Tuberculosis Infection and Latent Tuberculosis

Coinfections in Tuberculosis in Low- and Middle-Income Countries: Epidemiology, Clinical Implications, Diagnostic Challenges, and Management Strategies-A Narrative Review

Tuberculosis (TB) continues to be a major public health challenge in low- and middle-income countries (LMICs), where high burdens of coinfections exacerbate the disease's impact. In 2023, an estimated 8.2 million people were newly diagnosed with tuberculosis worldwide, reflecting an increase from 7.5 million in 2022 and 7.1 million in 2019. In LMICs, limited access to healthcare, inadequate nutrition, and poor living conditions contribute to higher coinfection rates among TB patients, leading to delayed diagnosis and treatment, which in turn exacerbates disease severity and facilitates transmission. This narrative review synthesizes the epidemiology, clinical implications, diagnostic challenges, and management strategies related to TB coinfections with viral pathogens including HIV, SARS-CoV-2, and influenza, bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa, fungi such as Aspergillus and Candida species, and parasites. This review highlights that overlapping symptoms, immune system compromise, and socioeconomic barriers in LMICs lead to delayed diagnoses and suboptimal treatment outcomes, while also addressing the challenges of managing drug interactions particularly in HIV-TB coinfections and underscoring the need for integrated diagnostic approaches, improved treatment regimens, and strengthened healthcare systems, thereby consolidating current evidence to inform future research priorities and policy interventions aimed at reducing the overall burden of TB and its coinfections in resource-limited settings.

Risk of malignant lymphoma in patients with previous tuberculosis infection: a cohort study

Tuberculosis (TB) is associated with chronic inflammation, which has been implicated in the pathogenesis of various malignancies, including lung cancer. However, the relationship between TB and hematological malignancies like lymphoma remains less understood. This study aimed to investigate risks of incident malignant lymphoma according to previous TB infection in a large prospective cohort of 347,204 individuals. Multiple logistic regression analyses were conducted to predict the probability of malignant lymphoma. Propensity score matching was employed to compare the incidence of lymphoma in individuals with and without previous TB infection. Among the overall population, 3.7% (12,694) reported previous history of TB. There was a significantly increased risk of lymphoma in individuals with a TB history, with an odds ratio of 2.14 (95% confidence interval (CI): 1.35-3.39, p = 0.001) and a hazard ratio of 2.13 (95% CI, 1.13-4.00; p = 0.019) in propensity-matched analyses. These findings underscore TB infection as a potential precursor to lymphoma, probably due to prolonged inflammatory and immune dysregulation. The study highlights the importance of considering a TB history in the risk assessment for lymphoma, emphasizing the need for vigilant clinical monitoring in population with high TB burden.

Latent Tuberculosis Infection among Household Contacts of Tuberculosis Patients, Healthcare Workers, and Tuberculosis Patients Using QuantiFERON-tuberculosis Gold Plus and Tuberculin Skin Test in a Tertiary Care Hospital Setting Bhubaneswar, Odisha - A Cross-sectional Study

Introduction

Contacts of tuberculosis (TB) patients have an increased risk of latent TB infection (LTBI). Currently, it is diagnosed using one of the two methods: Tuberculin skin test (TST) or QuantiFERON-TB Gold Plus. This study aims to estimate the concordance of TST and QFT-TB Gold Plus and associated factors among 73 healthcare workers (HCWs) and 172 household contacts (HHCs) who came in contact with active TB patients. This study was conducted from January to June 2023.

Methods

Prevalence and agreement were calculated. A regression analysis was performed to assess the predictors of discordance factors.

Results

The prevalence of latent TB was 20.40% (n = 50), defined as a positive result on either test. The overall agreement among participants was 62.04%, with a kappa coefficient of 0.26 (0.16-0.36, 95% confidence interval [CI]) (McNemar, P < 0.001). A higher risk of LTBI was associated with BCG vaccination history, odd ratio 1.63, (95% CI 0.78-3.43) for TST and 0.51 (95% CI 0.22-1.15) for QFT, but this was not significant. Moreover, in our study, only the body mass index of 18.5-25 kg/m2 yielded an odds ratio of 2.33 (95%CI 0.77-6.47) for TST and 1.72 (95% CI 0.48-6.05) for QFT, was significant. Compared with QFT-TB Gold Plus, the sensitivity and specificity of TST were 80.65 (68.63-89.58) and 55.74 (48.22-63.06).

Conclusion

TST exhibited a profound level of agreement with the QFT-Gold Plus assay but showed a higher rate of positivity due to some associated factors among HCWs, HHCs, and TB patients.

3,5-disubstituted pyridines with potent activity against drug-resistant Mycobacterium tuberculosis clinical isolates

Aim: We designed and synthesized a series of compounds with a 3,5-disubstituted pyridine moiety and evaluated them against Mycobacterium tuberculosis (Mtb) and drug-resistant Mtb clinical isolates.Methodology: A library of 3,5-disubstituted pyridine was synthesized. The compounds were screened for activity against M. tuberculosis H37Rv. The optimal substitutions needed for the activity were identified through structure-activity relationship (SAR) studies.Results: From the screening studies, compounds 24 and 26 were identified as potent members of this series with Minimum Inhibitory Concentration (MIC) of 1.56 μg/ml against M. tuberculosis H37Rv. These compounds did not show any inhibition against a panel of ESKAPE pathogens at >50 μg/ml indicating their selective killing of M. tuberculosis H37Rv. Importantly, compound 24 showed a selectivity index of 54.64 against CHO-K1 and 78.26 against VERO cell lines, while compound 26 showed a selectivity index of 108.5 against CHO-K1 and 63.2 against VERO cell lines, respectively. Compound 24 formed a stable complex with the target protein DprE1 with predicted binding energy -8.73 kcal/mol and inhibited multidrug-resistant clinical isolate of M. tuberculosis at 6.25 μg/ml.Conclusion: This study identified the 3,5-disubstituted pyridine derivative 24 with potent antituberculosis activity and can be taken forward to generate new preclinical candidate.

C1q Levels: A Reliable Biomarker for Differentiating Active and Latent Tuberculosis Infection

BACKGROUND

Tuberculosis (TB) poses a significant public health challenge, particularly because it can exist in an asymptomatic latent phase. Latent TB infection indicates the presence of Mycobacterium tuberculosis without clinical symptoms. Effectively distinguishing between active and latent TB is essential, especially in regions with high TB prevalence, as it may help reduce transmission rates. This study aims to evaluate C1q as a potential biomarker for differentiating active TB from latent forms.

METHODS

This prospective cross-sectional study was conducted from January 2017 to February 2018, involving HIV-negative adults aged 18 and older attending TB clinics. Participants were categorized based on clinical symptoms, imaging results, and laboratory tests into active or latent TB. Blood samples were collected to assess serum C1q levels, which were then compared between the two groups.

RESULTS

Out of 81 patients referred for TB evaluation, 38 were diagnosed with active TB. The overall median C1q level was 6.46 μg/ml (interquartile range 4.66-10). The active TB group exhibited significantly elevated C1q levels (10.21 μg/ml) compared to the latent TB group (6.03 μg/ml, P < 0.001). The area under the receiver operating characteristic curve for C1q in distinguishing active from latent TB was 0.74 (95% confidence interval, 0.63-0.85), with sensitivity varying between 61% and 82% at different threshold values.

CONCLUSIONS

C1q shows potential as a reliable and easily obtainable biomarker for differentiating active TB from latent infection, demonstrating high sensitivity. These results underscore the need for further research to explore the clinical application of C1q in TB diagnostics.

Trend of pulmonary tuberculosis and rifampicin-resistance among tuberculosis presumptive patients in Central Tigray, Ethiopia; 2018 -2023: a six-year retrospective study

BACKGROUND

Tuberculosis (TB) is a major public health concern in the developing countries. Moreover, the emergence of multidrug-resistant tuberculosis is challenging. However, there are no organized data on the trends of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis in the study area.

METHODS

A retrospective cross-sectional study was conducted to fill the information gap in Central Tigray at St. Mary General Hospital between 2018 and 2023. Data were collected from the GeneXpert™ tuberculosis registration logbooks using standard checklists and analyzed using Statistical Package for Social Science version 22. After performing logistic regression, a p-value < 0.05 with a corresponding 95% confidence interval was considered statistically significant. Moreover, chi square test for trend was performed to assess the percentage of annual detection of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis during the study years.

RESULT

Presumptive pulmonary tuberculosis patients with complete data (n = 3696) were included in the study. The overall prevalence of pulmonary tuberculosis was 11.7%, of which 8.1% were resistant to rifampicin. The study revealed that the incidence of pulmonary tuberculosis has been increasing, mainly in the recent four years. Likewise, an increase in rifampicin-resistant Mycobacterium tuberculosis was observed with considerable fluctuations. Age, human immunodeficiency virus infection, and presumptive rifampicin-resistant Mycobacterium tuberculosis infection were significantly associated with the presence of pulmonary tuberculosis. Moreover, pulmonary tuberculosis was more prevalent among participants in the productive-age group.

CONCLUSION

Although there have been fluctuations, an increasing of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis has been observed in recent years. Hence, prevention and treatment strategies for tuberculosis should be strengthened to alleviate the burden of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis in the study area.

Differential Epigenetic Regulation in Uninfected and Tuberculosis-Human Immunodeficiency Virus Co-Infected Patients

This study aimed to compare the degree of epigenetic modifications between a TB-HIV co-infected cohort and uninfected subjects. Formalin-fixed paraffin-embedded (FFPE) tissues were retrieved from 45 TB-HIV co-infected and 45 control individuals. Real-time PCR was applied to compare the level of expression of genes involved in epigenetic regulation. The protein multiplex assay was used to assess the degree of protein modification. DNA sequencing was used to determine the evolutionary relationships between the infecting HIV and Mtb strains. Our results indicated a significant increase in the expression of the five candidate genes in the patients with TB-HIV relative to the control cohort. A sharp increase in the degree of histone methylation, acetylation and phosphorylation was observed in TB-HIV co-infected patients. The phylogenetic analysis classified the strains into three distinct HIV clusters and five Mtb clusters. The disparities in the expression profiles of our candidate genes between the TB-HIV cohort and non-TB-HIV group highlights the important role played by various TB and HIV strains in regulating the host gene expression landscape.

Current development of therapeutic vaccines for the treatment of chronic infectious diseases

Chronic infectious diseases refer to diseases that require a long period of time from onset to cure or death, the use of therapeutic vaccines has recently emerged to eradicate diseases. Currently, clinical research is underway to develop therapeutic vaccines for chronic infectious diseases based on various vaccine formulations, and the recent success of the messenger RNA vaccine platform and efforts to apply it to therapeutic vaccines are having a positive impact on conquering chronic infectious diseases. However, since research on the development of therapeutic vaccines is still relatively lacking compared to prophylactic vaccines, there is a need to focus more on the development of therapeutic vaccines to overcome threats to human health caused by chronic infectious diseases. In order to accelerate the development of therapeutic vaccines for chronic infectious diseases in the future, it is necessary to establish a clear concept of therapeutic vaccines suitable for the characteristics of each chronic infectious disease, as well as standardize vaccine effectiveness evaluation methods, secure standards/reference materials, and simplify the vaccine approval procedure.

Multi-target Compounds against Trypanosomatid Parasites and Mycobacterium tuberculosis

Multi-target drug treatment has become popular as a substitute for traditional monotherapy. Monotherapy can lead to resistance and side effects. Multi-target drug discovery is gaining importance as data on bioactivity becomes more abundant. The design of multi-target drugs is expected to be an important development in the pharmaceutical industry in the near future. This review presents multi-target compounds against trypanosomatid parasites (Trypanosoma cruzi, T. brucei, and Leishmania sp.) and tuberculosis (Mycobacterium tuberculosis), which mainly affect populations in socioeconomically unfavorable conditions. The article analyzes the studies, including their chemical structures, viral strains, and molecular docking studies, when available. The objective of this review is to establish a foundation for designing new multi-target inhibitors for these diseases.

Elucidating the structural and functional prophecy of the Rv2326c gene, an ABC transporter of Mycobacterium tuberculosis H37Rv through computational approach

Tuberculosis is a fatal disease caused by Mycobacterium tuberculosis. M. tuberculosis becoming drug-resistant day by day, necessitating to know the mechanism behind the drug resistance and how to overcome this deadly malady. Drug resistance and reduced drug bioavailability are caused by a class of transporter proteins called the ATP-binding cassette (ABC) transporters, which pump a range of medicines out of cells at the price of ATP hydrolysis. By using computational approaches, we tried to elaborate the probable function of the Rv2326c gene of M. tuberculosis, perhaps involved in drug resistance mechanism. The presence of the signature motif of ABC transporters (LSGGELQRLALAAAL and LSGGQMRRVVLAGLL) and ATP binding motif (GXXXXGKT and GXXXXGKS) in the protein sequence signifying its importance in the ATP binding and transportation of molecules. Further, this manuscript elaborated about tertiary structure and validation, functional category, localization, phosphorylation site prediction, mutational analysis of conserved motifs. Ligand docking study shows the highest affinity with ATP than GTP justified its function as an ATP binding protein. The Rv2326c protein is present in the inner membrane and working as an ATP binding protein and might be playing a dynamic role in transportation. In this study, we found that Rv2326c protein might be working as an ABC transporter by which the drugs and other molecules are imported or exported into the bacterium. As a result, the current study provides a means to better understand its normal functioning and basic biology, which can help in the development of novel therapeutic targeting approaches for Rv2326c protein.

Antigen-Induced IL-1RA Production Discriminates Active and Latent Tuberculosis Infection

The IGRA (Interferon Gamma Release Assays) test is currently the standard specific test for Mycobacterium tuberculosis infection status. However, a positive test cannot distinguish between active tuberculosis disease (ATBD) and latent tuberculosis infection (LTBI). Developing a test with this characteristic is needed. We conducted longitudinal studies to identify a combination of antigen peptides and cytokines to discriminate between ATBD and LTBI. We studied 54 patients with ATBD disease and 51 with LTBI infection. Cell culture supernatant from cells stimulated with overlapping Mycobacterium tuberculosis novel peptides and 40 cytokines/chemokines were analyzed using the Luminex technology. To summarize longitudinal measurements of analyte levels, we calculated the area under the curve (AUC). Our results indicate that in vitro cell stimulation with a novel combination of peptides (Rv0849-12, Rv2031c-14, Rv2031c-5, and Rv2693-06) and IL-1RA detection in culture supernatants can discriminate between LTBI and ATBD.

Exploring biogenic chalcones as DprE1 inhibitors for antitubercular activity via in silico approach

Cases of drug-resistant tuberculosis (TB) have increased worldwide in the last few years, and it is a major threat to global TB control strategies and the human population. Mycobacterium tuberculosis is a common causative agent responsible for increasing cases of TB and as reported by WHO, approximately, 1.5 million death occurred from TB in 2020. Identification of new therapies against drug-resistant TB is an urgent need to be considered primarily. The current investigation aims to find the potential biogenic chalcone against the potential targets of drug-resistant TB via in silico approach. The ligand library of biogenic chalcones was screened against DprE1. Results of molecular docking and in silico ADMET prediction revealed that ZINC000005158606 has lead-like properties against the targeted protein. Pharmacophore modeling was done to identify the pharmacophoric features and their geometric distance present in ZINC000005158606. The binding stability study performed using molecular dynamics (MD) simulation of the DprE1-ZINC000005158606 complex revealed the conformational stability of the complex system over 100 ns with minimum deviation. Further, the in silico anti-TB sensitivity of ZINC000005158606 was found to be higher as compared to the standards against Mycobacterium tuberculosis. The overall in silico investigation indicated the potential of identified hit to act as a lead molecule against Mycobacterium tuberculosis.

Innovative Therapeutic Approaches Based on Nanotechnology for the Treatment and Management of Tuberculosis

Tuberculosis (TB), derived from bacterium named Mycobacterium tuberculosis, has become one of the worst infectious and contagious illnesses in the world after HIV/AIDS. Long-term therapy, a high pill burden, lack of compliance, and strict management regimens are disadvantages which resulted in the extensively drug-resistant (XDR) along with multidrug-resistant (MDR) in the treatment of TB. One of the main thrust areas for the current scenario is the development of innovative intervention tools for early diagnosis and therapeutics towards Mycobacterium tuberculosis (MTB). This review discusses various nanotherapeutic agents that have been developed for MTB diagnostics, anti-TB drugs and vaccine. Undoubtedly, the concept of employing nanoparticles (NPs) has strong potential in this therapy and offers impressive outcomes to conquer the disease. Nanocarriers with different types were designed for drug delivery applications via various administration methods. Controlling and maintaining the drug release might be an example of the benefits of utilizing a drug-loaded NP in TB therapy over conventional drug therapy. Furthermore, the drug-encapsulated NP is able to lessen dosage regimen and can resolve the problems of insufficient compliance. Over the past decade, NPs were developed in both diagnostic and therapeutic methods, while on the other hand, the therapeutic system has increased. These "theranostic" NPs were designed for nuclear imaging, optical imaging, ultrasound, imaging with magnetic resonance and the computed tomography, which includes both single-photon computed tomography and positron emission tomography. More specifically, the current manuscript focuses on the status of therapeutic and diagnostic approaches in the treatment of TB.

Epidemiology of TB in prisoners: a metanalysis of the prevalence of active and latent TB

BACKGROUND

Tuberculosis (TB) in prisons usually occurs at higher rates than in the general population, especially in developing countries. TB has been reported as the most common cause of death among prisoners. Studies have shown limitations for early detection of TB in prisons that seem to result from mistaken concepts about TB, delayed diagnosis mainly due to the naturalization of lack of healthcare for this population METHODS: A scoping review was performed using the methodology of the Joanna Briggs Institute to assess "What are the scientific evidences on the epidemiology of TB in the prison system?". Then, a meta-analysis was performed to assess the prevalence of TB (active and latent) TB in prisoners. The results are presented as prevalence, in percentage, through random effects models, with a confidence interval of 95%.

RESULTS

Regarding active TB, the results of the metanalysis showed that countries with a high burden of TB had a prevalence of 3.54% [2.71; 4.63], countries not considered to be high burden TB countries had a prevalence of 1.43% [0.86; 2.37]. Latent TB had a prevalence of 51.61% [39.46; 63.58] in high TB burden countries and a prevalence of 40.24% [23.51; 59.61] in countries with low TB burden. In terms of development, in low- and lower-middle-income countries, the prevalence of active TB was 3.13% [1.84; 5.29] and in high- and upper-middle income countries the prevalence was 2.25% [1.70; 2.99]. The prevalence of latent TB in high- and middle-income countries was 43.77% [28.61; 60.18] and of 49.42% [45.91; 52.94] in low and lower middle-income countries.

CONCLUSION

Our analysis suggests that TB, and probably other infectious diseases, find fertile ground in prisons where previous acquire social disadvantages seem to thrive-therefore, TB in prisons is a global public health problem and effective strategies are needed to control the disease are needed targeting the prison environment, including rapid health assessments to understand each context and to implement tailored and precision interventions.

Meta-analysis of active tuberculosis gene expression ascertains host directed drug targets

Multi-drug resistant tuberculosis still remains a major public health crisis globally. With the emergence of newer active tuberculosis disease, the requirement of prolonged treatment time and adherence to therapy till its completion necessitates the search of newer therapeutics, targeting human host factors. The current work utilized statistical meta-analysis of human gene transcriptomes of active pulmonary tuberculosis disease obtained from six public datasets. The meta-analysis resulted in the identification of 2038 significantly differentially expressed genes (DEGs) in the active tuberculosis disease. The gene ontology (GO) analysis revealed that these genes were major contributors in immune responses. The pathway enrichment analyses identified from various human canonical pathways are related to other infectious diseases. In addition, the comparison of the DEGs with the tuberculosis genome wide association study (GWAS) datasets revealed the presence of few genetic variants in their proximity. The analysis of protein interaction networks (human and Mycobacterium tuberculosis) and host directed drug-target interaction network led to new candidate drug targets for drug repurposing studies. The current work sheds light on host genes and pathways enriched in active tuberculosis disease and suggest potential drug repurposing targets for host-directed therapies.

Bedaquiline fumarate microemulsion: formulation optimization, rheological characterization and in vitro studies

Aim: Bedaquiline fumarate (BQF), an antitubercular drug, shows limited bioavailability due to solubility-limited intestinal absorption. In this research, the authors formulated a BQF-loaded microemulsion to improve BQF's oral bioavailability. Methods: Microemulsion was prepared by a spontaneous emulsification method and evaluated for thermodynamic stability, size, dispersibility, transmittance, rheology, microrheology, drug release, cytotoxicity and cellular uptake. Results: Microemulsion showed an average globule size of 26.50 ± 6.29 nm with spherical geometry and revealed gel-sol-gel behavior in microrheological studies. Cytotoxicity and cell uptake studies in Caco-2 cells showed that BQF microemulsion was cytocompatible at the highest concentration of 500 μg/ml with significantly higher cellular uptake than control. Conclusion: The present study indicates that BQF microemulsion could be explored further for effective treatment of multidrug-resistant tuberculosis.

The Multifaceted Roles of Autophagy in Infectious, Obstructive, and Malignant Airway Diseases

Autophagy is a highly conserved dynamic process by which cells deliver their contents to lysosomes for degradation, thus ensuring cell homeostasis. In response to environmental stress, the induction of autophagy is crucial for cell survival. The dysregulation of this degradative process has been implicated in a wide range of pathologies, including lung diseases, representing a relevant potential target with significant clinical outcomes. During lung disease progression and infections, autophagy may exert both protective and harmful effects on cells. In this review, we will explore the implications of autophagy and its selective forms in several lung infections, such as SARS-CoV-2, Respiratory Syncytial Virus (RSV) and Mycobacterium tuberculosis (Mtb) infections, and different lung diseases such as Cystic Fibrosis (CF), Chronic Obstructive Pulmonary Disease (COPD), and Malignant Mesothelioma (MM).

Very-Rapidly Dissolving Printlets of Isoniazid Manufactured by SLS 3D Printing: In Vitro and In Vivo Characterization

The focus of this research was to understand the effects of formulation and processing variables on the very-rapidly dissolving printlets of isoniazid (INH) manufactured by the selective laser sintering (SLS) three-dimensional (3D) printing method, and to characterize their physicochemical properties, stability, and pharmacokinetics. Fifteen printlet formulations were manufactured by varying the laser scanning speed (400-500 mm/s, X₁), surface temperature (100-110 °C, X₂), and croscarmellose sodium (CCS, %, X₃), and the responses measured were weight (Y₁), hardness (Y₂), disintegration time (DT, Y₃), and dissolution (Y₄). Laser scanning was the most important processing factor affecting the responses. DT was very rapid (≥3 s), and dissolution (>99%) was completed within 3 min. The root-mean-square error in the studied responses was low and analysis of variance (ANOVA) was statistically significant (p < 0.05). X-ray micro-computed tomography (micro-CT) images showed very porous structures with 24.6-34.4% porosity. X-ray powder diffraction and differential scanning calorimetry data indicated partial conversion of the crystalline drug into an amorphous form. The printlets were stable at 40 °C/75% RH with no significant changes in assay and dissolution. Pharmacokinetic profiles of the printlets and compressed tablets were superimposable. In conclusion, the rapidly dissolving printlets of the INH were stable, and oral bioavailability was similar to that of compositionally identical compressed tablets.

Risk of tuberculosis infection and serial changes in interferon-gamma release assays in elderly patients with psoriasis receiving biologic therapy

Elderly patients constitute a significant proportion of patients with psoriasis. Nonetheless, treatment for older patients is more challenging than that for younger ones. Biologic agents are preferable to other systemic drugs for elderly patients with moderate-to-severe psoriasis owing to their high efficacy and favorable tolerability. However, there are limited data on tuberculosis infection risk in elderly patients with psoriasis receiving biologic therapy. This study aimed to evaluate the risk of active tuberculosis and latent tuberculosis infection, assess the serial interferon-gamma release assay results, and evaluate treatment compliance and adverse effects of latent tuberculosis infection treatment in elderly patients with psoriasis on biologic therapy. In this single-center retrospective study, medical charts of elderly patients (age ≥ 65 years) with psoriasis who were treated with a biologic agent (guselkumab, adalimumab, secukinumab, or ustekinumab) between January 2015 and December 2020 were reviewed. We analyzed the results of chest X-rays and those of whole-blood interferon-gamma release assays performed for latent tuberculosis infection screening at baseline (IGRA0) and subsequently at follow-up after initiating biologic therapy (IGRA1). In total, 90 patients underwent IGRA0; 46 (51.11%) of them had latent tuberculosis infection before starting biologic therapy. Overall, four and two patients experienced seroconversion and active tuberculosis during biologic therapy, respectively. The interferon-gamma release assay reversion rate was 29.1%, and the interferon-gamma level significantly decreased in all patients after latent tuberculosis infection treatment (p = 0.004). Latent tuberculosis infection treatment was well tolerated in elderly patients (completion rate, 100%). The risk of latent tuberculosis infection in elderly patients with psoriasis on biologic therapy was comparable to that previously reported for all age groups. However, the active tuberculosis rate was relatively higher.

New developments in tuberculosis diagnosis and treatment

Tuberculosis (TB) is a major cause of morbidity and mortality worldwide. It is estimated that 25% of the world's population are infected with Mycobacterium tuberculosis, with a 5–10% lifetime risk of progression into TB disease. Early recognition of TB disease and prompt detection of drug resistance are essential to halting its global burden. Culture, direct microscopy, biomolecular tests and whole genome sequencing are approved methods of diagnosis; however, their widespread use is often curtailed owing to costs, local resources, time constraints and operator efficiency. Methods of optimising these diagnostics, in addition to developing novel techniques, are under review. The selection of an appropriate drug regimen is dependent on the susceptibility pattern of the isolate detected. At present, there are 16 new drugs under evaluation for TB treatment in phase I or II clinical trials, with an additional 22 drugs in preclinical stages. Alongside the development of these new drugs, most of which are oral medications, new shorter regimes are under evaluation. The aim of these shorter regimens is to encourage patient adherence, and prevent relapse or the evolution of further drug resistance. Screening for TB infection, especially in vulnerable populations, provides an opportunity for intervention prior to progression towards infectious TB disease. New regimens are currently under evaluation to assess the efficacy of shorter durations of treatment in this population. In addition, there is extensive research into the use of post-exposure vaccinations in this cohort. Worldwide collaboration and sharing of expertise are essential to our ultimate aim of global eradication of TB disease.

Early detection of drug resistance is essential to our goal of global eradication of TB. Tolerable drugs and shorter regimens promote patient adherence. Treating TB infection in vulnerable groups will prevent further global spread of TB disease.https://bit.ly/3oUW0SN

The Diagnostic Deceiver: Radiological Pictorial Review of Tuberculosis

Tuberculosis (TB) is a bacterial infection with Mycobacterium tuberculosis; it is a public health problem worldwide and one of the leading causes of mortality. Since December 2019, the COVID-19 pandemic has created unprecedented health challenges and disrupted the TB health services, especially in high-burden countries with ever-increasing prevalence. Extrapulmonary and even pulmonary TB are an important cause of nonspecific clinical and radiological manifestations and can masquerade as any benign or malignant medical case, thus causing disastrous conditions and diagnostic dilemmas. Clinical manifestations and routine laboratory tests have limitations in directing physicians to diagnose TB. Medical-imaging examinations play an essential role in detecting tissue abnormalities and early suspecting diagnosis of TB in different organs. Radiologists and physicians should be familiar with and aware of the radiological manifestations of TB to contribute to the early suspicion and diagnosis of TB. The purpose of this article is to illustrate the common radiologic patterns of pulmonary and extrapulmonary TB. This article will be beneficial for radiologists, medical students, chest physicians, and infectious-disease doctors who are interested in the diagnosis of TB.

Microfluidics as a Novel Technique for Tuberculosis: From Diagnostics to Drug Discovery

Tuberculosis (TB) remains a global healthcare crisis, with an estimated 5.8 million new cases and 1.5 million deaths in 2020. TB is caused by infection with the major human pathogen Mycobacterium tuberculosis, which is difficult to rapidly diagnose and treat. There is an urgent need for new methods of diagnosis, sufficient in vitro models that capably mimic all physiological conditions of the infection, and high-throughput drug screening platforms. Microfluidic-based techniques provide single-cell analysis which reduces experimental time and the cost of reagents, and have been extremely useful for gaining insight into monitoring microorganisms. This review outlines the field of microfluidics and discusses the use of this novel technique so far in M. tuberculosis diagnostics, research methods, and drug discovery platforms. The practices of microfluidics have promising future applications for diagnosing and treating TB.

Recent Progress and Challenges for Drug-Resistant Tuberculosis Treatment

Control of Mycobacterium tuberculosis infection continues to be an issue, particularly in countries with a high tuberculosis (TB) burden in the tropical and sub-tropical regions. The effort to reduce the catastrophic cost of TB with the WHO’s End TB Strategy in 2035 is still obstructed by the emergence of drug-resistant TB (DR-TB) cases as result of various mutations of the MTB strain. In the approach to combat DR-TB, several potential antitubercular agents were discovered as inhibitors for various existing and novel targets. Host-directed therapy and immunotherapy also gained attention as the drug-susceptibility level of the pathogen can be reduced due to the pathogen’s evolutionary dynamics. This review is focused on the current progress and challenges in DR-TB treatment. We briefly summarized antitubercular compounds that are under development and trials for both DR-TB drug candidates and host-directed therapy. We also highlighted several problems in DR-TB diagnosis, the treatment regimen, and drug discovery that have an impact on treatment adherence and treatment failure.

Cost-effectiveness of the latent tuberculosis screening program for migrants in Stockholm Region

INTRODUCTION

The majority of tuberculosis (TB) cases in Sweden occur among migrants from endemic countries through activation of latent tuberculosis infection (LTBI). Sweden has LTBI-screening policies for migrants that have not been previously evaluated. This study aimed to assess the cost-effectiveness of the current screening strategy in Stockholm.

METHODS

A Markov model was developed to predict the costs and effects of the current LTBI-screening program compared to a scenario of no LTBI screening over a 50-year time horizon. Epidemiological and cost data were obtained from local sources when available. The primary outcomes were incremental cost-effectiveness ratio (ICER) in terms of societal cost per quality-adjusted life year (QALY).

RESULTS

Screening migrants in the age group 13-19 years had the lowest ICER, 300,082 Swedish Kronor (SEK)/QALY, which is considered cost-effective in Sweden. In the age group 20-34, ICER was 714,527 SEK/QALY (moderately cost-effectives) and in all age groups above 34 ICERs were above 1,000,000 SEK/QALY (not cost-effective). ICER decreased with increasing TB incidence in country of origin.

CONCLUSION

Screening is cost-effective for young cohorts, mainly between 13 and 19, while cost-effectiveness in age group 20-34 years could be enhanced by focusing on migrants from highest incidence countries and/or by increasing the LTBI treatment initiation rate. Screening is not cost-effective in older cohorts regardless of the country of origin.

Diabetes Mellitus and Its Associated Factors in Tuberculosis Patients in Maekel Region, Eritrea: Analytical Cross-Sectional Study

BACKGROUND

Both diabetes mellitus (DM) and tuberculosis (TB) are among the leading causes of morbidity and mortality in Eritrea. TB-DM comorbidity is known to complicate TB care, control and prevention. However, systematically studied epidemiological data on TB-DM comorbidity and its associated risk factors are lacking in this country.

OBJECTIVE

This study aimed to assess the prevalence of DM and its associated factors among TB patients in the Maekel region, Eritrea.

METHODS

Analytical cross-sectional study was conducted in eleven TB diagnostic and treatment sites. Pretested data extraction tool was used to collect data from medical records. Prevalence data were analysed using frequencies, proportions and median. To determine DM risk factors, univariable and multivariable logistic regression analysis was done with 95% CI and p value < 0.05 considered significant.

RESULTS

Out of total eligible (1134) TB cases, DM prevalence was 9.88%. Age and BMI were identified as independent risk factors for DM among TB patients. Higher odds of DM were found among TB patients aged 45-54 (aOR: 4.85[1.39-16.94], p= 0.013) and those ≥55 (aOR: 6.99[2.12-23.04], p= 0.001). TB cases with normal BMI were two times more likely to have DM (aOR: 2.00[1.23-3.26], p= 0.005) compared to those underweight.

CONCLUSION

The prevalence of DM among TB cases observed in this study is high, a clarion call to scale up current efforts to integrate TB-DM services within routine care. Furthermore, age and BMI were identified as independent risk factors for DM in TB cases, pointing to the need to pay attention to age and BMI status when managing this co-morbidity.

Human leukocyte antigen associations with protection against tuberculosis infection and disease in human immunodeficiency virus-1 infected individuals, despite household tuberculosis exposure and immune suppression

BACKGROUND

To determine the association of human leukocyte antigen (HLA) alleles as correlates of risk for and protection against tuberculin skin test (TST) positivity and active TB disease amongst HIV-infected adults.

METHODS

Genomic DNA was extracted from 754 HIV-infected adults whole-blood. HLA-A, -B, -C and -DRB1 loci were genotyped by next generation sequencing methods. HLA alleles were analysed by the presence/absence of TST immune conversion and active TB disease and further stratified by exposure to a household TB contact, CD4⁺ T-cell count and, for active TB disease, TST-positivity.

RESULTS

HLA-A*29:11 and - B*45:01/07 were associated with TST-positivity, while HLA-A*24:02, -A*29:02 and -B*15:16 with TST-negativity. In participants with a household TB contact, HLA-A*66:01, -A*68:02 and -B*49:01 were associated with TST-negativity. For TB disease, HLA-B*41:01, -C*06:02, -DRB1*04:01 and -DRB1*15:01 were associated with susceptibility, while HLA-B*07:02 and -DRB1*11:01 were protective, even for CD4⁺ T-cell count <350 cells/mm³. For initial TST-positivity and subsequent TB disease, HLA-A*01:01 and -DRB1*11:01 conveyed protection including for those with CD4⁺ T-cell count <350 cells/mm³.

CONCLUSION

Several HLA alleles are noted as correlates of TB infection, risk and natural protection in HIV-infected individuals. HLA associations may enable risk stratification of those with HIV infection. Protective alleles may assist in future TB vaccine development.

Approaches to treating tuberculosis by encapsulating metal ions and anti-mycobacterial drugs utilizing nano- and microparticle technologies

Tuberculosis (TB) is caused by a bacterial infection that affects a number of human organs, primarily the lungs, but also the liver, spleen, and spine, causing key symptoms of fever, fatigue, and persistent cough, and if not treated properly, can be fatal. Every year, 10 million individuals become ill with active TB resulting with a mortality approximating 1.5 million. Current treatment guidelines recommend oral administration of a combination of first-line anti-TB drugs for at least 6 months. While efficacious under optimum conditions, 'Directly Observed Therapy Short-course' (DOTS) is not without problems. The long treatment time and poor pharmacokinetics, alongside drug side effects lead to poor patient compliance and has accelerated the emergence of multi-drug resistant (MDR) organisms. All this, combined with the limited number of newly discovered TB drugs to treat MDR-TB and shorten standard therapy time, has highlighted the need for new targeted drug delivery systems. In this respect, there has been recent focus on micro- and nano-particle technologies to prepare organic or/and metal particles loaded with TB drugs to enhance their efficacy by targeted delivery via the inhaled route. In this review, we provide a brief overview of the current epidemiology of TB, and risk factors for progression of latent stage tuberculosis (LTBI) to the active TB. We identify current TB treatment regimens, newly discovered TB drugs, and identify studies that have used micro- or nano-particles technologies to design a reliable inhalation drug delivery system to treat TB more effectively.

RP-HPLC method development and validation for bedaquiline fumarate to evaluate its forced degradation behaviour and stability in official dissolution media

Background

A simple, rapid and accurate reverse phase RP-HPLC method for the validation of antitubercular drug bedaquiline fumarate (BQF) was developed. The stability and forced degradation behaviour of bedaquiline fumarate (BQF) in official dissolution media (0.01 N HCl) and methanol were assessed.

Results

The method provided linear responses within the concentration range which varies from 10 to 100 μg/mL with LOD values of 2.6 μg/mL and LOQ of 7.9 μg/mL. Mean percent recovery varied between 97.46 and 103.82% and precise mean RSD of 0.31% (repeatability) and 0.48% (intermediate precision). The method was validated for other parameters like specificity, system suitability and robustness. Potential degradation of the BQF when exposed to direct sunlight in official dissolution media was 90.75% and in methanolic stock solution was 91.98%. Acid-alkali degradation study showed 86.59% loss of BQF in 0.5 N NaOH, and in acidic environment (0.5 N HCl), there was 6.15% loss. Thermal degradation of BQF was 70.11% loss in official dissolution media at 80 °C. No significant change in drug concentrations was noted when exposed and protected from normal daylight at room temperature and at 2–8 °C temperature.

Conclusion

The developed method has significant applicability for the qualitative and quantitative determination of BQF in different pharmaceutical formulations in the official dissolution media in routine quality control analysis.

Tuberculosis - Present Medication and Therapeutic Prospects

BACKGROUND

Tuberculosis (TB) has been present in the history of human civilization since time immemorial and has caused more deaths than any other infectious disease. It is still considered one of the ten most common epidemiologic causes of death in the world. As a transmissible disease, it is initiated by rod-shaped (bacillus) mycobacteria. The management of tuberculosis became possible owing to several discoveries beginning in 1882 with the isolation of the TB bacillus by Robert Koch. The diagnosis of TB was enabled by finding a staining method for TB bacteria identification (1883). It was soon realized that a large-scale policy for the treatment and prevention of tuberculosis was necessary, which resulted in the foundation of International Union against Tuberculosis and Lung Diseases (1902). An antituberculosis vaccine was developed in 1921 and has been in therapeutic use since then. TB treatment regimens have changed over the decades and the latest recommendations are known as Directly Observed Treatment Short-course (DOTS, WHO 1993).

METHODS

A search of bibliographic databases was performed for peer-reviewed research literature. A focused review question and inclusion criteria were applied. Standard tools were used to assess the quality of retrieved papers.

RESULTS

A total of 112 papers were included comprising original publications and reviews. The paper overviews anti-TB drugs according to their mechanism of action. The chemical structure, metabolism and unwanted effects of such drugs have been discussed. The most recent treatment regimens and new drugs, including those in clinical trials, are also presented.

CONCLUSION

Despite a 22% decrease in the tuberculosis fatality rate observed between 2000 and 2015, the disease remains one of the ten prime causes of death worldwide. Increasing bacterial resistance and expensive, prolonged therapies are the main reasons for efforts to find effective drugs or antituberculosis regimens, especially to cure multidrug-resistant tuberculosis.

Treatment of Isoniazid-Resistant Pulmonary Tuberculosis

Tuberculosis (TB) remains a threat to public health and is the leading cause of death globally. Isoniazid (INH) is an important first-line agent for the treatment of TB considering its early bactericidal activity. Resistance to INH is now the most common type of resistance. Resistance to INH reduces the probability of treatment success and increases the risk of acquiring resistance to other first-line drugs such as rifampicin (RIF), thereby increasing the risk of multidrug-resistant-TB. Studies in the 1970s and 1980s showed high success rates for INH-resistant TB cases receiving regimens comprised of first-line drugs. However, recent data have indicated that INH-resistant TB patients treated with only first-line drugs have poor outcomes. Fortunately, based on recent systematic meta-analyses, the World Health Organization published consolidated guidelines on drug-resistant TB in 2019. Their key recommendations are treatment with RIF-ethambutol (EMB)-pyrazinamide (PZA)-levofloxacin (LFX) for 6 months and no addition of injectable agents to the treatment regimen. The guidelines also emphasize the importance of excluding resistance to RIF before starting RIF-EMB-PZA-LFX regimen. Additionally, when the diagnosis of INH-resistant TB is confirmed long after starting the first-line TB treatment, the clinician must decide whether to start a 6-month course of RIF-EMB-PZA-LFX based on the patient's condition. However, these recommendations are based on observational studies, not randomized controlled trials, and are thus conditional and based on low certainty of the effect estimates. Therefore, further work is needed to optimize the treatment of INH-resistant TB.

Recent updates on drug resistance in Mycobacterium tuberculosis

Tuberculosis (TB) along with acquired immune deficiency syndrome and malaria rank among the top three fatal infectious diseases which pose threat to global public health, especially in middle and low income countries. TB caused by Mycobacterium tuberculosis (Mtb) is an airborne infectious disease and one-third of the world's population gets infected with TB leading to nearly 1·6 million deaths annually. TB drugs are administered in different combinations of four first-line drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) which form the core of treatment regimens in the initial treatment phase of 6-9 months. Several reasons account for the failure of TB therapy such as (i) late diagnosis, (ii) lack of timely and proper administration of effective drugs, (iii) lower availability of less toxic, inexpensive and effective drugs, (iv) long treatment duration, (v) nonadherence to drug regimen and (vi) evolution of drug-resistant TB strains. Drug-resistant TB poses a significant challenge to TB therapy and control programs. In the background of worldwide emergence of 558 000 new TB cases with resistance to rifampicin in the year 2017 and of them, 82% becoming multidrug-resistant TB (MDR-TB), it is essential to continuously update the knowledge on the mechanisms and molecular basis for evolution of Mtb drug resistance. This narrative and traditional review summarizes the progress on the anti-tubercular agents, their mode of action and drug resistance mechanisms in Mtb. The aim of this review is to provide recent updates on drug resistance mechanisms, newly developed/repurposed anti-TB agents in pipeline and international recommendations to manage MDR-TB. It is based on recent literature and WHO guidelines and aims to facilitate better understanding of drug resistance for effective TB therapy and clinical management.

Contact tracing strategies in household and congregate environments to identify cases of tuberculosis in low- and moderate-incidence populations

BACKGROUND

Tuberculosis is an infectious bacterial disease that is spread via respiratory droplets from infected individuals to susceptible contacts. To eliminate this disease from low- and medium-incidence settings, people who are most likely to be infected (contacts) must be identified. Recently, study authors have examined alternate approaches to contact tracing methods that demonstrate improved detection and prioritization of contacts. The comparative benefit of these methods has not been established.

OBJECTIVES

To assess the effectiveness of novel methods of contact tracing versus current standard of care to identify latent and active cases in low- to moderate-incidence settings.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, Web of Science, and CINAHL up to 15 July 2019. We also searched for clinical trials and examined reference lists and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and cluster-RCTs of contact tracing strategies that included alternate approaches (other than standard practice).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified articles for eligibility and quality using prespecified criteria.

MAIN RESULTS

No trials met the inclusion criteria of this review. Several study authors described an alternate method for examining contacts and performing social network analysis but did not compare this with the current contact tracing approach.

AUTHORS' CONCLUSIONS

This Cochrane Review highlights the lack of research in support of the current contact tracing method and the need for RCTs to compare new methods such as social network analysis to improve contact tracing processes.

Differential T cell responses against DosR-associated antigen Rv2028c in BCG-vaccinated populations with tuberculosis infection

The IFN-γ release assays (IGRAs) based on region of difference 1 (RD1) antigens have improved diagnosis of Mycobacterium tuberculosis (Mtb) infection. However, IGRAs with these antigens could not distinguish latent tuberculosis infection (LTBI) from active tuberculosis (ATB). DosR regulon genes are thought to be important for Mtb dormancy, and their products have higher immunogenicity in LTBI than ATB individuals, suggesting protective immunity mediated by DosR regulon-encoded antigens and potential utility of them for differential diagnostics of Mtb-infected populations or development of therapeutic vaccines against tuberculosis (TB). Among them, Rv2028c is a dormancy-related antigen that has demonstrated potential use in TB control, but its immunological characteristics in the BCG-vaccinated Chinese population are unknown. In this study, a total of 148 individuals, including 98 patients with ATB, 20 cases with LTBI and 30 healthy controls, were tested for Rv2028c-specific T cell responses by using an IFN-γ ELISA assay. The results showed that the T-cell responses in LTBI individuals were almost always higher than those in ATB patients, regardless of the site of infection or the results of bacteriological examination in the patients. This allowed for good differentiation between these two groups of Mtb-infected individuals even in the BCG-vaccinated high TB-incidence setting that pertains in China. In addition, the diagnostic efficacy for ATB was enhanced by combining the results from Rv2028c and RD1 antigen-based IFN-γ ELISA assays. In conclusion, Rv2028c-specific T-cell responses might contribute to natural protection against dormant Mtb infection, and the determination of these responses can aid discrimination between healthy LTBI individuals and ATB patients in the Mtb-infected populations.

Novel MprA binding motifs in the phoP regulatory region in Mycobacterium tuberculosis

MprAB and PhoPR are important two-component systems (TCSs) in Mycobacterium tuberculosis, and both regulate EspR, a key regulator of the ESX-1 secretion system. Although previous studies suggest that the response regulator PhoP does not directly regulate mprA, the interplay between MprAB and PhoPR remains unclear. In this study, we found that the response regulator MprA can bind to the phoP promoter. Four repeat motifs, D1-D4, constituting two predicted binding sites, were located in the region protected by MprA in DNA footprinting. D1-D4 lack the reported conserved MprA binding sequences, indicating that MprA can recognize a greater range of target sites. Interestingly, D1-D2 overlap a previously reported PhoP binding site, and mutation of D1-D2 inhibited PhoP binding, whereas the D3-D4 site, but not the D1-D2 site, was required for MprA binding. EMSA assays also suggest that MprA and PhoP compete to bind to the phoP promoter. The results of the transcriptional and western blot assays are consistent with a model in which MprA positively controls the phoP expression, which in turn upregulates the expression of espR. These findings reveal complex regulation of a major mycobacterial TCS by dual TCSs.

Impact of Pulmonary Tuberculosis on the EGFR Mutational Status and Clinical Outcome in Patients with Lung Adenocarcinoma

Purpose

Although it has been suggested that pulmonary tuberculosis (TB) is associated with increased risk of lung cancer, the exact mechanism is not clearly identified. We investigated the effect of pulmonary TB on the epidermal growth factor receptor (EGFR) mutational status and clinical outcome in patients with pulmonary adenocarcinoma.

Materials and Methods

We reviewed data of patients diagnosed with pulmonary adenocarcinoma harboring EGFR mutations and treated at our institution from 2008 to 2015. We divided our population into two groups: patients with pre-existing TB lesions on chest computed tomography scan (TB group) and those without the lesions (non-TB group). We compared the differences in EGFR mutational status, response to tyrosine kinase inhibitors (TKIs) and survival between the two groups.

Results

A total of 477 patients with pulmonary adenocarcinoma were analyzed. One hundred eighty-three patients (39%) had EGFR-mutated tumors and 100 (21%) patients had pre-existing TB lesions. The frequency of EGFR mutation was significantly higher in the TB group compared with the non-TB group (56% vs. 34%, p=0.038). Pre-existing TB lesions were independently associated with more frequent EGFR mutations in multivariate analysis (odds ratio, 1.43). In addition, both the progression-free survival (9.1 months vs. 11.6 months, p=0.020) and the overall survival (19.4 months vs. 24.5 months, p=0.014) after first-line EGFR-TKIs were significantly shorter in the TB group than in the non-TB group.

Conclusion

Previous pulmonary TB may be associated with more frequent EGFR mutations and poorer treatment response to EGFR-TKIs in patients with pulmonary adenocarcinoma.

Screening and identification of lncRNAs as potential biomarkers for pulmonary tuberculosis

Pulmonary tuberculosis (TB) is among the diseases with the highest morbidity and mortality worldwide. Effective diagnostic methods for TB are lacking. In this study, we investigated long non-coding RNAs (lncRNAs) in plasma using microarray and the potential diagnostic value of lncRNAs for TB. We found a total of 163 up-regulated lncRNAs and 348 down-regulated lncRNAs. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and coding-noncoding co-expression (CNC) analyses showed that functions of differentially expressed lncRNAs were mainly enriched in the regulation of alpha-beta T cell activation and the T cell receptor signalling pathway. Four differentially expressed lncRNAs, NR_038221 (fold change = 3.79, P < 0.01), NR_003142 (fold change = 1.69, P < 0.05), ENST00000570366 (fold change = 3.04, P < 0.05), and ENST00000422183 (fold change = 2.11, P < 0.001), were verified using RT-qPCR. Among those, NR_038221, NR_003142, and ENST00000570366 were found to be up-regulated, while ENST00000422183 was down-regulated. The value of the area under the curve (AUC) for the diagnostic model consisting of the four lncRNAs was 0.845 (sensitivity = 79.2%, specificity = 75%). We further predicted 85 mRNAs and 404 miRNAs that potentially interact with these lncRNAs. Our study revealed the potential value of lncRNAs as biomarkers for early diagnosis of TB and the underlying mechanisms of these abnormally expressed lncRNAs in the pathogenesis of TB.

Designing Epitope Ensemble Vaccines against TB by Selection: Prioritizing Antigens using Predicted Immunogenicity

Tuberculosis (TB) is a global health burden, and a major cause of mortality and morbidity in West Africa. Here, we select key conserved pathogen epitopes of proven immunogenicity to form a potential TB epitope ensemble vaccine. We compared two vaccine formulations: one comprising class I epitopes from the 13 most prevalent class I epitope-bearing antigens and class II epitopes deriving from the 20 most prevalent class II epitope-bearing antigens and another consisting of epitopes derived solely from 5 antigens identified as the most immunogenic by VaxiJen. In the prevalence analysis, 279 class I and 561 class II epitopes were collected and a subset selected using our published methodology, yielding 32 conserved epitopes. Combining 9 conserved epitopes gave a putative vaccine with predicted population coverage (PPC) over 95%. This consists of ISSGVFLLK, AVAGAAILV, WYYQSGLSI, YQSGLSIVM, MPVGGQSSF, QSSFYSDWY, WDINTPAFEWYYQSGLSIVM, DAPLITNPGGLLEQAVAVEE and NQAVTPAARALPLTSLTSAA. 5 immunogenic antigens VaxiJen-identified yielded 187 epitopes, which we again analyzed using published protocol. This identified 11 conserved epitopes. From this set the highest PPC value (<85%) was obtained by combining: GQQYQAMSAQAAAFH, DDIKATYDKGILTVSVAVSE and AVAGAAILV. We conclude that prioritizing epitope selection using predicted immunogenicity alone is likely to be unduly restrictive and is currently not an optimal or advisable strategy in the design of epitope ensemble vaccines.