuberculosis (TB) vaccine, bacillus Calmette-Guérin (BCG), highlights the need for novel vaccines to replace or improve BCG. In TB immunology, antigen-specific cellular immune response is frequently considered indispensable. Latency-associated antigens are intriguing as targets for TB vaccine development. The mycobacterial protein, dihydrolipoamide dehydrogenase (Lpd; Rv0462), the third enzyme of the pyruvate dehydrogenase (PDH) complex, facilitates Mycobacterium tuberculosis to resist host reactive nitrogen intermediates. Multicolor flow cytometry analysis of whole-blood cultures showed higher Lpd-specific Th1 recall response (IFN-γ, TNF-α, and IL-2; P = 0.0006) and memory CD4+ and CD8+ T cells (CCR7+ CD45RA- and CCR7- CD45RA-) in healthy household contacts (HHC) of TB (P < 0.0001), which is comparable with or higher than the standard antigens, ESAT-6 and CFP-10. The frequency of Lpd-specific multifunctional T cells was higher in HHC compared with PTB patients. However, there is no significant statistical correlation. Regulatory T cell (Treg) analysis of HHCs and active TB patients demonstrated very low Lpd-specific CD4+ Tregs relative to ESAT-6 and CFP-10. Our study demonstrates that the Lpd antigen induces a strong cellular immune response in healthy mycobacteria-infected individuals. In consideration of this population having demonstrated immunologic protection against active TB disease development, our data are encouraging about the possible use of Lpd as a target for further TB subunit vaccine development.

Disseminated Tuberculosis on an Otherwise Healthy Pediatric Patient

SESSION TITLE: Tuberculosis Global Case Reports SESSION TYPE: Global Case Report Poster PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM INTRODUCTION: Disseminated tuberculosis (TB) can involve several organs and clinically presents itself with multiple signs and symptoms. Pulmonary infection is generally the primary focus. The development of TB disease depends on inherent immunologic status of the host. Miliary disease and tubercular (TB) meningitis are the earliest and most deadly complications of primary TB. Genitourinary TB (GU TB) is the second most common form of extrapulmonary disease after peripheral lymphadenopathy. Despite it comprises 20% of nonpulmonary TB form, it is still misdiagnosed. CASE PRESENTATION: We report a case of an otherwise healthy, 11-year-old boy with disseminated tuberculosis who exhibited a wide spectrum of extrapulmonary involvement. He had nonspecific symptoms such as fever, weight loss (10 kg), fatigue, malaise, asthenia, anorexia, headache, and recurrent urinary infections for 4 months. Thereafter, a painful swelling appeared in his left scrotum and treated as a nonspecific abscess with drainage and antibiotics before admission at the tertiary hospital. His physical examination showed an extremely thin boy, palpable masses on left hypochondrium and flank, and a painful and erythematous scrotal mass ipsilateral. Urine analysis revealed hematuria and sterile pyuria but the urine was positive for acid-fast bacilli (AFB) on the third sample. Cerebrospinal fluid (CSF) yielded normal results. Bronchoalveolar lavage (BAL) smear produced a negative response for AFB.. Tuberculin Skin Test (TST) was anergic. There were no associated systemic disorders and HIV infection was not detected. A Chest Computed Tomography (CT) scan displayed well-defined randomly distributed nodules. Head CT scan showed hypoattenuating lesions on white matter. On a contrast, enhanced abdominal CT scans revealed intraluminal calcifications in the left kidney, hydronephrosis degree V, and a heterogeneous mass adjacent to left testis. A treatment with standard fixed-dose-combination tablets containing 4 drugs (RHZE) was initiated during the intensive care phase (2 months), R 150/H75/Z400/E275and 2 drugs (RH) during the continued treatment (7 months) and an oral corticosteroid (prednisone at a dose of 1mg/kg/day for 4 weeks). The patient showed marked recovery after initiation of anti-TB therapy and the scrotal mass had gradually subsided. DISCUSSION: Miliary tuberculosis (TB) is the widespread dissemination of Mycobacterium tuberculosis via hematogenous spread. It is estimated that it accounts for approximately less than 2% of all cases of TB in immunocompetent patients. In addition, miliary TB may mimic many diseases. GU TB comprises approximately 15-20% of extrapulmonary cases of TB in some developing countries, which is roughly twice that in developed areas. It is very uncommon in children. Persistent sterile pyuria and hematuria are the most classical findings in GU TB. In the case of epididymal TB, pain swelling, heaviness or mass lesion in the scrotum are the common presenting complaints, as observed in our case. Serial early-morning urine cultures (at least 3) for acid-fast bacilli (AFB) are still considered the criterion standard for evidence of active tubercular (TB) disease with a sensitivity of 65% and a specificity of 100%. Although microbiologic staining has a low sensitivity, our case presented AFB positive in the urine smear. Nonspecific clinical presentations may mimic other pathologic lesions. In this case, the patient was initially treated for the scrotal mass as a nonspecific abscess with drainage and usual antibiotics. Therefore, a high index of clinical suspicion for TB on a severely debilitated patient allowed prompting initiation of empirical therapy anti-TB. CONCLUSIONS: Tuberculosis (TB) is the most common cause of infection-related death worldwide. Therefore, a high index of clinical suspicion is important to obtain an early diagnosis and to ensure improved clinical outcomes. Early empirical treatment for possible but not yet definitive miliary TB increases the likelihood of survival and should never be withheld while test results are pending. Reference #1: Manual de Recomendações para o controle da tuberculose no Brasil. Ministério da saúde, 2010. Reference #2: Wise GJ, Marella VK. Genitourinary manifestation of tuberculosis.Urol Clin North Am 2003, 30:111-121 Reference #3: Klaus-Dieter Lessnau: Miliary Tuberculosis. Updated: Sep 13, 2013 http://emedicine.medscape.com/article/221777-overview#aw2aab6b2 (accessed in March 22, 2015) DISCLOSURE: The following authors have nothing to disclose: Lilian Pereira, Erica Cavalcante, Bernadete Silva, Waldonio Vieira, Roseana Sovano No Product/Research Disclosure Information

A small animal model of immune reconstitution inflammatory syndrome following antiretroviral therapy (CAM1P.159)

Abstract In HIV-infected patients with latent or subclinical tuberculosis (TB), the development of immune reconstitution inflammatory syndrome (IRIS) following restoration of T cell populations by anti-retroviral therapy (ART) can produce a life threatening inflammatory reaction. The objective of this study was to use our humanized mouse model of Mycobacterium tuberculosis (Mtb) and HIV co-infection to develop a small animal model of IRIS. Humanized BLT mice (HuMice) were infected i.n. with Mtb H37Rv, and following development of TB disease were given TB chemotherapy (rifampicin and isoniazid) by oral gavage. Bacteria were not detected in the lung following TB chemotherapy, but low numbers of Mtb were detected two months after stopping drug treatment, which mimics subclinical TB. When Mtb-infected and TB drug-treated HuMice were infected i.v. with HIV-1 Ada, the animals developed HIV-1 co-infection as determined by the presence of the HIV p24 capsid protein in peripheral blood by ELISA. ART was performed to reduce viral load in blood plasma and restore T lymphocyte function in animals with subclinical TB. In ongoing studies, the development of inflammatory responses, Th1 cell activation and lung pathology are being determined to understand how immune recovery, due to ART, drives inflammation in the setting of subclinical TB. This model will facilitate investigations to understand the mechanistic basis for IRIS and identify targets for host-directed therapies.

Tuberculin skin test reversion following isoniazid preventive therapy reflects diversity of immune response to primary Mycobacterium tuberculosis infection.

RationaleHealthy household contacts (HHC) of individuals with Tuberculosis (TB) with Tuberculin Skin Test (TST) conversions are considered to harbor latent Mycobacterium tuberculosis (Mtb), and at risk for TB. The immunologic, clinical, and public health implications of TST reversions that occur following Isoniazid preventive therapy (IPT) remain controversial.ObjectivesTo measure frequency of TST reversion following IPT, and variation in interferon-gamma (IFN-γ) responses to Mtb, in healthy Ugandan TB HHC with primary Mtb infection evidenced by TST conversion.MethodsProspective cohort study of healthy, HIV-uninfected, TST-negative TB HHC with TST conversions. Repeat TST was performed 12 months following conversion (3 months following completion of 9 month IPT course) to assess for stable conversion vs. reversion. Whole blood IFN-γ responses to Mtb antigen 85B (MtbA85B) and whole Mtb bacilli (wMtb) were measured in a subset (n = 27 and n = 42, respectively) at enrollment and TST conversion, prior to initiation of IPT.ResultsOf 122 subjects, TST reversion was noted in 25 (20.5%). There were no significant differences in demographic, clinical, or exposure variables between reverters and stable converters. At conversion, reverters had significantly smaller TST compared to stable converters (13.7 mm vs 16.4 mm, respectively; p = 0.003). At enrollment, there were no significant differences in IFN-γ responses to MtbA85B or wMTB between groups. At conversion, stable converters demonstrated significant increases in IFN-γ responses to Ag85B and wMtb compared to enrollment (p = 0.001, p<0.001, respectively), while there were no significant changes among reverters.ConclusionsTST reversion following IPT is common following primary Mtb infection and associated with unique patterns of Mtb-induced IFN-γ production. We have demonstrated that immune responses to primary Mtb infection are heterogeneous, and submit that prospective longitudinal studies of cell mediated immune responses to Mtb infection be prioritized to identify immune phenotypes protective against development of TB disease.

Functional Signatures of Human CD4 and CD8 T Cell Responses to Mycobacterium tuberculosis.

With 1.4 million deaths and 8.7 million new cases in 2011, tuberculosis (TB) remains a global health care problem and together with HIV and Malaria represents one of the three infectious diseases world-wide. Control of the global TB epidemic has been impaired by the lack of an effective vaccine, by the emergence of drug-resistant forms of Mycobacterium tuberculosis (Mtb) and by the lack of sensitive and rapid diagnostics. It is estimated, by epidemiological reports, that one third of the world’s population is latently infected with Mtb, but the majority of infected individuals develop long-lived protective immunity, which controls and contains Mtb in a T cell-dependent manner. Development of TB disease results from interactions among the environment, the host, and the pathogen, and known risk factors include HIV co-infection, immunodeficiency, diabetes mellitus, overcrowding, malnutrition, and general poverty; therefore, an effective T cell response determines whether the infection resolves or develops into clinically evident disease. Consequently, there is great interest in determining which T cells subsets mediate anti-mycobacterial immunity, delineating their effector functions. On the other hand, many aspects remain unsolved in understanding why some individuals are protected from Mtb infection while others go on to develop disease. Several studies have demonstrated that CD4+ T cells are involved in protection against Mtb, as supported by the evidence that CD4+ T cell depletion is responsible for Mtb reactivation in HIV-infected individuals. There are many subsets of CD4+ T cells, such as T-helper 1 (Th1), Th2, Th17, and regulatory T cells (Tregs), and all these subsets co-operate or interfere with each other to control infection; the dominant subset may differ between active and latent Mtb infection cases. Mtb-specific-CD4+ Th1 cell response is considered to have a protective role for the ability to produce cytokines such as IFN-γ or TNF-α that contribute to the recruitment and activation of innate immune cells, like monocytes and granulocytes. Thus, while other antigen (Ag)-specific T cells such as CD8+ T cells, natural killer (NK) cells, γδ T cells, and CD1-restricted T cells can also produce IFN-γ during Mtb infection, they cannot compensate for the lack of CD4+ T cells. The detection of Ag-specific cytokine production by intracellular cytokine staining (ICS) and the use of flow cytometry techniques are a common routine that supports the studies aimed at focusing the role of the immune system in infectious diseases. Flow cytometry permits to evaluate simultaneously the presence of different cytokines that can delineate different subsets of cells as having “multifunctional/polyfunctional” profile. It has been proposed that polyfunctional T cells, are associated with protective immunity toward Mtb, in particular it has been highlighted that the number of Mtb-specific T cells producing a combination of IFN-γ, IL-2, and/or TNF-α may be correlated with the mycobacterial load, while other studies have associated the presence of this particular functional profile as marker of TB disease activity. Although the role of CD8 T cells in TB is less clear than CD4 T cells, they are generally considered to contribute to optimal immunity and protection. CD8 T cells possess a number of anti-microbial effector mechanisms that are less prominent or absent in CD4 Th1 and Th17 T cells. The interest in studying CD8 T cells that are either MHC-class Ia or MHC-class Ib-restricted, has gained more attention. These studies include the role of HLA-E-restricted cells, lung mucosal-associated invariant T-cells (MAIT), and CD1-restricted cells. Nevertheless, the knowledge about the role of CD8+ T cells in Mtb infection is relatively new and recent studies have delineated that CD8 T cells, which display a functional profile termed “multifunctional,” can be a better marker of protection in TB than CD4+ T cells. Their effector mechanisms could contribute to control Mtb infection, as upon activation, CD8 T cells release cytokines or cytotoxic molecules, which cause apoptosis of target cells. Taken together, the balance of the immune response in the control of infection and possibly bacterial eradication is important in understanding whether the host immune response will be appropriate in contrasting the infection or not, and, consequently, the inability of the immune response, will determine the dissemination and the transmission of bacilli to new subjects. In conclusion, the recent highlights on the role of different functional signatures of T cell subsets in the immune response toward Mtb infection will be discerned in this review, in order to summarize what is known about the immune response in human TB. In particular, we will discuss the role of CD4 and CD8 T cells in contrasting the advance of the intracellular pathogen in already infected people or the progression to active disease in subjects with latent infection. All the information will be aimed at increasing the knowledge of this complex disease in order to improve diagnosis, prognosis, drug treatment, and vaccination.

Genetic Contribution of CISH Promoter Polymorphisms to Susceptibility to Tuberculosis in Chinese Children

Tuberculosis (TB) is the leading cause of death due to an infectious disease worldwide, particularly in developing countries. A series of candidate genes have been suggested to be associated with development of TB disease. Among them, the human Cytokine-inducible Src homology 2(SH2) domain protein (CISH) gene has been very recently reported to be involved in T cell activation and differentiation in response to Mycobacterium tuberculosis infection. Here, we studied the association between CISH promoter polymorphisms and pediatric TB. A case-control study enrolled 352 TB patients and 527 healthy controls, who were of Han Chinese ethnicity and aged from 0.2 to 18 years. CISH gene promoter SNPs rs414171, rs622502 and rs809451 were genotyped in all subjects and transcriptional activity, mRNA level, and plasma cytokine level of subjects with different genotypes were further examined. Carriers with rs414171TT homozygotes and rs809451GC heterozygotes had a 1.78-fold (95% CI,1.16–2.74) and 1.86-fold (95% CI, 1.26–2.74) excess risk of developing TB compared to those with wild-type genotypes. A greater risk of TB disease was observed in population carrying C−809451-T−414171-C−622502 haplotype (OR 3.66, 95% CI:2.12–6.32). The G−809451-A−414171-C−622502-containing CISH promoter drove a 5.43-fold increased reporter expression compared to the C−809451-T−414171-C−622502-containing counterpart in Hela cell lines (P = 0.0009). PBMCs carrying rs414171TT homozygotes and rs809451GC heterozygotes showed a reduced CISH mRNA level compared to cells carrying wild type genotypes. Individuals with the rs414171TT genotype had significantly increased IL-12p40 and IL-10 production. In conclusion, CISH promoter rs414171 and rs809451 polymorphisms may play a vital role in mediating individual susceptibility to tuberculosis.

Increased Frequency of Myeloid-derived Suppressor Cells during Active Tuberculosis and after RecentMycobacterium tuberculosisInfection Suppresses T-Cell Function

Inadequacy of T-cell responses may result in the development of tuberculosis (TB). Myeloid-derived suppressor cells (MDSCs) have been described as suppressors of T-cell function in cancer biology and recently in several infectious diseases. To explore the presence and role of MDSCs in TB. We analyzed surface markers of MDSCs in peripheral blood and at the site of disease in TB cases and in patients with lung cancer, and in peripheral blood of asymptomatic tuberculin skin test-positive individuals with recent (household) or remote exposure to Mycobacterium tuberculosis (M.tb) and in uninfected healthy control subjects. To evaluate the suppressive capacity of MDSCs, cells of household contacts infected with M.tb and TB cases were isolated and cocultured with CD3(+) T cells. Our results demonstrate an increased presence of MDSCs after recent M.tb infection and disease. We confirm their suppression of CD4(+) T-cell function, including reduced cytokine responses and inhibition of CD4(+) T-cell proliferation. Only MDSCs from TB cases reduced T-cell activation, altered T-cell trafficking, and suppressed CD8(+) T-cell functions. M.tb-expanded MDSCs were associated with significantly higher IL-1β, IL-6, IL-8, granulocyte colony-stimulating factor, and monocyte chemotactic protein-1, and reduced granulocyte-macrophage colony-stimulating factor and macrophage inflammatory protein-1 beta levels in coculture. These data reveal that innate MDSCs are induced not only during active TB at similar levels as found in cancer, but also in healthy individuals after recent exposure to M.tb. These cells diminish protective T-cell responses and may contribute to the inability of hosts to eradicate the infection and add to the subsequent development of TB disease.

Effects of Smoking Habit on the Development of Tuberculosis Disease

Effects of Smoking Habit on the Development of Tuberculosis Disease

Prevalence of Latent Infection with Mycobacterium Tuberculosis in Mazowieckie Province Using Interferon Gamma Release Assay after Stimulation with Specific Antigens ESAT-6 and CFP-10

Introduction: Over 8000 cases of tuberculosis (TB) are diagnosed annually in Poland. People infected with Mycobacterium tuberculosis (MTB) have a risk of active disease of around 10% during their whole life, and the risk is highest in the first two years after infection. Recognizing infection before TB disease development enables prophylaxis against its activation and ceases transmission of infection. Knowledge about the proportion of infected people in the population is crucial to predict the number of new cases of active disease. Materials and methods: The prevalence of latent TB infection (LTBI) was tested in 700 healthy adult inhabitants of the Mazowieckie province in different age groups, using both tuberculin skin test (TST) and interferon gamma release assay (IGRA). Commercial test QuantiFERON®-TB-Gold In Tube (QFT) was used. All participants were mandatorily BCG vaccinated according to the Polish vaccination schedule. Results: Twenty-three per cent of participants tested positively for QFT, which was significantly less than for TST (50.3%). The prevalence of positive QFT results increased with age, as well as the incidence of TB in Poland. Positive QFT was most frequent in the oldest age group (48.8%) and rarest in the youngest (7.1%). Conversely, positive TST occurred more often in younger participants (45%), who rarely suffer from TB. Among people over 60, with the highest TB incidence rate, only 33.8% tested positively with TST. Concordance between both tests was low, with a kappa value of 0.198. The prevalence of LTBI defined as positive QFT among health care workers (HCW) was significantly higher than among other participants (32.2% v. 20.4%, p &lt; 0.01). Conclusions: LTBI was diagnosed in 23.3% of the tested population of the Mazowieckie province. QFT is a better tool for diagnosing LTBI as it shows a positive correlation with age (as the incidence of TB disease does). Concordance between both tests is low. The prevalence of LTBI in HCW is higher than in other participants.