Immune cells in bronchoalveolar lavage fluid of Ugandan adults who resist versus those who develop latent Mycobacterium tuberculosis infection

Mycobacterium tuberculosis resisters despite HIV exhibit activated T cells and macrophages in their pulmonary alveoli

To understand natural resistance to Mycobacterium tuberculosis ( Mtb ) infection, we studied people living with HIV (PLWH) in an area of high Mtb transmission. Given that alveolar leukocytes may contribute to this resistance, we performed single cell RNA-sequencing of bronchoalveolar lavage cells, unstimulated or ex vivo stimulated with Mtb . We obtained high quality cells for 7 participants who were TST & IGRA positive (called LTBI) and 6 who were persistently TST & IGRA negative (called resisters). Alveolar macrophages (AM) from resisters displayed more of an M1 phenotype relative to LTBI AM at baseline. Alveolar lymphocytosis (10%-60%) was exhibited by 5/6 resisters, resulting in higher numbers of CD4 + and CD8 + IFNG -expressing cells at baseline and upon Mtb challenge than LTBI samples. Mycobactericidal granulysin was expressed almost exclusively by a cluster of CD8 + T cells that co-expressed granzyme B, perforin and NK cell receptors. For resisters, these poly-cytotoxic T cells over-represented activating NK cell receptors and were present at 15-fold higher numbers in alveoli compared to LTBI. Altogether, our results showed that alveolar lymphocytosis, with increased numbers of alveolar IFNG -expressing cells and CD8 + poly-cytotoxic T cells, as well as activated AM were strongly associated with protection from persistent Mtb infection in PLWH.

Mycobacterium tuberculosis-specific memory T cells in bronchoalveolar lavage of patients with pulmonary tuberculosis

BACKGROUND

Mycobacterium tuberculosis(MTB) most often infects the lungs and results in pulmonary tuberculosis(TB). MTB-specific memory T cells are able to respond quickly against antigens and help reduce the burden of pulmonary bacteria. The characteristics, function and chemotaxis axis of memory T cells in the lung remain unclear. The current study aimed to clarify the classification, function and recruitment of local antigen-specific memory T cells in the lung and the periphery blood of patients with pulmonary TB.

METHODS

A total of 85 patients with active pulmonary TB were included in the study. Bronchoalveolar lavage fluid (BALF) and Peripheral blood were collected for further detection. The cell-surface markers and intracellular staining of memory T cell subtypes were measured by flow cytometry. The level of CXCL9, CXCL10 and CXCL11 in Bronchoalveolar lavage fluid cells and peripheral blood mononuclear cells (PBMC) were measured by Real-time PCR.

RESULTS

The ratio of effective Memory T cells (TEM) were the highest in BALF of patients with pulmonary TB. In patients, CXCR3 and its ligands was increased in memory T cells of BALF compared with PBMC. IFN-γ+TNF-α+ effective Memory T cells and central memory T cells from BALF were increased after antigen stimulation. CXCR3 was higher in IFN-γ+ compared with IFN-γ- in CD4+ TCM and TEM from BALF of patients. Compared with PBMC, the PD-1 levels of terminal effector memory RA+(TEMRA) and TEM cells in CD4+ memory T cells of BALF were significantly increased. In addition, PD-1 was increased in IFN-γ+ compared with IFN-γ- in CD4+TEM from BALF of patients. There was no difference in Treg ratio between PBMC and BALF of TB patients.

CONCLUSIONS

The CXCL9/CXCL11-CXCR3 axis may participate in the chemotaxis of memory T cells from the peripheral to lung. CD4+TEM and TEMRA in BALF may have exhausted, especially the cytokine producing TEM. Our study clarified the characteristics of antigen-specific memory T cells in local lung and may have impact on strategies of therapy and vaccine.

Perceptions about and reasons for participation in research bronchoscopy in Uganda: A qualitative analysis

This study sought to assess perceptions towards and reasons for participation in research bronchoscopy studies in a high TB burden urban setting. Additionally, the study aimed to identify areas of pre- and post-procedural concern among healthy adults approached to participate in research bronchoscopy. A cross sectional qualitative study was undertaken at the Uganda-Case Western Reserve University Collaboration Tuberculosis Research Project Clinic at Mulago National Referral Hospital in Kampala, Uganda. In-depth interviews were conducted with participants at their pre-bronchoscopy visit (n = 17) and after they had undergone bronchoscopy (n = 23) to examine their perceptions and experiences with the procedure. Following consent, all interviews were audio recorded and later transcribed and typed in MS WORD. Local language interviews were translated into English by the social science interviewers. Qualitative analysis was performed manually following an inductive and emergent approach typical in thematic analysis. This study was approved by the Makerere University School of Social Sciences Research Ethics Committee (MAKSS REC 09.18.220) and registered with the Uganda National Council for Science and Technology (UNCST SS4785). Overall willingness to participate in bronchoscopy was high as many participants viewed the study as primarily a means of getting free health checks and determining their health status. Notably, despite extensive face to face counseling for this study coupled with the fact that our participants had been involved in prior research at the site, therapeutic misconception still played a pivotal role in willingness to participate in research bronchoscopy. Therapeutic misconception has important ethical and research implications in clinical research, which requires strategies to tackle it, even among a pool of potential participants who are knowledgeable about a disease or clinical care procedures. Continuous awareness and knowledge building about the difference between being a trial participant and therapeutic misconception must become a mainstay in trials to improve the process of informed consent for future research bronchoscopy studies.

Human Pulmonary Tuberculosis: Understanding the Immune Response in the Bronchoalveolar System

Mycobacterium tuberculosis, the causal agent of one of the most devastating infectious diseases worldwide, can evade or modulate the host immune response and remain dormant for many years. In this review, we focus on identifying the local immune response induced in vivo by M. tuberculosis in the lungs of patients with active tuberculosis by analyzing data from untouched cells from bronchoalveolar lavage fluid (BALF) or exhaled breath condensate (EBC) samples. The most abundant resident cells in patients with active tuberculosis are macrophages and lymphocytes, which facilitate the recruitment of neutrophils. The cellular response is characterized by an inflammatory state and oxidative stress produced mainly by macrophages and T lymphocytes. In the alveolar microenvironment, the levels of cytokines such as interleukins (IL), chemokines, and matrix metalloproteinases (MMP) are increased compared with healthy patients. The production of cytokines such as interferon (IFN)-γ and IL-17 and specific immunoglobulin (Ig) A and G against M. tuberculosis indicate that the adaptive immune response is induced despite the presence of a chronic infection. The role of epithelial cells, the processing and presentation of antigens by macrophages and dendritic cells, as well as the role of tissue-resident memory T cells (Trm) for in situ vaccination remains to be understood.

Detection of CEA and ProGRP Levels in BALF of Patients with Peripheral Lung Cancer and Their Relationship with CT Signs

Background

Lung cancer is a common clinical thoracic malignant tumor, which had a serious impact on the safety of patients, currently ranking first in all malignant tumors in morbidity and mortality, with generally less than 5% survival rate in 5 years.

Objective

To investigate the relationship and significance between carcinoembryonic antigen (CEA) and precursor gastrin-releasing peptide (ProGRP) changing levels in bronchoalveolar lavage fluid (BALF) and CT imaging features in patients with peripheral lung cancer.

Methods

A total of 90 patients diagnosed with peripheral lung cancer as the lung cancer group and 60 patients with benign lung diseases as the control group in our hospital from May 2019 to October 2021 were selected to compare the differences of CEA and ProGRP in BALF by the classification of CT features.

Results

The levels of CEA and ProGRP in the BALF of the lung cancer group were significantly higher than those of the control group; the proportion of patients with lobulation sign, burr sign, ground glass sign, pleural effusion, and lesion diameter ≥ 3.0 cm in the lung cancer group was higher than that in the control group; the CEA level in BALF of lung cancer patients with spicule sign, pleural effusion, and lesion diameter ≥ 3.0 cm was significantly higher than that without these symptoms, while ProGRP level in the BALF of lung cancer patients with lobulation sign, burr sign, ground glass sign, pleural effusion, and lesion diameter ≥ 3.0 cm was significantly higher than that of lung cancer patients without these symptoms.

Conclusion

The check of CEA and ProGRP in BALF in combination with CT features has a certain clinical value for the diagnosis of lung cancer. At the same time, the increased levels of CEA and ProGRP in BALF have a certain correlation with the changes of malignant signs of lung cancer in CT examination.

Monocyte Transcriptional Responses to Mycobacterium tuberculosis Associate with Resistance to Tuberculin Skin Test and Interferon Gamma Release Assay Conversion

Heavy exposure to Mycobacterium tuberculosis, the etiologic agent of tuberculosis (TB) and among the top infectious killers worldwide, results in infection that is cleared, contained, or progresses to disease. Some heavily exposed tuberculosis contacts show no evidence of infection using the tuberculin skin test (TST) and interferon gamma release assay (IGRA); yet the mechanisms underlying this "resister" (RSTR) phenotype are unclear. To identify transcriptional responses that distinguish RSTR monocytes, we performed transcriptome sequencing (RNA-seq) on monocytes isolated from heavily exposed household contacts in Uganda and gold miners in South Africa after ex vivo M. tuberculosis infection. Gene set enrichment analysis (GSEA) revealed several gene pathways that were consistently enriched in response to M. tuberculosis among RSTR subjects compared to controls with positive TST/IGRA testing (latent TB infection [LTBI]) across Uganda and South Africa. The most significantly enriched gene set in which expression was increased in RSTR relative to LTBI M. tuberculosis-infected monocytes was the tumor necrosis factor alpha (TNF-α) signaling pathway whose core enrichment (leading edge) substantially overlapped across RSTR populations. These leading-edge genes included candidate resistance genes (ABCA1 and DUSP2) with significantly increased expression among Uganda RSTRs (false-discovery rate [FDR], <0.1). The distinct monocyte transcriptional response to M. tuberculosis among RSTR subjects, including increased expression of the TNF signaling pathway, highlights genes and inflammatory pathways that may mediate resistance to TST/IGRA conversion and provides therapeutic targets to enhance host restriction of M. tuberculosis intracellular infection. IMPORTANCE After heavy M. tuberculosis exposure, the events that determine why some individuals resist TST/IGRA conversion are poorly defined. Enrichment of the TNF signaling gene set among RSTR monocytes from multiple distinct cohorts suggests an important role for the monocyte TNF response in determining this alternative immune outcome. These TNF responses to M. tuberculosis among RSTRs may contribute to antimicrobial programs that result in early clearance or the priming of alternative (gamma interferon-independent) cellular responses.