Myriocin enhances the clearance of M. tuberculosis by macrophages through the activation of PLIN2.

Myriocin is an inhibitor of de novo synthesis of sphingolipids and ceramides. In this research, we showed myriocin could significantly reduce Mtb burden and histopathological inflammation in mice. However, the underlying mechanism remains unclear. RNA-seq analysis revealed a significant increase in gene expression of PLIN2/CD36/CERT1 after myriocin treatment. The reduced bactericidal burden was only reversed after silencing the lipid droplets (LDs) surface protein PLIN2. This suggests that myriocin enhances the ability of macrophages to clear Mtb depending on the PLIN2 gene, which is part of the PPARγ pathway. Indeed, we observed a significant increase in the number of LDs following myriocin treatment.IMPORTANCEMycobacterium tuberculosis has the ability to reprogram host cell lipid metabolism and alter the antimicrobial functions of infected macrophages. The sphingolipids, such as ceramides, are the primary host lipids utilized by the bacteria, making the sphingomyelinase/ceramide system critical in Mtb infections. Surprisingly, the antimicrobial effect of myriocin was found to be independent of its role in reducing ceramides, but instead, it depends on the lipid droplets surface protein PLIN2. Our findings provide a novel mechanism for how myriocin enhances Mtb clearance in macrophages.

The interaction of macrophages and CD8 T cells in bronchoalveolar lavage fluid is associated with latent tuberculosis infection.

Mycobacterium tuberculosis (Mtb) infection, including active tuberculosis (TB) and latent Mtb infection (LTBI), leads to diverse outcomes owing to different host immune responses. However, the immune mechanisms that govern the progression from LTBI to TB remain poorly defined in humans. Here, we profiled the lung immune cell populations within the bronchoalveolar lavage fluid (BALF) from patients with LTBI or TB using single-cell RNA sequencing (scRNA-seq). We found that Mtb infection substantially changed the immune cell compartments in the BALF, especially for the three subsets of macrophages, monocyte macrophage (MM)-CCL23, MM-FCN1, and MM-SPP1, which were found to be associated with the disease status of TB infection. Notably, MM-CCL23 cells derived from monocytes after stimulation with Mtb were characterized by high levels of chemokine (CCL23 and CXCL5) production and might serve as a marker for Mtb infection. The MM-CCL23 population mainly recruited CD8-CCR6 T cells through CCL20/CCR6, which was a prominent feature associated with protection immunity in LTBI. This study improves our understanding of the lung immune landscape during Mtb infection, which may inform future vaccine design for protective immunity.

Pharmacokinetics of Antituberculosis Drugs in Plasma and Cerebrospinal Fluid in a Patient with Pre-Extensive Drug Resistant Tuberculosis Meningitis.

Drug-resistant tuberculous meningitis (TBM) is the most devastating and critical form of extrapulmonary tuberculosis. Here, we present a case of a 45-year-old male with pre-extensive drug-resistant tuberculosis meningitis (pre-XDR-TBM). He underwent emergency surgery for the long-tunneled external ventricular drainage (LTEVD). Molecular test and phenotypic drug sensitivity test (DST) of Mycobacterium tuberculosis in cerebrospinal fluid (CSF) showed that the isolate was resistant to both rifampin and fluoroquinolones. An anti-tuberculous regimen of isoniazid, pyrazinamide, cycloserine, moxifloxacin, clofazimine, and linezolid was tailored accordingly. We monitored the drug concentration in his plasma and CSF before (at 0-hour) and after anti-TB drugs administration (at 1-hour, 2-hour, 6-hour, and 12-hour) on 10th day after treatment initiation. We hope to provide reference values of drug exposures in plasma and CSF for patients with pre-XDR-TBM.

Pediatric isoniazid-resistant tuberculosis of the bone marrow manifesting as hemophagocytic syndrome: A case report.

Hemophagocytic syndrome (HPS) is a critical syndrome of ineffective hyperinflammatory immune response resulting in infiltration of lymphocytes and histiocytes in various organs. Causes can be hereditary or due to malignancy, autoimmune disease, or infection. HPS due to Mycobacterium tuberculosis is rare as only a handful of cases are reported, and they are mostly associated with severe disseminated tuberculosis (TB). We reported a 9-year-old boy with tuberculosis of the bone marrow accompanied with hemophagocytic syndrome. The patient presented with manifestation of HPS and had no respiratory symptoms or risk factors for TB but was later diagnosed of isoniazid-resistant TB in the bone marrow. He had a good outcome after receiving anti-TB drugs and corticosteroids on time. This case highlights that bone marrow might be a shelter for Mycobacterium tuberculosis. Concurrent testing for drug susceptibility in TB cases with an uncommon manifestation is recommended even for first episodes. Early diagnosis and etiological confirmation of the infection origin and appropriate treatment are essential to improve survival in this otherwise life-threatening condition.

Mycobacterium tuberculosis-Induced Upregulation of the COX-2/mPGES-1 Pathway in Human Macrophages Is Abrogated by Sulfasalazine.

Macrophages are the primary human host cells of intracellular Mycobacterium tuberculosis (M.tb) infection, where the magnitude of inflammatory reactions is crucial for determining the outcome of infection. Previously, we showed that the anti-inflammatory drug sulfasalazine (SASP) significantly reduced the M.tb bactericidal burden and histopathological inflammation in mice. Here, we asked which genes in human inflammatory macrophages are affected upon infection with M.tb and how would potential changes impact the functional state of macrophages. We used a flow cytometry sorting system which can distinguish the dead and alive states of M.tb harbored in human monocyte-derived macrophages (MDM). We found that the expression of cyclooxygenase-2 and microsomal prostaglandin E2 synthase (mPGES)-1 increased significantly in tagRFP+ MDM which were infected with alive M.tb. After exposure of polarized M1-MDM to M.tb (H37Rv strain)-conditioned medium (MTB-CM) or to the M.tb-derived 19-kD antigen, the production of PGE2 and pro-inflammatory cytokines increased 3- to 4-fold. Upon treatment of M1-MDM with SASP, the MTB-CM-induced expression of COX-2 and the release of COX products and cytokines decreased. Elevation of PGE2 in M1-MDM upon MTB-CM stimulation and modulation by SASP correlated with the activation of the NF-κB pathway. Together, infection of human macrophages by M.tb strongly induces COX-2 and mPGES-1 expression along with massive PGE2 formation which is abrogated by the anti-inflammatory drug SASP.

Clinical Evaluation of Active Tuberculosis-Related Deaths in Shenzhen, China: A Descriptive Study.

OBJECTIVE: The aim of this study was to assess active tuberculosis-related deaths in Shenzhen city of China to identify major causes of mortality in different age groups. PATIENTS AND METHODS: Medical records of mortality cases of patients with active TB diagnosed during 2013-2018 were reviewed. All TB deaths were classified into two broad age groups (the young group: 18-65 years old and the elderly group: >65 years old). Causes of death were analyzed based on medical records. RESULTS: A total of 279 mortality cases of active TB were reviewed during the study period. Among them, mean age was 54.0±20.5 years old; 80.6% (225/279) were male. There were 5.7% and 4.6% MDR/XDRTB patients in the young and elderly group. Newly treated TB accounted for 89.6% in the young group and 85.1% in the elderly group. Pulmonary TB was a major infection type in both groups (65.1% vs 77.0%). Advanced TB (23.4%) and HIV co-infection (20.8%) were the leading causes of deaths in the young group, but deaths in the elderly group were mostly associated with underlying diseases, including cardiovascular disease (52.9%), diabetes (33.3%), COPD (16.1%) and cancer (11.5%). Malnutrition was a significant condition in both groups (43.2% vs 35.6%). In terms of respiratory complications, bacterial infection was the leading comorbidity in both groups (27.1% vs 18.4%), followed by septic shock (18.2% vs 12.6%) and respiratory failure (12.0% vs 11.5%). There were no significant statistical differences between the two groups. CONCLUSION: Our findings suggest that screening for HIV co-infection and early diagnosis of TB is vital in lowering TB-related deaths in young patients. Most deaths in elderly TB patients were caused by underlying health conditions or complications other than TB.

Allogeneic Vγ9Vδ2 T-Cell Therapy Promotes Pulmonary Lesion Repair: An Open-Label, Single-Arm Pilot Study in Patients With Multidrug-Resistant Tuberculosis.

The WHO's "Global tuberculosis report 2020" lists tuberculosis (TB) as one of the leading causes of death globally. Existing anti-TB therapy strategies are far from adequate to meet the End TB Strategy goals set for 2035. Therefore, novel anti-TB therapy protocols are urgently needed. Here, we proposed an allogeneic Vγ9Vδ2 T-cell-based immunotherapy strategy and clinically evaluated its safety and efficacy in patients with multidrug-resistant TB (MDR-TB). Eight patients with MDR-TB were recruited in this open-label, single-arm pilot clinical study. Seven of these patients received allogeneic Vγ9Vδ2 T-cell therapy adjunct with anti-TB drugs in all therapy courses. Cells (1 × 108) were infused per treatment every 2 weeks, with 12 courses of cell therapy conducted for each patient, who were then followed up for 6 months to evaluate the safety and efficacy of cell therapy. The eighth patient initially received four courses of cell infusions, followed by eight courses of cell therapy plus anti-MDR-TB drugs. Clinical examinations, including clinical response, routine blood tests and biochemical indicators, chest CT imaging, immune cell surface markers, body weight, and sputum Mycobacterium tuberculosis testing, were conducted. Our study revealed that allogeneic Vγ9Vδ2 T cells are clinically safe for TB therapy. These cells exhibited clinical efficacy in multiple aspects, including promoting the repair of pulmonary lesions, partially improving host immunity, and alleviating M. tuberculosis load in vivo, regardless of their application in the presence or absence of anti-TB drugs. This pilot study opens a new avenue for anti-TB treatment and exhibits allogeneic Vγ9Vδ2 T cells as promising candidates for developing a novel cell drug for TB immunotherapy. Clinical Trial Registration: (https://clinicaltrials.gov/ct2/results?cond=&term=NCT03575299&cntry=&state=&city=&dist=) ( NCT03575299).

Identification and Treatment of Tuberculosis in Pediatric Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: Case Series and Review of the Literature.

BACKGROUND: Tuberculosis is a rare but life-threatening complication in patients who received hematopoietic stem cell transplantation. Early identification and intervention are essential to prevent severe complications. CASE PRESENTATION: We report two pediatric patients who developed tuberculosis after receiving hematopoietic stem cell transplantation for thalassemia major among 330 recipients between January 2012 and August 2019. Patient A presented with pulmonary tuberculosis and patient B presented with lymph node tuberculosis mimicking post-transplantation lymphoproliferative disorder associated with Epstein-Barr virus reactivation. Patient B's condition was deteriorated, and shortly after the initiation of anti-tuberculosis therapy, the patient was found to have disseminated pulmonary tuberculosis. Patient B was also found to have tuberculous granulomas, an uncommon manifestation of tuberculosis causing severe airway obstruction. Both patients developed critical respiratory failure and required mechanical ventilation; however, they recovered with almost full resolution of pulmonary lesions after multiple treatment adjustments. CONCLUSION: Tuberculosis must be carefully evaluated in all pediatric patients that receive hematopoietic stem cell transplantation, regardless of the identification of other pathogens. Prophylactic tuberculosis therapy should be considered for high-risk pediatric hematopoietic stem cell transplantation recipients from tuberculosis-endemic regions.

Allelic-Specific Regulation of xCT Expression Increases Susceptibility to Tuberculosis by Modulating microRNA-mRNA Interactions.

xCT forms part of the xc- cysteine-glutamate antiporter which inhibits antimicrobial inflammatory immune functions and thus increases susceptibility to tuberculosis (TB). However, the associations between xCT gene polymorphisms and susceptibility to TB, as well as whether these modulate xCT expression or affect treatment with the xCT inhibitor sulfasalazine (SASP), are unclear. In the present study, we genotyped xCT polymorphisms in a large Chinese cohort and found that the single-nucleotide polymorphism (SNP) rs13120371 was associated with susceptibility to TB. The rs13120371 AA genotype was strongly associated with an increased risk of TB and increased xCT mRNA expression levels compared to those with the GG or AG genotype. rs13120371 is located on the 3' untranslated (UTR) region of the xCT gene, in the putative binding site for miR-142-3p, and the results of luciferase reporter assays indicated that the rs13120371 AA genotype inhibited the binding of miR-42-3p to xCT. Bacterial burden was also significantly higher in cells with the AA genotype than in those with the GG genotype. Furthermore, pretreatment with SASP alleviated this burden in cells with the AA genotype but conferred no benefit in cells with the GG phenotype. In summary, we identified a functional SNP (rs13120371) in the xCT 3' UTR region that increases susceptibility to TB through interacting with miR-142-3p.IMPORTANCE Tuberculosis (TB) is the leading cause of death from a single infectious agent globally, and the development of multidrug resistance represents a serious health concern, particularly in the developing world. Novel effective treatments are urgently required. xCT expression is known to increase susceptibility to TB, and certain polymorphisms in the gene encoding this protein interrupt the binding of microRNA and prevent its suppression. Taking advantage of the FDA approval for the use of sulfasalazine (SASP), which inhibits xCT-mediated cystine transport in humans, we demonstrate how host genotype-specific therapies tailored to the xCT genotype can improve TB outcomes.

Cutting Edge: Characterization of Human Tissue-Resident Memory T Cells at Different Infection Sites in Patients with Tuberculosis.

Tissue-resident memory T cells (TRMs) have a key role in mediating the host defense against tuberculosis (TB) in mice, but their human counterparts have not been well characterized. In this article, we recruited patients with TB and determined TRM frequency, trafficking, activation marker expression, and cytokine production by flow or mass cytometry at different infection sites, including peripheral blood, pleural fluid, bronchoalveolar lavage fluid, and lung. We found a high frequency of TRMs at all infection sites apart from the peripheral blood. These TRMs exhibited a memory phenotype, were highly activated (based on CD38 and HLA-DR expression), and expressed high levels of trafficking (CCR5 and CXCR6) and exhaustion (PD-1) markers. When stimulated with Mycobacterium tuberculosis, TRMs secreted cytokines, including IFN-γ, TNF-α, and IL-2, and exhibited a multifunctional phenotype. TRMs limited intracellular M. tuberculosis replication in macrophages. These data inform our current understanding of immunosurveillance at different infection sites in patients with TB.

Identification of eight-protein biosignature for diagnosis of tuberculosis.

BACKGROUND: Biomarker-based tests for diagnosing TB currently rely on detecting Mycobacterium tuberculosis (Mtb) antigen-specific cellular responses. While this approach can detect Mtb infection, it is not efficient in diagnosing TB, especially for patients who lack aetiological evidence of the disease. METHODS: We prospectively enrolled three cohorts for our study for a total of 630 subjects, including 160 individuals to screen protein biomarkers of TB, 368 individuals to establish and test the predictive model and 102 individuals for biomarker validation. Whole blood cultures were stimulated with pooled Mtb-peptides or mitogen, and 640 proteins within the culture supernatant were analysed simultaneously using an antibody-based array. Sixteen candidate biomarkers of TB identified during screening were then developed into a custom multiplexed antibody array for biomarker validation. RESULTS: A two-round screening strategy identified eight-protein biomarkers of TB: I-TAC, I-309, MIG, Granulysin, FAP, MEP1B, Furin and LYVE-1. The sensitivity and specificity of the eight-protein biosignature in diagnosing TB were determined for the training (n=276), test (n=92) and prediction (n=102) cohorts. The training cohort had a 100% specificity (95% CI 98% to 100%) and 100% sensitivity (95% CI 96% to 100%) using a random forest algorithm approach by cross-validation. In the test cohort, the specificity and sensitivity were 83% (95% CI 71% to 91%) and 76% (95% CI 56% to 90%), respectively. In the prediction cohort, the specificity was 84% (95% CI 74% to 92%) and the sensitivity was 75% (95% CI 57% to 89%). CONCLUSIONS: An eight-protein biosignature to diagnose TB in a high-burden TB clinical setting was identified.

Closure of pulmonary cavity of a multidrug-resistant tuberculosis patient with catheter insertion - A case report.

The treatment of multidrug-resistant tuberculosis (MDR-TB) relies heavily on optimal chemotherapy, but interventional therapies can be adopted as adjuvant treatment to speed up illness control and increase the cure rate. We present a case of a 31-year-old MDR-TB male patient with a massive pulmonary cavity in the right lower lung cured by chemotherapy with a catheter inserted in the cavity as adjuvant treatment. This case illustrated that early interventional therapy increases the treatment success rate for pulmonary MDR-TB patients with empyema and massive cavity without the need of major invasive surgery and consequently preserve lung functions.

Activated pulmonary tuberculosis in a patient with melanoma during PD-1 inhibition: a case report.

BACKGROUND: PD-1 checkpoint inhibitors have shown a robust tumor response in the treatment of various cancers. Pembrolizumab is an anti-PD-1 checkpoint antibody approved for the treatment of unresectable or metastatic melanoma in more than 40 countries. Although autoimmune pneumonitis is considered a common immune-related adverse event of PD-1 inhibitors, only limited studies have assessed the development of opportunistic infections such as pulmonary tuberculosis (TB). CASE PRESENTATION: A patient with metastatic melanoma whose pulmonary TB was activated after administration of pembrolizumab for melanoma is reported. Anti-TB drugs were administered, followed by pembrolizumab (2 mg/kg, repeated every 28 days), which successfully cured the TB and achieved complete response for melanoma. CONCLUSION: Activated pulmonary TB was observed during the administration of pembrolizumab. It was safe and effective in the current patient to combine anti-TB drugs and PD-1 inhibitors. More importantly, screening pulmonary TB before administration of PD-1 inhibitors is recommended.

Empirical treatment with non-anti-tuberculosis antibiotics decreased microbiological detection in cervical tuberculous lymphadenitis.

Diagnosis of cervical tuberculous lymphadenitis (CTL), the most commonly occurring form of extrapulmonary tuberculosis, remains as a challenge in clinic. Detection of the presence of Mycobacterium tuberculosis (Mtb) in fine needle aspiration cytology (FNAC) samples is one golden criterion to confirm the CTL diagnosis. Due to the non-specific clinical presentation, CTL might be confused with other lymph node enlargement diseases; therefore empirical treatment with non-anti-TB antibiotics is often initially administered. However, it is still unclear whether this diagnostic antibiotic treatment affects the positivity of Mtb detection in FNAC. The demographics and clinical characteristics of 732 lymph node enlargement patients who had underwent FNAC were retrospectively analyzed and 605 (82.65%) of them were diagnosed as CTL. A total of 279 CTL cases (279/605, 46.11%) with completion of three Mtb tests (AFB, NAAT, and Mtb culture) in FNAC samples were selected for analyzing the effect of empirical antibiotic treatment on the positivity of Mtb tests. Compared to CTL patients without antibiotic treatment prior to FNAC, patients received empirical non anti-TB treatment had significantly lower positivity for acid fast bacilli staining (adjusted OR 0.11, 95% CI 0.06-0.21), nucleic acid amplification test (NAAT) (adjusted OR 0.38, 95% CI 0.21-0.71), and Mtb culture (adjusted OR 0.11, 95% CI 0.06-0.19). In conclusion, this study demonstrated that empirical non anti-TB antibiotic treatment reduced the opportunity to confirm CTL by microbiological analysis. Patients with cervical lymph node enlargement should undergo FNAC for Mtb tests prior to initiation of empirical non anti-TB treatment.

Tuberculosis infection in rural labor migrants in Shenzhen, China: Emerging challenge to tuberculosis control during urbanization.

During China's urbanization process, rural labor migrants have been suggested to be one important bridge population to change urban-rural distribution on tuberculosis (TB) burden. Aiming to estimate the prevalence of TB infection and to track the active disease development in rural labor migrants, a prospective study was conducted in Shenzhen city, southern China. TB infection was detected using interferon-γ release assay (IGRA). Here we mainly report the characteristics of TB infection in the study population based on the baseline survey. A total of 4,422 eligible participants completed baseline survey in July 2013. QuantiFERON (QFT) positivity rates 17.87% (790/4,422) and was found to be consistent with the local TB epidemic of the areas where the participants immigrated from. Age, smoking, residence registered place, and present of BCG scars were found to be independently associated with QFT positivity. Additionally, evidence for interaction between smoking and age was observed (p for likelihood ratio test < 0.001). Our results suggested that the development of TB control strategy including latent TB infection management should pay more attention to the rural flowing population due to their high mobility and higher prevalence of TB infection.

xCT increases tuberculosis susceptibility by regulating antimicrobial function and inflammation.

The physiological functions of macrophage, which plays a central role in the pathogenesis of tuberculosis, depend on its redox state. System xc-, a cystine-glutamate transporter, which consists of xCT and CD98, influences many ROS-dependent pathways by regulating the production of the antioxidant glutathione. xCT's ability to alter this critical host redox balance by increasing the glutathione synthesis aspect of phagocyte physiology suggested that it might influence tuberculosis pathogenesis. In this study, we found that the xCT expression was increased in peripheral blood monocyte of active tuberculosis. xCT expression in macrophage was induced by Mycobacterium tuberculosis (Mtb) through TLR2/Akt- and p38-dependent signaling pathway. Importantly, xCT deficiency conferred protection against tuberculosis, as xCT knock out mice displayed increased Mtb load and reduced pulmonary pathology in lung compared to wild type mice. xCT disruption enhanced the mycobateriacidal activity of macrophage through increasing the mycothiol oxidation. Importantly, chemical inhibition of xCT with sulfasalazine, a specific xCT inhibitor that is already approved by the FDA for treatment of inflammatory bowel disease, produces similar protective effects in vivo and in vitro, indicating xCT might be a novel and useful target for host-directed TB treatment strategy.