Impaired M. tuberculosis Antigen-Specific IFN-γ Response without IL-17 Enhancement in Patients with Severe Cavitary Pulmonary Tuberculosis

The association of IL-17A rs2275913 single nucleotide polymorphism with anti-tuberculous drug resistance in patients with pulmonary tuberculosis

BACKGROUND

Drug-resistant  Tuberculosis (DR-TB) is a global health burden with high morbidity and mortality in developing countries including Egypt. The susceptibility to infection with DR-TB strains may be genetically determined. Several interleukin gene polymorphisms were investigated as risk factors for tuberculosis infection but focusing on their association with DR-TB was limited. Therefore, the objective of this study is to assess the association of IL 17 - 197 G > A (rs2275913) single nucleotide polymorphism (SNP) with susceptibility to DR-TB strains in comparison to drug-sensitive tuberculosis (DS-TB) strains in Egyptian patients with pulmonary TB. This cross-sectional study was conducted on 80 patients with DR-TB strains and 80 with DS-TB strains as a control group. Both age and sex were comparable among the study's groups. IL-17 - 197 G > A (rs2275913) SNP was genotyped by real-time PCR, and IL-17 serum concentration was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The GA and AA genotype frequencies of IL 17 - 197 G > A (rs2275913) SNP were significantly higher in patients with DR-TB strains than those with DS-TB strains (p < 0.001). The frequency of the A allele was significantly (p < 0.001) higher in patients with DR-TB group (32.5%) compared to the control group (13.8%). Substantial higher serum levels of IL-17 were detected in the DR-TB group with significant association with AA and AG genotypes.

CONCLUSION

Polymorphism in IL-17 -197 G > A (rs2275913) resulted in higher serum levels of IL-17 and Egyptian patients with such polymorphism are three times at risk of infection with DR-TB strains than patients with wild type.

The Safety and Efficacy of Prolonged Use of Bedaquiline for the Treatment of Patients with Pulmonary Multi-Drug Resistant/Rifampin-Resistant Tuberculosis: A Prospective, Cohort Study in China

Objective

To evaluate the safety, tolerability, and efficacy of prolonged bedaquiline (Bdq) treatment in patients with multi-drug/rifampin-resistant tuberculosis (MDR/RR-TB).

Methods

This prospective cohort study was performed from August 2018 to August 2021. Patients diagnosed with MDR/RR-TB who met the inclusion criteria were prospectively included. Patients were treated with individual regimens of 18-20 months containing Bdq for six months or a prolonged course of nine or 12 months according to treatment demands, and the efficacy and safety with a different course of Bdq-containing regimens were compared and evaluated.

Results

A total of 159 MDR/RR-TB patients were included in the study, including 96 cases with six months of Bdq, 50 cases with nine months of Bdq, and 13 patients with 12 months of Bdq. The treatment success rates were 89.6%, 90%, and 84.6% in Bdq at six months, nine months, and 12 months, respectively, which were not statistically different (P = 0.85). The main adverse events (AEs) were anemia, thrombocytopenia, and liver dysfunction in all patients, with no significant difference among the three groups. Patients who had fewer drugs chosen, disseminated lesions or lesions that were slowly absorbed, and severe cavities were the common reasons for prolonged use of Bdq.

Conclusion

Prolonged course use of Bdq from six months to 12 months clinically proved to be safe and efficient, and patients with severe or disseminated lesions had the chance to prolong the use of Bdq for more than six months to achieve optimal treatment outcomes.

The effect of isolated probiotics from Indonesian <em>passiflora edulis</em> sims. on interferon gamma (ifn-γ) levels in peripheral blood mononuclear cell of adult tuberculosis patients <em>in vitro</em>

Background: Mycobacterium tuberculosis (M.tb) is unique because the bacteria live intracellularly and hide in macrophages so that they can escape from phagocytosis. This is one of the factors that complicate the treatment of M.tb infections. Interferon-gamma (IFN-γ) is a compound that plays an important role in macrophage activation to control intracellular pathogens. Objective: The purpose of this research is to analyze the concentration of IFN-γ in peripheral blood mononuclear cells of adult Tuberculosis patients (TB) after in vitro administration of multistrain probiotics from indigeneous Indonesian red passion fruit (Passiflora edulis Sims.). Method: The probiotics isolated from red passion fruit were introduced into Peripheral Blood Mononuclear Cell (PBMC) adult TB patients who were undergoing Anti-tuberculosis Drug Therapy (ATD) category one at the Trosobo Primary Health Center (Sidoarjo, East Java, Indonesia), and the patients who were undergoing ATD category one treatment were willing to be involved in this study. Result: The probiotics isolated from fermentation-broth of Indonesian red passion fruit were able to increase IFN-γ levels in PBMC of adult TB patients. Conclusion: The red passion fruit probiotics isolated can increase IFN-γ of adult TB patients increased from 0.82% to 23.17% after in vitro administration.

Tuberculosis Treatment Response Monitoring by the Phenotypic Characterization of MTB-Specific CD4+ T-Cells in Relation to HIV Infection Status

HIV infection causes systemic immune activation, impacts TB disease progression and hence may influence the diagnostic usability of Mycobacterium tuberculosis-specific T cell profiling. We investigated changes of activation and maturation markers on MTB-specific CD4+ T-cells after anti-tuberculosis treatment initiation in relation to HIV status and the severity of lung impairment. Thawed peripheral blood mononuclear cells from TB patients with (n = 27) and without HIV (n = 17) were analyzed using an intracellular IFN-γ assay and flow cytometry 2 and 6 months post-TB treatment initiation. H37Rv antigen was superior to the profile MTB-specific CD4+ T-cells phenotype when compared to PPD and ESAT6/CFP10. Regardless of HIV status and the severity of lung impairment, activation markers (CD38, HLA-DR and Ki67) on MTB-specific CD4+ T-cells declined after TB treatment initiation (p < 0.01), but the expression of the maturation marker CD27 did not change over the course of TB treatment. The MTB-specific T cell phenotype before, during and after treatment completion was similar between people living with and without HIV, as well as between subjects with severe and mild lung impairment. These data suggest that the assessment of activation and maturation markers on MTB-specific CD4+ T-cells can be useful for TB treatment monitoring, regardless of HIV status and the severity of lung disease.

The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4⁺ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4⁺ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37R_V with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4⁺ and CD8⁺ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4⁺ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4⁺ and CD8⁺ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4⁺ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4⁺ T cells. β-Catenin along with PD-1 and IFN-γ in CD4⁺ T cells had a high correlation with those in CD8⁺ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4⁺ T cell frequency in TB.

Humanized Mouse Model Mimicking Pathology of Human Tuberculosis for in vivo Evaluation of Drug Regimens

Human immune system mice are highly valuable for in vivo dissection of human immune responses. Although they were employed for analyzing tuberculosis (TB) disease, there is little data on the spatial organization and cellular composition of human immune cells in TB granuloma pathology in this model. We demonstrate that human immune system mice, generated by transplanted human fetal liver derived hematopoietic stem cells develop a continuum of pulmonary lesions upon Mycobacterium tuberculosis aerosol infection. In particular, caseous necrotic granulomas, which contribute to prolonged TB treatment time, developed, and had cellular phenotypic spatial-organization similar to TB patients. By comparing two recommended drug regimens, we confirmed observations made in clinical settings: Adding Moxifloxacin to a classical chemotherapy regimen had no beneficial effects on bacterial eradication. We consider this model instrumental for deeper understanding of human specific features of TB pathogenesis and of particular value for the pre-clinical drug development pipeline.

The Immune Mechanisms of Lung Parenchymal Damage in Tuberculosis and the Role of Host-Directed Therapy

Impaired lung function is common in people with a history of tuberculosis. Host-directed therapy added to tuberculosis treatment may reduce lung damage and result in improved lung function. An understanding of the pathogenesis of pulmonary damage in TB is fundamental to successfully predicting which interventions could be beneficial. In this review, we describe the different features of TB immunopathology that lead to impaired lung function, namely cavities, bronchiectasis, and fibrosis. We discuss the immunological processes that cause lung damage, focusing on studies performed in humans, and using chest radiograph abnormalities as a marker for pulmonary damage. We highlight the roles of matrix metalloproteinases, neutrophils, eicosanoids and cytokines, like tumor necrosis factor-α and interleukin 1β, as well as the role of HIV co-infection. Finally, we focus on various existing drugs that affect one or more of the immunological mediators of lung damage and could therefore play a role as host-directed therapy.

The immune characterization of interferon-β responses in tuberculosis patients

We aimed to assess the immunoregulatory effects of IFN‐β in patients with tuberculous pleurisy. IFN‐β, IFN‐γ and IL‐17 expression levels were detected, and correlations among these factors in different culture groups were analyzed. Pleural fluid mononuclear cells (PFMC) from tuberculous pleural effusions, but not peripheral blood mononuclear cells (PBMC) from healthy donors, spontaneously expressed IFN‐β, IL‐17 and IFN‐γ. Moreover, exogenous IFN‐β significantly inhibited the expression of IL‐17 in PFMC. By contrast, IFN‐β simultaneously enhanced the levels of IFN‐γ. To further investigate the regulation of IL‐17 and IFN‐γ by endogenous IFN‐β, an IFN‐β neutralizing antibody was simultaneously added to bacillus Calmette‐Guérin (BCG)‐stimulated PFMC. IL‐17 expression was significantly increased, but IFN‐γ production was markedly decreased in the experimental group supplemented with the IFN‐β neutralizing antibody. Simultaneously, IL‐17 production was remarkably increased in the experimental group supplemented with the IFN‐γ neutralizing antibody. Taken together, in our study, we first found that freshly isolated PFMC, but not PBMC from healthy donors, spontaneously expressed IFN‐β, IL‐17 and IFN‐γ in vivo. Moreover, IFN‐β suppressed IL‐17 expression and increased IFN‐γ production. Furthermore, both IFN‐β and IFN‐γ down‐regulated IL‐17 expression. These observations suggest that caution is required when basing anti‐tuberculosis treatment on the inhibition of IFN‐β signaling.

Efficacy of T Regulatory Cells, Th17 Cells and the Associated Markers in Monitoring Tuberculosis Treatment Response

Treatment monitoring is an essential aspect for tuberculosis (TB) disease management. Sputum smear microscopy is the only available tool for monitoring, but it suffers from demerits. Therefore, we sought to evaluate markers and cellular subsets of T regulatory (Treg) cells and T helper (Th) 17 cells in pulmonary TB patients (PTB) for TB treatment monitoring. Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro (with purified protein derivative (PPD)) overnight which was followed by a polychromatic flow cytometry approach to study Treg and Th17 markers and cellular subsets in PTB (n = 12) undergoing antituberculous treatment (ATT). The baseline levels of these markers and cellular subsets were evaluated in normal healthy subjects (NHS). We observed a significant decrease in the expression of CD25 (p<0.01) marker and percentage of T-cell subsets like CD4⁺CD25⁺ (p<0.001) and CD4⁺CD25⁺CD39⁺ (p<0.05) at the end of intensive phase (IP) as well as in the continuation phase (CP) of ATT. A decrease in CD25 marker expression and percentage of CD4⁺CD25⁺ T cell subset showed a positive correlation to sputum conversion both in high and low sputum positive PTB. In eight PTB with cavitary lesions, only CD4⁺CD25⁺FoxP3 Treg subset manifested a significant decrease at the end of CP. Thus, results of this study show that CD25 marker and CD4⁺CD25⁺ T cells can serve as better markers for monitoring TB treatment efficacy. The Treg subset CD4⁺CD25⁺FoxP3 may be useful for prediction of favorable response in PTB with extensive lung lesions. However, these findings have to be evaluated in a larger patient cohort.

Severe Tuberculosis in Humans Correlates Best with Neutrophil Abundance and Lymphocyte Deficiency and Does Not Correlate with Antigen-Specific CD4 T-Cell Response

It is generally thought that Mycobacterium tuberculosis (Mtb)-specific CD4⁺ Th1 cells producing IFN-γ are essential for protection against tuberculosis (TB). In some studies, protection has recently been associated with polyfunctional subpopulation of Mtb-specific Th1 cells, i.e., with cells able to simultaneously secrete several type 1 cytokines. However, the role for Mtb-specific Th1 cells and their polyfunctional subpopulations during established TB disease is not fully defined. Pulmonary TB is characterized by a great variability of disease manifestations. To address the role for Mtb-specific Th1 responses during TB, we investigated how Th1 and other immune cells correlated with particular TB manifestations, such as the degree of pulmonary destruction, TB extent, the level of bacteria excretion, clinical disease severity, clinical TB forms, and “Timika X-ray score,” an integrative parameter of pulmonary TB pathology. In comparison with healthy Mtb-exposed controls, TB patients (TBP) did not exhibit deficiency in Mtb-specific cytokine-producing CD4⁺ cells circulating in the blood and differed by a polyfunctional profile of these cells, which was biased toward the accumulation of bifunctional TNF-α⁺IFN-γ⁺IL-2⁻ lymphocytes. Importantly, however, severity of different TB manifestations was not associated with Mtb-specific cytokine-producing cells or their polyfunctional profile. In contrast, several TB manifestations were strongly correlated with leukocyte numbers, the percent or the absolute number of lymphocytes, segmented or band neutrophils. In multiple alternative statistical analyses, band neutrophils appeared as the strongest positive correlate of pulmonary destruction, bacteria excretion, and “Timika X-ray score.” In contrast, clinical TB severity was primarily and inversely correlated with the number of lymphocytes in the blood. The results suggest that: (i) different TB manifestations may be driven by distinct mechanisms; (ii) quantitative parameters and polyfunctional profile of circulating Mtb-specific CD4⁺ cells play a minor role in determining TB severity; and (iii) general shifts in production/removal of granulocytic and lymphocytic lineages represent an important factor of TB pathogenesis. Mechanisms leading to these shifts and their specific role during TB are yet to be determined but are likely to involve changes in human hematopoietic system.

Impairment of Wnt/β-catenin signaling in blood cells of patients with severe cavitary pulmonary tuberculosis

Tuberculosis (TB) remains as a leading infectious disease worldwide. Our previous study showed interferon (IFN)-γ and CD3 T cell impairment in patients with severe cavitary pulmonary TB (PTB). However, the cause of the change in immune responses during the progression of TB is still poorly understood. In this study, eight newly diagnosed patients with severe cavitary and mild lesion non-cavity PTB were recruited, and three healthy volunteers were recruited as the control. RNA extracted from blood was tested by whole genome oligo microarrays. A PCR array was used to further test the same samples. Two additional groups of patients were recruited according to the same criteria with healthy control(HC) recruited as well and subjected to peripheral blood mononuclear cell isolation (PBMC)and analysis of TCF-7, β-catenin, cyclin D2, IFN-γ, and tumor necrosis factor (TNF)-α expression in CD14- cells (lymphocytes) and CD14+ cells by quantitative PCR. The changes of expression of β-catenin, CD69+ and IFN-γ by CD3+, CD14- and CD14+ cells in vitro with stimulation of LiCl were tested by flow cytometry. Whole genome oligo microarrays showed a significant decrease in expression of the Wnt signaling pathway in severe PTB patients. Further analysis of the Wnt pathway by PCR array indicated that TCF-7, β-catenin, and cyclin D2 expression was significantly reduced in severe PTB patients compared with mild PTB patients. In the additionally recruited patients, TCF-7, β-catenin, and cyclin D2 were expressed in both CD14+ and CD14- cells, while β-catenin was decreased significantly in CD14- cells compared with CD14+ cells in severe PTB patients, and IFN-γ and TNF-α expression in CD14- cells was also reduced significantly in severe PTB patients. β-catenin can directly trigger T cell activation and IFN-γsecretion in PBMCs stimulated for 24 hours. These findings indicate that Wnt pathway and its key genes, such as β-catenin, were impaired in blood cells of patients with severe PTB. Therefore, Wnt/β-catenin pathway is closely associated with T cell proliferation and TB lesion deterioration.

Safety and Immunogenicity of the Recombinant Mycobacterium bovis BCG Vaccine VPM1002 in HIV-Unexposed Newborn Infants in South Africa

Tuberculosis is a global threat to which infants are especially vulnerable. Effective vaccines are required to protect infants from this devastating disease. VPM1002, a novel recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine previously shown to be safe and immunogenic in adults, was evaluated for safety in its intended target population, namely, newborn infants in a region with high prevalence of tuberculosis. A total of 48 newborns were vaccinated intradermally with VPM1002 (n = 36) or BCG Danish strain (n = 12) in a phase II open-labeled, randomized trial with a 6-month follow-up period. Clinical and laboratory measures of safety were evaluated during this time. In addition, vaccine-induced immune responses to mycobacteria were analyzed in whole-blood stimulation and proliferation assays. The safety parameters and immunogenicity were comparable in the two groups. Both vaccines induced interleukin-17 (IL-17) responses; however, VPM1002 vaccination led to an increase of CD8+ IL-17+ T cells at the week 16 and month 6 time points. The incidence of abscess formation was lower for VPM1002 than for BCG. We conclude that VPM1002 is a safe, well-tolerated, and immunogenic vaccine in newborn infants, confirming results from previous trials in adults. These results strongly support further evaluation of the safety and efficacy of this vaccination in larger studies. (This study has been registered at ClinicalTrials.gov under registration no. NCT01479972.).

MTB-specific lymphocyte responses are impaired in tuberculosis patients with pulmonary cavities

Objective

Tuberculosis (TB), an infectious disease caused by the bacillus Mycobacterium tuberculosis (MTB), is a global health problem. Because the failing immune response in the lung can lead to formation of a pulmonary cavity, this study was designed to clarify MTB-specific lymphocyte responses in TB patients with pulmonary cavities.

Methods

We utilized culture filtrate protein 10 (CFP-10) and early secretory antigenic target 6 (ESAT-6) as immunogenic MTB antigens following overnight stimulation of peripheral blood mononuclear cells (PBMCs). By flow cytometry, we then dissected CD4+ and CD8+ T lymphocytes secreting intracellular cytokines of IFN-γ and TNF-α to assess the local immune response of TB patients with pulmonary cavities compared with those having other radiological infiltrates.

Results

As expected, after 16 h of ex vivo activation using both ESAT-6 and CFP-10, the proportions of CD4+IFN-γ, CD4+TNF-α, CD8+TNF-α, and CD8+IFN-γ cells were all markedly increased in 46 patients with TB when compared with 23 household contacts. However, the IFN-γ and TNF-α responses of both CD4+ and CD8+ T lymphocytes were found to be relatively lower in 18 patients who had pulmonary cavities when compared with 28 patients who had radiological infiltrates. Moreover, patients with cavities had higher absolute numbers of neutrophils than patients with infiltrates. Further analysis indicated an inverse correlation between neutrophil counts and the proportions of IFN-γ-secreting T cells.

Conclusion

MTB-specific lymphocyte responses are impaired in TB patients with pulmonary cavities that are likely to play an important role in the pathogenesis of cavitary TB.

Decreased IL-17 during treatment of sputum smear-positive pulmonary tuberculosis due to increased regulatory T cells and IL-10

BACKGROUND

Tuberculosis (TB) remains a major public health concern worldwide. Previous studies have demonstrated that IL-17 plays an important role in initial immune response and is involved in both immune-mediated protection and pathology following infection with Mycobacterium tuberculosis (MTB). However, the alterations and regulation of plasma IL-17 level during TB treatment remain unclear. Moreover, the cell type responsible for the production of IL-17 in TB patients requires further study.

METHODS

A total of 20 acid-fast bacilli smear-positive (AFB-positive) pulmonary TB patients and 20 age- and gender-matched healthy volunteers were included in our study. Blood samples were collected in heparinized tubes at the time of diagnosis (AFB-positive group) and 3 weeks after the initiation of therapy, when the sputum smear conversion (AFB-negative group) occurred, followed by symptomatic improvement. IL-17 levels and IL-17-producing cells in PBMCs were detected. Lymphocyte populations in the peripheral blood between the AFB-positive and AFB-negative groups were compared by flow-cytometry. A549 cells, a cell line of alveolar epithelial cells, were applied to determine the extent of the pathological damage mediated by IL-17 following MTB infection. Recombinant human IL-10 was used to investigate the regulation of IL-17 expression after sputum smear conversion in AFB-positive pulmonary TB patients.

RESULTS

Plasma IL-17 level were elevated in patients with sputum AFB-positive pulmonary TB, but substantially decreased after TB treatment and smear conversion. Our data indicate that NKT-like cells might be the main source of IL-17, in addition to conventional T cells in AFB-positive pulmonary TB patients. The secretion of IL-17 may be suppressed by regulatory T (Treg) cells and IL-10 during TB treatment. Moreover, the IL-17 levels were positively correlated to both the C-reactive protein and erythrocyte sedimentation rate. Therefore, IL-17 was capable of alveolar epithelial cell damage following MTB infection.

CONCLUSION

The increase in the frequency of Treg cells and IL-10 levels was associated with a decrease in IL-17 in patients receiving TB treatment. Thus, IL-10 and Tregs may function to inhibit immune-mediated pathology in TB patients.